Managing the seeding rate to improve nitrogen-use efficiency of winter wheat

This study was conducted to determine whether grain yield and nitrogen-use efficiency (NUE) of winter wheat (Triticum aestivum L.) could be improved by managing the seeding rate. During the 2010-2011 and 2011-2012 crop seasons, two winter wheat cultivars (Tainong18 with lower tillering capability and Shannong15 with higher tillering capability) were evaluated to investigate the effect of seeding rate on grain yield and NUE. Significant increases in root length density (RLD), absorbed N from fertiliser (Nf) and soil (Ns), above-ground N uptake (AGN), N uptake efficiency (UPE), NUE and grain yield, as well as a significant reduction in N utilisation efficiency (UTE), were observed as the seeding rate increased from 135 to 405 seeds m−2 for Tainong18 and from 90 to 345 seeds m−2 for Shannong15. NUE was positively correlated with UPE but not with UTE, indicating that optimising the seeding rate improved NUE mainly by raising UPE due to increased AGN as a result of optimised RLD and a synchronous increase in Nf and Ns. Therefore, the seeding rate could be a factor useful to obtain higher grain yield and NUE in winter wheat.