Recovery of nitrogen by spring barley following incorporation of 15N-labelled straw and catch crop material

摘要: Abstract The recovery by spring barley ( Hordeum vulgare L.) of nitrogen mineralized from 15 N-labelled straw and ryegrass material was followed for 3 years in the field. effects separate combined applications were studied using cross-labelling with N. Reference plots receiving NH 4 NO included. Plant samples taken every second week until maturity during first growing season at two following years. Incorporation plant had no significant influence on above-ground dry matter yield barley. N derived not significantly different whether incorporated alone or combination material. mean 4.5% crop 2.7% 1.1% third crop. During season, higher when catch without straw, but differences only one sampling date. At 7.8% 10.2% recovered crop, respectively. Mean recoveries 2.3% year less than 1% after incorporation. mineral fertilizer application relatively low (29–40%), probably due to long periods drought all residual similar residues.