EFFECT OF BIO AND ¡ OR MINERAL NITROGENOUS FERTILIZERS ON MAIZE AND WHEAT CROPS PRODUCTION AND SOIL FERTILITY

This study was conducted during 2003 and 2003 — 2004 seasons at Gemmeiza Agric. Res. Stn., with maize (SC 15 hybrid) and wheat (Gemmeiza 7 var.), to findout the effect of bio — and / or N- fertilizers on yield production and soil fertility. The obtained results could be summarized as follows: The bio-ferlil,zer Azospirllum proved to be superior than Cyanobacteria one to increase, significant, maize grain and wheat(grain and straw) yields .Azospirillum still better than Cyanobactena in improving N-uptake, N-use efficiency, % biomass N recovered and available soil N for both crops. Increasing N-rate resulted in significant increases in maize grain and wheat(grain and straw) yields. Nitrogen concentration% of maize (grain and stover) and wheat(grain and straw) were increased significantly as N-rate increased. Nitrogen uptake and available soil N, after harvest, were increased, whereas, N- use efficiency tended to be reduced with increasing N-rate. Biomass-N recovered % for maize crop seemed to be increased with increasing N-rate 1whereas, an opposite trend was observed with wheat crop. Insignificant interaction effects were obtained due to the adopted biofertilizers and N-rates on the studied characters ,except the available soil N after maize harvest On conclusion, because of the inisignificant effect of adopted biofertilizers and N-rates , on the most investigated characters , it is recommended to apply the moderate N-rates under Azospirillum ¡n order the reduce the environmental pollution and to reduce, as well, maize and wheat production costs under Gemmeiza soil conditions