Effects of water-nitrogen interaction on absorption, translocation and distribution of nitrogen, phosphorus, and potassium in rice.

Hybrid rice Gangyou 527 was used to investigate the effects of three irrigation regimes (submerged irrigation,W1; dry cultivation,W3; and damp irrigation before booting stage plus shallow irrigation at booting stage plus wetting-drying alternation irrigation from heading stage to mature stage,W2) and different amounts of nitrogen (N) application on absorption,transport and distribution of N,phosphorus (P),and potassium (K) in rice,and study on correlations of N,P,and K absorption characteristics and its relationship with grain yield. The results showed that there was an obvious interaction between irrigation regime and among of N application. Correlation analysis indicated that there existed significantly or highly significantly positive correlations between the amounts of N,P,and K absorption,transfer,distribution,and between each of them and yield under water-nitrogen interaction at the mainly growth stages,and there existed highly significantly positive correlations between yield and the accumulations of N,P before heading stage and the amount of K absorption at tillering stage. Combining N,P,and K absorption characteristics and its relationship with grain yield performance,W2 with suitable N application amount (N180) was the best model in this paper referred as the water-nitrogen coupling management model,optimum N application amount was 180 kg ha-1 for submerged irrigation,and 90–180 kg ha-1 for dry cultivation conditions.