New Amphiphilic Composite for Preparing Efficient Coated Potassium

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Agricultural and Environmental Chemistry

New amphiphilic composite for preparing efficient coated potassium-fertilizers for top-dressing fertilization of annual crops Oscar Urrutia, Javier Erro, Andre Vinicius Zabini, Kent Hoshiba, Anne Francoise Blandin, Roberto Baigorri, Manuel Martin-Pastor, Yves Alis, Jean-Claude Yvin, and José María García-Mina J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.7b04596 • Publication Date (Web): 20 Apr 2018 Downloaded from http://pubs.acs.org on April 20, 2018

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Journal of Agricultural and Food Chemistry

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New amphiphilic composite for preparing efficient coated potassium-fertilizers for

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top-dressing fertilization of annual crops.

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Oscar Urrutia1 *, Javier Erro1, Andre Zabini2, Kent Hosiba3, Anne F. Blandin4; Roberto

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Baigorri5; Manuel Martín-Pastor6, Yves Alis4, Jean C. Yvin7, José M. García-Mina1

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1

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Irunlarrea n 1. 31008. Pamplona, Spain.

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2

BACh Research Group. Department of Environmental Biology. University of Navarra,

“Agronomico”. Laboratorio de Suelos y Consultoría. Edificio Azar, 2º Piso, Av. Paraná.

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1617. Hernandarias, Paraguay.

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3

Centro de R&D. Roullier Latino. Roullier Group. Minga Guaçu Km 5. 7420. Paraguay.

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4

Centre d´ Etudes de Recherche Apliqueés “CERA”. Roullier Group. 55 Boulevard Jules

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Verger 35800. Dinard. France.

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5

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Barrio Feculas s/n. 31508 Lodosa. Spain.

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6

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Spain.

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7

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Franklin Roosevelt. 35400. Saint Malo. France.

Departamento de Desarrollo e Inovación Timac Agro España S.A. Roullier Group.

Departamento de NMR C.A.C.T.U.S. University of Santiago de Compostela. 15706.

Centre Mondial d´Innovation CMI. Roullier Group. Atalante Saint-Malo. 18 avenue

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* Corresponding Authors:

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Oscar Urrutia, Tel +34 948 425600 Ext 806669;

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ORCID: 0000-0003-3739-662X.

Email: [email protected];

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Abstract

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This study describes the efficiency of a new coating material for preparing granulated

29

potassium-fertilizers with a potassium release to the soil solution sensitive to rainfall

30

intensity. The composite is prepared by reaction of an alkyd-resin with cement in the

31

absence of water. The complementary use of diverse analytical techniques showed that

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the presence of the cement fraction induced alkyd resin reticulation and gradual cement-

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resin hardening. Scanning electron microscopy revealed the formation of micro and

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nanopores within cement-clusters, whose water permeability is affected by the resin

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reticulation and amphiphilic character. Potassium release was evaluated in water, soil-

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columns, and in soil-plant trials in pots and open-field. Agronomic results were

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consistent with potassium release rates obtained in water solution and soil columns. The

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composite-coated potassium fertilizer was more efficient than the non-coated one in

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providing plant available potassium, with this effect being dependent on water presence

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in soil.

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Key words Potassium, controlled release fertilizers, alkyd resin reticulation, cement,

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coating, nutrient use efficiency.

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INTRODUCTION

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Top-dressing fertilizer application is mainly employed to split nitrogen (N)

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fertilization into several consecutive applications at specific stages of crop cycle,

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principally in cereals but also in other crops1,2. This practice allows the farmers to

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optimize N-Fertilizers use efficiency by crops and minimize N losses. However, this

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application mode is also employed for potassium (K) fertilization in tropical countries for

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important annual crops, such as soya or maize, which are very sensitive to K nutrition3-5.

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This need becomes especially relevant when these crops are cultivated in poor or

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degraded sandy soils where K leaching risk is very high5,6 and the K dose 2 ACS Paragon Plus Environment

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recommendation is also large and very dependent on soil texture and soil organic matter

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content7,8 . This is the case of important agronomic areas located in southern Brazil and

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Paraguay9. In fact, top-dressing fertilization management is becoming very common for

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industrial crops in the current context of both increasing global food demand and

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decreasing in soil fertility due to intensive production rates and massive use of mineral

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fertilizers10-12. This situation becomes extremely worrying for fruit and biomass

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productive crop systems, in which K-plant uptake is often very high and relevant in order

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to assure crop yields and quality10,13- 16.

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However, the single top-dressing application of high doses of water-soluble K

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fertilizers may have deleterious effects on both soil fertility and plant growth. For

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instance, high concentrations of K salts in soil solution may negatively affect both the

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soil structure and the plant root uptake of other relevant cations such as NH4+, Mg2+ and

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to a lesser extent Ca2+ 17. In addition, high doses of potassium chloride (KCl), the main K

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salt used in most industrial crop fertilization-plans, may also cause negative effects on

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plant development resulting from both a punctual increase in soil electrical conductivity

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(EC) and the root uptake of high concentrations of Cl- 18. An alternative might be to split

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top-dressing K-fertilizer application into several consecutive applications as in the case

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of N. However, this solution is not very suitable for crops cultivated in sandy soils and in

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tropical zones where intense rainfall happens very frequently7,19,20.

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Taken together, these reasons indicate that the use of some type of technique

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allowing the production of special K-fertilizers for top-dressing application with the

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ability to modulate the release of K to the soil solution, principally under intense rainfall

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regimes, has great interest21,22. A number of studies have shown that traditional technical

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approaches for the preparation of slow and control release mineral fertilizers (CRF) are

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not adequate for the fertilization of annual crops2. This is the case of most CRF based on 3 ACS Paragon Plus Environment


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coating techniques involving synthetic polymers like urethane-based polymers and

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sulfur-based polymer. Although CRF have proven to be highly efficient to delay nutrient

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release into soil solution, and are -in fact -extensively used in perennial crops and

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gardening, their efficiency to provide available nutrients to cope with the nutritional

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needs of annual crops is quite poor23. This is because annual crops are characterized by

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having intense nutritional demands in short time periods throughout their cycle, and the

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nutrient release pattern of traditional CRF is not adapted to this fact23. Moreover, this

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limitation of CRF becomes more evident when used for top-dressing fertilization. Thus,

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in most CRF the nutrient release pattern is mainly governed by the diffusion of nutrients

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through micro- and nano-pores present in the coating layer, in a process driven by soil

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water solution (osmotic gradient) and temperature24-29. For a given temperature, CRF

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nutrient release rates are directly proportional to the water amount located around the

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grain. Therefore, traditional CRF are not very sensitive to rainfall variations and

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intensity, in the sense of reducing nutrient release rates under intense rainfall while

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maintaining them under low or normal rainfall regimes.

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One property of coating materials that might modulate the nutrient release pattern

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in the presence of different amounts of water around coated fertilizer granules is the

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balance between hydrophobicity and hydrophilicity26,28-31. Our working hypothesis is that

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a coating composite with some amphiphilic character may favor a prompt water

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repulsion reaction against high soil water concentration around the fertilizer granule

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resulting from its hydrophobic character, while maintaining some permeability due to its

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hydrophilic character. This behavior might favor more controlled release of K from the

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fertilizer under high and intense rainfall (prevalence of the hydrophobic character), but

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maintaining an effective balance between nutrient protection and nutrient release under

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medium or low rainfall32,33. In this framework, amphiphilic polymers obtained from the

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esterification of fatty acids with polysaccharides, sugar alcohols or polyols, and some 4 ACS Paragon Plus Environment

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type of organic anhydrides, known as amphiphilic alkyd-resins34-37, might become good

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candidates as coating ingredients for the preparation of special K-fertilizers with a K

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delivery to the soil solution sensitive to rainfall intensity32-36.

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In this study we describe the suitability of a new coating material based on the

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reaction of an amphiphilic alkyd resin (AR) with cements (C), to prepare coated

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granulated K-fertilizers for top-dressing application. The main role of C is to potentiate

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the hardness of the coating composite by inducing both resin reticulation and hardening,

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through the interaction between C components (mainly silicates and metals) and the

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hydrophilic fraction of the AR. In this work, the fertilizer efficiency of the K-fertilizers

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employed in the experiments is evaluated in experiments performed in water solution,

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soil columns; and crop trials conducted in both pots and open field.

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MATERIALS AND METHODS

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Production of the reticulated amphiphilic composite (RAC).

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The RAC was obtained by chemical reaction of a specific amphiphilic AR (Agronyl

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base Supra provided by Luengo Color, Barcelona, Spain) and a Portland type C (provided

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by Portland Valderribas, Pamplona, Spain), under diverse temperature conditions and

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AR:C ratios (WO2015150645 patent)37. In this study we present the physico-chemical

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characterization and features of the RAC obtained for the optimum AR:C ratio range

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(1:4), which was used for the preparation of the RAC coated K-fertilizer employed in both

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K-solubility tests and agronomical studies. The amount of the coating material in relation

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to bulk fertilizer formula was 6% 37. The AR structure was elucidated by using Attenuated

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Total Reflectance Infrared spectroscopy (ATR-FTIR) and liquid Nuclear Magnetic

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Resonance spectroscopy in CDCl3 (1H-NMR and 13C-NMR) (Figure S1). The ATR-FTIR

127

spectra were recorded over the 4000-650cm-1 range with a resolution of 4cm-1 in a Thermo

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Scientific Nicolet iS10 (Madison, USA). The 1H-NMR and

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measured at 11.7 T in a Bruker Avance XDR-500 spectrometer (Karlsruhe, Germany) 5 ACS Paragon Plus Environment

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C-NMR experiments were


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operating at 500 MHz. The spectra were processed and the signals were assigned with

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MestreNova software v10.0. The mineral analysis of C after microwave digestion at

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200ºC (Milestone Ethos Easy device, Shelton, USA) and ICP-OES analysis (Thermo

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iCAP 7400, Waltham, USA) is presented in Table S1.

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RAC physico-chemical characterization.

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The increase of firmness of RAC (resulting from the setting and hardening process)

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with time, was monitored by using two complementary techniques: (i) The variation of

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firmness for time period of 26 days on a 20x40mm cylinder prepared in laboratory using

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a Wagner P020 durometer; and (ii) the Vicat needle method (Standard Method

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AASHTO Designation: T 131-06; ASTM Designation: C 191-04a) (Ibertest SA

140

Instrument, Madrid Spain) complemented by the shore hardness measurement using a

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scale A (Baxlo device) at the beginning, at setting time and after 60 days. The setting and

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reticulation and of RAC composite were studied by the Vicat needle method, ATR-FTIR

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(Golden Gate diamond-Nicolet Avatar 360, Madison, USA) and Thermogravimetric

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analysis (TG and DTG)38. The TG analyses were carried out by heating 40mg samples

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in open Al2O3 crucible continuously from 25 to 500°C at a heating rate of 5ºC min-1

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on a Mettler Toledo Thermo analyzer TGA/SDTA 851, Ohio USA). The RAC

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curves were compared to those of AR alone and AR in presence of 0.3% of Co2+

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(ARCo).

149 150

Study of the physical structure of RAC on fertilizer granule surface by scanning electron microscopy (SEM) analysis.

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The SEM study was made with a Jeol JSM-6400 SEM Microscope (Tokyo, Japan).

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Micrographs over the border of equatorial cuts of the fertilizers coated with both RAC

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composite and AR alone were acquired using a 20 kV beam voltage, 56x, 500x and 2100x

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of magnification and low vacuum large-field gaseous detection (LFD)39.

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Granulated K-fertilizer used in the study. 6 ACS Paragon Plus Environment

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A granulated NK fertilizer (N-P-K: 3-0-49) was prepared as model K-fertilizer (KF)

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for this research. It was fabricated at pilot scale in the Centre d'Etudes et de Recherches

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Appliquées (C.E.R.A. Dinard, France) using urea, KCl and K2SO4 as its main

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components. The granules were sieved by 2 to 4mm. This fertilizer was used as the model

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fertilizer for RAC coating tests at both laboratory and industrial scales. The RAC-coated

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KF samples used in this study were prepared according to the above-described conditions

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of AR:C component ratio in RAC (1:4) and RAC proportion with respect to bulk fertilizer

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formula (6%). In vitro evaluation of the efficacy of RAC coating to delay K-release to water

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solution.

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In order to evaluate the efficacy of RAC coating and each of its components to slow

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K-water solubilization with time, different laboratory KFs lots were coated with RAC and

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with its separated components (AR and C), and subjected to the following test: 2.5g of

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KF, with and without coating treatment, was added to a vessel containing 1.5L of

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deionized water under continuous stirring at 150 rpm at 25ºC (Dissolutest, Prolabo,

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France). The increase of EC in the water solution was monitored as a function of time

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until complete solubilization of the fertilizer after 180min. The EC increase with time was

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expressed in % according to the following formula: (%) =

∑ 100

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The K -dissolution patterns corresponding to each KF were compared to each other

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by measuring the slope associated with the linear adjustment of EC vs time values during

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the first 90 min. Every fertilizer was tested in triplicate. The solubilization process of both

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RAC-coated and uncoated KF granules in in vitro tests was recorded in video by using a

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binocular loupe x10 magnification coupled to software (IC Capture v2.3) for more than

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3h. 7 ACS Paragon Plus Environment


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Nutrient leaching in soil column tests under different simulated rainfall regimes.

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After checking the efficacy of RAC coating in in vitro studies, the nutrient leaching of

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the RAC-coated and uncoated KF was evaluated in soil column models at room

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temperature41, following three different predefined simulated rainfall regimes as described

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below. Two different substrates were used for the column leaching tests: i) a standard

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silica sand with a particle size lower than 1mm and CEC = 0.58 cmol dcm-3 as a model of

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inert substrate (none nutrient fixation on the substrate was expected), and ii) an agronomic

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sandy soil from Minga Guaçú (Paraguay) with CEC = 4.16 cmol dcm-3 as a model of

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nutrient leaching and soil fixation under realistic conditions. The soil composition and

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texture is presented in Table 1. Soil column tests were carried out as follow: 1g of each

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fertilizer was placed on the substrate surface at the top of the column (height 40cm;

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diameter 7.5cm) and portions of water equivalent to 30mm (30Lm-2) were added

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consecutively with a different pattern and time schedule depending on the rainfall regime

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that is expected to be simulated: 1) Intense: ten water portions applied in one day

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(30mm/30min), 2) Severe: ten water fractions applied in 10 days (30mm/day) and 3)

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Moderate: ten water fractions applied in 30 days (30mm/3days). Precipitation rates were

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chosen according to the average cumulative rainfall recorded during the culture period in

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an

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data.org/location/513824/)20. In this way, these different rainfall regimes expose RAC-

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coated and uncoated KF to different wetting models: 1) Intense: intense and continuous

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rainfall; 2) Severe: strong but alternant rainfall, where granule surface is subjected to both

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direct rain and continuous soil moisture; 3) Moderate: severe punctual rainfall but spread

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out over a longer period of time in which the fertilizer granule is alternatively exposed to

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dry and wet environments. Leachates fractions were weighed and the contents of total K

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and total N were analyzed by Atomic Absorption (AA) (Perkin Elmer AAnalyst 800,

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Waltham, USA) and Kjeldahl method respectively. In order to compare the efficacy of

agronomic

zone

of

Paraná

in

Southern

8 ACS Paragon Plus Environment

Brazil

(http://es.climate-

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RAC-coated and uncoated KF for each simulated rainfall regime in a more accurate way,

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a relative nutrient Leaching Ratio (LRvol) was calculated on the basis of the cumulative

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leaching of K expressed in mg as a function of the water volume added (CLvol): (,) =

() !()

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Crop experiments

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Significant amounts (2-10 tons) of uncoated and RAC-coated granulated K fertilizers

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(NPK: 3-0-49) were manufactured in the C.E.R.A. pilot-plant and used for crop field

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trials. The efficiency of KF, was evaluated by measuring crop yields and leaf mineral

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composition. From these values the Fertilizer use Efficiency (FusE) and K uptake

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Efficiency (KupE) were calculated42, 43. The fertilizer use efficiency (FusE) was calculated

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for each treatment as the ratio between the increment in grain yield (or shoot dry weight)

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per hectare (ha) in relation to control 0 (no fertilization), and the dose of fertilizer (F)

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applied (Kg ha-1) "# =

$%& %'( ()* *'% ℎ, ) " ()* ℎ, )

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The K uptake efficiency (KupE) was determined as the ratio between the increment in

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the K extracted in grains (or shoot dry weight) per ha in relation to control 0, and the K

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dose applied (Kg ha-1): )- =

) ' %'( (* ℎ, ) ) ()* ℎ, )

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Greenhouse study with soybean. The RAC-coated and uncoated KFs were tested in a

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dose-response experiment on soybean (Glycine max., var. FT-Abyara), cultivated in open

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pots containing 10 Kg of a model sandy soil prepared by mixing 15% of a soil obtained

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from Colonia Yguaçú (Table 1) and 85% of silicic sand (Table 1). Fertilizer doses used in

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the experiment were 0.25, 0.50, 0.75 and 1.00 g per pot, equivalent to 75, 150, 225 and

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300 Kg ha-1 respectively. The KFs were applied in top-dressing. All plants received the 9 ACS Paragon Plus Environment


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same N-P, Ca, Mg fertilization applied before sowing. Two soybean plants were grown in

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every pot and four replicates were made for each fertilizer and dose. The experiment was

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watered once a day in order to maintain 100% of field water capacity. The plants were

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grown in such conditions for 60 days and harvested. The shoot dry weight and the total K

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content in both plant shoot and soil were measured for each pot.

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Field trial with soybean. Two field trials on soybean (Glycine max. var. NA 5909)

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were carried out in two neighboring locations in the State of South Paraná (Brazil),

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Umuarama (U) and Moreira de Sales (MS). The analyses of the two soils are presented in

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Table 1. The same experimental design was set out in both trials with the difference that

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natural rainfall in U (1500 mm) was complemented with 250 mm by sprinkler irrigation

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(10x25 mm). As a result, the total watering in U was higher (1750 mm) and more uniform

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than in MS (Figure S4). The protocol followed in both trials was the same. The RAC-

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coated and uncoated KF, were compared in a dose-response trial, following a randomized

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block experimental design with four replications. Soybean plants were grown in two

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separated (1 m) lines. The treatments were applied in top-dressing on 20th November in

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MS and on 30th December in U, on an area of 9m2 and the doses of K2O compared were

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0, 37, 74, 110 Kg ha-1 equivalent to 0, 75, 150, 225 Kg ha-1 of N-P-K 3-0-49. All

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treatments received the same N, P, Ca and Mg fertilization, which were applied at

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showing. The parameters analyzed were: i) the soybean yield, ii) the K concentration in

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leaves at flower set, iii) the K extracted in the aerial part of soybean plants, and iv) the

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residual K in soil after plant harvest.

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Field trial with wheat. A field trial on wheat (Triticum aestivum, var. Itapua 75) was

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carried out in Colonia Iguaçu (Paraguay) following a randomized block experimental

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design with four replications. Each treatment was applied on 9th of august on an area of

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15m2 and the dose of K2O applied was 49 and 98 Kg ha-1 equivalent to 100 and 200 Kg

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ha-1 of KF, (N-P-K: 3-0-49). All treatments received the same N, P, Ca and Mg 10 ACS Paragon Plus Environment

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fertilization, which was applied at sowing. Soil analysis is shown in Table 1 and the

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parameters analyzed were: i) the mineral nutrient content of leaves, 30 days upon fertilizer

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application; ii) grain yield and mineral content; and iii) the residual K in soil at 0-10cm

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and 10-20cm depths at harvest time.

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Statistical analysis.

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Mean significant differences between treatments were calculated by the Fisher LSD

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Anova Post-hoc analysis (p≤0.05), using Statistica v6.0 software.

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RESULTS AND DISCUSSION

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Physico-chemical properties of the new coating composite (RAC).

350

The results obtained from the TG and DTG analysis of AR alone, AR treated with

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Co2+ as metal catalyst (ARCo), and RAC are summarized in Figure 1. The thermogram of

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AR presented two main peaks corresponding to two significant mass losses at 202ºC and

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456ºC, which are normally associated with AR reticulation and AR calcination

354

respectively. In agreement with that, the addition of Co2+ as metal catalyst to AR (ARCo)

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caused a shift of the first peak from 202 ºC to 168ºC that is interpreted as an induction of

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AR reticulation at lower temperatures. When C is mixed with AR in order to form the new

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composite (RAC), the shift of the reticulation peak moved to even a lower temperature

358

(128ºC) than that for ARCo, thus indicating that C contains some components that can act

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as good catalyst of AR reticulation44,45. It is likely that these components are the metal

360

fraction of C that is soluble in the AR, which involved several metal cations such as Fe,

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Cu, Zn, Ca, and Al (Table S1).

362

On the other hand, FTIR analysis of RAC shows several important changes in relation

363

to AR and C spectra (Figure 2A). These changes become clearer when AR spectrum is

364

compared to the [RAC – C] subtraction spectrum (Figure 2B). It is very remarkable the

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presence of wide and intense bands between 1620 and 1510 cm-1 corresponding to C=C

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olefinic groups (max 1550 cm-1). The peak shoulder at 1600cm-1 might be associated with 11 ACS Paragon Plus Environment


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conjugated or aromatic C=C bonds. This peak assignation agrees with the presence of

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intense bands between 1450 and 1380 cm-1 (max 1409 cm-1) which probably correspond

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to C=C aromatic bonds. Taking into account that AR reticulation results from the catalytic

370

oxidation and crosslinking involving the olefinic bonds of esterified fatty acids, FTIR

371

changes observed confirm the C ability to induce AR reticulation. In addition, the increase

372

of C=C conjugation observed in RAC also suggests the involvement of aromatic rings in

373

crosslinking reactions.

374

The analysis of RAC hardness over time using a standard durometer device (Wagner

375

P020 durometer) clearly showed that although there is no water in the media, RAC

376

undergoes a progressive increase in hardness (Figure 3). The study of the hardening

377

process using the Vicat needle method shows that the setting of RAC starts after15 min

378

from the onset of the AR-C reaction, and ends after 379 min, when composite hardness

379

was 55 shore units (scale A). The progressive increase of RAC hardness up to 88 shore

380

units after 60 days confirms the slow but continuous hardening of RAC (Table 2), also

381

displayed in Wagner P020 durometer-graphics (Figure 3). Complementary studies showed

382

that

383

allowing RAC to reach chemical stability (curing) (data not shown). Regarding the

384

mechanism responsible for the gradual hardening of RAC composite, it is probable that

385

the process is the consequence of two main factors working together at granule surface:

386

AR reticulation and C hardening. The fact that C undergoes hardening in the lack of water

387

might be explained by the insertion of some groups of the hydrophilic moiety of AR in C

388

silicate layers (Figure 4). However, more studies are needed in order to better understand

389

this process.

temperatures at granule surface around 40ºC accelerated RAC hardening, thus

390

Texture features of the KF granule surface coated with RAC, and AR applied alone,

391

were studied by SEM. The SEM micrographs presented in Figure 4 show a clear plastic-

392

like texture when AR is applied alone on KF granule surface, what probably reflects the 12 ACS Paragon Plus Environment

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absence of significant reticulation (may be some auto-oxidation) and hardening. However,

394

in the case of RAC textures, SEM micrographs show the formation of a coating layer at

395

granule surface, with around 35µm of thickness, which integrates both AR and C.

396

Furthermore, SEM micrographs also show that the inclusion of C particles (lighted white

397

forms) into the reticulated resin is not complete, thus favoring the existence of micro and

398

nanopores (see x2100 magnifications front micrographs) in the composite matrix (dark

399

points) (Figure 4). The coating with C alone did not lead to the formation of a stable layer

400

at granule surface, since the lack of water avoided C setting and hardening (data not

401

shown). In order to investigate the RAC behavior in the presence of water, the dynamics

402

of water-RAC interaction was studied by using image analysis. The results obtained

403

confirmed our hypothesis showing the evolvement of a primary reaction involving water

404

exclusion from granule surface probably resulting from the interaction of the hydrophobic

405

part of RAC with water molecules. The addition of drop waters on RAC powder is

406

followed by clear exclusion of water molecules that is associated with drop water runoff

407

(Figure 5A, 5B). Thus, this fact is clearly reflected in the accumulation of water bubbles

408

on RAC granule surface in comparison to AR coated granules (Figures 5C, 5D, Figure S2

409

and videos S2 and S3). These facts suggest a physical layout of the components in the

410

composite as proposed in Figure 5E34.

411 412

RAC-coating treatment significantly affected KF nutrient release pattern to water solution

413

In order to compare the ability of RAC coating to delay the delivery of mineral

414

nutrients into water solution, EC variation of water solutions containing KF granules

415

under continuous stirring were monitored over time until complete dissolution. The results

416

showed that solutions containing RAC-coated KF presented a significant slower increase

417

in EC than those for uncoated KF, AR-coated KF and C-coated KF. This RAC effect

418

could not be explained as a result of an additive effect of AR and C separated effects 13 ACS Paragon Plus Environment


419

(Figure 6A). On the other hand, results also show that the nutrient release pattern of RAC-

420

coated KF is totally different from those of traditional slow release coated fertilizers

421

involving very stable synthetic polymers as coating, which presented a negligible increase

422

in EC under similar experimental conditions (data not shown). These results were

423

consistent to the fact that nutrient release curves for RAC-coated KF were not sigmoidal

424

as in the case of conventional slow release coated fertilizers. This fact is quite relevant

425

considering that this new KF fertilizer is employed for annual crop top-dressing

426

fertilization, a fertilization mode requiring a relatively rapid action29,32. Regarding the

427

mechanism behind this nutrient release pattern for RAC-coated fertilizers, these results

428

indicate that although the first reaction of RAC is to exclude water molecules from

429

granule surface, continuous water exposure of the fertilizer granules leads to a gradual

430

RAC hydration and further nutrient release from the fertilizer granule (Figure S2 and

431

Videos S1, S2 and S3).

432

Differences between fertilizer types were better quantified by comparing the slopes

433

obtained from the linearization of each EC vs time curve (Figure 6B). The results show

434

that the nutrient release rate from RAC-coated KF is linear and 19 times slower than that

435

of uncoated KF. In this sense, the results show that RAC-coated KF presents a steady

436

linear EC increase that was proportional with time (slope = 0.93~ 1). Therefore, the

437

nutrient release process in RAC-coated KF can be described as a steady controlled

438

diffusion through the micro and nanopores distributed throughout RAC coating layer40.

439

Fertilizers coated with either C or AR, also show a noticeable decrease in the nutrient

440

release rate in comparison with uncoated KF considering the ratio of slopes in the fastest

441

range (2.2 times and 5.8 times slower respectively), but much less important than that of

442

RAC-coated KF (20 times slower). These results also confirm that the efficacy of RAC-

443

coating is not a simple additive (2.2 + 5.8 = 8) effect of their components, but a

444

consequence of the new composite arising from the chemical reaction between AR and C. 14 ACS Paragon Plus Environment

Page 14 of 44

Page 15 of 44


445

As it was expected, the results also indicate that the controlled release effect associated

446

with AR is larger than that of C under these experimental conditions.

447

K-leaching in column tests containing different substrates.

448

In order to evaluate RAC-KF efficacy under more realistic conditions,

449

complementary studies employing soil columns were performed at laboratory scale, by

450

using inert silicic sand and an agronomic sandy soil as column filling substrates. Likewise,

451

the K leaching rates of each fertilizer was compared by applying three different water

452

addition protocols in order to simulate three rainfall regimes with different potential

453

leaching dynamics (intense, severe or moderate). The variations of EC in leachates are

454

presented in Figure 7. The results indicate a very efficient nutrient protection associated

455

with RAC coating under simulated intense rainfall regime, which progressively decreases

456

for the other simulated rainfall patterns (severe and moderate rainfall regimes) that are

457

associated with less potential leaching risk. There were no large differences between the

458

EC variation results obtained from inert substrate model (silicic sand) columns and real

459

sandy soil columns (Figure 7). On the contrary, cumulative K leaching rates where

460

significantly different when experiments were made on sandy soil columns or silicic sand

461

columns. Thus, accumulated K in leachates was clearly lower in real sandy soil for all

462

fertilizers types and rainfall regimes (Figure 8). Treatments with the non-coated KF

463

showed that whereas all applied K was leached in the silicic sand columns, in sandy soil

464

columns subjected to simulated intense and severe rainfall conditions K leaching was

465

reduced to 50% of the total applied K, and under simulated moderate rainfall regime K

466

leaching was reduced to 20-25% of the total added K. This fact shows the relevant role of

467

soil CEC and soil organic matter in controlling K leaching process. Likewise, these results

468

also indicate the convenience of measuring both EC and nutrient concentration in

469

leachates.

470

In relation to the RAC´s efficacy to control K release from KF, cumulative K leaching 15 ACS Paragon Plus Environment


471

plots show a remarkable K leaching decrease with respect to uncoated KF at simulated

472

intense and severe rainfall regimes (Figure 8). However, under moderate rainfall regime

473

both RAC-coated and uncoated- KF presented similar K-leaching patterns (Figure 8). On

474

the other hand, the residual K content within the 0-20 cm-depth soil layer in sandy soil

475

columns at the end of each simulated rainfall regime application is significantly higher for

476

RAC-coated KF than for uncoated KF, in good agreement with the K leaching dynamics

477

described before (Table 3). This effect was larger for the simulated moderate rainfall

478

regime than for the simulated intense and severe rainfall regimes (Figure 8 and Table 3).

479

However, there were no differences between the two fertilizers concerning the K fraction

480

remaining within the column bottom layer (20-40 cm). Considering that the K fraction

481

within the top layer (0-20 cm) is likely representative of the fertilizer remaining into the

482

soil, while that contained in the bottom layer (20-40 cm) is related to the exchangeable K

483

fraction in soil, the results obtained indicate that RAC was able to slow KF water

484

solubilization.

485

In order to better quantitate the above-discussed results in the context of the balance

486

between nutrient protection and nutrient solubilization, the results were quantified by

487

using a leaching ratio (LR) that is defined as the ratio between the cumulative K leachate

488

(CL) for RAC-coated and for uncoated KF for a specific added water amount range (from

489

150 mm to 270 mm). The results, presented in Table 4, show that while the RAC-coated

490

KF LR values are very high for the simulated intense rainfall regime in both soil and

491

silicic sand columns, it declines to value = 1 for simulated moderate rainfall regime. These

492

results indicate that RAC coating was able to delay K delivery from KF under conditions

493

of high water presence surrounding KF granule (intense rainfall simulation) while

494

maintaining a K release pattern similar to that of uncoated KF under conditions of low or

495

moderate water presence around KF granules. In principle, these results match quite well

496

the technical requirements for a special fertilizer that has to be adapted to annual crop top16 ACS Paragon Plus Environment

Page 16 of 44

Page 17 of 44


497

dressing fertilization, and also support the use of a coating with amphiphilic character for

498

this purpose. Finally, the dynamics of N leaching is coherent with that observed for K,

499

though the degree of protection is much lower than that for K, probably due to the

500

nonionic character of urea (Figure S3). This result and the fact that other charged ions -

501

such as Ca2+ and SO42- also present in the fertilizer - underwent a pattern of release to the

502

soil solution close to that of K+ indicate that nutrient protection mechanisms probably also

503

include some type of electrostatic interactions between ionized nutrients and some RAC

504

component40.

505 506

Agronomic efficacy of top-dressing application of RAC-coated KF to provide plant available K to annual crops.

507

In order to evaluate the real efficiency of RAC-coated KF to provide plant available

508

K, while decreasing K leaching, for annual crops cultivated in sandy soils and subjected to

509

intense rainfall regimes, several studies in both greenhouse and open field were conducted

510

in regions of Brazil and Paraguay subjected to high pluviometry.

511

Soybean greenhouse study. A dose-response experiment was conducted on soybean

512

plants cultivated in open pots containing a sandy acidic soil, as described in Materials and

513

Methods. The results concerning both yield expressed in dry weight (g DW/plant) and

514

foliar K concentration (mg/g DW) are shown in Figure 9.

515

The results showed that RAC-coated KF fertilization was associated with a significant

516

increase in both dry matter production and K-leaf concentration, principally for the lower

517

K-doses (75, 150 and 225 Kg ha-1, and 75 and 150 Kg ha-1, respectively). These results

518

were linked to very significant increases in K plant extraction from the soil. There were no

519

differences between fertilizers for the highest dose (300 Kg ha-1), thus indicating the lack

520

of problems of K availability for plants at this K dose.

521

Regarding the concentration of K remaining in soil at the end of the experiment, there

522

were no significant differences between treatments except for the medium fertilizer dose 17 ACS Paragon Plus Environment


523

(150 Kg ha-1).

524

Overall, these results show higher efficiency of RAC-coated KF when compared to

525

uncoated KF to provide available K to plants growing in a sandy soil under conditions of

526

high soil moisture. This fact was reflected in the values of FusE and KupE, which were

527

much higher for RAC-coated KF than those for uncoated KF (Table 5).

528

Field trials in relevant annual crops: Soybean and Wheat.

529

Soybean field trials in Moreira de Sales and Umuarama (South Paraná Brazil). In

530

order to test RAC coating efficiency under different agronomic frameworks, field trials in

531

soybean where carried out in two closer locations in South Paraná in Brazil: Moreira de

532

Sales (MS) and Umuarama (U). The protocol followed in both locations (see Materials

533

and Methods) was the same with the only difference that in U, the natural rainfall was

534

complemented with sprinkler irrigation (Figure S4). Agronomic results for each location

535

and trial were evaluated by monitoring the effects of RAC-coated KF and uncoated KF on

536

yield and K concentration in leaves. Regarding rainfall in both locations, precipitations in

537

MS were intermittent but quite intense, with some short periods of drought (Figure S4). In

538

the case of U, rainfall regime was similar to that of MS, but drought periods were avoided

539

by complementing irrigation. Then, we have two diverse scenarios regarding soil moisture

540

for studying the K-delivery pattern for KF. In MS we have alternate dry/wet soil periods,

541

while in U we have wet soil throughout crop cycle.

542

The results obtained in MS location show that RAC-coated KF application was

543

associated with a significant yield increase with respect to untreated control and uncoated

544

KF for all doses tested (Table 6). In line with these results, both FusE and KupE were

545

higher for RAC-coated KF than for uncoated KF (Table 5). Moreover, the concentration

546

of exchangeable K remaining in soil after harvesting was significantly increased by RAC-

547

coated KF application with respect to both untreated control and uncoated KF treatment

548

(Table 6). However, no significant differences between the two fertilizer treatments were 18 ACS Paragon Plus Environment

Page 18 of 44

Page 19 of 44


549

observed regarding K foliar concentration (Table 6). These facts indicate that the

550

beneficial action of RAC-coated KF might result from not only better K nutrition but also

551

by reducing the increase in ion concentration, and thereby EC (salinity), around plant

552

roots; a fact that might be specially relevant in wet to dry soil periods when salinity is

553

favored. Likewise, a K-mediated plant protection to drought stress cannot be ruled out,

554

since recent studies reported a beneficial effect of K in plants subjected to water

555

deficiency that is not explained by its nutritional action45.

556

In the case of the field trial in U, no significant differences in yield were obtained

557

even when KF treatments were compared to the untreated control (Table 6). These results

558

indicate that the concentration of potentially plant available K in U soil was enough to

559

cover crop demands, thus favoring no response to K exogenous application. This fact is

560

supported by the large difference between plant available K (soil exchangeable K) in MS-

561

soil (0.06 cmol dm-3) and in U-soil (0.14 cmol dm-3) (Table 1). However, the results

562

showing an increase in soil exchangeable K remaining after harvesting associated with

563

RAC-coated KF, as in the case of MS-trial, reflect the ability of RAC-coating to control K

564

delivery to the soil solution (Table 6). In the case of U-trial, this effect was relevant

565

because soil parcels were provided with enough water irrigation throughout all crop cycle,

566

a fact that moreover is probably behind the higher yield harvested in U. In this case, the

567

continuous presence of water in soil throughout the cycle may reduce an eventual stress

568

caused by salinity due to the dilution of the salt concentration in soil solution.

569

Furthermore, these results -which were in good agreement with those obtained in

570

soybean cultivated in greenhouse - also indicate that RAC-coating provides KF granules

571

with a K-delivery pattern that is adapted to cope with K soybean nutritional needs all over

572

the cycle when applied in top-dressing.

573

Wheat field trial in Minga Guaçú (Paraguay). Another dose-response field trial in

574

wheat was also conducted in Minga Guaçu (Paraguay). The experiment was carried out 19 ACS Paragon Plus Environment


575

employing two doses of fertilizers – RAC-coated KF and uncoated KF – with 100 and

576

200Kg ha-1 of fertilizer, which corresponded to 49 and 98 Kg K2O per ha. The KF were

577

applied in top-dressing after tillering. Rainfall in this area was high and uniformly

578

distributed throughout the whole crop cycle (Figure S5).

579

The results showed significant differences in crop yield only for the highest dose of

580

fertilizer (Table 6). There were no significant differences between treatments for K-leaf

581

concentrations, but a slight increase in the plant-available K (soil exchangeable K)

582

remaining in soil after harvesting into the first 10 cm of soil profile was associated with

583

RAC-coated KF application (Table 6). All these results were reflected in the values of

584

FusE and KupE that were significantly higher for RAC-coated KF in comparison with

585

uncoated KF for the highest dose of fertilizer applied (Table 5). The fact that the positive

586

effects associated with RAC-coating treatment was only expressed for the highest dose

587

might be linked to an effect of RAC decreasing K-delivery rates and, thereby, salt

588

concentration in the rhizosphere (saline stress).

589

Taken together these results indicate that the reaction of an amphiphilic alkyd resin

590

with cement has proven to be an efficient way to prepare a new composite with

591

amphiphilic features that is well adapted to be used as coating for preparing special K-

592

fertilizers for top-dressing annual-crop fertilization. The RAC-coating efficiency was

593

likely associated with the RAC ability to exclude water interaction with granule surface

594

under conditions of punctual (transient) high water amount surrounding fertilizer granule

595

in soil (conditions of high and intense-intermittent rainfall regime), while maintaining

596

water permeation under conditions of low or moderate, in some cases persistent, water

597

presence around the granule in the soil. This behavior is likely driven by the amphiphilic

598

character of RAC.

599

ACKNOWLEDGMENTS

600

We would like to thank CDTI, the Government of Navarra and the Roullier Group for 20 ACS Paragon Plus Environment

Page 20 of 44

Page 21 of 44


601

providing us with economical support to carry out this study.

602

ABREVIATIONS AND NOMENCLATURE

603

K: potassium, N: nitrogen, CFR: controlled release fertilizer, EC: electrical

604

conductivity, CEC cation exchange capacity, AR: alkyd resin, C: cement, RAC:

605

reticulated amphiphilic composite, ICP-OES: induced coupled plasma optical emission

606

spectrometer, TG: Thermo Gravimetric analysis, DTG: Difference Thermo Gravimetric

607

ATR-FTIR: attenuated total reflectance fourier transformed infrared spectroscopy, NMR:

608

nuclear magnetic resonance, ARCo: alkyd resin reticulated with Co2+ catalyst, SEM:

609

secondary electron microscopy KF: uncoated potassium fertilizer, RAC-KF: potassium

610

fertilizer coated with RAC, U: Umuarama, MS: Moreira de Sales, MG: Minga Guaçú,

611

CY: Colonia Yguaçú.

612

SUPPORTING INFORMATION DESCRIPTION

613

The Supporting information consist on a table and five figures (PDF) and three videos

614

(AVI); the table S1 shows the ion content of the cement; the figure S1 confirms the

615

chemical structure of the alkyd resin; the figure S2 and accelerated (x60) Videos S1, S2

616

and S3 summarize the water solubilization of a single granule of K fertilizer: uncoated

617

(KF), coated with AR and coated with RAC with time; the figure S3 shows the efficacy of

618

RAC to delay nitrogen release in soil column tests; the figures S4 and S5 show the annual

619

rainfall in soya and wheat field trials.

620

REFERENCES

621 622

(1) Wang, F. L.; Alva, A. K. Leaching of nitrogen from slow-release urea sources in sandy soils. Soil Sci. Soc. Am. J. 1996, 60, 5, 1454-1458.

623

(2) Trenkel, M. E. Slow and controlled-release and stabilized fertilizers: an option for

624

enhancing nutrient efficiency in agriculture. International Fertilizer Industry Association

625

IFA. 2010, Paris, France.

626

(3) Oliveira, M. W.; Trivelin, P. C.; Boaretto, A. E.; Muraoka T.; Mortatti, J. Leaching 21 ACS Paragon Plus Environment


627

of nitrogen, potassium, calcium and magnesium in a sandy soil cultivated with sugarcane.

628

Brasília 2002, 37, 6, 861–868.

629

(4) Inglese, P.; Gullo, G.; Pace, L.S. Fruit growth and olive oil quality in relation to

630

foliar nutrition and time of application. ISHS Acta Hort. 2002, 586, IV International

631

symposium on olive growing.

632

(5) Ghiberto, P.; Libardi, P.; Brito, A.; Trivelin P. Leaching of nutrients from a

633

sugarcane crop growing on an ultisol in Brazil. Agric. Water Manag. 2009, 96, 10, 1443–

634

1448.

635

(6) Gomes de Moura, E.; Silva, S. S.; Donizetti, J. G.; Reis, S. J.; Sobrinho, C.; Ferreira,

636

A. C. Nutrient use efficiency in alley cropping systems in the Amazonian periphery. Plant

637

and Soil 2010, 335, 1, 363-371.

638

(7) Cantarella, H.; Van Raij, B.; Quaggio, J. A. Soil and plant analyses for lime and

639

fertilizer recommendations in Brazil. Commun. Soil Sci. Plant Anal. 1998, 29, 11-14,

640

1691-1706.

641 642

(8) Wang, F. L.; Huang, P. M. Effects of organic matter on the rate of potassium adsorption by soils. Can. J. Soil Sci. 2001, 81, 325–330.

643

(9) Schlindwein, J.A.; Bortolon, L.; Fioreli-Pereira, E. C.; Bortolon, E. S. O.; Gianello,

644

C. Phosphorus and potassium fertilization in no till southern Brazilian soils. Agricultural

645

Sciences 2013, 4, 12A, 39–49.

646

(10). Food and Agriculture Organization of the United Nations FAO. Manual of integrated

647

soil management and conservation practices. Land and Water Bulletin. 2000, 8, 50–51.

648

ISSN 1020-8127. ISBN 92-5-304417-9.

649 650 651 652

(11) Manning, D. Mineral sources of potassium for plant nutrition. A review. Agron. Sustain. Dev. 2010, 30, 2, 281–294. (12) Römheld, V.; Kirkby, E. A. “Research on potassium in agriculture: needs and prospects. Plant Soil 2010, 335, 155–180. 22 ACS Paragon Plus Environment

Page 22 of 44

Page 23 of 44


653 654 655 656 657 658

(13) Campbell, B.; Mann, W.; Meléndez-Ortiz, R.; Streck, C.; Tennigkeit, T. Agriculture and climate change. A scoping report. 2011, ISBN: 978-0-615-49585-9. (14) Cakmak, I. The role of potassium in alleviating detrimental effects of abiotic stresses in plants. J. Plant Nutr. Soil Sci. 2005, 168, 521–530. (15) Wang, M.; Zheng, Q.; Shen, Q.; Guo, S. The critical role of potassium in plant stress response. Int. J. Mol. Sci. 2013, 14, 7370-7390.

659

(16) Hawkesford, M; Horst, W; Kichey, T; Lambers, H; Schjoerring, J; Skrumsager, I;

660

White, P. Chapter Functions of Macronutients In Marschner´s Mineral Nutrition of Higher

661

Plants, edition no.3; Marschner, P., Ed.; Academic Press, Elsevier: London, United

662

Kingdom, 2012, 178-189.

663

(17) Daliparthy, J.; Barker, A. V.; Mondal, S. S. Potassium fractions with other nutrients

664

in crops: A review focusing on the tropics. Journal of Plant Nutrition 1994, 17, 11, 1859-

665

1886.

666

(18) Zehler, E; Kreipe, H. Chapter 2. Plant physiology and the choice of potash fertilizer.

667

In Potassium sulphate and potassium chloride. Their influence on the yield and quality of

668

cultivated plants. lng. agr. Agricultural Research Station BUntehof Hannover/Federal

669

Republic of Germany P.A. Gething, M.A. Nuffield, Ox.on./United Kingdom. Publisher:

670

International Potash Institute IPI. CH-3048 Worblaufen-Bern/Switzerland, 1981, IPI

671

Resarch Topics nº 9, pp 9–14.

672 673 674 675

(19) Ashley, M. K.; Grant, M.; Grabov, A. Plant responses to potassium deficiencies: a role for potassium transport proteins. J. Exp. Bot. 2006, 57, 2, 425–436. (20) Sanches Oliveira, P. T.; Wendland, E.; Nearing, M. A. Rainfall erosivity in Brazil: A review. Catena 2012, 100, 139–147.

676

(21) Shaviv, A.; Mikkelsen, R. L. Controlled-release fertilizers to increase efficiency of

677

nutrient use and minimize environmental degradation - A review. Fertilizer Research

678

1993, 35, 1-12. 23 ACS Paragon Plus Environment


679

(22) Sitthaphanit, S.; Limpinuntana, V.; Toomsan, B.; Panchaban, S.; Bell, R. W.

680

Fertiliser strategies for improved nutrient use efficiency on sandy soils in high rainfall

681

regimes. Nutr. Cycl. Agroecosyst. 2009, 85, 123– 139.

682

(23) Simonne, E. H.; Hutchinson. C. M. Controlled-release fertilizers for vegetable in the

683

era of best management practices: Teaching new tricks to an old dog. Hort. Technol. 2005,

684

15, 36–46.

685

(24) Ni, B.; Liu, M.; Lü, S.; Xie, L.; Zhang, X.; Wang, Y. Novel slow-release

686

multielement compound fertilizer with hydroscopicity and moisture preservation. Ind.

687

Eng. Chem. Res. 2010, 49, 10, 4546–4552.

688

(25) Morgan, K. T.; Cushman, K. E.; Sato, S. Release mechanisms for slow- and

689

controlled-release fertilizers and strategies for their use in vegetable production.

690

HortTechnology 2009, 19:10–12.

691

(26) Du, C. W., Zhou, J. M.; Shaviv, A. Release characteristics of nutrients from

692

polymer-coated compound controlled release fertilizers. J. Polym. Environ. 2006, 14, 3,

693

223−230.

694

(27) Ma, Z.; Jia, X.; Hu, J.; Liu, Z.; Wang, H.; Zhou, F. Mussel-inspired thermo-

695

sensitive polydopamine- graft-poly N-isopropylacrylamide. coating for controlled-release

696

fertilizer. J. Agric. Food Chem. 2013, 61, 12232−12237.

697

(28) Shaviv, A.; Raban, S.; Zaidel, E. Modeling controlled nutrient release from polymer

698

coated fertilizers: Diffusion release from single granules. Environ. Sci. Technol. 2003, 37,

699

10, 2251–2256.

700

(29) Shaviv, A.; Raban, S.; Zaidel, E. Modeling controlled nutrient release from polymer

701

coated fertilizers: Statistically base model for diffusion release. Environ. Sci. Technol.

702

2003, 37, 10, 2257–2261.

703 704

(30) Davidson, D.; Gu, F. X. Materials for sustained and controlled release of nutrients and molecules to support plant growth. J. Agric.Food Chem. 2012, 60, 870−876. 24 ACS Paragon Plus Environment

Page 24 of 44

Page 25 of 44


705

(31) Lubkowski K.; Smorowska, A.; Grzmil, B.; Kozłowska, A. Controlled-release

706

fertilizer prepared using a biodegradable aliphatic copolyester of polybutylene succinate.

707

and dimerized fatty acid. J. Agric. Food Chem. 2015, 63, 10, 2597–2605.

708

(32) Liu, G.; Zotarelli, L.; Li, Y.; Dinkins, D.; Wang, Q.; Ozores-Hampton, M.

709

“Controlled-Release and Slow-Release Fertilizers as Nutrient Management Tools”

710

HS1255, one of a series of the Horticultural Sciences Department, UF/IFAS Extension.

711

October 2014, EDIS website at http://edis.ifas.ufl.edu.

712 713

(33) Suresh, B.; Gubler, R.; He, X.; Yamaguchi, Y. Controlled- and Slow-Release Fertilizers. 2015, https://chemical.ihs.com/CEH/Public/Reports/535.8000.

714

(34) Gooch, J. W. Alkyd resins, Vegetable oils and autoxidative polymerization. In

715

Emulsification and Polymerization of Alkyd Resins. Topics in Applied Chemistry

716

Katritzky, A. R; Sabongi, G. J.; Meth-Cohn, O. Eds. Publisher: Kluwer Academic, New

717

York, 2002; 1–29.

718 719 720 721

(35) Montero de Espinosa, L.;, Meier M. A. R. Plant oils: the perfect renewable resource for polymer science. Eur. Polym. J. 2011, 47, 837–852. (36) Wool, R. P. Polymers and composite resins from plant oils In Bio-Based Polymers and Composites. Ed. 1st. Publishers: Elsevier Academic Press, Amsterdam 2005, 56–68.

722

(37) Alis, Y.; Blandin, A.F.; Erro, J.; García Mina, J.M.; Jaquot, V.; Urrutia, O.; Yvin

723

J.C.; Zabini, A. Delayed release fertilising product, manufacturing and spreading methods

724

2015, patent WO 2015150645

725

(38) Raquez, J. M., Deléglise, M., Lacrampe, M. F., Krawczak, P. Thermosetting bio.

726

materials derived from renewable resources: a critical review. Prog. Polym. Sci. 2010, 35,

727

487–509.

728 729 730

(39) Jarosiewicz, A.; Tomaszewska, M. Controlled-release NPK fertilizer encapsulated by polymeric membranes. J. Agric. Food Chem. 2003, 51, 2, 413–417. (40) Organisation for Economic Co-operation and Development OECD.. Guideline for 25 ACS Paragon Plus Environment


731 732 733 734 735 736 737

testing of chemicals. Test No. 312 Leaching in soil columns. Paris 2004. (41) Hawkesford, M. J. Improving Nutrient Use Efficiency in Crops. Chichester: eLS John Wiley Sons, Ltd. 2012, 1–7. (42) Rengel, Z.; Daemon, P. M. Crops and genotypes differ in efficiency of potassium uptake and use. Physiol. Plant. 2008, 133, 624–6236. (43) Van Gorkum, R.; Bouwman, E. The oxidative drying of alkyd paint catalysed by metal complexes. Coord. Chem. Rev. 2005, 249, 1709–1728.

738

(44) Merad, L.; Cochez, M.; Jochem, F.; Ferriol, M.; Bourson, P.; Benyoucef, B. Study

739

of Reticulation RTM6 System by DSC and FTIR Spectroscopy. IREPHY 2008, 2, 2, 74-

740

79.

741 742

(45) Sayed A. A. Chapter 2 Plant and crop science. In Soil Conditions and Plant Growth. Gregory, P. J.; Nortcliff, S. Eds. Publisher: Wiley-Blackwell. Oxford, 2013, pp 32–39.

743


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Tables

746



747 748 749 750

Page 28 of 44

Table 1.- Analysis of soils used in column test, and all plant experiments carried out in MG (Minga Guaçu); CY (Colonia Yguaçu), MS (Moreira de Sales); U (Umuarama).

751 Experiment

Soil column

Soil Location

Field trials

Methodology

MG

CY

MS

U

Parameter

Units

Sand

Soil

Soya

Wheat

Soya

Soya

pH (H20)

-

6.58

5.38

5.5

6.00

5.75

5.19

OM

%

0.07

0.29

1.21

1.17

0.90

0.03

0.06

0.03

0.31

0.08

K Ca Mg

cmol dm-3

Al CEC

Extract

Valoration

1/10

pHmeter

1.41

Oxidation

UV-Vis

0.18

Mehlich 1

0.29

1.55

2.8

3.50

0.65

0.92

KCl 1M

0.16

0.19

0.7

0.73

0.25

0.53

KCl 1M

0.00

0.14

0.13

1.21

0.06

0.58

KCl 1M

EDTA-Na2 -

0.58

4.16

5.6

7.11

3.08

4.73

Water

P

3.3

5.1

90.0

16.5

25.11

12.47

Mehlich 1

Fe

104

83

70

45

93.5

87

Mehlich 1

Mn

9.6

27.2

60

130.1

18.4

19

Mehlich 1

0.19

0.61

4

2.90

0.4

0.2

Mehlich 1

Cu

-

MG

Glasshouse

mg dm-3

AA*

AA

Zn

0.47

1.23

8.4

1.40

0.85

0.71

Mehlich 1

B

0.53

0.62

0.6

0.66

0.575

61

HCl

UV-Vis

Ca3(PO4)

BaCl2

S

4.7

4.8

160

11.1

3.82

5.23

Sand

980

920

280

720

900

880

13

20

170

140

20

30

7

60

550

140

80

90

Silt

g dm-3

Clay * Atomic Absortion

752 753


Densitometry (Bouyoucos)

Page 29 of 44


754 755 756 757 758

Table 2. RAC setting analysis by Vicat needle method and Shore hardness (scale A) at each time. RAC composite

Vicat needle

Setting phase

time

Initial End

Shore hardness (scale A) Shore units

Recovery (mm)

15 min

0

0

59 min

51

1

379 min

55

2

759 760



761 762 763 764

Page 30 of 44

Table 3.- Residual K (mg) in sandy soil columns at 0-20cm and 20-40cm, after the application of the simulated rainfall regimes: intense, severe and moderate (significant differences between means were obtained by the Anova Post Hoc Fisher test LSD for p≤0.05 at each depth).

765 Column

Rain regime Intense

Sandy soil

Severe Moderate

Depth (cm)

soil (mg K)

KF (mg K)

RAC-KF (mg K)

0-20

12 ± 2

c

103 ± 6

b

136 ± 7

a

20-40

11 ± 1

b

88 ± 5

a

68 ± 6

a

0-20

11 ± 1

c

88 ± 6

b

109 ± 7

a

20-40

10 ± 1

b

82 ± 4

a

89 ± 4

a

0-20

10 ± 2

c

111 ± 8

b

126 ± 8

a

20-40

10 ± 1

b

89 ± 8

a

68 ± 6

a

766 767


Page 31 of 44


768 769 770

Table 4.- Cumulative leached Potassium (CL) and Leaching Ratio (LR) for uncoated K fertilizer (KF) and RAC coated fertilizer (RAC-KF), after 150mm to 270mm, in each rainfall simulation (Intense, Severe and Moderate), on both soil and sand columns.

771 Column

Cummulative rain Rain Intense

Soil

Severe Moderate Intense

Sand

Severe Moderate

Fertilizer

150mm CL

KF

29

RAC-KF

1.5

KF

92

RAC-KF

15

KF

29

RAC-KF

30

KF

119

RAC-KF

2

KF

214

RAC-KF

126

KF

195

RAC-KF

210

LR 19.4 6.0 1.0 61.0 1.7 0.9

180mm CL 57 2.6 108 36 43 48 186 6.3 239 175 230 240

LR 22.0 3.0 0.9 30.1 1.4 1.0

210mm CL 79 4.7 121 48 51 54 227 13 253 197 244 249

772 773


LR 17.0 2.5 0.9 17.2 1.3 1.0

240mm CL 96 9 134 53 58 57 249 30 262 208 253 256

LR 11 2.5 1.0 8.2 1.3 1.0

270mm CL 107 16 144 56 66 59 257 48 268 213 261 263

LR 6.5 2.6 1.1 5.3 1.3 1.0


774 775 776

Page 32 of 44

Table 5.- Fertilizer use efficiency (FusE) and K uptake efficiency (KupE) for uncoated K fertilizer (KF) and RAC coated fertilizer (RAC-KF), calculated for each agronomic trial. (Significant differences between means were calculated using the Fisher LSD p≤0.05).

777 Agronomic trials

Greenhouse

Field trials

CROP

Soya

Soya

Soya

Wheat

Location (soil)

Minga Guaçu

Moreira de Sales

Umuarama

Colonia Yguaçu

Kg ha-1 75

150*

225*

300

Fertilizer

FusE

KupE

FusE

KupE

FusE

KupE

FusE

KupE

KF

0.4 b

6b

3.8 b

152 b

4.3 a

181 a

-

-

RAC-KF

4.8 a

33 a

10.6 a

392 a

1.8 b

76 b

-

-

KF

4.6 b

9b

2.5 b

192 b

1.9 b

168 b

1.81 a

79 a

RAC-KF

9.8 a

29 a

6.2 a

437 a

2.6 a

230 a

1.76 a

81 a

KF

1.7 a

30 b

2.1 a

248 b

0.6 b

78 b

0.86 b

80 b

RAC-KF

4.1 a

112 a

5.0 a

512 a

2.9 a

379 a

2.38 a

129 a

KF

1.8 a

151 b

-

-

-

-

-

-

RAC-KF

3.0 a

192 a

-

-

-

-

-

-

* F doses for wheat field trial = 100 and 200 Kg ha-1

778 779 780 781


Page 33 of 44


782 783 784 785 786 787

Table 6.- Results of the soya field trials carried out in Moreira de Sales (MS) and Umuarama (U) for Yield, Residual K in soil at harvest time and Foliar K (significant differences between means were obtained by the Anova Post Hoc Fisher test LSD for p≤0.05 at each dose).

Field trial result

Crop

Location KgF/ha

MS Soya Yield (Kg bean/ha)

U

Wheat

CY

MS Soya Foliar K (g/gDW)

U

Wheat

CY

MS Soya Residual K (cmol/dm3)

U

Wheat

CY

Control 0

KF

RAC-KF

75

3102 ± 232 b

3405 ± 344

b

3884 ± 290

a

150

3102 ± 232 c

3485 ± 260

b

4011 ± 156

a

225

3102 ± 232 c

3599 ± 243

b

4204 ± 279

a

75

4220 ± 511 a

4785 ± 244

a

4515 ± 511

a

150

4220 ± 511 a

4745 ± 536

a

4774 ± 691

a

225

4220 ± 511 a

4595 ± 292

a

5037 ± 617

a

100

2055 ± 138 b

2236 ± 272

a

2232 ± 114

a

200

2055 ± 138 b

2227 ± 183

ab

2531 ± 103

a

75

24.6 ± 2.6

a

25.0 ± 2.9

a

27.2 ± 0.9

a

150

24.6 ± 2.6

b

25.9 ± 1.8

b

28.6 ± 2.1

a

225

24.6 ± 2.6

b

27.7 ± 2.4

ab

28.6 ± 1.6

a

75

25.9 ± 4.6

a

26.1 ± 1.4

a

28.2 ± 3.9

a

150

25.9 ± 4.6

a

24.8 ± 3.1

a

28.6 ± 4.2

a

225

25.9 ± 4.6

a

26.5 ± 2.1

a

27.7 ± 4.2

a

100

13.5 ± 0.8

b

15.0 ± 0.6

a

14.7 ± 0.3

a

200

13.5 ± 0.8

b

14.9 ± 0.5

a

15.2 ± 0.5

a

75

0.06 ± 0.01 a

0.07 ± 0.01

a

0.07 ± 0.01

a

150

0.06 ± 0.01 c

0.08 ± 0.01

b

0.09 ± 0.01

a

225

0.06 ± 0.01 c

0.08 ± 0.01

b

0.11 ± 0.02

a

75

0.14 ± 0.04 b

0.15 ± 0.04

ab

0.22 ± 0.03

a

150

0.14 ± 0.04 b

0.20 ± 0.04

ab

0.25 ± 0.05

a

225

0.14 ± 0.04 b

0.24 ± 0.05

a

0.26 ± 0.05

a

100

0.34 ± 0.03 b

0.43 ± 0.05

a

0.44 ± 0.04

a

200

0.34 ± 0.03 b

0.42 ± 0.04

ab

0.52 ± 0.05

a

788 789 790



791 792

Figures

793


Page 34 of 44

Page 35 of 44


794 795 796

Figure 1.- (A) Thermo Gravimetric analysis (TG) and (B) Difference Thermo Gravimetric analysis (DTG) of the RAC in comparison to AR and AR treated with Co2+ (ARCo).

797



798 799

AA

800

B

1552

1409

801 802 803

Figure 2. (A) FTIR analysis of C, AR and RAC and (B) comparison between AR and RAC-C (1:4) substraction spectra. Grey shadow areas indicate new peaks formation.

804


Page 36 of 44

Page 37 of 44


805 13.5 12.0 10.5

Kg/mm2

9.0 7.5 6.0 4.5 3.0 1.5 0.0 0

50

100

150

200

250

300

350 400 Time (h)

450

500

550

600

650

700

806 807

Figure 3.- RAC firmness increase with time measured with the Wagner P020 durometer.

808 809 810 811 812



813

RAC-KF

AR-KF

814 815 816 817

Figure 4. Comparison of RAC and AR coated KF granules by using SEM analysis for the hemispheric-cut granule view and front granule surface view.

818 819


Page 38 of 44

Page 39 of 44


820

821 822 823 824 825 826

Figure 5. Series of images showing the hydrophobic nature of RAC: Images of water repulsion reaction after water drops application on RAC composite powder (A, B); Images showing the same effect during the dissolution test of RAC coated granule (C) in comparison to AR coated one (D); Scheme of the polar disposition of AR and C in RAC composite coating a KF fertilizer granule (E).

827



828 829 830

831

A

B

832 833 834 835

Figure 6. Increase in EC (expressed in %) for non-coated KF granules and KF granules coated with C, AR and RAC after 200min (A). Release kinetic equations and slopes obtained from linear adjustment of the EC increase after 90 min (B).

836


Page 40 of 44

Page 41 of 44


837 838 839 840 Intense rainfall regime 5,25

5,25

B

4,50

4,50

3,75

3,75

EC (mS cm-1)

EC (mS cm-1)

A

3,00 KF 2,25

RAC-KF

3,00 KF 2,25

1,50

1,50

0,75

0,75

0,00

RAC-KF

0,00 0

30

60

90

120 150 180 210 240 270 300 330 Rain (mm)

0

30

60

90

120 150 180 210 240 270 300 330 Rain (mm)

Severe rainfall regime

A

5,25

B 4,50

4,50

3,75

3,75

EC (mS cm-1)

EC (mS cm-1)

5,25

3,00 KF 2,25

RAC-KF

3,00 KF 2,25

1,50

1,50

0,75

0,75

0,00

RAC-KF

0,00 0

30

60

90

120 150 180 210 240 270 300 330 Rain (mm)

0

30

60

90

120 150 180 210 240 270 300 330 Rain (mm)

Moderate rainfall regime 5,25

B 4,50

4,50

3,75

3,75

3,00 KF 2,25

RAC-KF

KF 2,25 1,50

0,75

0,75

RAC-KF

0,00 0

842 843 844

3,00

1,50

0,00

841

EC (mS cm-1)

EC (mS cm-1)

A

5,25

30

60

90

0

120 150 180 210 240 270 300 330 Rain (mm)

30

60

90

120 150 180 210 240 270 300 330 Rain (mm)

Figure 7.- Electrical Conductivity (EC) of each leachate collected from columns filled with different substrates: Silicic sand (A) and a sandy soil (B), for each simulated rainfall regime.

845



846 847 848 849

850 851 852 853

Figure 8.- Cumulative Potassium leached from columns filled with silicic sand (A) and a sandy soil (B), after applying the simulated rainfall regimes (intense, severe and moderate). Results evaluated in relation to the drained volume.

854


Page 42 of 44

Page 43 of 44


855 A

KF

B

RAC-KF

14,0

20

a

Foliar K ( mg/gDW)

Dw (g/pot)

8,4

a

b b

c c

5,6

2,8

b

b

b 15

bc

c

c

c

10

5

0,0

0 0

75 150 225 Dose of fertilizer (Kg/ha)

KF

C

300

0

RAC-KF

0,18

RAC-KF

a

a

a

a a

176

K extracted ( mg/pot)

bb

300

220

a

0,12

75 150 225 Dose of fertilizer (Kg/ha) KF

D a a

0,15

K in soil (cmol dm-3)

a a

a b

RAC-KF

25

a

11,2

KF

b

0,09

c 0,06

a b

132

88

b

b

c

c

44

0,03

0

0,00 0


300

0


300

856 857 858 859 860

Figure 9.- Greenhouse experiment in soya. Shoot dry weight (A); foliar K concentration (B); residual K in the soil (C), and total K extracted by plants (D) (significant differences between means were obtained by the Anova Post Hoc Fisher test LSD for p≤0.05). (Nonfertilized Control 0 in light grey).

861



862 863 864

TOC Graphic

865


Page 44 of 44

New Amphiphilic Composite for Preparing Efficient Coated Potassium

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