the effect of soil drying and rewetting on dissolve organic carbon, organic and inorganic phosphorus and nitrogen

abstract soil drying and rewetting (drw) cycles are considered as environmental stress that would affect the physical, chemical and biological properties of soil and nutrient cycles. the study of soil drying and rewetting effects on plant nutrition and soil fertility is very important and crucial specially their environmental effects. in this study, the effects of 1, 2, 3, 4 and 5 drying and rewetting cycles on dissolved organic carbon (doc) and phosphorus (dop) and available forms of nitrogen (nitrite, nitrate and ammonium) in two alfisols in a completely randomized design with three replications were investigated. the results showed that with increasing drw cycles dissolved organic carbon, organic and inorganic phosphorus and ammonium decreased significantly in soil solution compared to control (samples were kept in wet condition). reduction in doc and dop could be due to the higher mineralization of organic carbon and phosphorus. dissolved organic nitrogen decreased significantly after three and four drying and rewetting cycles in soil 1 and soil 2 respectively. the highest amount of dissolved organic nitrogen was obtained in five drying and wetting cycles treatment.