EFFECT OF ORGANIC AND SYNTHETIC SOIL CONDITIONERS WITH DIFFERENT NITROGEN LEVELS ON THE PERFORMANCE OF WHEAT IN SANDY SOIL

The main problems of sandy soil are its inability to hold on to nutrients, its fast drainage, its lack of soil structure and its small buffering capacity. It cannot hold on to nutrients because it has little or no clay and organic matter. Therefore, the objective of this study was to determine the effect of the combined application of some synthetic soil conditioners with two forms of humic acids (HA) as organic soil conditioners in reducing nitrogen fertilizer requirements to maximize wheat yield productivity. So, two experiments were designed in a split-split plot design with three replicates at the Experimental Station Farm in El-Ismailia governorate during the two successive winter seasons using wheat plant (Triticum Sativacv Giza 168). The treatments included two forms of organic acids and synthetic soil conditioners in the presence of three levels of nitrogen fertilizer. The common agricultural practices for growing wheat according to the recommendations of the Ministry of Agriculture were followed. Obtained results revealed that the application of humic acids type either HK or HCa in combination with PVA or bitumen emulsion under different application rates of nitrogen fertilizers enhanced wheat plant productivity (yield, straw, and grains kg/fed) along with uptake macronutrient as compared to control treatment. The superior one was HCa in combination with PVA and B in presence of 75% N application in the first and second season, respectively. Moreover, soil fertility was improved by adding soil conditioners in different forms with/without nitrogen fertilizers as compared to the control treatment i.e. EC values, OM, and available NPK were significantly increased in all treatments applied; the maximum increase was observed with HCa combination with B at 75% from nitrogen dose. Also, the same trend was observed with dry stable aggregates and total porosity of sandy soil for an average of two seasons. An opposite trend was observed with bulk density whose values generally decreased with all treatments. In conclusion, can be clarified that the application of humic materials either HK or HCa was increasing soil fertility which is reflected in wheat plant productivity but it was more efficient when in combination with synthetic polymers especially B, and can save about 25% from nitrogen fertilizer applied.