Impact of tillage practices on nitrogen accumulation and translocation in wheat and soil nitrate-nitrogen leaching in drylands

Although the effects of tillage practices on soil properties and root growth is well studied, how they affect nitrogen accumulation and translocation in wheat in dryland regions is poorly understood. Here, the impact of different tillage practices, namely, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), and rotary tillage after subsoiling (RS), on nitrogen accumulation and translocation, grain yield, and economic benefit in wheat and soil nitrate-nitrogen leaching in drylands was studied over three wheat growing seasons from 2009 to 2012. The results showed that compared with R, nitrogen accumulation amount under SRS increased by 36.8% from jointing to maturity in 2009-2011 and by 12.9 and 16.4% from sowing to maturity in 2009-2010 and 2010-2011, respectively. Postanthesis nitrogen accumulation, its contribution rate to grain and nitrogen accumulation in grains at maturity under SRS were 48.3, 31.3 and 12.7% higher, respectively, compared to that under R in 2009-2010. On the other hand, nitrate-nitrogen accumulation under SRS in 0-60 cm soil layers was lower in comparison to that under SR and R, which suggested that SRS promoted absorption of nitrate-nitrogen in soil layers by wheat. However, no significant difference in nitrate-nitrogen accumulation in the 60200 cm soil layers was observed between SR and R. Average grain yield, nitrogen production efficiency and economic benefit were all the highest under SRS at 598.78 gm(-2), 39.9 kg kg(-1) and 8350.8 RMB (sic) ha(-1), respectively, over the study period. Therefore, we propose that SRS is the optimal tillage practice for wheat production in this region. (C) 2015 Elsevier B.V. All rights reserved.