土壤水分与农作物生育及产量构成因素关系之研究

RESEARCH ON RELATIONSHIP AMONG SOIL MOISTURE, CROP GROWTH AND DEVELOPMENT AND YIELD FORMATION

经调查和系统的土壤水分观测,对土壤水分与麦类作物生育及产量构成因素之关系进行研究的结果表明,在西藏气候生态田间条件(1)可将土壤含水量3％定为凋萎湿度,7％含水量定为麦类作物拨节前适宜水分下限,10—12％含水量定为抽穗开花前后适宜水分下限指标;(2)作物生育期间的田间耗水量因受灌水量和降水量多少变化较大、从高产要求,冬小麦耗水量350mm、春小麦330mm即可;(3)冬、春小麦大量耗水时期正值西藏雨季,是应重视利用的有利条件;(4)麦类作物拔节、抽穗后处于雨季、土壤上层水分已能满足作物需求,因此,0—50cm土层水量变化可反映土壤供水情况。

Research has been made on the relationship among crop growth and development and yield formation through investigation and systematic soil moisture determination. the results show that in the Tibetan Meterological ecology field conditions, (1) 3% of soil moisture can be defined as the wilting humidity. 7% of soil moisture as the index of the optimum moisture minimum limit before wheat crop in the elongating stage. 10-12% of soil moisture as the index of the optimum moisture minimum limit before and after wheat crop in the heading and flowering stages; (2) Field water consumption in the crop growth and development stages varies considerably with the amount of irrigation water and rainfall water. According to the water requirement of high yields of wheat crop, water consumption for winter wheat is 350mm; for spring wheat 330mm; (3) High water consumption spell for both winter and spring wheat is just in the Tibetan rainy season so that special attention must be paid to the utilization of this favourable condition; and (4) After the elongating and heading, wheat crop is just in the rainy season so that soil moisture in the upper layer can meet the needs of crop water requirement. Thus, moisture change in the 0-50 cm soil layer can reveal the dynamics of soil water supplies.