Long‐Term Effects of Manure, Fertilizer, and Plow Depth on Chemical Properties of Soils and Nutrient Movement in a Monoculture Corn System

Abstract

AbstractAn evaluation of soil chemical properties, organic matter and nutrient accumulations, and nutrient movement and recovery after 6 and 9 years of annual fertilizer and manure applications to continuous corn (Zea mays L.) was conducted on two soil types (Conover‐Hodunk loam and Metea sandy loam). Plow depths of 18 versus 30 cm had little or no effect on soil test values or nutrient accumulation patterns in the surface of a Conover‐Hodunk loam soil. The pH value of both soils decreased slightly more than 0.1 pH unit per year with the annual application of 168 kg of N/ha as ammonium sulfate.Soil organic matter, available P, and exchangeable K, Ca, and Mg increased with increasing rates of manure. The organic matter content of the Metea sandy loam soil increased about 0.1% each year by the yearly application of 67.2 metric tons/ha (fresh wt.) cattle manure. The differential removal of nutrients by grain and silage had no effect on soil available P. Soil test changes for K, Ca, and Mg were proportional to the net addition of each nutrient; but less than 30% of the net nutrients added could be accounted for in surface samples from the silage area where 67.2 tons of manure was annually applied.The most favorable rate of manure for the Metea sandy loam soil was found to be 22.4 metric tons/ha (10 tons/acre). Larger applications caused a significant buildup of exchangeable K in the surface and subsurface horizons and resulted in inefficient use of all nutrients. The K buildup was less critical on the loam soil or where silage rather than grain was removed.