西南地区玉米养分管理现状分析与评价

Current status and evaluation of nutrient management for maize in southwest China

为了解西南地区玉米施肥现状与养分管理存在的问题,对西南地区4个省10个县的202份玉米养分调查数据进行了分析和评价。结果表明:(1)西南地区玉米生产中基肥以复合(混)肥为主,追肥以尿素和复合(混)肥为主;有机肥、玉米专用肥、缓(控)释肥等新型肥料使用率低。(2)化肥N、P_2O_5和K_2O平均投入量分别为323.52、80.93和56.55 kg·hm^(-2),总体表现为氮肥过量和钾肥不足,氮肥超量施用比例为62.38%,钾肥施用不足比例为60.89%,且区域之间差异较大。(3)玉米基肥以穴施覆土为主,但追肥养分管理粗放,第1次和第2次追肥中采用穴施不覆土的农户比例分别为63.22%和59.76%,表土撒施的比例分别为10.34%和25.61%。建议分区域明确玉米氮肥投入限量标准,引导农户降低氮肥用量;增施有机肥,发挥养分替代效应,同时推行秸秆还田,补充土壤钾素,提高土壤持续生产能力;推进玉米机械化生产,实现种、肥同播和化肥深施,降低农田养分流失。

In order to understand the current situation of fertilization and nutrient resource input problems of maize in Southwest China,and put forward countermeasures to solve the problems,household survey data which were collected from ten different counties from 2016~2017 were used to evaluate the situation.The results showed that in this area,compound fertilizer was the main type of basal fertilizer for maize,and topdressing fertilizer was mainly depended on urea and compound fertilizer.Inputs of regional special compound fertilizer and slow-controlled-release fertilizers were heavily deficient in total southwest China,as well as organic manure in Sichuan hilly area and Chengdu Plain.The average rates of total N,P and K inputs for maize were N 323.52,P2O5 80.93 and K2O 56.55 kg·hm^-2,respectively.It was found that 62.38%of farmers used too much nitrogen fertilizer for maize,and 60.89%of farmers were insufficient for K2O application.Hill placement and backfilled with soil of basal fertilizer was accepted by most of farmers,but 63.22%of them chose hill placement with no backfilling in first topdressing and that of 59.76%in second topdressing,and more than10%farmers even broadcasted fertilizer on soil surface with no backfilling for topdressing fertilizer.Therefore it is important to make sure the safety threshold of chemical fertilizer application for maize in southwest China,to reduce chemical fertilizer especially nitrogen application amount,and improve the technologies of organic fertilizer combined with chemical fertilizer,straw returning,fertilizing and sowing at the same time by planter,otherwise,deep application of fertilizer also should be involved.