Effects of different potassium (K) fertilizer rates on yield formation and lodging of rice

Abstract

As one of the most important nutrients for plants, potassium (K) has substantial effects on growth and development of crops. Present study was conducted in three different sites in South China in late season in 2019 with the objective to study the effects of different applied amounts of K fertilizer on yield formation and lodging of rice. Four K fertilizer treatments, K0: 0 kg potassium oxide (K2O) ha−1 (control); K1: 64.20 kg K2Oha−1;K2: 128.55 kg K2Oha−1 and K3 153.90 kg K2Oha−1 were applied in the field experiment. The results showed that K2 and K3 treatments significantly increased panicle number per unit area, grain number per panicle, seed-setting rate and the grain yield of rice compared with K0 treatment. Higher net photosynthetic rates were recorded in K2 and K3 treatments than K0 treatment at tillering stage, heading stage and maturity stage. K fertilizer treatments also increased the chlorophyll content and dry matter accumulation by 6.16–23.52% and 21.32–64.59% compared with K0 treatment, respectively. Moreover, the total N and K accumulation in the aboveground tissues of rice significantly increased under K2 and K3 treatments compared with K0 treatment. Furthermore, compared with K0 treatment, K fertilizer treatments significantly enhanced the breaking-resistant strength by 40.94–144.24% and reduced the lodging index of rice by 13.14–36.72%.