| The experiment was carried out with pond culture under rain-proof shelter condition to investigate the release of mineral elements in soil and the absorption of mineral elements by upland rice plants.The results indicated that soil moisture influenced remarkably N,P and K content in soil and nutrients absorption by plants.With the increase of soil moisture,the NO-3-N content in soil was markedly decreased and the NH4+-N content was increased;The content of P changed with low-high-high curve under low soil moisture,and with high-low-high curve under high soil moisture;The content of K in the early tillering stage changed with low-high tendency under different soil moisture treatments,and its content in 65% and 100% treatments was higher than others during the mid and late tillering stage.As for the nutrients absorption by plants,the N content in upland rice was decreased continuously under 100% soil moisture,the P content assumed the "U" curve under 65% and 75% treatments,while the N,P and K content in upland rice assumed the "W" curve under other moisture treatments.With the increase of soil moisture,the total absorption quantity of N,P and K in upland rice was all added. |