POSSIBILITY OF USING CLOVER RESIDUES, GREEN MANURES AS A PARTIAL SUBSTITUTE OF MINERAL NITROGEN FERTILIZER TO WHEAT PLANTS GROWN ON NORMAL AND SALINE SOILS

Reducing synthetic nitrogen fertilization is an important issue nowadays due to its environmental hazards and raising the soil quality. So a field trial was executed aiming to assess the possibility of using clover residuals and green manure as a partial substitute for mineral nitrogen fertilizer for wheat plants grown on normal and saline soils. The green manure, as the main factor, was Egyptian clover (variety FAHL), split-plot design with three replicates was used were the main treatments were as follows; M1: without green manure (soil without cultivation between rice and wheat), M2: tillage of clover roots alone with soil and M3: tillage the whole plant with soil. While, the sub-main factor consisted of three rates of mineral N fertilizers i.e., 100, 75, and 50 % of nitrogen recommended dose (NRD) for wheat as mineral fertilizer. Regarding the effect of green manure, the M3 treatment was superior compared to others. Concerning N treatments, 100% of NRD as mineral fertilizer was superior compared to other rates. On the other hand, in both soils (normal & saline) the wheat plants which received 75 % of NRD as mineral fertilizer and simultaneously fertilized with Egyptian clover as green manure (M3) realized performance and productivity as similar as the corresponding wheat plants which received 100 % of NRD as mineral fertilizer without green manure (M1) or in other words, there weren't significant between them for the most of studied parameters. The studied green manure increased nutrient uptake and enhanced the synthesis of chlorophyll in the tissues of the wheat plants grown in either non- saline or saline soils and this may be the reason for increasing the ability of wheat to tolerate salinity. Generally, it can be concluded that mineral N fertilizer rates could be reduced after the incorporation of Egyptian clover as green manures having high nutrient contents and increased nitrogen use efficiency in saline soil which increases wheat yield.