Responses of root growth and distribution of maize to nitrogen application patterns under partial root-zone irrigation

Abstract

A field experiment was carried out to investigate the effects of varying nitrogen (N) supply and<br />irrigation methods on the root growth and distribution of maize (Zea mays L.) in Wuwei,<br />northwest China in 2011 and 2012. The irrigation treatments included alternate furrow irrigation<br />(AI), fixed furrow irrigation (FI) and conventional furrow irrigation (CI). The N supply treatments<br />included alternate N supply (AN), fixed N supply (FN) and conventional N supply (CN), were<br />applied at each irrigation method. The root growth across the plant row was measured in 0-100 cm<br />soil profile (20 cm as an interval) at maturity. The results showed that root distribution of two<br />sides of the row was uniform for AI or CI coupled with CN or AN. Root length density (RLD) in<br />0-40 cm soil depth was significantly increased by AI compared to other irrigation methods while<br />decreased by FN compared to other N supply treatments. Though RLD decreased more with soil<br />layer deepening under AI, RLD in 60-100 cm soil depth in AI treatment was still larger than that<br />in CI and FI treatments. In general, total fine root (diametersurface area, and grain yield of maize were significantly increased by AI coupled with CN or AN<br />when compared to other treatments. These results indicate that alternate partial root zone irrigation<br />coupled with conventional or alternate nitrogen supply is useful to improve the root growth and<br />grain yield of maize in the arid area.