EFFECT OF RICE STRAW COMPOST AND MINERAL NITROGEN FERTILIZER ON SOME SANDY SOIL CHEMICAL " PROPERTIES AND NITROGEN USE EFFICIENCY FOR MAIZE AND WHEAT PLANTS

Two successive field experiments were carried out for two seasons 2002 and 2003 at Ismailia Agric. Res. Station to study the effect of rice straw compost with application of different rates of nitrogen fertilizer on some chemical properties of soil (pH, organic matter and available nitrogen). plant growth, nitrogen uptake and maize – wheat productivity. Such effect was studied during two successive growth stages for maize and wheat (flowering stage and harvest stage). The experiment was designed in a split-split design with three replications. Three rates of rice straw compost (OM) and nitrogen mineral fertilizer (N) in presence of Nz-fixing bacteria inoculation. Data indicate that application of compost and different mineral nitrogen fertilizer rates were. generally, slightly decreased the pH values in soil tested at flowering stage for maize plants. an opposite trend being observed for wheat plants. At harvest stage 53? both seasons (maize and wheat), the pH took the opposite trend of those obtained at flowering stage. Concerning soil organic matter content and availability of nitrogen, at flowering and after harvest stages of both first and second seasons. they were higher than those recorded by control when the rates of compost and mineral nitrogen were the used fertilizers. The percentages of organic matter content as well as the values of available nitrogen increased significantly with the application of high rate of compost combined with high rate of nitrogen fertilizer. Results also revealed that, at flowering and harvest stages, treatments of compost and nitrogen fertilizer had positively affected the dry matter of plant parts for both maize and wheat along with the content of nitrogen compared to control. At the same stages, data showed that the use of compost at the rate of 20 malfed. (0M3) in combination with the high rate of nitrogen fertilizer had significantly affected the dry matter content. nitrogen uptake and yield components of maize (straw, seeds and weight of 100—seeds). On the other hand, the application of rice straw compost at the rate of 10 mailed (0M2) in combination with the high rate of nitrogen fertilizer recorded high values of all previously tested parameters for wheat plants. Such significant increases were obtained for dry matter, nitrogen content, crude protein and yield components for both maize and wheat plants as a result of increasing the applied rates of both compost and nitrogen fertilizer.
The nitrogen use efficiency (NUE) showed that the application of moderate rate of mineral nitrogen fertilizer in combination with high and moderate rates of compost was significantly favorable for NUE in both maize and wheat plants, respectively.
The correlation matrix between all studied parameters, generally, was positively significant for maize and wheat plants at both tested stages, an exception being obtained with pH values.