全膜双垄沟覆盖条件下不同施氮量对春玉米氮素吸收利用及分配的影响

通过田间试验研究了黄土旱塬旱作全膜双垄沟覆盖栽培条件下,不同施氮量（0、100、200、250、300及400 kg/hm²）对春玉米氮素吸收、利用及分配的影响,为提高春玉米氮素利用效率及合理施氮提供理论依据。结果表明:（1）春玉米植株及籽粒含氮量、氮素累积量随施氮量增加而提高,但当施氮量超过250 kg/hm²后增加效果不显著。（2）春玉米植株含氮量随生育期推进而降低,但氮素累积量则随生育期推进而增加。（3）玉米叶片及茎+叶鞘氮素转移量及对籽粒氮素贡献量高于其他器官。（4）春玉米籽粒产量随施氮量增加先增加后降低,并在施氮量为250 kg/hm²时产量最大（11 932 kg/hm²）,此时氮素收获指数最大（69.12%）并显著高于其余处理,氮肥农学效率也显著高于施氮量为300、400 kg/hm²的处理。因此,从春玉米产量、氮素利用角度考虑,该试验条件下的合理施氮量为250 kg/hm²。

Effect of Different Nitrogen Rates on Nitrogen Absorption and Allocation of Spring Maize in Double Ridges Mulched with Plastic Film

A field experiment was carried out on dryland of loess plateau to study the effect of different nitrogen rates on nitrogen absorption and allocation of spring maize in double ridges mulched with plastic film.Six nitrogen rates are 0,100,200,250,300 and 400 kg/hm².The experimental results showed that:(1)The content of nitrogen and the nitrogen accumulation and kernel increased with the improvement of levels on nitrogen application,while the effect is not significant when nitrogen application exceed 250 kg/hm².(2)With the growing stage increasing,the nitrogen content of spring maize decreased while the nitrogen uptake of spring maize increased.(3)The nitrogen translocation amount and the transferred nitrogen contribution ratio of leaf and stem+sheath are higher than that of other organs.(4)With the increase of nitrogen application,the kernel yield increased firstly and then decreased.The kernel yield is the maximum when nitrogen rate is 250 kg/hm² and the kernel yield is 11 932 kg/hm².In addition,the nitrogen harvest index,nitrogen agronomic efficiency of the nitrogen level of 250 kg/hm² are higher than that of the nitrogen level of 300 and 400 kg/hm².From the consideration of spring maize yield,nitrogen utilization point of view,250 kg/hm² is a reasonable nitrogen rate.