The Effect of Dry Cultivation on Yield, Water, and Iron Use Efficiency of Rice

Core Ideas Dry cultivation reduces yield, except for the absence of significant differences between plastic film mulching cultivation and continuously flooded in paddy rice. Dry cultivation increases Fe use efficiency and water use efficiency. The Fe per unit mass of rice grains in upland rice is richer than that in paddy rice. Dry cultivation is a good water conservation cultivation method in arid and semi‐arid regions with unstable irrigation sources while temperature is favorable to rice growth. Iron is not only an essential trace element for plant growth and development, but also an indispensable trace element for humans. The objective of this study was to investigate the Fe absorption and utilization, water use efficiency (WUE) and grain yield difference between upland rice ( Oryza sativa L.) cultivar Zhonghan 3 ( japonica ) and paddy rice cultivar Wuxiangjing 99‐8 ( japonica ) which were grown on the farm of the Yangzhou University under three cultivation patterns of continuously flooded condition (CF, control), plastic film mulching cultivation (PFMC), and bare cultivation (BC) under non‐flooded conditions. Compared with the CF, the grain yield was significantly lower under the PFMC for upland rice, but no significant difference was found for paddy rice, and grain yield was significantly reduced under BC for both upland rice and paddy rice. Dry cultivation lowered the Fe concentration in the rice plants and grain under the PFMC and the BC, and lowered the amount of Fe absorption in aboveground plants. Whereas, Fe use efficiency and WUE were all higher with dry cultivation. Compared with paddy rice, the Fe concentration in the whole root system of upland rice was 39.5% lower, but that in the roots was 11.3% higher at heading stage, and in the aboveground plants and rice flour was 3.4 to 11.1% higher at heading and maturity stages. The results indicate that dry cultivation is a good water conservation cultivation method in arid and semiarid regions with unstable irrigation sources while temperature is favorable to rice growth, such as in Southeast China.