EVALUATION OF ENRICHED COMPOST AND ITS ROLE IN SYNERGY WITH RHIZOBACTERIA AND N-FERTILIZATION FOR IMPROVING MAIZE PRODUCTIVITY IN SANDY SOIL

Chopped rice straw supplemented with differ-ent amendments, namely organic (farmyard ma-nure and vinass); bio (mixture of Trichoderma har-zianum and Trichoderma viridi) and mineral (rock phosphate, bentonite, elemental sulfur and com-mercial nitric acid) to prepare enriched compost. After elapsing of composting process the prepared compost was monitored for its physio-chemical and microbiological characteristics as well as some maturity indices. Afterwards, enriched compost was evaluated in synergy with rhizobacteria (mix-ture of Serratia sp and Paenibacillus polymyxa) and graded levels of N-fertilizer as integrated ferti-lizer strategy for improving the growth and produc-tivity of maize plants grown in sandy soil through two field experiments executed at Ismailia Agricul-ture Research Station during successive summer season of 2005 and 2006. Results of enriched compost monitoring revealed that this product has an acceptable degree of the main physio-chemical properties such as color, bulk density, WHC, pH, EC and C/N ratio. Also, enriched compost exhibit-ed a valuable degree of fertilizer value, which re-flected by its content from macro and micronutri-ents. This end product has a high degree of micro-biological traits, which exhibited through the high counts of the main groups of microorganism and remarkable values of dehydrgenase and nitrogen-ase activities. In addition, all examined maturity indices exerted that this product has a reasonable degree of maturity and it can applied to plants without causing phytotoxicity or immobilization. Results of field experiments showed that growth aspects of maize plants were extremely affected by the mineral fertilization rather than organic and/or bio one. However, the highest values of plant vigor and N-content were attained as a results of the integrated fertilization strategy, particularly when maize plants received 120kg N/fed in combination with compost (at rate of 5 ton/fed) and rhizobacte-ria. The maize yield and its attributes appeared high response to applied N-fertilizer levels and organic fertilization. Irrespective of bio-organic ferti-lization, addition of N-fertilizer at levels of 60, 90 and 120 kg N/fed led to increase the grain yield by 103.70, 141.12 and 174.77%, respectively over control treatment (30 kg N/fed). On the other hand, topdressing of soil with enriched compost led to increase the grain yield of maize by 19.70% and this percentage increase raised to 25.76% when the organic manuring was conjugated with rhizo-bacteria under any level of N-fertilizer. However, the highest yield of maize was achieved in case of synergy between the high dose of N-fertilizer and 5 ton/fed from enriched compost for rhizobacterial inoculated grains.