عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this investigation, the effects of rice (Oryza sativa cv. Ali Kazemi) cultivation, sewage sludge compost and chemical fertilizers on changes in pH, EC, potassium and sodium in an alkaline soil solution after submergence were studied under greenhouse conditions. A factorial experiment based on randomized complete blocks design with two replications including duration of submergence at 10 levels (2, 11, 30, 37, 42, 49, 56, 63, 78, 92 days) and source and amount of organic and chemical fertilizers in six levels (control, 100% chemical fertilizers, 20g sewage sludge compost per kg of soil with and without 50% chemical fertilizers, 40g sewage sludge compost per kg of soil with and without 50% chemical fertilizers) and rice cultivation at two levels (cultivated and uncultivated) was carried out. The results showed that by increasing the duration of soil submergence, the pH of alkaline soil solution in the treatment with 100% chemical fertilizers increased, while in the treatments including 20 and 40g sewage sludge compost/kg of soil with and without 50% chemical fertilizers it decreased. In the all treatments, after submergence the EC of soil solution initially increased and after reaching a maximum decreased. In the all treatments, by increasing duration of submergence, concentration of potassium in soil solution decreased, while sodium concentration in soil solution increased. The pH of soil solution increased by application of chemical fertilizers while it decreased by application of sewage sludge compost. The EC and concentrations of sodium and potassium in soil solution increased by application of sewage sludge compost and chemical fertilizers compared to the control. At the end of growth period, the pH of soil solution in cultivated treatments (rhizosphere) was lower than that of uncultivated (non-rhizosphere) treatments. The effect of rice cultivation on the EC of soil solution was not significant while its effect on the concentrations of sodium and potassium in soil solution was significant.