STUDIES ON SOME SOIL ENHANCERS USED IN ARID REGIONS

Abstract

The current work is interested in studying the nature of some selected soil amendment enhancers in the laboratory in terms of some mineralogical initial characters, i.e., their X-ray diffraction as well as their response to the metal bioleaching due to the inoculation with P or K- solubilizing bacteria and/or their co-culture. Furthermore, studying their effect on P & K uptake of maize plants and the soil available P & K in a greenhouse experiment. In addition, a field experiment was laid out to evaluate their effect on maize growth, maize ear yield, maize seed yield. The obtained results could be summarized as in the following: 1- Laboratory work: 1.1. Bioleaching of K from feldspar, bentonite and biochar: Any of Bacillus circulans, Serratica mercescenes, Pseudomonas fluorescence and their co-culture mixture was able to act as bioleaching agent to liberate K from any of feldspar, bentonite and biochar. Their Co-culture mixture recorded the highest available bioleached K amount from biochar followed by those scored by Ps. fluorescence, B. circulans and Serratica mercescenes in respective order compared to control without inoculation. Also, the bioleached available K amount from biochar was much higher than that bioleached from feldspar. 1.2. Bioleaching of P from rock phosphate and biochar: - Both Bacillus polymyxa and Bacillus megaterrium and their co-culture and/or their co-culture ware able to release P from rock phosphate and biochar. - Inoculation with co-culture bacterial mixture achieved the highest amount of available bioleached P from rock phosphate. This available bioleached P from rock phosphate was quite higher than that leached by biochar.