Water use Efficiency and Physiological Responses of Oat under Alternate Partial Root-zone Irrigation in the Semiarid Areas of Northeast China

Water use efficiency (WUE) and some crop physiological responses were studied when oat (Avena nuda L.) was applied with alternate partial root-zone irrigation (APRI). A field experiment was carried out with two organic fertilizer levels (e.g. 0 and 240 kg hm-2) and three irrigation levels (i.e. 60, 90 and 120 mm). The irrigation methods included the conventional irrigation (CI) and APRI. Compared with CI, APRI under the moderate water stress reduced water consumption by 9.97-12.46%, and improved WUE by 0-9.09%, but the grain yield was slightly reduced by 2.1-12.76%. APRI under the severe water stress would significantly (P<0.05) reduce the plant height than CI. APRI with organic fertilizer could increase the root shoot ratio by 18.18-45.45% after the grain filling stage. Under the severe water stress APRI significantly reduced the net photosynthetic rate (Pn), and these treatments with organic fertilizer generally had much higher Pn than those without organic fertilizer. Our results indicate that APRI under the moderate water stress improves WUE and root shoot ratio, and slightly reduce grain yield and Pn with applied organic fertilizer.