The Use of Cover Crops After a Maize Crop in the North of Spain

This work intends to study N leaching losses in a field assay when crimson clover (Trifolium incarnatum) and italian ryegrass (Lolium multiflorum) was incorporated into the soil and quantify the their effect on N2O, N total gaseous losses under controlled soil moisture and temperature conditions. Field assay: A split-plot design where main plot was the cover crop and the subplot was the rate of fertilizer (0 and 150 kg N ha-1) applied to the subsequent maize crop. Laboratory assay: Residues of italian ryegrass and crimson clover were mixed with soil in containers, leaving one set of unamended controls. Incubations of soil during 27 days with a 0, 5 or 0.01 % C2H2 atmosphere allow us to obtain potential N2O and N total gaseous losses. In the field experiment crimson clover incorporation was better than ryegrass to resolve nitrate leaching losses due to 150 kg N ha-1 applied to maize although clover incorporation in the laboratory assay seemed to increase the risk of N2O emissions despite most gaseous losses were in the form of N2