INFLUENCES OF USING SOME COMPOUNDS THAT RETAIN WATER UNDER WATER STRESS CONDITIONS ON THE PRODUCTIVITY OF WHEAT (TRITICUM ACTIVIUM L.) GROWN IN SANDY SOIL)

Abstract

Two field experiments preceded by an incubation lab experiment were carried out to study the effect of a composite soil amendment prepared by the physical mixing of bentonite, feldspar, and/or zeolite with the compost and/or the gelatin and carboxy methyl cellulose (CMC) on sandy soil. Treatments in triplicates were distributed in a split-plot experimental design including a control treatment (without application). The main factor (I) was two irrigation levels: I-1 = 70% and I-2 = 100% of the wheat water consumptive use (CU m3 ha-1). The sub-factor (A) was the composite soil amendments applied at a rate of 3.5 Mg ha-1 in 11 treatments. The wheat (Triticum activism L.) was cultivated during the two successive winter seasons of 2021 and 2022. The lab results have indicated that the composite feldspar/compost/gelatin/CMC has increased the soil aggregation and moisture content after one day and 100 days of incubation. The mixed composite compost/gelatin/CMC has resulted in a significant variation in the aggregate fractions >1.0, 1.0-0.25, and <0.25 mm. The fine aggregates (<0.25 mm) were decreased compared to the CL up to the 1st 45 days. The moisture content for the CL, compost/gelatin/CMC mixed with the bentonite, feldspar and zeolite after 100 days were 18.1, 28, 29.4 and 25.5%, respectively. The field results showed that the most significant relative increase in the mean values of the available N, P, and K were for the feldspar/compost/gelatin/CMC composite by 90.7, 65.6, and 32.6%, %, respectively. For the wheat grains yield (Mg ha-1), the most significant increase in the mean values relative to the CL was by 62.1% obtained by the feldspar/compost/gelatin/CMC composite. The bentonite/compost/gelatin/CMC and the zeolite/compost/gelatin/CMC composites have increased the yield mean value by 45.3% relative to the CL. The studied soil amendments can be recommended as effective tools for increasing the water retention and soil aggregation so that improving water conservation in sandy soil.