关键词: 小麦, 玉米秸秆还田, 土壤水分, 根系生长, 根系活性, 水分利用效率

Abstract: 【Objective】To evaluate the influence of soil moisture and corn stalks returning practice on wheat root growth, grain yield and water use efficiency, a 2-year micro-plot experiment was conducted under rain-proof shelter condition, aiming at provide reference for improving effect and application of stalks returning to field. 【Method】Prior to wheat sowing, corn stalks were cut and incorporated into soil by plowing (stalks returning, RS), with non-stalks returning as control (CK). Both RS and CK were subjected to 50%-55% (Drought, D), 60%-65% (Slight Drought, SD) and 70%-75% (Normal, N) of field moisture capacity, respectively.【Result】The results showed that nodal roots per plant at maturity, root activity, root dry weight density within 0-25 cm soil layer of winter wheat in D treatments at different growing stages were dramatically decreased compared with those in either SD or N treatments, grain yield was decreased by 4.34%-38.30% and 14.30%-36.63%, respectively, though consumption of soil water storage and water use efficiency in D treatments increased by 7.92%-25.56% and 31.34%-90.72%, 12.69%-30.09% and 11.83%-32.88%, respectively. In D treatment, nodal roots per plant were 17.17%-29.41% and 5.60%-27.86% higher than those in CK at re-growing and maturity stages, but root dry weight density within 0-25 cm soil layer at different growing stages was lower in RS treatments than that in CK. The decrement in both root vigor and root dry weight density within 25-50 cm soil layer after flowering was significant higher than those in CK, grain yield and water use efficiency in RS were significantly decreased by 15.02%-19.52% and 7.51%-14.56% compared with that in CK. In SD and N treatment, nodal roots per plant were higher at different growing stages and the decrement in both root vigor and root dry weight density within 25-50 cm soil layer were lower in RS treatments, while irrigation amount and total water consumption were all decreased. Consumption of soil water storage was significantly increased, except for the N treatment in 2013-2014, grain yield and water use efficiency were dramatically increased by 6.09%-9.18% and 6.77%-11.13% compared with those in CK treatments. In addition, the present study also showed a significant interaction both of grain yield and water use efficiency between corn stalks returning and soil moisture conditions.【Conclusion】Corn stalks returning practice reduced irrigation amount, improved grain yield and water use efficiency by conserving soil water storage and improving root physiological function during the whole growing period under normal soil water and even slight drought conditions, but decreased grain yield and water use efficiency under drought condition.

Key words: wheat (Triticum aestivum L.), returning corn stalks to field, soil moisture content, root growth, root vigor, water use efficiency (WUE)