摘要
定量研究水分在农田-植物系统中的循环和利用过程,是提出合理化农田水分管理措施的基础。基于HYDRUS-1D模型,对三种典型土壤(砂性壤土,壤土,黏性壤土)的灌溉方式进行数值实验,模拟灌溉后及灌溉24h之后的土壤剖面含水量变化和土壤表面的径流情况。结果表明,砂壤土在不产生径流的情况下,可以接受更大的灌溉速率进行灌溉,可以有更灵活的灌溉方式可供选择,灌溉入水量也比较多;壤土和黏壤土的灌溉方式选择单一;砂壤土中,最大灌溉深度为61cm,壤土、黏壤土的最大灌溉深度分别为34cm和18cm。灌溉后及灌溉24h之后的土壤剖面的湿润锋面变化明显,这就要求在对作物进行灌溉时应该考虑灌溉水在土壤中自身运动。本研究推算的不同类型土壤在不同条件下的需水量,可为不同根深的作物选择合理灌溉方式提供参考。
Quantitative research of water circulation and utilization in the soil-plant system is the basis for rational use of agricultural water. In this study, a systematic investigation of the optimal irrigation rate and time by numerical simulations for various soils is carried out using HYDRUS-1D model. Three typical and contrasting soils, including sandy loam, loam and clay loam, are used in the simulations. Surface runoff during irrigation and water content distribution in the soil profile immediately after irrigation as well as 24 hours after irrigation are simulated. The results reveal that the sandy loam can subject to a great irrigation rate; even for the ir- rigation rate of 5 cm/h, no significant surface runoff occurs after 2 h irrigation; however, for both the loam and clay loam, the maxi- mum irrigation rates without significant runoff are greatly reduced; the maximum rate is about 1.25 cm/h and 0.4 cm/h for the loam and clay loam, respectively; the 24 h soil wetting depth after the 2 h maximum irrigation rate for reached to 61 cm in the sandy loam, compared with that of 34 cm and 18 cm in the loam and clay loam. This indicates that irrigation can wet the root zone of deep-rooted crops in the sandy loam, while it can only wet the root zone for shallow-rooted crops in the loam and clay loams. Furthermore, it is simulated that the 24 h soil wetting depth after irrigation is considerably greater than that immediately after irrigation, suggesting that the movement of irrigation water in the soil should be taken into consideration in estimating soil wetting depth caused by soil wa ter re-distribution. The results from this study are helpful for irrigation planning for crops grown in different soils with different roo- ting depths.
出处
《节水灌溉》
北大核心
2015年第3期46-51,58,共7页
Water Saving Irrigation
基金
国家自然科学基金资助项目(51379187)
