Bio-indicators of soil fertility in rice rotation

ABSTRACT

The relationship between enzyme activities and some soil properties under rice rotation at two governorates was studied to find out whether or not the enzyme activities can be taken as a bioindicator to soil fertility. The results indicated that there are clear differences in soil enzyme activities [dehydrogenase, phosphatase, invertase and urease] at the different localities of the two governorates according to its soil fertility level. Significant positive correlation was established between the activities of dehydrogenase and urease and total bacterial counts, total fungi, phosphate-dissolving bacteria [PDB], ureolytic microorganisms and CO2 evolution. Phosphatase activity was positively correlated with total baccarat counts, total fungi and CO2 evolution but not correlated with PDB and ureolytic organisms. On the other hand, positive correlations were detected between invertase activity and each of total fungi, PDB, ureolytic organisms and evolved CO2