摘要
由于灌水频率高、定额小,在新疆地区大面积应用膜下滴灌进行棉花种植时,常出现根系分布浅、植株易早衰等影响产量的问题,灌水湿润区域相对较深的地下滴灌可能是解决上述问题的方法之一。但因顾及机械耕作和多次使用,传统地下滴灌带通常埋深较大,致使苗期灌水及管理维护极其不便。随着工艺水平提高和生产成本降低,地下滴灌生产实际中采用一次性滴灌带已成为可能,本研究通过数值模拟方法来探讨地下滴灌一次性滴灌带的合理埋深问题。为了验证所建立的数值模型和选用的土壤物理参数,首先在新疆玛纳斯地区开展了地下滴灌田间试验,继而采用HYDRUS-2D/3D软件对该试验条件下的土壤水盐动态进行了模拟。结果表明,模拟值与实测值之间整体吻合较好,其中土壤含水量分布的平均绝对误差Me和均方根差Rm分别不高于0.034、0.040 cm^3/cm^3,相关系数R最小值为0.8,Nash效率系数Ns在0.34~0.62之间;含盐量Me、Rm也分别不超过3.31、4.24 g/kg,R最小值为0.6,Ns在-0.06~0.38之间,相关模型和参数较为合理可靠。在此基础上,对该地区不同滴灌带埋深(分别设为5、15、30 cm)情景下灌水过程中的水盐运动规律进行了进一步模拟与分析,结果表明:不同埋深导致土壤淡化和积盐区域分布不同,淡化区域主要集中在滴灌带附近,在远离滴灌带的湿润锋边缘出现积盐;随着滴灌带埋深加大,土面蒸发损失逐渐降低,但对表层土壤供水能力也相应减弱;综合考虑回收利用、棉花苗期水分供应、根区淡化脱盐需求及单方水的淡化脱盐效率等因素,当地地下滴灌棉田一次性滴灌带不宜埋设过深,建议布置在15 cm左右。
The technology of film mulched drip irrigation （FMDI） is applied widely to cotton cultivation in Xinjiang, China. Resulted from its characteristics of high ratio and small amount of irrigation, a problem of shallow roots and weak adversity resistance is often found in practice and thus would limit further development of FMDI. Since the irrigation water is supplied deeper in the root zone, the subsurface drip irrigation （SDI） is easily to be considered as an alternative to solve the problem. To avoid probable damage from mechanical farming and prolong the application duration, the irrigation tape in a traditional SDI system is usually buried in deeper root zone （e. g. beneath 35 cm from the soil surface） , which might be extremely inconvenient for seedling irrigation and management maintenance of the irrigation system. In fact, with the technological progress and cost reduction for manufacturing the irrigation tape, the practical use of disposable drip irrigation tape is becoming more and more popular. The objective was to explore the reasonable depth of disposable drip irrigation tape in SDI by using numerical simulation method. The HYDRUS-2D/3D software was used to simulate the dynamics of soil water and salt, and a field experiment was conducted in Manasi County of Xinjiang autonomous region to validate the numerical model and selected hydraulic parameters. Simulated and observed soil watercontent distributions were in good agreement with the maximum mean absolute error （Me） and root mean square error （R,,） of 0. 034 cm3/cm3 and 0. 040 em3/cm3, the minimum correlation coefficient （R） of 0.8 and Nash - Sutcliffe efficiency coefficient （ N, ） of 0.34 - 0.62, respectively, between them. Correspondingly for soil salinity distributions, the values of maximum Me and Rm were 3.31 g/kg and 4.24 g/kg, the minimum R was 0.6 and Ns were -0.06 -0.38, respectively, which was also in acceptable range. Then the transport processes of soil water and salt under SDI with different burying depths H （5 cm, 15 cm and 30 em, respectively） for irrigation tape were simulated by using the validated numerical model and hydraulic parameters. The results showed that salt was gradually driven away from the tape by irrigation water, with soil salinity decreased around the tape but increased near the wetting front. While the increase of H resulted in decrease of evaporation loss, the shallow soil layers near surface would be more and more difficult to be wetted by irrigation water. Synthesizing the factors such as recycling convenience of disposable tape, water requirement for cotton seedling, desalination demand of root zone and water use efficiency for desalination, local disposable tape of SDI was recommended to set at about 15 cm, a moderate depth from the soil surface.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2017年第9期191-198,222,共9页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家重点研发计划项目(2016YFC0501401
2016YFD02003003)
关键词
地下滴灌
一次性滴灌带
合理埋深
数值模拟
HYDRUS-2D/3D
水盐运动
subsurface drip irrigation
disposable drip irrigation tape
reasonable depth
numericalsimulation
HYDRUS - 2D/3D
water and salt dynamics
作者简介
李显激（1986-），男，博士生，主要从事节水灌溉理论与技术研究，E-mail：lxwei5945@163．com
通信作者：左强（1965-），男，教授，博士生导师，主要从事土壤物理与节水农业机理研究，E-mail：qiangzuo@cau．edu．cn
