Comparison of Solid vs. Liquid Dairy Manure Applications on Corn Yield and Soil Composition

Abstract

AbstractA 6‐yr field experiment was conducted to determine the effects of liquid and solid dairy (Bos taurus) manure applications on a Crosby silt loam (Aerie Ochraqualfs) soil cropped to corn (Zea mays L.). Liquid manure at rates of 112, 224, and 336 Mg ha−1 and solid manure at rates of 34, 67, and 101 Mg ha−1 were spread annually for 5 yr. No manure was applied the 6th yr, but the soil was cropped to determine residual nutrient effects. Check and inorganic fertilizer treatments were also included in the study. Manure addition increased corn yields when compared to the check (no fertilizer). There were variable weather conditions and nutrient concentrations of the manure sources, and the manure application rates were relatively high. Corn yields were as great or greater from plots supplied with manure and manure slurries as those supplied with commercial fertilizer. Over the 5 yr of manure application, the 224 Mg ha−1 rate of liquid manure and the 67 Mg ha− rate of solid manure results in maximum corn yields that were 1% higher than commercial fertilizer. Accumulations of nutrients in the soil from high liquid manure application rates (224 and 336 Mg ha−1) increased corn yields during the residual cropping year. Corn leaf N and P concentrations tended to reflect N and P rates applied with the manures and the fertilizer treatment compared to the check, but not consistently each year. Source of manure had little affect on corn leaf composition. Soil P, K, and Na increased with each additional year of manure application and tended to increase with higher application rates. Extractable P accumulated in the upper profile of soil, whereas exchangeable K and Na increased at lower depths in the soil profile, especially with the highest manure application rates. Based on this study, both solid and liquid dairy manures are valuable sources of nutrients for corn production; however, they are less efficient than commercial fertilizers when comparing equivalent nutrient levels and when they are applied to the soil surface. Excessive application of either manure source causes potential for considerable groundwater pollution.