Human Urine as a Fertilizer in the Cultivation of Snap Beans

Dec 4, 2018 - Accordingly, the goal of this research was to compare human urine fertilizer and synthetic fertilizer in the cultivation of snap beans a...
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Agricultural and Environmental Chemistry

Human Urine as a Fertilizer in the Cultivation of Snap Beans (Phaseolus vulgaris) and Turnips (Brassica rapa) Madelyn Pandorf, George Hochmuth, and Treavor H Boyer J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b06011 • Publication Date (Web): 04 Dec 2018 Downloaded from http://pubs.acs.org on December 9, 2018

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Human Urine as a Fertilizer in the Cultivation of Snap Beans (Phaseolus vulgaris) and Turnips (Brassica rapa) Madelyn Pandorfa,b*, George Hochmuthc, and Treavor H. Boyera aSchool

of Sustainable Engineering and the Built Environment (SSEBE) Arizona State University P.O. Box 873005, Tempe, Arizona, 85287-3005, USA bDepartment

of Environmental Engineering Sciences Engineering School of Sustainable Infrastructure & Environment (ESSIE) University of Florida P.O. Box 116450, Gainesville, Florida 32611-6450, USA cDepartment

of Soil and Water Sciences Institute of Food and Agricultural Sciences (IFAS) University of Florida P.O. Box 116450, Gainesville, Florida 32611-6450, USA *Corresponding author. Tel.: 1-727-417-3764. E-mail addresses [email protected] (M. Pandorf).

Submitted to Journal of Agricultural and Food Chemistry 27 November 2018

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Abstract

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The main reason for implementing human urine diversion is to produce a local and renewable

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source of fertilizer for agriculture. Accordingly, the goal of this research was to compare human

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urine fertilizer and synthetic fertilizer in the cultivation of snap beans and turnips by evaluating

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the yield, plant tissue chemical composition, nutrient uptake efficiency, soil nutrient content, and

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leachate nutrient content between plots. Four fertilizer treatments were evaluated: 1) synthetic

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fertilizer, 2) urine supplemented with synthetic fertilizer, 3) urine-only, and 4) a no-fertilizer

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control, referred to as treatments 1, 2, 3, and 4, respectively. Plants fertilized by treatments 1 and

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2 produced the highest yield for fall turnips and spring snap beans. The turnip yield for the urine-

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only treatment was significantly higher than the no-fertilizer control. Overall, the results showed

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that supplemented urine fertilizer can be used as an alternative to synthetic fertilizer with

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comparable yields, and urine-only fertilizer can significantly increase yields over the no-fertilizer

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control. The results also suggest that nutrients in urine are available in a form favorable for plant

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uptake.

15 16 17 18 19 20 21 22 23

Keywords: human urine fertilizer, leachate, lettuce, snap beans

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1. Introduction

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Agriculture has become increasingly dependent on synthetically derived fertilizers, and has in

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turn created a burden on Earth’s non-renewable resources, such as phosphate rock and natural

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gas.1-4 Synthetic fertilizer production has a high energy demand of 78,230, 17,500, and 13,800 kJ

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of energy per kg of nitrogen, mined phosphate rock, and potash fertilizer produced,

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respectively.1, 5 Fertilizer demands will continue to rise with the growing populations and

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increased need of food production. The Food and Agriculture Organization of the United Nations

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has predicted that nitrogen (N), phosphorus (P), and potassium (K) demands, collectively known

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as NPK, will increase by 1.5, 2.2, and 2.4% per year through 2020.6 The current conventional

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agriculture system requires synthetic fertilizer inputs to grow crops, which are then consumed by

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animals and humans with excretion of excess nutrients. The use of alternative fertilizers and soil

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amendments such as animal waste is well established. However, the use of human waste as a

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fertilizer is more complicated as illustrated by varying policies on the land application of

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wastewater biosolids.2, 7

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Urine diversion takes a different approach where urine can be applied directly as an alternative to

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synthetic fertilizer. The composition of urine partially fulfills the primary macronutrients needed

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to grow plants (i.e., N, P, and K). Urine has high concentrations of nitrogen, and when used as an

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N fertilizer would reduce the need for the Haber Bosch process. Therefore, reducing the energy

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demand, fossil fuel consumption, and greenhouse gas emissions associated with N fixation for

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synthetic fertilizers. Additional benefits of urine diversion include potable water savings due to

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reduced toilet and urinal flushing, and a decreased load of N and P to wastewater treatment

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plants thereby decreasing energy requirements for operation.8-10 A survey in Switzerland showed

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42% of farmers were willing to purchase a urine-derived fertilizer product, implying it could be

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an acceptable alternative to synthetic fertilizer.11 Urine-derived fertilizer could also have

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significant implications in areas where there is limited access to affordable synthetic fertilizer or

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waste disposal issues, such as in developing countries.12-13

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Urine has been used to effectively grow a variety of crops around the world, primarily in

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Northern Europe and Africa, see Table 1. Applying urine as a liquid fertilizer resulted in higher

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yields of cucumber, cabbage, and amaranth, compared to synthetic fertilizer, indicating urine can

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provide plants with essential nutrients.14-16 The high concentration of N in urine can allow for

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adequate crop growth; however, a limitation of urine is the low concentrations of P and K, other

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key macronutrients. Therefore, several studies have investigated supplementing urine with

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different materials such as wood ash, gypsum, compost, humanure (human waste), and poultry

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manure to supply the plant with nutrients that urine is lacking.13, 19-22 Liquid urine was combined

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with wood ash to provide P, K, calcium, and magnesium and resulted in a higher yield for red

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beets with supplemented urine compared to urine only and synthetic fertilizer.17 Pradhan et al.,

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compared three treatments, urine with wood ash, animal manure, and a no-fertilizer control with

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supplemented urine producing the highest yields for radish, mustard, cauliflower, and cabbage.18

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A field experiment in Nigeria investigated urine combined with different ratios of compost to

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grow amaranths and found urine-only fertilizer to outperform the compost combinations and the

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synthetic fertilizer considering the nutrients in urine are readily available to the plant.16 Fewer

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studies have investigated combining urine with synthetic P and K fertilizers. Germer et al.,

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combined urine with triple super phosphate and potassium chloride to grow sorghum and

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concluded that this combination can fully substitute the synthetic N fertilizer needs of the plant.19

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Experiments using urine as a liquid fertilizer have been conducted in many regions of the world

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which are highlighted in the EcoSans Series Report and Table 1.13 However, the performance of

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urine can be dictated by the soil composition and crop, making it important to assess urine

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fertilizer under a variety crops and soil types.13

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A salt tolerant crop was desired due to the elevated levels of sodium and chloride found naturally

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in urine. Snap beans and turnips were chosen as viable salt tolerant crops that have not been

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previously investigated using urine fertilizer (Table 1).13 The gap in knowledge concerning urine

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application as a liquid fertilizer is that there are no published studies conducted in the United

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States. Furthermore, many urine studies have been conducted using pot experiments or

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greenhouses and are lacking both a positive (synthetic fertilizer) and negative (no fertilizer)

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control.13 The EcoSanRes report highlights a wide range of studies that have used urine as a

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liquid fertilizer, e.g., greenhouse studies in South Africa to grow beetroot, cabbage, carrot,

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maize, spinach, and tomato.13, 20-22 Studies from different countries are important to show that

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urine can be used effectively in different soil types and climates. In addition, studies from

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different countries raise awareness in the agriculture community that urine fertilizer can be an

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alternative to synthetic fertilizers with comparable yields. There is sparse previous research that

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has supplemented urine to meet the N, P, and K requirements for plant growth to fully satisfy the

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nutrient demands of the plant. Furthermore, previous studies did not include tissue data, soil

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analysis, and leachate composition to compute nutrient uptake efficiency. Studies have used

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lysimeters to collect leachate and evaluate different nutrient leaching rates from synthetic

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fertilizers; however, leachate data from urine is scarce. To date only one study has evaluated the

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nutrient leaching rate using cow urine as a liquid fertilizer.23

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The goal of this study was to compare snap bean and turnip cultivation under three fertilizer

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treatments of synthetic fertilizer, urine supplemented with synthetic fertilizer (U + Syn), and

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urine-only fertilizer. The specific objectives of this study were to (i) determine the effectiveness

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of urine as a liquid fertilizer by comparing yields of snap beans and turnips over two growing

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seasons; (ii) analyze the plant tissue chemical composition to compare the nutrient content and

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uptake efficiency between treatments; (iii) analyze soil samples to assess nutrient build up

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between treatments; and (iv) compare the nutrient leaching rates between treatments.

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2. Materials and Methods

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Planting provisions and field setup

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Snap bean (Phaseolus vulgaris var. Roma II) (Alachua Farm and Lumber, Gainesville, FL) and

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turnip (Brassica rapa var. Purple Top White Globe) (Alachua Farm and Lumber, Gainesville,

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FL) were sown in a plot at the University of Florida’s Plant Science Research and Education

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Unit in Citra, FL (29°24̍ 21.4̎ N and 82°08̍ 25.5̎ W). Snap beans were planted on August 19,

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2015 (fall) and April 12, 2016 (spring), and turnips were planted on October 29, 2015 (fall) and

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February 16, 2016 (spring). A push planter was used to plant the fall beans and turnips along

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with the spring turnips. A Monosem vacuum planter was used to plant the spring snap beans. The

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average temperature and total monthly rainfall data from the Florida Automated Weather

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Network (FAWN) Citra station are presented for each month (August 2015 to June 2016) in

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Table S1 (Supporting Information (SI)). The four different fertilizer treatments of: synthetic

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fertilizer, urine supplemented with synthetic fertilizer (U + Syn), urine-only, and a no-fertilizer

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control were done in triplicate for each crop. The cultivation area was split into twelve 7.32 m

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(24 ft) by 7.32 m (24 ft) squares. Each square consisted of a different fertilizer treatment in a

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randomized complete block design that was paired with a drainage lysimeter. Within each

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square, only two 7.32 m (24 ft) rows were planted and fertilized directly over the lysimeter

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barrel. The total cultivation area for each crop was 0.016 hectares (0.04 acres or 1728 ft2). A

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schematic of the south half of the field is given in Figure S1 in SI. There were 0.91 m (3 ft)

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buffer zones vertically, and 3.7 m (12 ft) buffer zones horizontally between treatments. The fall

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beans were planted on the south half of the field and the fall turnips were planted on the north

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half. For the spring growing season the setup was reversed but kept the same fertilizer treatment

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locations to mimic a typical crop rotation pattern that may be used by farmers.

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Urine collection and composition

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Urine was collected using source separating collection devices to minimize any cross

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contamination from feces. The urine was stored for a minimum of 1 month at temperatures

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ranging from 14°C to 27°C in 30 and 55-gallon drums (114 L and 208 L) with tight sealing lids.

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All the urine applied as fertilizer had a pH above 9 indicating that it was hydrolyzed. The urine

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was stirred to homogenize the tank contents and then a diaphragm pump was used to transfer the

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necessary amount of urine for fertilization into five-gallon (19 L) jugs.

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The composition of the urine was analyzed for each fertilizer treatment applied with the average

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values reported in Table 2 and details for each trial and dose in Tables S2–S5 in SI. Total dissolved

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N (TDN) was analyzed on the Shimadzu TOC-VCPH/TNM-1 equipped with an ASI-V autosampler.

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The urine was acidified using 12 M hydrochloric acid to a pH ≤ 2 in order to convert all the

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unionized ammonia to aqueous ammonium ions. Ion chromatography (Dionex ICS-3000) was

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used to measure K+, Na+, Ca2+, Mg2+, Cl-, NO3-, and SO42-. Analysis for total dissolved P (TDP)

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followed Standard Method 4500-P using U-2900 UV-visible spectrophotometer (Hitachi High

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Technologies) at a wavelength of 880 nm and a 1 cm quartz cuvette.24 An Orion High-Performance

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Ammonia electrode was used to measure NH3-N following Standard Method 4500-NH3. pH was

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measured using a Fisher Scientific Accumet AP71 meter with pH AP55 electrode. The pH meter

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was calibrated before each use using 4, 7, and 10 buffer solutions. Conductivity was measured

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using an Orion 013005MD Conductivity Cell. All analytical stock solutions were prepared using

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deionized (DI) water and ACS reagent grade purity chemicals. Urine was filtered before testing

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on instruments using a 0.45 μm nylon syringe filter (Environmental Express).

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Fertilizer treatments

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The four fertilizer treatments were: synthetic fertilizer (treatment 1), urine supplemented with

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synthetic fertilizer (U + Syn) (treatment 2), urine-only (treatment 3), and a no-fertilizer control

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(treatment 4). The rate of NPK nutrients for fall beans and turnips were determined using the soil

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sample results for P and K combined with the Vegetable Production Handbook for Florida for

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the amount of N.25 Treatments 1, 2, and 3 were formulated to supply the same amount of N.

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Treatment 2 had ~14% more P than treatment 1 due to the P already in the urine. Treatment 3

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plots purposefully received less P and K due to lower concentrations of both constituents in

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urine. The mineral fertilizer used for the treatment 1 was a blend of ammonium nitrate (30-0-0)

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from Mayo Fertilizer Inc., Live Oak, FL, triple super phosphate (0-46-0), and potassium chloride

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(0-0-62) both from Growers Fertilizer Corporation, Trenton, FL. The parenthesis after each of

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the mineral fertilizers indicates the weight percentage of (N-P2O5-K2O) in each bag of fertilizer,

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e.g. 30-0-0 specifies that the fertilizer bag composition consists of 30% nitrogen by weight. The

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synthetic fertilizers used for the P and K additions for treatment 2 were triple super phosphate

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and potash from Growers Fertilizer Corporation. An application of micronutrients (5% S, 2.4%

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B, 2.4% Cu, 14.4% Fe, 6% Mn, and 5.8% Zn) was added upfront at a dose of 29 kg/ha to

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treatments 1 and 2 for fall and spring beans and turnips. All granular fertilizer was applied by

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hand. Urine was measured in beakers and then poured into watering cans for application. All

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fertilizer was side dressed along each row (approximately 15 cm) on either side. The irrigation

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system was turned on after each fertilization to ensure no burning of the leaves occurred. The

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target fertilizer rates for each season and crop are listed in Table 3. The fall beans were fertilized

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on cultivation days of 0, 30, and 40 after planting at varying rates depending on the fertilizer

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treatment and date (see Table S6 in SI). Fall turnips were fertilized on cultivation days of 0, 25,

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and 59 with details in Table S7 in SI. Spring turnips were fertilized on cultivation days of 0, 35,

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and 57 with details in Table S8 in SI. The spring snap beans were fertilized on the cultivation

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days of 0, 23, and 44 with details in Table S9 in SI. The values of P and K in Tables S6–S9 in SI

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represent P as P2O5 and K as K2O.

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Plant maintenance, tissue analysis, and harvest

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Fall snap beans were irrigated as needed using a water reel sprinkler that watered for

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approximately 1 h each time to replace the amount of water lost by evapotranspiration (ET). Fall

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turnips, spring turnips, and spring beans were all watered with micro-jet sprinklers on 0.30 m (12

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in) stakes twice a day for either 15 or 30 min depending on the time of year and ET. The

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irrigation supply line was placed in the center between the two planted rows with sprayers every

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1.8 m (6 ft). Crop diseases and pests were controlled using recommended herbicides and

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pesticides based on frequent crop scouting.

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Throughout the growing season, whole-leaf samples were taken at different stages of growth to

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determine sufficient nutrient concentrations. Five to eight newly matured leaves were removed

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per row within each plot. The beans had whole-leaf samples taken when the plants were

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flowering and small bean pods were emerging. The turnips had whole-leaf samples pulled after

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the third fertilizer treatment. Whole-plant samples were collected at harvest time for nutrient

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analyses to determine nutrient uptake totals. All whole-leaf and whole-plant samples were dried

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for a minimum of a week at 60°C and then ground using a Thomas Scientific 3383-L10 Wiley

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Mill. The samples were sent to the Analytic Research Laboratory on the campus of University of

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Florida, for analysis of N, P, and K. Total Kjeldahl Nitrogen (TKN) was the form on N analyzed

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for plant tissue.

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Each vegetable crop for both seasons was harvested twice in order to preserve the fully grown

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vegetable while also allowing the smaller developing turnips/beans to keep growing. For

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harvesting, each row within each treatment was marked off in three-foot sections that were a

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minimum of three feet from the end of the row. The same three-foot sections were used for the

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first and second harvest. The beans were removed from the plant and split into marketable and

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culls before getting the fresh weights. The same process took place for the second harvest with

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the addition of all the harvested plants being pulled. After a week in the 60°C drying oven, the

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dry weights of the marketable and cull beans were measured. All the beans from the two harvests

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were then combined and ground in a Wiley mill for nutrient concentrations. The whole plants

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were ground separately for analysis of N, P, and K. For the first harvest of turnips, only the

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turnips with a diameter larger than 6.35 cm were taken. During the second turnip harvest, turnips

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were separated into larger (>6.35 cm) and smaller ( 0.05) for fall snap beans due to the suboptimal growing

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conditions that occurred in the field causing poor snap bean growth. Even though fall beans were

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not statistically significant, both seasons showed a trend of enhanced biomass production with

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the addition of urine fertilizer compared to the control (Table 4). This also implies that extra

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nutrients are still necessary to add even though snap beans can fix their own N from the

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atmosphere. Hochmuth and Hanlon summarized that N, P, and K are all essential to add for

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maximum bean yield as long it is not in excess of the recommended amount based on soil

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sampling.30 The yield results indicate that urine supplemented with P and K could be used as an

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alternative to traditional synthetic fertilizers. Additional research should be conducted to confirm

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this result.

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Turnips received the same amount of N for treatments 1–3 (Tables S7 and S8 in SI). In treatment

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2 urine supplied 100% of the N fertilizer, 19% of P fertilizer, and an average of 25% of the K

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fertilizer. Treatment 1 resulted in the highest yields for fall and treatment 3 for spring. The turnip

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yield was affected by the interaction of treatment and season, and the leaf yield by the main

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effects of season and treatment (Table 5). This interaction can be attributed to plant damage from

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an herbicide in the spring that reduced the plant growth compared to the fall. For the fall turnip

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season, treatments 1 and 2 resulted in higher yields than plants with treatments 3 and 4 (p
11,000 kg/ha and would enhance biomass growth by 143% over no-fertilizer control.

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Additionally, urine-only increased biomass growth by 35% over the no-fertilizer control. In

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studies of cabbage, sorghum, red beet, banana, and maize, urine increased the yield over the no-

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fertilizer control and in some studies outperformed the synthetic fertilizer when supplemented.15,

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17, 19, 31-32

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sensitivity to the ammonium form of N, which is the dominant form of N in urine. Simmone

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found that when ammonium was the dominant N form, the turnip greens showed reduced

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growth.33 Turnips are also moderately sensitive to salinity, which could have had an effect on

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their yield considering urine has an elevated salt content.13, 34 Overall, urine resulted in an

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improved turnip yield over the no-fertilizer control demonstrating that urine is supplying

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essential nutrients for plant growth, and could be used in areas where synthetic fertilizer is not

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accessible or affordable.

In this study, the turnip yield fertilized with urine may have been reduced due to turnip

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Plant tissue chemical composition

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Plant tissue nutrient content between treatments was analyzed to establish the chemical

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composition of the crops at different growth stages and if urine is able to supply adequate

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nutrients. Whole-leaf samples were taken to perform plant diagnostics and assess nutrient uptake

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of N, P, and K (Tables 4-5: Leaf N, P, K). At harvest, whole plant samples were collected for

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crops to evaluate the nutrient content with different fertilizer treatments. The harvest tissue is

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labeled as plant N, P, or K for the whole plant samples without the beans and bean N, P, or K for

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the beans. Harvest turnip tissue is labeled as turnip N, P, or K for marketable turnips (turnip

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diameter > 6.35 cm), tops N, P, or K for marketable leaves (turnip diameter > 6.35 cm), and

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biomass N, P, or K for all turnips combined with leaves that were unmarketable.

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The analysis showed that the whole-leaf snap bean samples taken at the time of flowering

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differed significantly between treatments and seasons for N, P, and K (Table 4). Whole-leaf

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samples were used to asses if the beans were receiving adequate nutrients at the time of

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flowering and initial bean production.35 Table 6 shows that N was adequate/high in fall for

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treatments 1-3 and deficient for all treatments in spring. The bean plants at flowering were

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deficient in P in the fall season and had adequate to high P in the spring season (Table 6).35

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Treatments 1 and 2 had high K at flowering in fall and deficient levels in treatments 1 through 4

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in spring (Table 6).35 However, at time of harvest treatment 1 resulted in the highest N, P, and K

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content in the snap bean pod followed by treatment 2 for both seasons (Table 4). The statistical

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analysis showed the bean and plant N (Table 4) data at time of harvest for treatments 1, 2, and 3

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had resulted in significantly higher N uptake over treatment 4. Treatments 1 and 2 resulted in the

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highest N and K content in the harvest plants and all plants had similar P content (Table 4). The

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higher N and K content with treatments 1 and 2 is most likely due to their larger plant size

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coupled with better overall growth. Similar results for P and K were found in red beets grown

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with synthetic, urine with wood ash, and urine-only fertilizers. K content was highest in the

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synthetic and supplemented urine fertilizers and similar between all treatments for P.17 The

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slightly lower K content in urine fertilized plants could be a result of the high Na concentrations

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in urine causing cation competition between the K and Na.17, 36 A significant increase of K

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uptake considering treatments 1 and 2 had the highest dose of K added and therefore the largest

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uptake. Snap bean tissue was affected by the significant interaction between season and

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treatment for leaf N, P, and K and bean P and K illustrating that the treatments performed

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differently between seasons. Beans in the fall season had increased N uptake in the bean pod,

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while in the spring there was increased plant P and K uptake across all the treatments. There was

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an ample amount of P already in the soil (Table S12 in SI) that resulted in no significant

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difference between treatments for the whole harvest plant P content. Overall, the tissue samples

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showed different patterns of nutrient uptake but in both seasons, treatments 1 and 2 resulted in

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higher nutrient uptake for N and K for the bean and whole plant. This implies that the forms of

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nutrients in urine are favorable for plant uptake, and if supplemented urine were to be used as an

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alternative to synthetic fertilizer the N, P, and K uptake should remain consistent if the urine is

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supplemented to meet plant nutrient requirements.

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The fall and spring turnips had different tissue composition results most likely due to the plant

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damage to the spring crop. Table 7 shows that the fall turnips had adequate to high N, P, and K

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for all treatments in the initial stages of turnip development. However, treatments 2 and 4 were

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deficient in N, and treatments 3 and 4 were deficient in K during turnip development in the

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spring (Table 7). The diagnostic leaf samples showed no significant difference of nutrient uptake

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of N, P, and K between each treatment (Table 5). This trend continued in the harvest tissue

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samples for turnip P and K and tops N, P, and K. In the cultivation of red beets with urine there

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was no significant statistical difference of N content between urine and no fertilizer.17 Treatment

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1 resulted in the highest turnip N content in the fall and treatment 3 had the highest in the spring.

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Increased N uptake in the urine-only treatment in spring could be a function of the herbicide

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damage affecting nutrient uptake and overall growth to the other treatments. This can also be

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seen by the main effects of season on the N, P, and K of the tops, which shows higher nutrient

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absorption in the fall season (Table 5). In a urine application to pumpkin, higher N uptake in

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plant tissue was also observed in the synthetic treatment.29 Lower N uptake in urine fertilized

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plants could be attributed to N loss through volatilization, slower or reduced nitrification due to

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the high chloride content, and salt stress effecting overall growth.29, 34, 37-38 There was

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consistently greater nutrient uptake in fall over spring demonstrating that the herbicide most

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likely had an impact on nutrient content in the spring.

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Nutrient use efficiency

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A nutrient use efficiency (NUE) was calculated using an apparent recovery efficiency by

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difference (RE) approach for N, P, and K for both turnips and snap beans, described in Section

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2.4 using Equation E1.26 The purpose of the NUE was to investigate if urine is supplying

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nutrients in a form that plants can uptake resulting in equal or better nutrient use efficiency

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compared with synthetic nutrient sources. The beans showed a trend of treatment 1 having the

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largest NUE for N in both seasons. The snap beans had improved growth in the spring and

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averaged 30%, 26%, and 9% NUE for N and 26%, 21%, and 20% NUE for K in treatments 1, 2,

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and 3, respectively (Table S11 in SI). The fall turnips had an increased uptake of nutrients over

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the spring crop due to herbicide damage that influenced turnip growth in the spring. The N NUE

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for turnips in the fall was 38%, 21%, and 12% compared with 6%, 4%, and 17% in spring for

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treatments 1, 2, and 3, respectively. Potassium NUE was 38%, 30%, and N/A for fall compared

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to 22%, 12%, and 42% for spring turnips for treatments 1, 2, and 3, respectively (Table S11 in

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SI). It has been reported that the N NUE of cereal crops can range from 40–65% and 30–50% for

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K.26 Common N NUE values for maize, wheat, and rice were 65%, 57%, and 46%,

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respectively.26, 39

415 416

Nutrient uptake efficiency in the urine could have been affected by several factors specific to

417

urine such as its high salt content and volatile form of N coupled with the variability in yield

418

between treatments and season. Ammonia is the prominent form of N in hydrolyzed urine and

419

has been shown to have a lower N uptake compare to nitrate. In a study by Haynes and Goh

420

(1976), it was found that in different types of soils, plants had greater N uptake of nitrate over

421

ammonium.40 Kirchmann and Pettersson (1994) also showed lower N uptake and larger gaseous

422

losses in urine fertilized barley over ammonium nitrate fertilizer.41 Considering the high Na+

423

concentrations in urine, it is possible the plants took up sodium ion over potassium ion due to

424

cation competition as seen in studies growing red beet and tomatoes, and it was suggested as a

425

reason for lower K content in red beet and pumpkin.17, 29, 42 In a study done on the responses of

426

different turnip cultivars to salt stress, it was found that an increased salt level had negative

427

effects on plant growth and reduced the uptake of calcium and K, which is seen when comparing

428

the potassium uptake efficiency for treatments one and two.34 The higher K NUE for spring

429

turnips can be a function of the overall small quantity of K that was applied in combination with

430

high yield results. There was variability between seasons and treatments with nutrients taken up

431

in the tissue changing due to smaller growth and plant damage. Treatments 1 and 2 showed

432

similar N NUE for the spring snap beans. Treatment 1 followed by treatment 2 had the largest N

433

NUE for the fall turnips.

434 435

Residual nutrients in soil

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436

Soil samples were taken before planting and after harvesting to assess for nutrient build up in the

437

soils (Table S12 in SI). Soil testing results showed that the P in the soil before and after

438

cultivation was high for all fall and spring treatments due to the naturally high levels of P found

439

in the soils. For fall beans, the residual left in the soil was evenly distributed between all

440

treatments except for the levels of K and magnesium (Table S12 in SI). The post-harvest K

441

levels for fall beans fell within a medium range in treatments 1 and 2 and very low for treatments

442

3 and 4, indicating a nutrient buildup of K in the soil for treatments 1 and 2. This can be

443

attributed to the higher levels of K additions along with the smaller than average plants

444

throughout the entire field. Treatment 3 did not result in any nutrient buildup considering the

445

only K applied to the soil was the small amount that is naturally in urine. The spring snap beans

446

showed no buildup of nutrients indicating appropriate levels of nutrients were applied to

447

accomplish adequate plant growth and yield. Turnips had relatively consistent levels of nutrients

448

in the soil between treatments (Table S12 in SI). The constant levels of low K for pre and post-

449

harvest samples indicated that there was little to no nutrient loading across all treatments. In

450

urine fertilizer application of red beet, pumpkin, and spinach it was also found that soil

451

conditions were similar between treatments.17, 22, 29 In general, there was minimal nutrient

452

loading for all treatments, which is important in order to avoid nutrient leaching and loss to the

453

environment.

454 455

Leachate composition

456

Leachate was collected biweekly or as needed depending on rainfall events. Figure 2 shows an

457

average cumulative leaching of N and K between replicates with Tables S13–S16 in SI showing

458

averages by collection date for all components analyzed. There was variability between averages

21 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

459

and treatments due to functionality of the lysimeters and fall data was not included due to

460

lysimeter performance. Potassium followed the expected trend of treatments 1 and 2 having a

461

higher amount of K leaching considering they received the two largest doses of K through

462

fertilization. This is consistent with a study done using lysimeters that looked at cow urine

463

combined with synthetic fertilizers in which they found higher K leaching in the supplemented

464

urine over the no-fertilizer control.23 Naturally occurring N easily leached due to the sandy

465

nature of the soil seen in the no treatment for both bean and turnips (Figure 2). There have been

466

studies investigating the effect of cow urine on nitrogen leaching, but none to the authors’

467

knowledge observing leaching effects of human urine, which has a significantly higher

468

concentration of N compared to cow urine.23, 43-44 This data has an important contribution,

469

considering there is very limited published data on leachate for urine fertilizer studies.

470 471

Implications

472

Urine can have a significant impact as an alternative fertilizer through energy and water savings

473

along with sanitation improvements; however, investigation of pharmaceutical removal and

474

sustainable options to supplement urine are still needed. The removal of pharmaceuticals from

475

urine is an important aspect that was not considered in this study. Ion exchange resins and

476

biochar have shown promising results of pharmaceutical removal in human urine; therefore, a

477

comprehensive study using these as a pretreatment and investigating the fate of pharmaceuticals

478

and the effect on crop growth would be valuable.45-46 Additionally, further studies should be

479

conducted testing different urine matrices such as fresh urine compared to a urea synthetic

480

fertilizer accompanied with a comprehensive nutrient balance and leaching study. Agricultural

481

nutrient runoff has significant effects on the surrounding ecosystems; hence, a nutrient leaching

22 ACS Paragon Plus Environment

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Journal of Agricultural and Food Chemistry

482

analysis of different alternative fertilizers can provide insight and motivation for using

483

sustainable fertilizer sources. This research provides evidence from field trails over two growing

484

seasons that urine can be used to grow snap beans and turnips with improved yield over the no -

485

fertilizer control and similar yield between synthetic fertilizer and supplemented urine.

486

Additionally, the plant tissue chemical composition showed that urine can deliver nutrients in an

487

uptake ready form, and can provide sufficient levels of N, P, and K when supplemented.

488

Experiments investigating sustainably sourced options to supplement urine such as gypsum,

489

wood ash, and compost exist, however; additional studies looking at other crops and supplements

490

such as anaerobic digester effluent can further close the nutrient loop.16-18, 32 There is a need for

491

alternative methods of supplementing human urine in combination with understanding the effects

492

of alternative fertilizers on nutrient uptake and leaching through a nutrient balance between the

493

plant tissue, soil, and leached water. Urine can increase the yield of crops, which in turn

494

increases a farmer’s income while also mitigating the environmental effects of synthetic fertilizer

495

production through reduced energy use and greenhouse gas production.

496 497

Abbreviations Used

498 499 500 501 502 503 504 505 506 507 508

U+Syn: human urine supplemented with synthetic fertilizer None: no-fertilizer control N: nitrogen P: phosphorus K: potassium TDN: total dissolved nitrogen TDP: total dissolved phosphorus ET: evapotranspiration NUE: nutrient use efficiency RE: nutrient recovery efficiency by difference

509

23 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

510

Acknowledgements

511

The authors would like to thank Buck Nelson, Mike Holder, and Kevin Guinn at the UF IFAS

512

Plant Science Research and Education Unit, Citra, FL, and Avni Solanki for assisting with the

513

graphic design.

514 515

Funding Sources

516

This publication is based upon work supported by the National Science Foundation, NSF

517

CAREER grant CBET-1150790 and the University Scholars Program at the University of

518

Florida (2015). Any opinions, findings, conclusions or recommendations expressed in this

519

publication are those of the authors and do not necessarily reflect the views of NSF.

520 521

Supporting Information Description

522 523 524 525 526 527 528 529 530 531 532

Description of lysimeter construction and repair Table S1 average monthly temperature and total rainfall for cultivation periods Tables S2-S5 urine compositions of fertilizer applied to fall snap beans, fall turnips, spring turnips, and spring snap beans Tables S6-S9 breakdown of fertilizer treatments by dose for fall snap beans, fall turnips, spring turnips, and spring snap beans Table S10 dimensions of lysimeter Table S11 nutrient mass balance Table S12 soil analysis summary Table S13-S16 summary of leachate collection averages by date and treatment for each component analyzed Figure S1 layout of the field experiments

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References 1. Gellings, C. W.; Parmenter, K. E., Energy efficiency in fertilizer production and use. In Efficient Use and Conservation of Energy, Gellings, C. W., Ed. Eolss Publishers Co. Ltd.: Oxford, United Kingdom, 2016; Vol. II, pp 123-136. 2. Singh, R. P.; Agrawal, M., Potential benefits and risks of land application of sewage sludge. Waste Management 2008, 28 (2), 347-358. 3. Gilbert, N., Environment: the disappearing nutrient. Nature News 2009, 461 (7265), 716718. 4. Filippelli, G. M., Balancing the Global Distribution of Phosphorus With a View Toward Sustainability and Equity. Global Biogeochemical Cycles 2018, 32 (6), 904-908. 5. Helsel, Z. R., Energy and alternatives for fertilizer and pesticide use. Energy in farm production 1992, 6, 177-201. 6. World fertilizer trends and outlook to 2020. Nations, F. a. A. O. o. t. U., Ed. Rome, 2017. 7. Pritchard, D. L.; Penney, N.; McLaughlin, M. J.; Rigby, H.; Schwarz, K., Land application of sewage sludge (biosolids) in Australia: risks to the environment and food crops. Water Science and Technology 2010, 62 (1), 48-57. 8. Larsen, T. A.; Gujer, W., Separate management of anthropogenic nutrient solutions (human urine). Water Science and Technology 1996, 34 (3–4), 87-94. 9. Wilsenach, J.; van Loosdrecht, M., Impact of separate urine collection on wastewater treatment systems. Water Science and Technology 2003, 48 (1), 103-110. 10. Landry, K. A.; Boyer, T. H., Life cycle assessment and costing of urine source separation: Focus on nonsteroidal anti-inflammatory drug removal. Water Research 2016, 105, 487-495. 11. Lienert, J.; Haller, M.; Berner, A.; Stauffacher, M.; Larsen, T. A., How farmers in Switzerland perceive fertilizers from recycled anthropogenic nutrients (urine). Water Science and Technology 2003, 48 (1), 47-56. 12. Winker, M.; Vinneras, B.; Muskolus, A.; Arnold, U.; Clemens, J., Fertiliser products from new sanitation systems: their potential values and risks. Bioresour Technol 2009, 100 (18), 4090-6. 13. Richert, A.; Gensch, R.; Jönsson, H.; Stenström, T. A.; Dagerskog, L., Practical guidance on the use of urine in crop production. SEI: 2010. 14. Heinonen-Tanski, H.; Sjoblom, A.; Fabritius, H.; Karinen, P., Pure human urine is a good fertiliser for cucumbers. Bioresour Technol 2007, 98 (1), 214-217. 15. Pradhan, S. K.; Nerg, A.-M.; Sjöblom, A.; Holopainen, J. K.; Heinonen-Tanski, H., Use of Human Urine Fertilizer in Cultivation of Cabbage (Brassica oleracea)––Impacts on Chemical, Microbial, and Flavor Quality. Journal of Agricultural and Food Chemistry 2007, 55 (21), 86578663. 16. AdeOluwa, O.; Cofie, O., Urine as an alternative fertilizer in agriculture: effects in amaranths (Amaranthus caudatus) production. Renewable Agriculture and Food Systems 2012, 27 (04), 287-294. 17. Pradhan, S. K.; Holopainen, J. K.; Weisell, J.; Heinonen-Tanski, H., Human urine and wood ash as plant nutrients for red beet (Beta vulgaris) cultivation: impacts on yield quality. J Agric Food Chem 2010, 58 (3), 2034-2039. 18. Pradhan, S. K.; Piya, R. C.; Heinonen-Tanski, H., Eco-sanitation and its benefits: an experimental demonstration program to raise awareness in central Nepal. Environment, Development and Sustainability 2011, 13 (3), 507-518. 25 ACS Paragon Plus Environment

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19. Germer, J.; Addai, S.; Sauerborn, J., Response of grain sorghum to fertilisation with human urine. Field Crops Research 2011, 122 (3), 234-241. 20. Mnkeni, P. N. S.; Kutu, F. R.; Muchaonyerwa, P.; Austin, L. M., Evaluation of human urine as a source of nutrients for selected vegetables and maize under tunnel house conditions in the Eastern Cape, South Africa. Waste Management & Research 2008, 26 (2), 132-139. 21. Mnkeni, P.; Austin, A.; Kutu, F. In Preliminary studies on the evaluation of human urine as a source of nutrients for vegetables in the Eastern Cape Province, South Africa, ecological sanitation: a sustainable, integrated solution. Conference documentation of the 3rd international ecological sanitation conference, Durban, South Africa, 2005; pp 418-426. 22. Kutu, F. R.; Muchaonyerwa, P.; Mnkeni, P. N., Complementary nutrient effects of separately collected human faeces and urine on the yield and nutrient uptake of spinach (Spinacia oleracea). Waste Management & Research 2011, 29 (5), 532-539. 23. Hogg, D. E., A lysimeter study of nutrient losses from urine and dung applications on pasture. New Zealand Journal of Experimental Agriculture 1981, 9 (1), 39-46. 24. Agency, U. E. P., Methods for Chemical Analysis of Water and Wastes. EPA‐600/4‐79‐020. Cincinnati, Ohio. 1979. 25. Stephen M. Olson, B. S., Vegetable Production Handbook for Florida. University of Florida, IFAS Extension, Gainesville, FL 2011. 26. Fixen, P.; Brentrup, F.; Bruulsema, T.; Garcia, F.; Norton, R.; Zingore, S., Nutrient/fertilizer use efficiency: measurement, current situation and trends. Managing water and fertilizer for sustainable agricultural intensification 2015, 8-38. 27. Rao Mylavarapu, T. O., Kelly Morgan, George Hochmuth, Vimala Nair, Alan Wright, Extraction of Soil Nutrients Using Mehlich-3 Reagent for Acid-Mineral Soils of Florida. 2014. 28. Båth, B., Field trials using human urine as fertilizer to leeks. Manuscript, Department of Ecology and Plant Production Science, Swedish University of Agricultural Sciences, Uppsala, Sweden 2003. 29. Pradhan, S. K.; Pitkänen, S.; Heinonen-Tanski, H., Fertilizer value of urine in pumpkin (Cucurbita maxima L.) cultivation. Agricultural and Food Science 2009, 18, 57-68. 30. Hochmuth, G. J.; Hanlon, E., A Summary of N, P, and K Research with Snapbean in Florida. University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS: 2000. 31. Sridevi, G.; Srinivasamurthy, C.; Bhaskar, S.; Viswanath, S., Studies on the effect of anthropogenic liquid waste (human urine) on soil properties, growth and yield of maize. Crop Research (Hisar) 2009, 38 (1/3), 11-14. 32. Sridevi, G.; Srinivasamurthy, C.; Bhaskar, S.; Viswanath, S., Evaluation of source separated human urine (ALW) as a source of nutrients for banana cultivation and impact on quality parameter. ARPN J Agric Biol Sci 2009, 4 (5), 44-48. 33. Simonne, E. H.; Smittle, D. A.; Mills, H. A., Turnip growth, leaf yield, and leaf nutrient composition responses to nitrogen forms. Journal of plant nutrition 1993, 16 (12), 2341-2351. 34. Noreen, Z.; Ashraf, M.; Akram, N., Salt‐Induced Regulation of Some Key Antioxidant Enzymes and Physio‐Biochemical Phenomena in Five Diverse Cultivars of Turnip (Brassica rapa L.). Journal of agronomy and crop science 2010, 196 (4), 273-285. 35. G. Hochmuth, D. M., C. Vavrina, E. Hanlon, E. Simonne, Plant Tissue Analysis and Interpretation for Vegetable Crops in Florida.

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36. Pradhan, S. K.; Holopainen, J. K.; Heinonen-Tanski, H., Stored human urine supplemented with wood ash as fertilizer in tomato (Solanum lycopersicum) cultivation and its impacts on fruit yield and quality. J Agric Food Chem 2009, 57 (16), 7612-7617. 37. Kirchmann, H.; Pettersson, S., Human urine - Chemical composition and fertilizer use efficiency. Fertilizer research 1994, 40 (2), 149-154. 38. Rodhe, L.; Richert Stintzing, A.; Steineck, S., Ammonia emissions after application of human urine to a clay soil for barley growth. Nutrient Cycling in Agroecosystems 2004, 68 (2), 191-198. 39. Ladha, J. K.; Pathak, H.; Krupnik, T. J.; Six, J.; van Kessel, C., Efficiency of fertilizer nitrogen in cereal production: retrospects and prospects. Advances in agronomy 2005, 87, 85156. 40. Haynes, R.; Goh, K. M., Ammonium and nitrate nutrition of plants. Biological Reviews 1978, 53 (4), 465-510. 41. Kirchmann, H.; Pettersson, S., Human urine-chemical composition and fertilizer use efficiency. Nutrient Cycling in Agroecosystems 1994, 40 (2), 149-154. 42. Tuna, A. L.; Kaya, C.; Ashraf, M.; Altunlu, H.; Yokas, I.; Yagmur, B., The effects of calcium sulphate on growth, membrane stability and nutrient uptake of tomato plants grown under salt stress. Environmental and Experimental Botany 2007, 59 (2), 173-178. 43. Silva, R. G.; Cameron, K. C.; Di, H. J.; Hendry, T., A lysimeter study of the impact of cow urine, dairy shed euent, and nitrogen fertiliser on nitrate leaching. Soil Research 1999, 37 (2), 357-370. 44. Silva, R. G.; Cameron, K. C.; Di, H. J.; Jorgensen, E. E., A Lysimeter Study to Investigate the Effect of Dairy Effluent and Urea on Cattle Urine n Losses, Plant Uptake and Soil Retention. Water, Air, and Soil Pollution 2005, 164 (1), 57-78. 45. Landry, K. A.; Sun, P.; Huang, C.-H.; Boyer, T. H., Ion-exchange selectivity of diclofenac, ibuprofen, ketoprofen, and naproxen in ureolyzed human urine. Water Research 2015, 68, 510-521. 46. Solanki, A.; Boyer, T. H., Pharmaceutical removal in synthetic human urine using biochar. Environmental Science: Water Research & Technology 2017, 3 (3), 553-565. 47. Heinonen-Tanski, H.; Pradhan, S. K.; Karinen, P., Sustainable Sanitation—A CostEffective Tool to Improve Plant Yields and the Environment. Sustainability 2010, 2 (1), 341353. 48. Amoah, P.; Adamtey, N.; Cofie, O., Effect of Urine, Poultry Manure, and Dewatered Faecal Sludge on Agronomic Characteristics of Cabbage in Accra, Ghana. Resources 2017, 6 (2), 19. 49. Guadarrama, R. O.; Pichardo, N. A.; Morales-Oliver, E. In Urine and Compost Efficiency Applied to Lettuce Cultivation under Greenhouse Conditions, Intemixco, Morelos, Mexico', Proceedings of the First International Conference on Ecological Sanitation, Nanning, China, November 2oo1, 2002. 50. Guzha, E.; Nhapi, I.; Rockstrom, J., An assessment of the effect of human faeces and urine on maize production and water productivity. Physics and Chemistry of the Earth, Parts A/B/C 2005, 30 (11–16), 840-845. 51. Akpan-Idiok, A. U.; Udo, I. A.; Braide, E. I., The use of human urine as an organic fertilizer in the production of okra (Abelmoschus esculentus) in South Eastern Nigeria. Resources, Conservation and Recycling 2012, 62, 14-20.

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52. Pradhan, S. K.; Pitkänen, S.; Heinonen-Tanski, H., Fertilizer value of urine in pumpkin (Cucurbita maxima L.) cultivation. 2010. Figure Captions Figure 1: (a) Fall and spring snap bean marketable yield in kg/ha. (b) Fall and spring turnip marketable yield in kg/ha. None refers to the no fertilizer control. Letters represent ANOVA Fisher’s Least Significant Difference statistical analysis; yields with same letter mean no statistical difference. Figure 2: Nitrogen and potassium leaching for spring snap beans and turnips. Each date represents the average of collectable leachate from each treatment. Snap beans were fertilized on 8/19/2015, 9/18/2015, and 9/28/2015 for fall and 4/12/2016, 5/5/2016, and 5/26/2016 for spring. Turnips were fertilized on 10/29/2015, 11/23/2015, and 12/27/2015 for fall and 2/16/2016, 3/22/2016, and 4/13/2016 for spring. None refers to the no fertilizer control. Tables Table 1: Summary of studies done using urine as a fertilizer, unless specified all yield is given in t/ha. None refers to the no-fertilizer control. Crop Treatments Yield Plot Region Reference t/ha Type Amaranth

Banana

Beetroot

Urine: 100 kg N/ha Urinea: 100 kg N/ha Compost: 100 kg N/ha Mineral: 100 kg N/ha None Urine Urineb Urinec Urined Urinee Urinef Urineg Urineh Mineral None Urine: 50 kg N/ha Urine: 100 kg N/ha Urine: 200 kg N/ha Urine: 400 kg N/ha Urine: 800 kg N/ha None

58.2 33.9 32.5 34.3 23.2 24.9 28.7 27.4 30.0 23.7 24.9 24.9 24.9 28.4 19.9 7.70 g dry/pot 9.50 g dry/pot 9.50 g dry/pot 15.2 g dry/pot 14.4 g dry/pot 7.30 g dry/pot

Field

Nigeria

16

Field

India 13°02'36.1"N 77°30'02.9"E

32

Greenhouse : Pot

S. Africa

20

28 ACS Paragon Plus Environment

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Journal of Agricultural and Food Chemistry

Crop

Treatments

Yield t/ha

Plot Type

Cabbage

Urine: 180 kg N/ha Mineral: 180 kg N/ha None Urine: 121 kg N/ha Urinei: 121 kg N/ha Urinej: 121 kg N/ha NPKi: 121 kg N/ha None Urinek: 78 kg N/ha Manure: 73 kg N/ha None Urinel: 3.6 Urinel: 6.4 Urinel: 9.4 None Urine: 50 kg N/ha Urine: 100 kg N/ha Urine: 200 kg N/ha Urine:400 kg N/ha Urine: 800 kg N/ha None Urinek: 78 kg N/ha Manure: 73 kg N/ha None

83.6 76.5 55.1 19.8 20.9 21.3 21.1 15.6 638 g/plant 359 g/plant 302 g/plant 89 g/pot 68 g/pot 57 g/pot 27 g/pot 1.30 dry g/pot 2.00 dry g/pot 2.00 dry g/pot 1.60 dry g/pot 0.90 dry g/pot 2.20 dry g/pot 638 g/plant 359 g/plant 302 g/plant

Field

Finland 62.9° N 27.7° E

15, 47

Seeded: Greenhouse Moved to field

Ghana 5°36'42.6"N 0°12'21.1"W

48

Field

Nepal 27.72°N 83.89°E

18

Greenhouse : Pot

South Africa

21

Greenhouse : Pot

South Africa

20

Field

Nepal 27.72°N 83.89°E

18

Cucumber

Urine: 233 kg N/ha Mineral: 34 kg N/ha

30.0 25.0

Finland 60°10N 22°24E

14

Leek

Urine: 150 kg N/ha Urinem: 150 kg N/ha Urinen: 150 kg N/ha None Urine: 150 kg N/ha Urinea:150 kg N/ha Compost: 150 kg N/ha None Urine: 50 kg N/ha Urine: 100 kg N/ha Urine: 200 kg N/ha Urine: 400 kg N/ha Urea: 50 kg N/ha Urea: 100 kg N/ha

51.0 54.0 55.0 17.0 1234 g/plot 905 g/plot 1001 g/plot 334 g/plot 252 g/pot 373 g/pot 536 g/pot 520 g/pot 247 g/pot 368 g/pot

Seeded: Greenhouse Moved to field Field

Sweden

13, 28

Greenhouse : Plot

Mexico 25º 10' 8"N 99º 14' 2"W

49

Greenhouse : Pot

S. Africa

20

Cabbage

Cabbage Cabbage

Carrot

Cauliflower

Lettuce

Maize

29 ACS Paragon Plus Environment

Region

Reference

Journal of Agricultural and Food Chemistry

Page 30 of 38

Crop

Treatments

Yield t/ha

Plot Type

Maize

Urea: 200 kg N/ha Urea: 400 kg N/ha None Urine Mineral Humanureo None

446 g/pot 543 g/pot 128 g/pot 2.76 3.31 3.86 1.65

Field

Zimbabwe

50

Urine Urinec Urinep Urineq Urinee Urinef Urineg Urineh Mineral None Urinek: 78 kg N/ha Manure: 73 kg N/ha None Urine: 45.8 kg N/ha Urine: 68.70 kg N/ha Urine: 91.60 kg N/ha Mineral: 60 kg N/ha None Urinek: 49 kg N/ha Manure: 48 kg N/ha None Urine: 113 kg N/ha Mineral: 113 kg N/ha None Urinek: 52 kg N/ha Manure: 50 kg N/ha None Urine: 133 kg N/ha Urinek : 133 kg N/ha Mineral: 133 kg N/ha None Uriner,s Minerals Minerals,t

8.41 8.47 8.80 8.92 7.91 8.67 8.67 8.81 8.80 4.45 371 g/plant 131 g/plant 135 g/plant 23.5 g/plant 26.2 g/plant 33.8 g/plant 31.5 g/plant 16.2 g/plant 300 g/plant 281 g/plant 311 g/plant 17.1 kg/plot 48.4 kg/plot 11.9 kg/plot 657 g/plant 346 g/plant 348 g/plant 17.8 20.5 16.2 3.30 1.83 1.37 1.50

Field

India 13°4'22.6"N and 77°29'43.5"E

31

Field

Nepal 27.72°N 83.89°E

18

Field

Nigeria 5°30ꞌN 8°24ꞌE

51

Field

Nepal 27.72°N 83.89°E

18

Greenhouse : Plots

Finland 62.9°N and 27.7°E

52

Field

Nepal 27.72°N 83.89°E

18

Field

Finland 62°53'39"N and 27° 37'17" E

17

Field

Ghana 5°47'N 0°7'W

19

Maize

Mustard Okra

Potato Pumpkin Radish Red Beet

Sorghum

30 ACS Paragon Plus Environment

Region

Reference

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Journal of Agricultural and Food Chemistry

Crop

Spinach

Spinach

Tomato

Tomato

Treatments

Yield t/ha

Composts,u None Urine: 3.6l Urine: 6.4l Urine: 9.4l None Urine: 200 kg N/ha Urinev: 200 kg N/ha Urinev: 200 kg N/ha Urinev: 200 kg N/ha Urinev: 200 kg N/ha Urinev: 200 kg N/ha Urinev: 200 kg N/ha Urinev: 200 kg N/ha Humanure: 200 kg N/ha Mineral: 200 kg N/ha None Urine: 50 kg N/ha Urine: 100 kg N/ha Urine: 200 kg N/ha Urine: 400 kg N/ha Urea: 50 kg N/ha Urea: 100 kg N/ha Urea: 200 kg N/ha Urea: 400 kg N/ha None Urine: 135 kg N/ha Urinek: 135 kg N/ha Mineral: 135 kg N/ha None

2.34 0.57 56 g/pot 70 g/pot 40 g/pot 18 g/pot 162 g/pot 129 g/pot 139 g/pot 152 g/pot 143 g/pot 170 g/pot 159 g/pot 179 g/pot 123 g/pot 150 g/pot 88.9 g/pot 63.0 g/pot 41.2 g/pot 67.0 g/pot 166 g/pot 43.4 g/pot 58.3 g/pot 113 g/pot 106 g/pot 74.5 g/pot 86.4 79.7 110 20.4

Plot Type

Region

Reference

Greenhouse : Pot

South Africa

21

Greenhouse :pot

South Africa 32°47'9.3"S 26°50'54.8 "E

22

Greenhouse : Pot

S. Africa

20

Greenhouse : Pot

Finland 62.9° N and 27.7° E

36

a: Urine was supplemented with compost b: Urine was applied as fertilizer 30 days after planting c: Urine was supplemented with gypsum d: Urine was supplemented with gypsum and applied 30 days after planting e: 40% of the total recommended nitrogen was through urine and 60% was from urea f: 40% of the total recommended nitrogen was through urine and 60% was from urea with the addition of gypsum g: 60% of the total recommended nitrogen was through urine and 40% was from urea h: 60% of the total recommended nitrogen was through urine and 40% was from urea with the addition of gypsum i: Urine supplemented with dewatered fecal sludge j: Fertilizer supplemented with poultry manure 31 ACS Paragon Plus Environment

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k: Urine was supplemented with wood ash l: Total nitrogen applied is in units of gram of nitrogen added per week to each 10 L pot. Urine was diluted 1:3 m: Urine used as fertilizer every two weeks n: Urine used as fertilizer every two weeks and supplemented with potassium o: Humanure was supplemented with urine p: Urine was split into 6 doses q: Urine was split into 6 doses with the addition of gypsum r: Urine was supplemented with Triple Super Phosphate and Potassium Chloride s: 100 kg/ha of nitrogen was the fertilizer dose the first year, it was then reduced to 50 kg N/ha the other two years t: Water was added to mineral fertilizer dose u: Compost was supplemented with Triple Super Phosphate and Potassium Chloride v: Humanure and urine were combined at different ratios to achieve 200 kg N/ha Table 2: Average urine composition for each crop and growing season Crop

Fall Snap Bean Fall Turnip Spring Snap Bean Spring Turnip

TDN mg N/L 5909 6736 7650 6782

TDP mg PO4-P/L 437 409 478 442

Na mg/L

Ca mg/L

Mg mg/L

K mg/L

Cl mg/L

1897 1754 1878

26 23 12

16 N/A N/A

1961 1927 1475

3089 2888 3019

1481 1613 1505

9.32 9.37 9.22

56 34 40

1768

13

N/A

1631

3014

1559

9.18

40

Table 3: Target fertilizer application rates (kg/ha)a Crop

Season

Snap Bean Turnip Snap Bean Turnip

Fall Fall Spring Spring

a Multiply

N kg/ha 111 133 111 133

P2O5 kg/ha 78 95 0 0

K2O kg/ha 294 227 121 166

by 0.437 to convert from P2O5 to P and 0.833 to convert K2O to K.

32 ACS Paragon Plus Environment

SO4 mg/L

pH

Conductivity mS/cm

Page 33 of 38

Journal of Agricultural and Food Chemistry

Table 4: Summary of significant interactions between season and treatment and significant main effects of season and treatment for snap beans. Means followed by same letter are not significantly different by Fisher’s Protected LSD (0.05). A * indicates means that are significantly different by p < 0.05, and a ** indicates means that are significantly different by p