播种密度对雨养夏玉米产量形成的调控效应

Effects of Plant Densities on Rain-fed Summer Maize Yield Formation

为探究种植密度对宜籽粒机收夏玉米产量形成的调控效应,以‘京农科728’为材料,设置60000株·hm^(-2)(PD1)、67500株·hm^(-2)(PD2)、75000株·hm^(-2)(PD3)、82500株·hm^(-2)(PD4)和90000株·hm^(-2)(PD5)5个密度水平,测定农艺性状、叶面积指数、干物质积累与分配及产量。结果表明:在试验密度范围内,‘京农科728’在PD3和PD5穗位高比PD1显著增高10.4和12.2 cm;吐丝期叶面积指数PD1处理最低,为2.42,PD5最高,为4.61;成熟期PD3和PD4叶面积指数最大,为1.50~1.53。随着种植密度的增加,单株干物质积累量降低,但收获期群体干物质积累量显著提高,收获期PD3和PD4籽粒物质占比最高。行粒数和百粒质量随种植密度的增加而减少或降低;产量随种植密度呈抛物线变化趋势,PD3和PD4产量最高。综上,在华北平原北部地区,选用适宜籽粒机收玉米品种,增加密度至75000~82500株·hm^(-2),通过提高叶面积指数和干物质积累量,优化穗数、穗粒数和粒质量,实现产量稳定在11000 kg·hm^(-2)以上。

In order to study the effects of planting density on the yield formation of grain machine harvesting summer maize.'Jingnongke 728'(JNK 728)was used as the material,with 5 leves of density were set as 60000 plants·hm^(-2)(PD1),67500 plants·hm^(-2)(PD2),75000 plants·hm^(-2)(PD3),82500 plants·hm^(-2)(PD4)and 90000 plants·hm^(-2)(PD5),and plant agronomic traits,leaf area index,dry matter accumulation and distribution,and yield were measured.The results showed that,in the experimental density range,'JNK 728'ear height at PD3 and PD5 were significantly higher than PD1 by 10.4 cm and 12.2 cm.At silking stage,the leaf area index(LAI)under PD1 was the lowest as 2.42,and the PD5 was highest as 4.61,but at maturity stage the LAI of PD3 and PD4 were the highest as 1.50-1.53.Dry matter accumulation per plant were decreased with density increased,but population dry matter accumulation increased significantly at maturity stage,while stemratio was higher than leaf at silking stage,and PD3 and PD4 grain proportion at maturity stage were the highest.With the density increased,row grains number and 100-grains weight were decreased,but grain yield showed a quadratic trend,and PD3 and PD4 treatments obtained the highest yield.In conclusion,grain machine harvesting summer maize plant density increased to 75000-82500 plants·hm^(-2),it could achieve a stable yield above 11000 kg·hm^(-2) through increase LAI and dry matter accumulation,optimize ears number,ear grains number and grain weight in northern region of the North China Plain.