Effects of Non-flooded Mulching Cultivation on the Yield and Quality of Rice

Abstract

Plastic film or straw mulching cultivation under non-flooded condition has been considered as a new water-saving technique in rice production. This study aimed to investigate the yield performance in terms of quality and quantity under such practices. Two super rice cultivars, Wujing 15 (a japonica cultivar) and Liangyoupeijiu (an indica hybrid cultivar) were used with four cultivation treatments from transplanting to maturity: traditional flooding as control (TF), no-flooded plastic film mulching (PM), non-flooded wheat straw mulching (SM), and no flooding and no mulching (NM). Compared with that under TF, grain yield showed some reduction under all the non-flooded cultivations but differed largely among the treatments. The reduction in yield was 38.7-46.5% under NM, 9.8-17.4% under PM, and 1.7-7.0% under SM. The difference in grain yield was significant between NM and TF or between PM and TF, and was not significant between SM and TF. SM significantly improved milling, appearance, and cooking qualities, whereas PM or NM decreased these qualities. SM also significantly increased the peak visco- sity and breakdown value, and reduced setback value, and PM or NM had the opposite effect. The two cultivars showed similar trends in quality and quantity of rice yield. SM significantly increased root oxidation activity, leaf photosynthetic rate, and activities of key enzymes in sucrose-to-starch conversion in grains during the grain filling period, whereas PM and NM significantly reduced these parameters. The results indicate that SM could not only maintain a high grain yield, but also improve quality of rice. Increases in leaf photosynthetic rate, root activity, and activities of the key enzymes involved in the sucrose-starch metabolic pathway in grains under SM contributed to a higher grain yield and better quality of rice.