有限供水对冬小麦根系生长发育的影响及其对底墒的利用特征

试验在中国气象局固城农业气象试验基地人工控制农田水分试验场进行。在底墒充足的条件下采用三种水分处理:I₁拔节期一次性供水75 mm; I₂返青期供水37.5 mm, 拔节期供水37.5 mm; I_CK生长季内无水分供应。生育期内遮去自然降水。试验结果表明, I₁处理由于有充足的底墒配合有限水分胁迫, 有助于减少冬小麦表土层 (0~30 cm) 的根生物量, 增加根系干物质向土壤深层分配, 挖掘深层土壤水分, 提高了土壤水供应量和有效底墒供水率.另外, I₁处理增加了需水关键期的有效蒸腾耗水比例, 提高了水分利用效率.虽然由于前期的水分胁迫降低了I₁处理总穗数, 但由于增加了籽粒数和籽粒重, 产量反而有所增加。

Effect of Limited Water Supply on Root Growth and Development of Winter Wheat and the Characters of Soil Moisture Use Before Planting

Experiments were conducted in the man-controlled water supply field at the Gucheng Agrometeorological Experimental Base of the Chinese Academy of Meteorological Sciences. Under the condition of sufficient soil moisture before planting, water was supplied for winter wheat with three scheme: I_1, 75 mm supplied water at jointing stage;I_2, 37.5 mm supplied water at returning-green stage and 37.5 mm at jointing stage;I_ CK, no water supply during whole growth season. The precipitation during the growth season was kept out. Results indicated that under I_1, the sufficient soil moisture before planting and limited water stress reduce the winter wheat root weight in the upper soil layer, and allocate more dry matter to the deeper root system. It contributes to the increase of the water use in deeper soil and the soil moisture use before planting. In addition, the water supply for winter wheat at jointing stage under I_1 helps increase the effective transpiration proportion at the key water demanding stage, and improves the water use efficiency. Although water stress decreases ears per m 2 in I_1, but the increase of grain numbers and grain weight contributes to the yield increase.