EFFECT OF SULFUR AND ORGANIC MATTER LEVELS ON ABUNDANCE AND ACTIVITY OF PHOTOAUTOTROPIC SULFUR AND THIOSULFATE BACTERIA IN SOIL UNDER DIFFERENT INCUBATION TIME

Abstract

The study was conducted to specify the effect of three levels 0, 1,2 S/Kg soil (S0, S1, S2)respectively of agricultural sulfur and two types of organicsubstance (Manures) without adding CO and the dry powder of alfalfa C1 andmanures C2, added within the average of 6 grams C/Kg soil on the presence andactivity of minute photo autotrophic sulfur oxidation by an experience conductedunder laboratory conditions by utilizing silty soil achived under factorialexperiments of CRD design. All samples were incubated at 280 C for differentperiods 15, 30, 45 days (T1, T2, T3) respectively. Activity and diversity of bacteriarelated to types Thiobacillus of T. thioparus was estimated through measuring thequantity of thiosulphate oxidation and the differences of values related pH at themedia specified for this bacteria.The results showed that increasing the addition of agricultural sulfur has a greateffect (P<0.05) on increasing the density and activity of photo-autotrophic sulfuroxidizing bacteria its number is 0.98*102 cfu/g and 1.31*102 cfu/g when addingalfaalfa and cow manures respectively compared with 1.96*102 cfu/g on the controltreatment. Differences in incubation periods showed that 30 days is the highest levelof density 0.73*102 cfu/g. Interferences among levels of sulfur, organic substanceand incubation period showed that the highest level of (P<0.05) is 3.071*102 cfu/gwith treatment S1-CO T3. It was obvious that the soil utilized in the study wascontaining oxidizing thiosulphate T. thioparus photo-autotrophic bacteria in wich itsactivity increased with the treatment S1-CO T3. The amount of oxidation ofthiosulphate was 377 mg/100 ml, and the Ph at the media was 5.71. the soil utilizedwas void of sulfur oxidizing bacteria.