遮阴及氮肥对新疆南疆冬小麦粒重和灌浆特性的影响

Effects of shading and nitrogen fertilizer on grain weight and grain-filling characteristics of winter wheat in Southern Xinjiang

关键词:  遮阴  氮肥  粒重  灌浆特性  小麦

Key words:  shading  nitrogen fertilizer  grain weight  grain-filling characteristics  wheat

摘要:

为明确遮阴及氮肥对新疆南疆冬小麦籽粒灌浆特性的影响，大田条件下以‘新冬20号’为材料，设置4种遮阴处理(S₀，S₁，S₂和S₃)和4种氮肥水平(N₀，N₁，N₂和N₃)，分析遮阴和氮肥互作对南疆冬小麦粒重和籽粒灌浆特性的影响。结果表明:遮阴和施氮对冬小麦千粒重的影响均达显著水平，且遮阴处理对冬小麦千粒重的影响大于施氮影响。千粒重与灌浆速率、阶段籽粒累积量呈极显著正相关。不遮阴(S₀)和轻度遮阴(S₁)处理，灌浆速率随着施氮量的增加先增加后降低，随遮阴程度的增加而降低；灌浆持续时间随遮阴程度和施氮量的增加而延长；N₂S₁处理阶段籽粒重量和千粒重高于其他处理(除N₀S₁外)；在中度遮阴(S₂)和重度遮阴(S₃)条件下，灌浆速率随遮阴程度和施氮量的增加而降低，虽然快增期和缓增期持续时间有所延长，但阶段籽粒重量和千粒重随遮阴程度和施氮量的增加而降低。因此，在轻度遮阴(拔节期~抽穗期遮阴10%，抽穗期~成熟期遮阴25%)条件下，可以通过适量增施氮肥延长灌浆持续时间来弥补遮阴导致的灌浆速率下降，进而增加小麦粒重；在中度遮阴(拔节期~抽穗期遮阴20%，抽穗期~成熟期遮阴50%)和重度遮阴(拔节期~抽穗期遮阴30%，抽穗期~成熟期遮阴75%)条件下，应控制氮肥用量，拔节期追施纯氮103.5 kg/hm²以上虽然快增期和缓增期持续时间延长，但无法弥补遮阴和施氮下灌浆速率下降的不利影响，阶段籽粒重量和千粒重降低。

Abstract:

This study aims to determine the effects of different shading and nitrogen application rates on grain filling characteristics of winter wheat, and to provide theoretical basis for high yield and high efficiency cultivation of wheat under “Fruit-Wheat” intercropping mode in Southern Xinjiang. ‘Xindong 20'was used as experimental material. Four levels of shading treatments(S₀, S₁, S₂ and S₃)were designed and four levels of nitrogen fertilizer(N₀, N₁, N₂ and N₃)treatments were set at the jointing stage(after shading)to analyze that effect of different shading and nitrogen application rates on the grain weight and grain filling characteristics of winter wheat. The results showed that: The effects of shading and nitrogen application rates had an extremely significant effect on 1 000-grain weight of wheat, and the effect of shading on 1 000-grain weight was greater than that of nitrogen application. Correlation analysis between grain filling parameters and 1 000-grain weight indicated that 1 000-grain weight was positively correlated with grain filling rate and stage grain accumulation, and negatively correlated with grain filling duration. Under the conditions of no shading(S₀)and slight shading(S₁), the grain filling rate increased and then decreased with the increase of nitrogen application rates and it decreased with the increase of shading extent. The grain filling duration prolonged with the increase of shading extent and nitrogen application rates. The grain weight at growth stages and 1 000-grain weight of N₂S₁ treatment were higher than those of other treatments(except N₀S₁). The grain filling rate decreased with the increase of shading extent and nitrogen application rate under the moderate shading(S₂)and severe shading(S₃)treatments. Although the duration of rapidly and slowly growth stages were prolonged, the grain weight at growth stages and 1 000-grain weight decreased with the increase of shading extent and nitrogen application rate. Therefore, under the slight shading(shading at jointing stage-heading stage 10%, shading at heading stage-maturity stage 25%), the declining grain filling rate caused by shading can be compensated by increasing application of nitrogen fertilizer to prolong the filling duration at the gradually, rapidly and slowly growth stages, thus increasing the grain weight of wheat. Under the conditions of moderate shading(shading at jointing stage-heading stage 20%, shading at heading stage-maturity stage 50%)and severe shading(shading at jointing stage-heading stage 30%, shading at heading stage-maturity stage 75%), the duration of rapidly and slowly growth stages prolonged more than 103. 5 kg/hm² of pure nitrogen at jointing stage. However, it was unable to make up for the reduction of grain filling rate caused by shading and nitrogen application rates, and finally led to the decrease of grain weight at growth stages and 1 000-grain weight.