湖北双季稻区免耕直播油菜生长及产量形成

长江流域双季稻区因茬口紧、土壤黏重，晚稻收获后大都未种植下茬作物而形成冬闲田。本研究以华双5号油菜品种为材料，在湖北双季稻区三试验点进行裂区试验，测定油菜各生育期在不同氮素及密度水平下的个体及群体指标，成熟期考察经济性状及产量构成，为双季稻区免耕直播油菜示范及管理提供依据。结果表明：(1)双季稻区免耕直播油菜全生育期尤其是苗期显著缩短，苗期生长量严重不足，蕾薹期至开花期油菜生长快，春发特性明显；(2)氮肥及种植密度水平对双季稻区免耕直播油菜生长及产量有着显著影响，增施氮肥可改善个体素质、增加产量，提高密度可提高群体素质、增加产量；(3)湖北各试点每公顷纯氮用量270 kg、种植密度为45万株及60万株处理的产量均接近或达到2 250 kg hm^–2，超湖北平均单产，说明油菜免耕直播栽培模式可在湖北双季稻区试验示范；(4)生产实践中，应重视氮肥与密度的双重调节，以肥促长、以密补迟，相互配合。

Growth and Yield Formation of No-Tillage Direct-Seeding Rapeseed in Hubei Double Cropping Rice Area

After harvest of late rice, most farmlands in the Yangtze River basin are often fallow through winter due to tight rotation and heavy clay soil. For evaluating the possibility in application of the no-tillage and direct-seeding model for rapeseed production in the double cropping rice area, the split-plot experiments were carried out in the three locations in double cropping rice area of Hubei. Several parameters related to growth in terms of plant individual and population, grain yield and its components w...