论文部分内容阅读
我们从1976年开始,在河南省封丘县进行了关于黄河背河洼地低矿化地下水条件下的稻区水盐状况方面的调查和定位试验,试验结果表明: 1.背河洼地地下水矿化度不高,土壤应该不容易盐渍化,但由于主要为轻壤土和砂壤土,毛管传导性强,盐分向地表累积,产生盐害。种稻之所以能改良盐渍土,是因为稻田淹灌水,有淋洗土壤盐分和淡化地下水的作用。2.稻田灌水引起周围地下水位抬高,是稻田周围土壤次生盐渍化的主要原因。次生盐渍化由稻田附近向外发展,一方面是由于稻田边缘的地下水位比远处为高,土壤返盐快。另一方面是因为稻田周围土壤水分存在着水势梯度、水盐由稻田附近总水势高的地方,向远处总水势低的地方移动和累积。3.背河洼地排水困难,地下水位浅,稻田回旱以后,轻质土容易返盐。引黄放淤,地表淤积粘土,粘土层有很好的抑制返盐作用。粘土愈厚,返盐愈慢。4.灌排渠系是调控稻区水盐运行的重要措施,背河洼地排水系统由临时毛排以及农排与支排组成。毛排和农排主要是配合灌渠调节水分,排盐作用不大,深度和间距可以适当放宽。支排有排盐和排地下水作用,对土壤改良影响很大,深度不宜过浅,间距亦不可过大。水旱交界处布置深而通畅的截渗沟,对防治稻田周围盐渍化有一定的效果。5.背河洼地种稻时还必须考虑:(1)根据灌排条件,确定种稻面积;(2)井渠结合,以井水补河水之不足,井灌并有排水作用;(3)稻改与引黄放淤结合,上游放淤,下游稻改;(4)稻田连片布置,减少对旱地的不良影响。
We started from 1976 in Fengqiu County of Henan Province on the Yellow River backwater depression under low mineralized groundwater conditions of rice water and salt conditions survey and positioning test results show that: 1. Backwater depression groundwater mineralization Degree is not high, the soil should not be easily salinized, but due to the main light loam and sandy loam soil, capillary conductivity, salt accumulation to the surface, resulting salt damage. The reason why rice can improve saline soil is that paddy soil is flooded with water, has the effect of leaching soil salt and desalinating groundwater. 2. Paddy field irrigation caused by the surrounding groundwater level elevation, is the main reason for secondary soil salinization around the paddy field. Secondary salinization develops from near the paddy fields, on the one hand due to the high groundwater level at the edge of the paddy fields and the rapid salt return to the soil. On the other hand, there is a gradient of water potential in the soil moisture around the paddy field. Water and salt are moved and accumulated in areas with low total water potential in the distance where the total water potential is high near the paddy field. 3. Backwater depressions drainage difficulties, shallow groundwater, paddy fields back to drought later, light soil easily return salt. Dredging the Yellow River, surface silting clay, clay layer has a good inhibitory effect of salt back. The thicker the clay, the slower the salt return. 4. Irrigation and Drainage Canal System is an important measure to control the operation of water and salt in the rice area. The drainage system of the Back River depressions consists of temporary hairy rafts and the rows of peat and rafts. Maoris and peat mainly with the irrigation canal to adjust the water, salt is not, the depth and spacing can be properly relaxed. Sub-row of row of salt and row of groundwater effect, a great impact on soil improvement, the depth should not be too shallow, the spacing can not be too large. Drainage junction at the junction of deep and unobstructed cutoff ditch, the prevention and control of salinization around the rice have a certain effect. 5. Backwater depression must also be considered when planting rice: (1) According to the irrigation and drainage conditions, determine the area for planting rice; (2) Combination of wells and drains, Change combined with the Yellow River drainage silt, upstream siltation, downstream rice change; (4) paddy field contiguous arrangement to reduce the adverse effects on dry land.