Effect of cotton-seed acid delinting product and gin trash on soil nitrification and the possibility in disseminating cotton pathogens

Abstract

An experiment was carried out where gin trash that is a weakly alkaline material and a commercial organic fertiliser was added to an acid soil. Also, the residues of cottonseed acid delimiting product, were added to a calcareous soil. After nine weeks of incubation the effect of the above mentioned added materials on soil nitrification was evaluated. Another experiment was carried out to investigate the possibility of gin trash, cottonseed acid delimiting product, a commercial organic fertiliser and a sample of dried manure in disseminating important cotton pathogens (Fusarium oxysporum, Verticillium dahliae, Rhizoctonia solani, Pythium ultimum and Thielaviopsis basicola); also to test their effect on the growth of the above mentioned pathogens. The cottonseed gin trash acted effectively to nitrification process only at the rate 3% in organic matter, whereas cottonseed acid delimiting product demonstrated a negative effect on nitrification at the rates 2% and 3% in organic matter. All tested materials (cotton-seed acid delimiting product, gin trash, organic fertilizer and manure) when added to selective culture media, did not find to carry any inoculum of the above mentioned cotton pathogens but favoured saprophytic organisms growth. On the other hand, only the cottonseed acid delimiting product obscured the growth of all tested cotton pathogens, whereas gin trash promoted growth of P. ultimum and R. solani, when these two materials were used as soil amendments.