INFLUENCE OF ORGANIC AND MINERAL FERTILIZERS ON SOME SOIL PHYSICAL PROPERTIES AND ZEA MAYS PRODUCTIVITY

A field experiment was conducted on a clay soil using Zea mays (single cross 10) during 2009 season at Agricultural Experimental Station Fac of. Agric, Mansoura Univ., to study the influence of combined use of mineral fertilizers (urea) and organic fertilizers in the form of farmyard manure (FYM) and composted rice straw (CRS) on soil bulk density ,porosity (E) ,Void ratio (e), soil organic matter(Soil-O.M)  and Zea mays productivity at certain times 25, 45 and 110 days from Zea mays planting. The Randomize complete blocks design with three replications was used. The mineral fertilizer (urea) was applied at the rate of N₁=100 and N₂=200 kg N fed^-1.The amounts of various organic fertilizers used were (10 and 20 m³ fed^-1), for both FYM and CRS. Organic fertilizers added either alone or in combinations with urea to the soil.
Results indicated that the maximum increase in 100 grain weight, grain yield and straw yield (42.81, 998.22 and 2395.73 g.m²) were recorded with N₂CRS₂.
While, the minimum (35.23, 745.44 and 1789.07 g.m²) were recorded with the control.
Multiple linear regressions illustrated that:
1- bulk density, porosity and O.M% had role in predicting the grain yield (g/m²)              (R² = 60.1%) and the expected equation to predict the grain yield as follow:
Grain Yield (g/m²) = 989 - 70 bulk density - 586 porosity + 225 OM%
2- bulk density and O.M% had role in predicting the porosity (R² = 100.0%) and the expected equation to predict the porosity as follow:
PROSITIY = 1.00 - 0.377 bulk density + 0.000130 OM%
3- porosity and O.M% had role in predicting the bulk density  (R² = 100.0%) and the expected equation to predict the bulk density as follow:
BULK DENSITY = 2.65 - 2.65 porosity + 0.000351 OM%
Therefore, it could be concluded that the integration of organic and inorganic fertilizers was better than inorganic fertilizer only. Where using the high amount of organic fertilizers with urea gave the highest Zea Mays yield and increased the soil storing of (Soil-O.M) and accordingly raising the soil fertility.