Effect of addition of humic acid and Leaching Factor under irrigation with different levels of saline water on Clay Soils content of Organic Matter and yield of wheat crop .

An experiment was carried out under the conditions of the green house at the Faculty of Agriculture, University of Aleppo. The aim of research is determine the effect of the addition of humic acid to the irrigated soils by saline water in their organic carbon content and the yield of the wheat crop. The experiment was designed in a split-spilt dissection method. The main sections comprising three levels of irrigation water salinity (W1:0, W2:3, W3:6 g-1 NaCl). Three levels of gypsum were mixed with soil: (G1:0, G2:25, G3:50 g). Three levels of humic acid were added with irrigation water (H3:48, H2:24, H1:0 kg/h). The coefficient Leaching with irrigation water for W3 and W2 was applied at %10 and %20 of the field capacity, respectively. The results showed that the addition of humic acid contributed to the increase in the stock of organic carbon. The highest percentage of organic matter (2.70%) was found in the deep layer (W3G3H3), while the lowest ratio was (1.41%) in the surface layer of treatment (W3G2H1). The role of humic acid, especially at the level of H3, was clearly demonstrated in increasing the productivity and weight of the 1000 grains for the wheat crop. The study confirmed the role of the leaching factor in the organic carbon losses of the soil, where organic carbon was losses (%26.31) with leaching factor 10%, where the losses (%44.74) with leaching factor was 20%.