This USDA study compared the profitability of moldboard plow, chisel plow, and no-tillage with or without composted animal manure in a corn/soybean/wheat/clover rotation over three rotation cycles. Compost amendments increased corn, soybean, wheat and seed yields by 4-8% and increased overall profitability by 5-15% across all tillage systems compared to manure treatments.
This study found that incorporating compost over a 2-year period positively affected the structure, porosity, water holding capacity, compression strength, nutrient content, pH and organic matter content of the soil, which resulted in improved plant growth, crop yield and quality for the crops being studied.
This Southern Illinois University Agricultural Science Research Facility study compared the effect of using compost amended fertilizer treatments with Drip Irrigation Circuit Design and Lateral Lines Lengths on water use efficiency (WUE), and fertilizer use efficiency (FUE) on corn. In compost amended trials, corn yield increased by 10%, stover yield by 6%, WUE by 10% and FUE increased by 10% (N), 10% (P) and 5% (K) compared to fertilizer only plots.
This 2-year study showed that annual compost applications increased soil organic matter, promoted aggregation of fine soil particles, lowered soil bulk density and increased the water holding capacity of the soil from 1.3 to 1.9 inches of water in the plow layer (equivalent to a two week water supply). In addition, they found that annual amendments of compost sustained higher yields of most vegetables when compared to unamended soil and reduced fertilizer needs by 1/3 and 2/3 the normal rate.
The results of this study indicate that compost amended soils exhibited higher potential denitrification rates, greater denitrification efficiency, higher organic matter, and greater microbial activity while reducing harmful nitrate leaching by 5 times compared to the conventionally farmed soils.
The results of this study determined that humic acids extracted from vermicomposts significantly increased the plant heights, leaf areas, shoot dry weights, root dry weights of peppers, tomatoes and marigolds and numbers of fruits of strawberries.
When compost was added to a sandy or clayey soil, the bulk density of each soil was reduced proportionally to the rate of compost addition. Adding 25 percent compost to a sandy or clayey soil increased the cation exchange capacity 500 to 600 percent. At an optimum level of saturation, the increased cation exchange capacities would increase the soils ability to hold potassium (from 195 to 1,014 pounds per acre), calcium (from 1,200 to 6,240 pounds per acre), and magnesium (180 to 936 pounds per acre ) in a plant-available form. Consequently, the soils’ structure, tilth, moisture retention capacity, and the water infiltration rate of the clay soil were improved. Compaction and crusting were reduced.
This 6-year Illinois study compared continuous corn (CC) vs. a soybean–corn (SC) rotation at six N fertilizer rates. Averaged across all years, yield at the agronomic optimum N rate for CC was 8.84 Mg ha–1 and for SC was 10.20 Mg ha–1, resulting in a CCYP of 1.36 Mg ha–1 (~39 bu/acre); values ranged yearly from 0.47 to 2.23 Mg ha–1.
This study determined that high-quality compost significantly suppressed Pythium and Rhizoctonia soil diseases and induced systemic resistance (ISR) to soil diseases even after 1-year from its application.
This 4-year USDA study at the Iowa State University Research Farm in Boone, Iowa determined that corn and soybean producers enhanced soil organic matter and crop yields by 9 – 11% with multiple compost applications and eliminated yield differences between conventional and no-till systems.
This 12-year study found (1) Soils containing <2% organic matter benefit from management strategies designed to increase organic matter. (2) Compost treatments increased organic carbon (C), total nitrogen (N), microbial activity, nutrient cycling and crop growth.(3) Compost + N fertilizers increased corn yields by 10% compared to fertilizer only treatment.
This 6-year study found no significant differences in yields of maize and alfalfa between nitrogen (N) treatments but the manure treatments had 57% higher nitrate (NO3) leaching compared to compost.
The results of this study showed that corn inoculated with AMF increased drought tolerance, nutrient uptake, above ground biomass yields and grain yields.
The results of this study showed high-quality compost applications increased nutrient uptake, plant dry weight and tomato yield by 20% while reducing the incidence of root rot by 32% compared to N, P, K treatment.