nitrogen, phosphor and potassium changes in soil and wheat under foliar application of leonardite, n and k

this study was carried out in order to evaluate the changes of nitrogen, phosphor and potassium uptake by wheat and remaining of them in soil under foliar application of leonardite and foliar application of n and k. the experiment was conducted in gorgan university of agricultural sciences and natural resources during 2013- 2014. the experiment was laid out a using split-plot arrangement based on complete block design with four replications. treatments were nitrogen and nitrogen+potassium fertilizers in main plots and foliar application of nitrogen, potassium, humic power and mega humat with control in subplots. the results showed that, the effect of chemical fertilizers was significant on soil k content in harvesting stage, plant p and k content at heading beginning stage and grain n, p and k content at maturity. the effect of foliar application of leonardite, urea and potassium was significant on p and k content at heading beginning and harvesting stages, plant n, p and k content at heading beginning stage and grain n, p and k content at maturity. interaction effect of chemical fertilizers and foliar application of leonardite, urea and potassium was significant on plant k content. mean comparison results showed that, foliar application of urea increased soil, plant and grain nitrogen content rather than other treatments. however, application of humic power and megahumat increased p uptake by wheat and accumulate in plant and grain tissues. also results showed that integrated application of nitrogen+potassium and foliar application of potassium increased wheat k content. in final these results suggested that application of chemical fertilizers and foliar application of leonardite, urea and potassium had more effective on npk supplying for wheat and uptake of these nutrients by wheat. also improvement in soil properties and fertility status was recorded when chemical fertilizers were integrated with leonardite, urea and potassium as foliar application.