Effects of irrigation schedules and phosphorus fertilizer rates on grain yield and quality of upland rice and paddy rice

Abstract

With the shortage of water resources and environmental pollution caused by unreasonable fertilization, the research on water-nutrition interaction has become a hot topic. However, the synergistic effects of effects of phosphorus (P) application rates and irrigation schedules on grain yield and quality of paddy rice and upland rice were less studied. Field experiments were conducted on upland rice (japonica Zhonghan 3) and paddy rice (japonica yangfujing 8) under three P (P2O5) application rates, 50 (low amount, LP), 100 (normal amount, NP) and 150 kg ha −1 (high amount, HP) and two irrigation schedules, bare-dry (BD) and continuous flooding (CF, control). BD with HP and CF with HP were conducive to the highest yield of upland rice, but there was no significant difference between NP and HP for two varieties except for paddy rice under BD. The head rice rate of upland rice and paddy rice was the highest at LP under BD and CF, but there was no significant difference between NP and LP. The setback viscosity was the lowest and the breakdown viscosity was the highest for two varieties under BD with LP and under CF with NP, however, NP had no significant difference for two varieties compared to LP under BD and compared to HP under CF. Compared with CF, BD reduced grain yield, improved processing quality and appearance quality. The results suggested that bare-dry combined with normal P application for upland rice cultivation and continuous flooding combined with normal P application for paddy rice cultivation are promising options for increasing grain yield, processing quality and cooking quality.