不同密度下施氮量对夏玉米产量和氮肥利用效率的影响

Effects of Nitrogen and Density on Summer Maize Yield and Nitrogen Use Efficiency

为明确施氮量对不同密度夏玉米的产量和氮肥利用效率的调控效应,以京农科728(JNK728)为材料,设置密度和施氮量的二因素随机区组试验。结果表明:施氮量增加显著提高JNK728叶片叶绿素含量(SPAD值);与N180相比,N300和N360叶面积指数(LAI)和单株干物质积累量(DM)显著增加。增加密度显著降低同等施氮水平下JNK728吐丝后穗位叶SPAD值和DM,但显著提高V12-R1+20阶段的LAI。增加施氮量和增加密度均可显著提高JNK728的产量,低密度下施氮量超过240 kg/hm^2显著增加穗行数和千粒质量而提高产量,高密度下施氮量超过300 kg/hm^2显著增加行粒数,增加密度通过增加穗数提高产量。施氮量增加氮肥偏生产力降低31.2%~72.3%,氮肥农学利用效率提高12.5%~52.6%,增加密度后氮肥偏生产力和氮肥农学利用效率均显著提高。总之,在本研究条件下,耐密抗倒夏玉米在7.5×104株/hm^2时,施氮量宜低于300 kg/hm^2,产量可达9.5×10~3 kg/hm^2;增加密度至9.0×10~4株/hm^2时施氮量在300~360 kg/hm^2为宜,产量可达12.0×10~3 kg/hm^2。总之,在本研究条件下,耐密抗倒夏玉米选择耐密抗倒品种在中密度(7.5×10~4株/hm2)时,施氮量宜低于300 kg/hm^2,产量可实现9.5×10~3 kg/hm^2,增加密度至9.0×10~4株/hm^2,施氮量在300~360 kg/hm^2为宜,产量可以达到12.0×103 kg/hm2。

In order to study the effects of nitrogen application on summer maize yield and nitrogen use efficiency under different plant density, a two-factor randomized block test design was conducted by Jingnongke 728(JNK728). The results showed that, maize ear leaf SPAD values increased significantly with nitrogen application increasing, and compare with N180, leaf ares index(LAI) and dry matter per plant(DM) were increased significantly under N300, N360. JNK728 leaf SPAD after silking and DM were significantly decreased with density increase under same N treatments, while LAI among V12 to R1+20 growth period increased significantly. Summer maize yield increased significantly with nitrogen application higher than 240 kg/ha by ear line number and 1000-grain weight increased under D7.5, while only by line grain number under D9.0. As well as, yield increased by ear number increased with density increasing. The N partial factor productivity(PFPN) significantly reduced 31.2%-72.3% with increasing N application, while nitrogen agronomic use efficiency(ANUE) increased 12.5%-52.6%. Maize PFPN and ANUE increased significantly by density increasing. In conclusion, the summer maize had resistant to lodging character under plant density was 7.5×10~4 plants/ha could obtained 9.5×10~3 kg/ha by nitrogen application lower than 300 kg/ha, while density increased to 9.0×10~4 plants/ha, nitrogen application should amonge 300-360 kg/ha could obtain higher yield of 12.0×10~3 kg/ha.