麦秸还田与实地氮肥管理对直播水稻生长的影响

大田直播粳稻品种扬粳9538，设置麦秸还田与不还田、不施氮肥、习惯施肥法(FFP)和基于叶绿素仪(SPAD)测定值的实地氮肥管理(SSNM)处理。结果表明，SSNM的氮肥施用量较FFP减少30.0%~31.3%，产量较FFP平均增加7.61%，施氮区秸秆还田的产量较秸秆未还田的平均增加2.65%。与秸秆未还田或FFP相比，秸秆还田和SSNM降低生育前期的分蘖数、叶面积指数和干物质积累，但抽穗及以后各处理间差异较小。秸秆还田增加了叶片中有机酸含量，增大了田间昼夜温湿度差；秸秆还田和SSNM处理提高了茎蘖成穗率与ATP酶活性，增加了结实期叶片的光合速率以及根系活力，有利于直播水稻生育后期群体的光合生产和提高物质生产效率。对秸秆还田和SSNM的产量和生育特性进行了讨论。

Effects of Wheat-Residue Application and Site-Specific Nitrogen Management on Growth and Development in Direct-Seeding Rice

The annual total amount of crop residue straw exceeds billion tons in China. However, about 45–60% of them are burnt or discarded, which not only wastes organic fertilizer source, but also pollutes the environment. Meanwhile, heavy use of nitrogen fertilizer has become a serious problem in rice production. The objective of this study was to investigate the effects of wheat straw incorporation to soil and site-specific nitrogen management (SSNM) on the growth and development in direct-seeding rice. A mid-season japonica rice cultivar Yangjing 9538 was directly sown in field with three nitrogen (N) fertilizer treatments, no N application, farmers’ fertilizer-N practice (FFP), and SSNM based on chlorophyll meter (SPAD) readings. The results showed that, compared with FFP, SSNM reduced N application by 30.0–31.3% and increased grain yield by 7.61%, on average. The grain yield in the wheat residue-incorporated treatment was 2.65%, on average, higher than that in the residue-removed treatment. In comparison with those under the residue removal and FFP, the number of stems and tillers, leaf area index, and biomass accumulation were less or lower under the residue incorporation and SSNM during the early growth period, but showed no significant difference at heading and thereafter. The residue incorporation increased the content of organic acid in leaves and the difference in temperature and relative humidity between day and night. Both the residue incorporation and SSNM increased the percentage of productive tillers, photosynthetic rate of the flag leaves, root activity, and ATPase activity during grain filling. The results suggest that both the residue incorporation and SSNM benefit the photosynthetic production of direct-seeding rice during the later growth period and an increase in the production efficiency.Reasons for the characteristics of the grain yield, growth and development under the residue incorporation and SSNM were discussed.