Effect of Crop Residues on Soil Properties, Plant Growth, and Crop Yield. Agronomy Farm, Lincoln, Nebraska

摘要

Progress is reported in a study designed to evaluate the effects of quantity of crop residues left on soil surface on soil properties, plant growth, and crop yield and to determine the effects of quantity of surface residues upon soil, fertilizer, and residue N transformations, availability, and efficiency of use. In a dryland corn-sorghum-soybean rotation produced on a clay loam, residues remaining after harvest of the previous crop were removed and respread on plots at rates of 0, 0.5, 1.0, and 1.5 times the quantity of residues originally present. The above crops were planted in four replications the following spring without tillage, after broadcasting 50 kg N/ha as ammonium nitrate. In 1980, exp 15 N-depleted NH sub 4 NO sub 3 was applied to half of each plot. After harvest, crop residues produced on the half-plot receiving the N-isotope were transferred to the half-plot receiving regular fertilizer, and visa versa. In 1981, exp 15 N-depleted NH sub 4 NO sub 3 was applied to half of each plot again, except at right angles to the fertilizer applied in 1980. After planting each year, thermocouples were installed in each plot and soil temperatures were recorded. Also access tubes were installed in all plots and soil water content was measured to the 150 cm soil depth periodically during the growing season. Dry matter production and N uptake by the plant tissue was measured periodically during the growing season and at maturity. Additional measurements taken included leaf area index, xylem water potentials, and soil microbial populations. Data are presented on corn and soybean production characteristics as affected by rate of crop residue on soil surface. Results are also given on leaf area index (LAI) and dry matter production of corn and soybeans as affected by surface residue rate. Total N content of corn and soybean plant materials and surface residues, and total and inorganic soil N (1980) are reported. (ERA citation 07:051714)