تقدير متطلبات غسيل التربة من مياه الري للمحاصيل الزراعية في واحة الأحساء بنموذج محاكاة جيو كيميائي

الملخص EN

Sustainable development of water and soil resources in irrigated arid lands requires accurate estimation of soil leaching requirements (LR) to prevent: (i) soil salinization, (ii) unwarranted overdraft of water resources, (iii) environmental pollution, and (iv) maximizing the economic profitability of agricultural projects.

Hassa oasis which is the largest and most important oasis in the Arabian Peninsula faces many challenges including shortage of fresh water resources, soil salinization from irrigation with marginal quality water, and environmental pollution with agricultural drainage water.

This work uses a gcochcmically-bascd simulation model to obtain better estimates of LR for selected crops in the area of Hassa oasis that is served by irrigation and drainage networks operated by Hassa Irrigation and Drainage Authority (HIDA).

The model accounts for irrigation water chemistry, plant root water uptake, leaching fraction, and precipitation of carbonate minerals from soil solution.

Estimation of LRs were based on mean concentrations of major ions of irrigation water that were distributed by the main irrigation channels of HIDA during 2014.

The simulation results indicate that mean root zoon soil salinity in Hassa oasis is higher than tolerance of low salt tolerant crops such as tomatoes, cucumber, spinach, lettuce, pepper, onion, eggplant, carrot, clover, com, grapes, orange, lemon and olive even at a high leaching fraction of 0.4.

The estimated LRs for date palm, guava, zucchini, wheat, barely crops in Hassa oasis arc 0.3, 0.21, 0.19, 0.12 and 0.06, respectively.

Such estimates indicate that the traditional LR model currently used by HIDA overestimates LR for salt-tolerant crops such as wheat and barley while underestimating LR for low and moderate salt-tolerant crops such as date palm.

Overestimation of LR by the traditional model for salt-tolerant crops is attributed to ignoring carbonate minerals precipitation from soil solution.

Since LR underestimation causes soil salinization which leads to crop’s yield reduction, soil erosion and environmental pollution while LR overestimation causes unwarranted depletion of the limited water resources, removal of fertilizers from plant root zoon.

pollution of groundwater, and higher production costs, LR estimates in this study arc indispcnsiblc for HIDA for sustainable development of the soil and water resources in Hassa oasis.