免耕对土壤理化性状和直播稻生长及产量形成的影响

Impact of zero tillage on the soil characters and the growth and yield formation in direct seeding rice

为探明免耕直播稻的生长规律和免耕直播的环境效应,研究了稻田免耕直播对土壤理化性状和水稻生长及产量形成的影响。结果表明,稻田免耕后,土壤容重降低和孔隙性得到改善,土壤养分在土壤表层富集。与翻耕直播相比,免耕直播稻分蘖能力较弱,但无效分蘖较少,成穗率高。直播条件下,免耕更有利于叶面积的扩展。除齐穗期外,其它生育时期免耕稻的根系活力强,平均比翻耕提高4.45%。在最高分蘖期,免耕直播稻的根冠比和单蔸根干重高于翻耕直播稻。在翻耕和免耕条件下,干物质积累量及在茎、叶和穗中的分配比例无显著差异。免耕直播稻的实际产量为8.6t/hm2,比翻耕直播稻增产5.8%。另外,免耕直播稻的收获指数比翻耕直播稻高,增幅为13.3%,但未达到5%的显著差异水平。

To ascertain the growth pattern of no tillage and direct seeding (NT-DS) rice and its environment effects, the impact of NT-DS on the soil characters and the growth and yield formation of rice were studied. The results showed that NT-DS reduced the soil bulk density and improved the void properties. It is beneficial to enrich the soil nutrient in the surface layer of soils. Compared with conventional tillage and direct seeding (CT-DS) rice, NT-DS rice displayed weaker tillering capability, less unproductive tiller number and higher productive tiller percentage. It is beneficial to increase the leaf area index by using NT-DS. Except for fully heading stage, the α-NA oxidation ability of rice roots under NT-DS was 4.45% higher than that of CT-DS at other growth stages. The root/cap ratio and dry mqtter weight of root per punch under NT-DS were higher than that of CT-DS at maximum tillering stage.There were significant differences of the dry matter accumulation and its partition of rice between NT-DS and CT-DS. The actual yield of NT-DS rice was reach to 8.6 t/hm^2 and increased by 5.76% compared with CT-DS rice. In addition, the harvest index of NT-DS rice was 13.3% higher than that of CT-DS rice, but the difference was not significant between NT-DS and CT-DS.