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Effects of different forms of selenium fertilizers on Se accumulation, distribution and residual effect in winter wheat-summer maize rotation system Qi Wang, Yao Yu, Jixiang Li, Yanan Wan, Qingqing Huang, Yanbin Guo, and Huafen Li J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.6b05149 • Publication Date (Web): 19 Jan 2017 Downloaded from http://pubs.acs.org on January 23, 2017
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Journal of Agricultural and Food Chemistry
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Effects of different forms of selenium fertilizers on Se accumulation, distribution
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and residual effect in winter wheat-summer maize rotation system Qi Wang1, Yao Yu1, Jixiang Li1, Yanan Wan1, Qingqing Huang1, 2, Yanbin Guo1,
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Huafen Li*1
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1
Key Laboratory of Plant-Soil Interactions of the Ministry of Education, College of
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Resources and Environmental Sciences, China Agricultural University, Beijing
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100193, China
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Key Laboratory of Agro-environment and Agro-product Safety, Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China
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Contact information for Corresponding Author:
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Huafen Li
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E-mail:
[email protected] 13
Tel/Fax: 0086-10-62731165
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Abstract
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Foliar Se fertilizers were applied to investigate the effects of Se forms on Se
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accumulation and distribution in the wheat−maize rotation system and residual
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concentration of Se in subsequent crops. Sodium selenite, sodium selenate,
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selenomethionine, chemical nano-Se, humic acid + sodium selenite and compound
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fertilizer + sodium selenite were applied once at the flowering stage of wheat (30 g
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ha-1) and at the bell stage of maize (60 g ha-1). Compared with the control treatment,
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foliar Se applications significant increased the grain Se concentration of wheat and
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maize by 0.02−0.31 mg kg−1 and 0.07−1.09 mg kg−1, respectively. Wheat and maize
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grain Se recovery was 3.0%−10.4% and 4.1%−18.5%, respectively. However, Se
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concentrations in the grain of subsequent wheat and maize significantly decreased by
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77.9% and 91.2%, respectively. The change of Se concentration in soil was a dynamic
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process with Se depletion after harvest of maize.
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Keywords: selenium fertilizers; wheat; maize; biofortification; residual effect
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Introduction
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Selenium (Se) is considered as an essential trace element for human and animal
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health because of its critical role in antioxidative defense and anticancer agents.1-2 It
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has been estimated that 0.5−1 billion people globally may have inadequate intakes of
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Se,
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intake of Se by human can cause health disorders, such as Keshan disease,
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Kashin-beck disease, cardiovascular disease, infertility, and even death. 4,7-9 Therefore,
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an adequate daily Se intake is required to maintain human health.
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including those in China, UK, and Australia.
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However, insufficient dietary
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Cereal and its products are a primary source of Se in diets and they contribute to
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70% of Se intake in low-Se intake areas of China. 10 Se-enriched fertilizers by soil or
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foliar application for agronomic biofortification in cereals, provides the best
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short-term solution for improving Se concentrations in crops.
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application is simpler, more practicable and more effective than soil application to
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produce Se-enriching food, especially Se fertilizer application in the acid soil under
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strongly reduced soil conditions. 13-17 Under the strongly reduced soil conditions (pH
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< 4 and Eh < 0), selenate and selenite are easily reduced to selenide or even elemental
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selenium, which is less available for plants. 18,19
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Generally, foliar
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Foliar fertilization with inorganic Se has been used in fruit, vegetable and cereal
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productions. Selenite and selenate are the main inorganic forms of foliar application.
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Foliar application of selenate exhibited higher efficiency in increasing the Se
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concentration in rice products than selenite.
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nano-Se over the past few years because of its potential benefits for improving human
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health and lowering poisoning risk. Nano-Se is bright red, soluble, highly stable,
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nano-size and has a redox state of zero (Se0), and it has been reported to have higher
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efficiency in promoting seleno-enzymes activities and alleviating toxicity, compared
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with selenite and SeMet.
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nutritional supplements and medical therapy. Moreover, a recent work has found that
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the accumulation and translocation intensity of Se nanoparticles in perennial onions
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treated with different forms of Se followed decreased in the order Se+6 > Se0 > Se+4. 23
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Compared with inorganic Se, organic Se (selenomethionine) can easily be taken up
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There has been increasing interest in
As a result, nano-Se has been manufactured for both of
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and translocated to above-ground plant tissues. 24 However, much less is known about
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the effects of nano-Se and SeMet as foliar application.
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Wheat and maize were selected as tested plants in the current study because they 10
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are the major source of Se intake by humans and domestic animals.
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the North China Plain, the winter wheat−summer maize rotation system accounts for
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43.4% of the total national wheat−maize production and 40.4% of wheat−maize
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planting area in China.
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of different forms of foliar Se fertilizers on Se concentration and distribution in crops,
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especially of organic Se and nano-Se, (2) to identify the residual effect of Se on the
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subsequent crops, (3) to test the effect of Se in combination with other chemical
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fertilizers, and (4) to assess the potential environment risk of Se fertilization in the
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local wheat−maize rotation system.
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Materials and methods
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Description of field experimental site
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Moreover, in
The objectives of this study were: (1) to examine the effect
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Two field experiments were conducted from November 2013 to October 2015 at
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Huantai Experimental Station of China Agricultural University, located at Huantai
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county, Zibo City, Shandong province, in north China (36°56′N, 117°50′E). This area
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has a warm temperate continental monsoon climate, with an annual mean temperature
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of 13.4℃ and annual precipitation of 604 mm. According to the soil genetic types,
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soil type of this field is classified as lime concretion black soil. The physical and
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chemical properties of the soil (0−20cm) were: pH (H2O), 7.82; organic matter, 25.70
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g kg−1, total N, 1.06 g kg−1; available P, 9.07 mg kg−1; available K, 191.00 mg kg−1;
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and total Se, 0.46 mg kg−1.
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Experimental design
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A common local rotation system of winter wheat (Triticum aesticum L.) and
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summer maize (Zea mays L.) was carried out in the field experiments; the two crop
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varieties were Luyuan 502 (wheat) and Zhengdan 958 (maize). Before planting, both
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wheat and maize were fertilized with base fertilizer which consisted of 90 kg N ha−1,
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90 kg P ha−1 and 90 kg K ha−1, with a topdressing rate of 103.5 kg N ha−1 at the
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jointing stage. Herbicide (tribenuron-methyl) was sprayed once at seeding time of
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wheat and maize in November and June, respectively. Pesticide (melamine
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chrysanthemum ester) was applied once at the flowering stage (April) of wheat and
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twice at the small bell stage (July) and large bell stage (August) of maize.
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The aim of Experiment 1 was to investigate the effects of four foliar Se fertilizers
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on the Se accumulation in plants and retention in soil in the wheat−maize rotation
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system. This field experiment was conducted from November 2013 to September
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2014, including five foliar treatments with three replications in a completely
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randomized block design. These treatments were: (1) control (CK, water without Se);
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(2) sodium selenite (SeIV); (3) sodium selenate (SeVI); (4) selenomethionine (SeMet);
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(5) chemical nano-Se (Nano-Se). Wheat seeds were sown about 3.0 cm deep in
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November 2013 and harvested in June 2014. The maize seeds were sown just one
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week after the harvest of wheat and maize crops were harvested in September 2014.
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Foliar Se fertilizers were applied both at the flowering stage of wheat in April 2014
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and at the bell stage of maize in August 2014. The application rates were 30 g Se ha−1
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and 60 g Se ha−1 for wheat and maize, respectively. Foliar Se fertilizer was applied
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with a motorized backpack sprayer. Analytical reagents of Se were dissolved in water
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and the solutions were applied at a rate of 400 L ha−1. The plot size was 50 m2 with a
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1 m long buffer zone on each side. The Se reagents (Na2SeO3 and Na2SeO4) were
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obtained from Sigma (St Louis, MO, USA); SeMet was provided by Shanxi
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University. Chemical nano-Se was prepared using the method described by Lin and
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Wang (2005)
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were dissolved into deionized water, assuring the final the concentrations of those
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reagents were 5 mM, 20 mM, 10 mM and 10 mM respectively. Suspended nano-Se
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particles form from these solutions after each reaction proceeds for a sufficient time (6
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h). The sizes distributing within the selenium nanoparticle dispersion were measured
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by transmission electron microscopy (TEM-EDAX, Hitachi HT7700, Japan). The
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particle size was 142.8 ± 9.1 nm.
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. In brief, Na2SeO3, Na2S2O3·5H2O, lauryl sodium sulfate and HCl
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The aim of Experiment 2 was to examine the residual effect of Se applied in
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2014 on the wheat and maize planted in 2015 (no Se application in 2015) and to test
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the effect of Se in combination with other fertilizers. Four treatments were arranged in
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the this experiment, including control (water), humic acid (without Se), humic acid +
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sodium selenite and compound fertilizer + sodium selenite, which are referred to as
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CK, HA, HA+SeIV and CF+SeIV, respectively. The planting method, Se application
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time, Se dosage and frequency were all the same as in Experiment 1. After the harvest
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of maize, wheat seeds were sown in November 2014 and harvested in June 2015, just
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one week after the harvest of wheat; then maize crops were harvested in September
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2015. The HA, HA+SeIV and CF+SeIV fertilizer were provided by Sino International
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Ltd (Hong Kong, China). The effective components in the liquid compound fertilizer
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were humic acid ≥ 4.0% and N+P2O5+K2O ≥ 20%.
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Sample and analysis
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For the calculation of yield, all the above-ground plants in 7.5 m2 of each plot
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were entirely collected and divided into unpolished grain, husk, straw or cob at the
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mature stage. The yield of every part of the plant was weighed, calculated and
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expressed in ton per hectare (t ha−1).
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For the determination of elements in wheat and maize, five samples of plants
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(divided into straw, grain, husk or cob and root) and the corresponding rhizosphere
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soil samples (0−20cm) were collected in an S shape from each plot. Plant samples
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were rinsed with deionized water, dried at 105℃ for 30 min and then at 75℃ for 48
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h. All dried soil and plant samples were sieved to
