Using Farm Residues Amended with Cellulase Enzyme as Bio-organic Manure for Alleviation the Hazard Effect of Mineral Fertilizers Added to Field Crops

摘要

AFIELD experiment was conducted on a calcareous soil at Agric.Rec. Center Station at El-Fayome Governorate to study the effective role of using cellulase enzyme pure or derived from Trichoderma vessel (TR fungi) for decomposition of some organic farm residues, i.e., straw wheat maize and rice, under wheat and soybean cropping sequence during two successive seasons of 2008-2009.Such study aimed at identifying the beneficial effects of these amended plant residue on soil properties and their influences for alleviating the hazard effect of chemical pollution of the grown crop grains. The amended soil samples were carried out for two periods, i.e., 16 and 24 weeks at soil moisture content 60% of the water holding capacity. The amended soils were analyzed to determine enzyme activities of dehydrogenase, celluase, urease and invertasc. The obtained data show that wheat straw amended with cellulase enzyme exhibited an effective role for improving soil properties {i.e., bulk density, structure factor, soil strength, hydraulic conductivity, available water, organic matter, CEC and pH followed by maize and rice straw in the first season. However, the different TR amended straw reached the maximum activities in soil during the next season due to complete decomposition of these organic in soil likely more susceptible to microbial attack. These beneficial effects were positively reflected on grains and straw yields either for wheat in the first season or soybean in the second one. That means application of amended organic farm residues leads to improve soil properties, nutrients availability and the biological activity, which enhancing growth of grown plants up to the harvest stage. It is noteworthy to mention that although the grain and straw yield of the tested crops (wheat and soybean) showed a significantly decreasedin case of applying amended organic residues as compared to the control treatment (recommended doses of N, P and IC) yet the grain yield for both crops achieved a high quality. That was true, since the applied organic manure is not completely enough to supply the nutrient requirement of the grown plants, especially macronutrient. In addition, the improvement of grain quality is due to its low content of chemical hazard constituents. This is confirmed by the relatively low nutrients content in crop grains for amended organic residues as compared to those treated with the recommended doses of N, P and K.