| Abstrakt: |
A 2‐year field experiment was conducted to study the effects of salt (0.2 and 0.5%) in swine rations, liquid waste handling systems (aerobic and anaerobic), and application rates on the recycling of swine wastes to Fox silt loam and Chalmers silt loam soils cropped to corn (Zea maysL.). Liquid swine waste (1.8 to 3.0% dry matter) was applied annually at rates of 45, 90, and 134 metric tons/ha. The high rate provided an average of 378 kg N, 113 kg P, 163 kg K, and 42 kg Na per ha. Check and inorganic fertilizer (168 kg N/ha, 56 kg P/ha, 112 kg K/ha) treatments were included. Soil Na, nitrate N, and extractable P concentrations increased with increasing waste application rates. Soil electrical conductivity was not affected by waste application rate. The effects of dietary salt levels and waste handling systems on the chemical composition of the soils were inconsistent. There was evidence for downward movement of Na, K, and NO3−in the soil profile of plots receiving waste and fertilizer. Downward movement of NO3−was observed to a greater extent in fertilizer‐treated plots than in waste‐treated plots. Under climatic conditions prevailing in this study, 2 years of waste application had no detrimental effects on the chemical composition of the two silt loam soils. Soil application of waste resulting from different dietary salt levels and waste handling systems resulted in similar corn yields and leaf chemical composition. Yields were higher from plots treated with waste and inorganic fertilizer compared to the check plot. Corn yields increased with increasing rates of waste application up to the 90‐metric tons/ha rate, then leveled off. Nitrogen, P, and K concentrations in corn ear leaf tissue increased with increasing waste applications. |
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