Abstract
The current farming system in China is heavily reliant on synthetic fertilizers, which adversely affect soil quality and crop production. Therefore, the aim of this study was to assess the effect of different nitrogen (N) and phosphorous (P) fertilizer application rate on the growth, yield, and yield components of rice cultivars in the Binyang, Beiliu and Liucheng sites of southern China in the early (March to July) and late season (August to December). The study consisted of three fertilization regimes-CK (N(0)P(0)); N(180)P(90) (180 kg N + 90 kg P(2)O(5) ha(-1)) and N(90)P(45) (90 kg N ha(-1) + 45 kg P(2)O(5))-conducted at each of three different experimental sites with four cultivars (Baixang 139, Y Liangyou 1, Guiyu 9, and Teyou 582). Results showed that the leaf area index (LAI) was 38.8% found higher in Guiyu 9 compared with Baxiang at reduced fertilization (N(90)P(45)). N(90)P(45) resulted higher dry matter production at the heading (9411.2 kg ha(-1)) and maturity (15319.5 kg ha(-1)) stages in Teyou 582 at Beiliu. Fertilization (N(180)P(90)) had higher effective panicle number (4,158,800 panicle ha(-1)) and grains panicle(-1) (113.84 grains) compared with other treatments. Teyou 582 treated with N(90)P(45) and Y Liangyou 1 treated with N(180)P(90) improved seed setting rate average by 82.91% and 72.17% compared with other treatments at Beiliu in both seasons, respectively. N(0)P(0) and N(90)P(45) increased the thousand-grain weight (TGW) of Y Liangyou 1 at Binyang (27.07 g) and Liucheng (27.84 g) during the early and late seasons, respectively. In Beiliu, the N(90)P(45) treatment (6611.7 kg ha(-1)) of Teyou 582 increased grain yield compared with other treatments. Overall, our results suggested that reducing N and P at the ratio of 90:45 kg ha(-1) in Teyou 582 and Y Liangyou 1 could increase rice grain yield and yield components.