稻鱼共作头季稻栽植密度及留桩高度对水稻产量的影响OA

A plot comparative experiment of rice-fish culture under different planting densities and cutting height of the first-season crop was conducted to provide scientific basis for optimizing the green,simple and high-efficient technology system of rice-fish culture"good quality rice + ra-tooning rice".In the experiment,6 planting densities ranging from 15×104 to 27×104 holes·hm-2 and 5 cutting heights ranging from 0 to 30 cm were set up to observe,record and analyze the first-season rice and ratooning rice.The rice sheath blight grew severer and the annual yield of rice in treatment C(21×104 holes·hm-2)was the highest(9628.50 kg·hm-2),followed by treatment B(18×104 holes·hm-2,9614.3 kg·hm-2),treatment D(24×104 holes·hm-2,9555.0 kg·hm-2).The yield of ratooning rice increased with the increase of the cutting height and the cutting height of treatment D(25 cm)was the highest(1988.8 kg·hm-2).Among the yield components of rice,according to the yield contri-bution to from high to low was effective panicles per hm-2>filled grains per panicle>1000-grain weight;as cutting height decreased,heading stage was delayed accordingly(2～9 d);under the test conditions,rice in the 3 treatments with cutting height higher than 20 cm had normal grain filling and setting.The appropriate first-season rice planting density for rice-fish culture was 18×104～21×104 holes·hm-2;and the suitable cutting height of rice should be kept within 20～25 cm could resist autumn low temperature and obtain high yield.