秸秆覆盖与施磷对旱地小麦小花发育与结实特性的影响

中国西南丘陵旱地气候冬干春旱且速效磷缺乏，是冬小麦生产的主要限制因素。为明确秸秆覆盖与施磷对西南丘陵旱地小麦小花发育与结实特性的影响，以川麦104为供试材料，采用裂区设计，主区为玉米秸秆覆盖(SM)和不覆盖(NSM),裂区为0、75和120 kg P₂O₅·hm^-23个施磷水平，比较分析了不同处理下小麦小花分化及结实特性的差异。结果表明，秸秆覆盖与施磷均可提高小麦小花分化数和可孕小花数，且磷素效应大于秸秆覆盖效应。与不施磷相比，施磷75和120 kg·hm^-2条件下最大分化小花数分别增加了17.4%和78.0%,可孕小花数分别增加27.0%和94.1%,小花存活率提高了16.5个百分点。施磷后穗基部可孕小花数和结实粒数增幅较大，穗中部和顶部增幅较小。与不施磷相比，施磷75和120 kg·hm^-2条件下，穗基部可孕小花数均极显著增加，增幅分别为100.0%和127.2%;结实粒数显著增加，增幅分别为186.4%和193.2%。秸秆覆盖后产量较不覆盖提高20.5%;施磷75和120...

Effects of Straw Mulching and Phosphorus Fertilization on Floret Development and Seed-Setting Rate of Dryland Wheat

The main limiting factors of winter wheat production are less rainfall in winter and spring, as well as serious lack of available phosphorus in hilly dryland of Southwest china. In order to clarify the relationship of straw mulching with phosphorus fertilization on floret development and seed-setting rate of dryland wheat, Chuanmai 104 was used as experimental material. The spilt plot design was employed with main plot of maize straw mulching (SM) and no mulching (NSM), and three kinds of phosphorus fertilization of 0, 75 and 120 kg·hm^-2 as sub-plot. The results showed that straw mulching and phosphorus application could increase the number of maximum florets and fertile florets, and phosphorus efficiency was higher than that of straw mulching. Compared with no fertilization of phosphorus, phosphorus fertilization at 75 kg·hm^-2 and 120 kg·hm^-2 increased the number of maximum florets and fertile florets by 17.4% and 27.0%, 78.0% and 94.1%, respectively, and the florets survival rate was increased by 16.5 percentage points. Phosphorus fertilization increased the number of fertile florets and grains number mostly at the basal of spike than at the central and apical position. Compared with no fertilization of phosphorus, phosphorus fertilization at 75 kg·hm^-2 and 120 kg·hm^-2 increased the number of fertile florets at the basal position of spike by 100.0% and 127.2%, and grain number per spike was increased by 186.4% and 193.2%, respectively. The grain yield under straw mulching was 20.5% greater than that under no mulching. Phosphorus at levels of 75 kg·hm^-2 and 120 kg·hm^-2 increased grain yield by 62.5% and 78.1%, respectively. It suggested that straw mulching with phosphorus could reduce florets degeneration, promote the number of fertile florets, and thus increase grain number per spike and grain yield.