Haj-Amor Zied, Ibrahimi Mohamed-Khaled, Feki Nissma, Lhomme Jean-Paul, Bouri Salem
Water, Energy and Environment Laboratory, National Engineering School of Sfax, 3038, Sfax, Tunisia.
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Environ Monit Assess. 2016 Aug;188(8):497. doi: 10.1007/s10661-016-5488-8. Epub 2016 Jul 30.
The continuance of agricultural production in regions of the world with chronic water shortages depends upon understanding how soil salinity is impacted by irrigation practises such as water salinity, irrigation frequency and amount of irrigation. A two-year field study was conducted in a Saharan oasis of Tunisia (Lazala Oasis) to determine how the soil electrical conductivity was affected by irrigation of date palms with high saline water. The study area lacked a saline shallow water table. Field results indicate that, under current irrigation practises, soil electrical conductivity can build up to levels which exceed the salt tolerance of date palm trees. The effects of irrigation practises on the soil electrical conductivity were also evaluated using model simulations (HYDRUS-1D) of various irrigation regimes with different frequencies, different amounts of added water and different water salinities. The comparison between the simulated and observed results demonstrated that the model gave an acceptable estimation of water and salt dynamics in the soil profile, as indicated by the small values of root mean square error (RMSE) and the high values of the Nash-Sutcliffe model efficiency coefficient (NSE). The simulations demonstrated that, under field conditions without saline shallow groundwater, saline irrigation water can be used to maintain soil electrical conductivity and soil water content at safe levels (soil electrical conductivity <4 dS m(-1) and soil water content >0.04 cm(3) cm(-3)) if frequent irrigations with small amounts of water (90 % of the evapotranspiration requirements) were applied throughout the year.
在世界长期缺水地区，农业生产的持续取决于了解诸如水盐度、灌溉频率和灌溉量等灌溉方式如何影响土壤盐度。在突尼斯的一个撒哈拉绿洲（拉扎拉绿洲）进行了一项为期两年的田间研究，以确定用高盐水灌溉枣椰树对土壤电导率的影响。研究区域没有浅层咸水水位。田间结果表明，在当前灌溉方式下，土壤电导率可能会累积到超过枣椰树耐盐性的水平。还使用不同频率、不同加水量和不同水盐度的各种灌溉制度的模型模拟（HYDRUS - 1D）来评估灌溉方式对土壤电导率的影响。模拟结果与观测结果的比较表明，模型对土壤剖面中的水盐动态给出了可接受的估计，均方根误差（RMSE）值较小以及纳什 - 萨特克利夫模型效率系数（NSE）值较高表明了这一点。模拟结果表明，在没有浅层咸水地下水的田间条件下，如果全年频繁进行少量灌溉（蒸散需求的90%），则可以使用咸水灌溉水将土壤电导率和土壤含水量维持在安全水平（土壤电导率<4 dS m(-1)且土壤含水量>0.04 cm(3) cm(-3)）。
