Abstract: In order to investigate effects of straw returning and nitrogen application on dry matter accumulation and yield of indica hybrid rice in karst region of Guizhou province. The dry matter production characteristics of indica hybrid rice Nei5You5399 were studied as under different straw treatments and nitrogen application rates. The results showed that the yield and total biomass of rice first increased and subsequently decreased slowly with the increase of nitrogen application. Meanwhile, plant height, maximum tiller number, leaf area index, dry matter accumulation at key growth stages, dry matter accumulation at main growth stages, post-panicle ratio and total grain number per panicle increased with the increase of nitrogen application. In contrast, panicle rate and 1000-grain weight showed the opposite trends. Compared with straw leaving treatment at late growth stage, the dry matter accumulation and total grains per panicle of straw returning treatment increased by 10.9% and 2.4%, respectively, while the dry matter output rate, dry matter conversion rate, apparent dry matter output and seed setting rate of straw leaving treatment increased by 45.3%, 60.3%, 41% and 1.4%, respectively. In summary, under the experimental conditions, the optimum combination of rice straw treatment and nitrogen application rate in this area was straw returning and N 150 kg·hm^-2 application. The maximum actual yield could reach 9 758.02 kg·hm^-2, which increased by 18.9% compared with the combination of straw leaving the field and no N application. This study provid technical support for the sustainable development of indica hybrid rice in the karst region of Guizhou Province.

Key words: straw returning, nitrogen application, indica hybrid rice, dry matter accumulation, yield

摘要： 为探明秸秆还田和施氮量对贵州省喀斯特地区杂交籼稻干物质积累和产量的影响,以内5优5399为试验材料,在不同秸秆处理和施氮量条件下,研究杂交籼稻的产量和干物质积累特性。结果表明,随着施氮量的增加,水稻的产量和总生物量呈先增加后缓慢下降的趋势;株高、最高分蘖数、叶面积指数、关键生育期干物质积累、主要生育阶段干物质积累、穗后比例和每穗总粒数均随着施氮量的增加总体呈增加的趋势,而成穗率和千粒重与之相反。生育后期,秸秆还田处理的干物质积累量、每穗总粒数较秸秆离田处理分别增加10.9%、2.4%,而秸秆离田处理的茎鞘物质输出率、茎鞘物质转化率、茎叶物质的表观输出量和结实率较秸秆还田处理分别增加45.3%、60.3%、41%、1.4%。综上,本试验条件下,水稻最优组合为秸秆还田和施用N 150 kg·hm^-2,最高实际产量可达到9 758.02 kg·hm^-2,较秸秆离田和不施氮组合增产18.9%。本研究结果为贵州省喀斯特地区杂交籼稻的可持续发展提供了技术支持。

关键词: 秸秆还田, 施氮量, 杂交籼稻, 干物质, 产量