氮磷养分供应及调控对夏玉米干物质及养分累积分配的影响

The effects of nitrogen and phosphorus application and regulation on accumulation and distribution of dry matter and nutrients in maize

采用田间小区试验方法,研究了不同氮磷养分供应及养分增效剂(机械活化磷MRP、长效复合肥增效剂NAM、聚合氨基酸肥料增效剂PAA)调控对夏玉米干物质及养分累积分配的影响。结果表明:缺施氮素(-N)或磷素(-P)显著影响干物质和氮磷钾养分在地上部各器官中的累积量,但在一定程度上刺激了氮磷在各生育时期向生长发育中心器官的分配。与不施增效剂的对照相比,MRP处理使收获时叶片中磷累积量增加34.8%~47.8%,分配比例增加22.1%~29.4%。NAM处理能改善拔节期玉米植株的氮素营养,促进灌浆后氮素向穗中的转移分配,使籽粒中氮素和干物质累积量分别增加9.4%和7.9%,分配比例分别增加6.5%和2.7%。PAA对玉米灌浆后营养器官中干物质及氮磷钾累积分配均有促进作用,但对籽粒影响不显著。综上说明,氮磷养分胁迫主要通过影响氮磷钾养分在玉米各器官中的累积量,影响其干物质的累积和产量形成,因此平衡施肥是保证高产的前提;施用MRP通过促进生育后期叶片中磷素累积分配提高磷肥利用率;施用NAM通过改善玉米生育前期氮素营养,最终提高籽粒中氮素及干物质累积量,获得较高产量和氮肥利用率;施用PAA能提高玉米灌浆后营养器官干物质和氮磷钾养分的累积分配,进而获得较高的干物质和养分累积总量。

In the present study, a field experiment was conducted to investigate the effects of applying nitrogen （N） and phosphorus （P） fertilizers as well as nutrient synergists （mechanical ground rock phosphorus ‘MRP’, long effect compound fertilizer synergist ‘NAM’, polymeric acid fertilizer synergist ‘PAA’） on the accumulation and distribution of dry matter （DM） and nutrients （i.e. N, P and K） in maize. The results showed that the accumulation of DM and nutrients in the above-ground organs of maize decreased significantly without N or P supply, while the distribution of N and P in the central organs of different growth stages was stimulated to a certain extent. Comparing with non-synergist control （NP）, the application of MRP significantly increased the accumulation and the proportionally distribution of P in leaves by 34.8%-47.8% and 22.1%-29.4% at harvest, respectively. Applying NAM promoted the distribution of N in ear after grain filling stage,resulting in increased accumulation of N and DM in kernel by 9.4% and 7.9%, and the proportion of distribution by 6.5% and 2.7%, respectively. Application of PAA could promote the accumulation and distribution of DM and N, P, K in vegetative organs after grain filling stage, but no significant effect on kernels was found. In conclusion, the lack of N and P influenced the accumulation of DM and grain yield mainly through reduced nutrients accumulation in organs of maize. Applying MRP increased P fertilizer use efficiency by enhancing the accumulation and distribution of P in leaves in later growth stages. The nutritional status of N at earlier growth stages was improved by NAM application that improved the accumulation of N and DM in kernels, thus leading to higher yield and N fertilizer use efficiency. Moreover, the application of PAA could improve the accumulation of DM and nutrients in vegetative organs after grain filling stage, resulting in higher total amount of DM and nutrients.