Document Type

Article

Domestic/International

Domestic

Location

New London, CT USA

Publication Date

2026

Abstract

Six years of management have left measurably different soils across Sprout Garden's six rotation plots, and crops grown in those soils respond differently. Since 2019, Sprout, Connecticut College's student-run farm, has rotated brassicas, potatoes and sweet potatoes, alliums, the three sisters, and solanaceous crops through six plots, combined with cover cropping, leaf mulch, tarping, and compost. We wanted to understand how these practices have shaped soil biological activity, nutrient availability, and the ability of plants to access those nutrients. We sampled 36 beds (six per plot) and measured soil respiration by CO2 accumulation in sealed jars, soil moisture, available nitrate, permanganate-oxidizable (active) carbon, and pH. We then grew six crops (corn, kale, lettuce, tomato, watermelon, and chives) in soil from each plot, with eight replicates each (288 pots), and measured leaf chlorophyll (SPAD) at four weeks and dry biomass at harvest. Soil respiration and active carbon differed among plots (p < 0.05). Plot 1 had more than twice the respiration of Plot 2 (about 1,300 vs. 590 ppm CO2 per day), and Plot 2 had the lowest active carbon. Plants grown in Plot 1 soil had the highest chlorophyll readings for four of the five crops we measured, and the plot effect on SPAD was significant (p < 0.001). Biomass differed less among plots (p = 0.035). These results suggest that biological activity, more than nitrate alone, may shape how well crops access nitrogen at Sprout. They also show that simple, low-cost methods can give a farm useful information on its soils.

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The views expressed in this paper are solely those of the author.