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Data were collected from the research garden at the University of St. Thomas in Saint Paul, Minnesota (44.93833°N, 93.19620°W) between 2017-2021. 32 replicated 4-meter-squared plots received one of six soil amendment treatments:

(1) a low level of municipal compost (mixture of food waste, yard waste, and other municipal organics wastes) based on estimated crop P demand, supplemented with inorganic N fertilizer

to meet estimated crop N demand (“Municipal_P”);

(2) a high level of municipal compost based on estimated crop N demand (“Municipal_N”);

(3) a low level of manure compost based on estimated crop P demand, supplemented with inorganic N fertilizer to meet estimated crop N demand (“Manure_P”);

(4) a high level of manure compost based on estimated crop N demand (“Manure N”);

(5) inorganic N and P corresponding to estimated crop N and P demand (“Synthetic”);

(6) a control treatment with no fertilizer application (“No_fertilizer”).

Compost application rate to fulfill crop N or P demand was determined according to Shrestha et al. (2020).

Compost application rates to fulfill crop N or P demand were determined from Shrestha et al. (2020).

Plots were subdivided into 1-square-meter subplots, each with a different crop variety representing four different plant families: bell peppers (Solanaceae); bush beans (Fabaceae); carrots (Apiaceae); and cabbage (2017) or collard greens (2018-2021) (Brassicaceae). Crops were rotated among subplots annually in a clockwise direction. Seeds or seedlings were planted between 24 May and 1 June each year. We used X3R Red Knight (F1) pepper seeds, E-X Pick Organic bean seeds, Nectar Organic Pelleted (F1) carrot seed, Omero (F1) cabbage seed, and Flask collard seeds, purchased from Johnny’s Selected Seeds. Peppers, beans, cabbages and collards were started in a greenhouse and transplanted after reaching a height of approximately 10 cm. Carrots were planted directly from seed. Peppers were planted in two rows of three (6 plants/m^2 ), beans in two rows of six (12 plants/m^2 ), cabbages/collards in two rows of three (6 plants/m^2 ), and carrots in three rows of twenty (60 plants/m^2 ). Any seedlings that died during the first two weeks of each growing season were replaced. Plots were regularly weeded and received ambient rainfall and supplemental irrigation (equal amounts across all pots) as needed depending on antecedent rainfall conditions.

==================== Data Sources =========================

Henriksen, A., and A. R. Selmer-Olsen. 1970. Automatic methods for determining nitrate and nitrite in water and soil extracts. Analyst 95:514-518. RFA Methodology. 1986. Ammonia Nitrogen A303-S171. Astoria-Pacific International PO Box 830, Clackamas, OR 97015.

Shrestha, P., G. E. Small, and A. Kay. 2020. Quantifying nutrient recovery efficiency and loss fromcompost-based urban agriculture. PLoS ONE 15(4): e0230996. https://doi.org/10.1371/journal.pone.0230996

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Meteorological data was collected at hourly intervals beginning in June 2017. Rainfall was measured using an ECRN-50 rain gauge (Part # 40,655, METER); solar radiation was measured using a PAR sensor (Part # 40,003, METER); temperature and relative humidity were measured using a VP-4 sensor (Part #40,023, METER); and wind speed was measured using a Davis Cup anemometer (Part # 40,030, METER). Data was recorded using an Em50 data logger (Part 40,800, METER). Leachate flux was measured in the center of this plot (Plot 9, no_fertilizer treatment) using a Drain Gauge G3 closed-wick lysimeter with stainless steel divergence control tube, and a CTD-10 probe measuring electrical conductivity, temperature, and depth of water in the lysimeter. Water was manually pumped out of this lysimeter at approximately 1-month intervals. Volume of supplemental irrigation was also estimated, by measuring the time required to fill up a 12 L bucket. All study plots were then watered evenly for a set amount of time (typically 45 seconds), and the volume of water and rainfall-equivalent depth of irrigation were calculated.

In May 2021, HydraProbe soil moisture sensors (Stevens) were installed at depths of 10 cm, 20 cm, and 30 cm, in plot 17a (No_fertilizer), plot 21a (Municipal_P), and plot 22a (Manure_N). Soil moisture and temperature data are recorded hourly. Soil moisture measurements have an accuracy of ± 0.01 WFV, and temperature measurements have a resolution of ± 0.3 degrees C.

From July-September, crops were harvested each week, and the wet mass of plant material harvested from each subplot was measured using a portable electronic balance and recorded. Weekly totals were added to obtain seasonal yields (g wet mass/m2/year).

At the start of the experiment, lysimeters were installed in the center of each subplot at a depth of 0.4 m for leachate water collection. Lysimeters were custom-built and consisted of a 23-cm diameter (0.0129 m2 ) plastic funnel in 2017, and 11.8 cm (0.0109 m2 ) plastic funnel for 2018-2021, secured to a 1 L wide mouth plastic Nalgene bottle. Tygon tubing (inside diameter of 0.2 cm) extended from the base of the Nalgene bottle through the funnel, extending above the soil surface. Rock wool was placed in the funnel around the tubing to exclude soil particles from entering the bottle. Lysimeters were originally installed in all 128 subplots and five adjacent reference turfgrass plots in 2017, and all were replaced in 2018 and 2019. Lysimeters were not replaced in 2020 or 2021, except for several with missing tubing. Leachate water was collected from each lysimeter each week from June-October, using a polypropylene

syringe. The total volume of water removed from each bottle was recorded, and a subsample was saved in a 20 mL plastic scintillation vial for nutrient analysis. Leachate PO 4 -P was analyzed using a Hannah Instruments Phosphate Low Range Portable Photometer (HI96713) with a resolution of 0.01 mg/L. Samples were diluted (typically 1:10) with de-ionized water to bring water samples into the range of 0.00-2.50 mg/L. Concentrations of NO 3 -N and NH 4 -N were measured using a YSI Pro Plus Multiparameter Instrument with nitrate (YSI 605106) and ammonium (YSI 605104) ion selective electrodes. Standard curves were created using six standards between 0-1000 mg/L NO 3 -N and 0-1000 mg/L NH 4 -N.

In 2017, composite soil samples were collected before soil amendment treatments were initially applied (27 May 2017), and soil samples were collected from each A subplot at the end of the first growing season (20 October 2017). From 2018-2021, composite soil samples were collected from the A subplot of all replicates of each soil amendment treatment every two weeks during the growing season (June-

October). Soil samples were analyzed at the University of Minnesota Research Analytical Laboratory for pH, organic matter, Bray-1 extractable P, NH 4 OAc-K, NO 3 -N, and NH 4 -N. Soil pH is determined based on a 1:1 (V/V) soil/water mixture, stirred and equilibrated for 15 minutes, with pH measured using a Mettler Toledo Seven-Multi pH meter with InLab Routine Pro combination electrode, calibrated to buffers 4, 7, and 10.

Organic matter is measured using the loss-on-ignition method, in which a volumetric scoop is dried for 2 h at 105°C, weighed, and then ashed for 2 hours at 360°C and reweighed. Bray-1 extractable phosphorus was measured by extracting P by shaking 1 g of air-dried soil in 10 mL of 0.025 M HCl and 0.03 M NH4F for 5 minutes. Samples were filtered and filtrate was measured colorometrically using the molybdate blue method using ascorbic acid as a reductant (Frank et al. 1998). Available potassium is extracted from 1 g air-dried soil using 1 M NH4OAc, shaking for 5 minutes. The sample is filtered and analyzed by atomic emission in a Perkin Elmer Analyst 100 spectrometer.

Nitrate is extracted by shaking 2 g of air-dried soil in 30 mL CaSO4 for 15 minutes followed by filtration.

The nitrate in the filtrate is measured on a Lachat Quikchem 8500 Flow Injection Analyzer following the cadmium-reduction method described by Henriksen and Selmer-Olsen (1970).

Ammonium is extracted by shaking 2 g of moist soil with 30 mL of 2 M KCl for 30 min. The extract is analyzed on a Lachat QuikChem 8500 Flow Injection Analyzer, with ammonium reacting with salicylate in the presence of a nitroprusside catalyst (RFA Methodology 1986).

==================== Data Sources =========================

Frank, K., D. Beagle, and J. Denning. Phosphorus. P. 21-29 in Recommended Chemical Soil Test Procedures for the North Central Region. North Central Regional Research Publication No. 221 (Revised). Jan. 1998. Missouri Agricultural Experiment Station SB 1001.

RFA Methodology.1986. Ammonia Nitrogen A303-S171. Astoria-Pacific International PO Box 830, Clackamas, OR 97015.

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