Cover crops and nutrient retention for subsequent sweet corn production

The use of high rates of N fertilizer in intensive sweet corn (Zea mays L) production may result in leaching losses and contamination of adjacent waterways and ground Hater, Cover crops planted alter sweet corn harvest could absorb residual soil N and minimize losses of fertilizer in gravitational water. Field experiments Here conducted on a Ste. Rosalie heavy clay (fine, mixed, frigid, Typic Humaquept) and a St. Bernard sandy clay loam (fine loamy, mired, nonacid, frigid Typic Eutrochrept). Cover crop effects on nutrient uptake, subsequent N release, loss of N, P, and Ii in leaching Hater, and denitrification rates Here measured. Fertilizer N rates were 0, 75, and 150 kg ha(-1). Cover crops Here red clover (Trifolium pratense L.), crimson clover (Trifolium incarnatum L,), forage radish (Raphanus sativus L.), canola (Brassica rapa L.), barley (Hordeum vulgare L), and annual ryegrass (Lolium multiflorum L). A control treatment with no cover crop was also included. Three replicates Here used in a split-plot arrangement of a randomized complete block design. Fall residual soil NO3--N levels Here higher in control plots than cover crop plots. Gravitational water NO3--N was greater in control plots and ranged from 17 to 76 kg N yr(-1) N, compared with col er crop plot values of 1 to 55 kg N yr(-1). Cover crops had no effect on denitrification rates, or on NH4+-N, P, or li concentrations in gravitational Hater, Forage radish, canola, and barley were effective cover crops in reducing soil NO3--N. Cover crop effects on subsequent sweet corn were found only in grain N uptake.