Nitrogen Uptake and N Use Efficiency of Spring Wheat Grown in Soils Amended With Different Livestock Manures and Urea.

Nitrogen uptake and N use efficiency of wheat was investigated in soils amended with different animal manures in comparison with urea fertilizer on a loamy soil at Carman and a heavy clay soil at the Glenlea research stations of the University of Manitoba, Canada, in two growing seasons (2009 and 2011). The experiment was laid out in randomized complete block design with six treatments and four replications. The treatments were: three solid beef cattle manures from Morden (MBM), Carman (CBM) and Glenlea (GBM), one traditional liquid swine manure (LSM), urea and the control (no amendment), applied at 50 kg ha-1 of available N. Generally, N uptake and N use efficiency (NUE) were highest in urea compared to LSM and the beef cattle manures in 2009 at both sites. The NUE from Urea was 46% (52% at Glenlea), from LSM it was 22% at both sites, for the beef manures NUE ranged from 20 to 30% at Carman but smaller on a heavy clay soil with a range of 7 to 17%. While LSM and urea behaved similarly at both sites N release on the heavy clay soil was smaller from the beef manure probably due to a wetter and cooler soil conditions. In 2011, NUE response pattern at Glenlea was similar to that of 2009 at the same site and followed the order: urea (38%) > MBM (16.2%) > LSM (7.4%) = CBM (7.4%) > GBM (2.7%).  However, at Carman the NUE followed the trend: CBM (47.5%) > Urea (27.7%) > MBM (27.3%) > GBM (10.7%) > LSM (5.7%) in 2011. The NUE of LSM was about one-half of that of urea at both sites while for beef manure the NUE was about one-half on a loam and one-quarter of urea on a heavy clay soil.   Key words: N uptake, N use efficiency, manure, urea