覆草对旱种直播稻产量与品质的影响

Effect of Non-flooded Straw-mulching Cultivation on Grain Yield and Quality of Direct-seeding Rice

直播水稻品种扬稻6号（籼稻）和扬粳4038（粳稻）,并设覆草（麦秸秆）旱种、无覆盖旱种和无覆盖水种（出苗后保持浅水层）处理,研究了对水稻产量与品质的影响及其生理原因。结果表明,与无覆盖水种（对照）相比,两旱种处理的产量都有不同程度的降低,覆草旱种减产1.9%~6.6%,差异不显著,无覆盖旱种减产18.0%~27.6%,差异显著。覆草旱种显著提高了稻米的整精米率、胶稠度、清蛋白和谷蛋白含量,显著降低了垩白米率、垩白度和醇溶蛋白含量,还改善了稻米的食味性。无覆盖旱种直播结果则相反。覆草旱种可以获得较高的产量并可改善稻米品质的重要生理原因是增加了结实期剑叶膜质过氧化酶活性、光合速率、根系活力以及根系中吲哚-3-乙酸和玉米素＋玉米素核苷的含量。无覆盖旱种降低了上述指标值,致产量显著下降、米质变劣。

There are two problems in rice production in China： the one is the water shortage and another is labor shortage because of the climate change and economic development. Therefore, water-saving and labor-saving techniques should be developed. The direct-seeding is considered as a labor-saving while the non-flooded mulching cultivation as a water-saving practice. The aim of this study was to investigate if non-flooded straw mulching cultivation could maintain both grain yield and quality of direct-seeding rice. Two rice cultivars currently used in the production, Yangdao 6 （an indica） and Yangjing 4038 （a japonica）, were field grown using a direct-seeding method, and three treatments, non-flooded wheat-straw-mulching （SM）, non-flooded and no mulching （NM）, and traditional flooding and no mulching （control, TF）, were imposed from 10 days after sowing to maturity. Compared with that under TF, grain yield showed some reduction under both SM and NM. The reduction in yield was 1.9-6.6% under SM, and 18.0-27.6% under NM. The difference in grain yield was not significant between SM and TF, and was significant between NM and TF. SM significantly improved head rice, gel consistency, albumin, glutelin and eating quality, and significantly reduced chalky kernels, chalkiness and prolamine content, and NM had the opposite effect. The results indicated that non-flooded wheat-straw-mulching could maintain a high grain yield and improved grain quality for direct-seeding rice. Greater leaf photosynthetic rate, root activity, and contents of indole-3-acetic acid and zeatin＋zeatin riboside under such a practice contributed to a high grain yield and better quality, whereas NM significantly reduced these physiological parameters, and consequently reduced grain yield and quality.