施氮量对直播虾稻抗倒性的影响

Effects of Nitrogen Fertilization on Lodging Resistance of Directly Seeded Rice Plants in Crayfish-Rice

【目的】虾稻模式是湖北省乃至南方稻区农业生产的重要模式,倒伏是影响这一模式水稻产量的主要因素之一,研究直播虾稻适宜施氮量可为其合理施肥提供理论依据。【方法】在虾稻连作模式下,采用典型虾稻品种玉针香、黄华占和鄂丰丝苗为试验材料,以不施肥为对照,设置3个施氮水平(120、150、180 kg·hm^(−2))的裂区试验,探讨施氮量对直播虾稻抗倒伏能力的影响。【结果】3个虾稻品种主茎倒5、倒4节的节间长度、株高及重心高度、弯曲力矩及倒4节间大小维管束数目随施氮量增加而增加,折断弯矩、大小维管束面积及茎壁厚度随施氮量增加呈先升后降趋势,倒伏指数随施氮量增加呈先降后升趋势。【结论】施氮量在不同虾稻品种的抗倒性存在差异,玉针香适宜施氮量为120 kg·hm^(−2),鄂丰丝苗适宜施氮量为120~150 kg·hm^(−2),黄华占适宜施氮量为150 kg·hm^(−2)。

【Objective】Crayfish-rice mode is the important mode for agriculture production in Hubei and even southern China.Lodging is one of the main factors that affect the yield of rice.The study on the suitable nitrogen application rate of direct seeding shrimp rice can provide a theoretical basis for its rational fertilization.【Method】Under the continuous cropping mode of crayfish-rice,using typical crayfish-rice varieties Yuzhenxiang,Huanghuazhan and Efengsimiao as experimental materials and no fertilization as control(CK),a split plot experiment was set up at three nitrogen application levels(120,150 and 180 kg·hm^(−2))to explore the effect of nitrogen application rate on the lodging resistance of direct seeding crayfish-rice.【Result】With increasing N application,the internode length,plant height,and gravity center height,bending momen of the 4th and 5th internode from the top,and big and small vascular bundles number of the 4th internode from the top of the rice plants increased,while the breaking momente,big and small vascular bundles area,and culm wall thickness increased initially followed by a decline,and the lodging index decreased at first and then rose.【Conclusion】The lodging resistance of the crayfish-rice cultivated rice plants in response to different N fertilizations varied among the 3 varieties.The optimal N application rate for Yuzhenxiang was 120 kg·hm^(−2),for Efengsimiao 120-150 kg·hm^(−2),and for Huanghuazhan 150 kg·hm^(−2).