东北玉米化肥减施增效技术途径探讨

减肥增效是提高我国玉米竞争力、保护生态环境的重大需求。论文重点以东北玉米为研究对象,从玉米养分需求规律、养分高效品种的节肥潜力、化肥高效施用的4R技术、化肥的有机替代技术等方面论述减肥增效的技术途径。研究表明,东北地区每生产100 kg玉米籽粒产量的平均N、P_2O_5、K_2O的需求量范围分别为1.56—1.89、0.60—0.88和1.27—2.30 kg;吐丝后对氮磷的需求量分别占全生育期需求量的20%—30%和20%—40%,对籽粒氮磷的贡献率分别为20%—30%和30%—38%。在目前东北土壤生产力状况下,实现玉米12 000 kg·hm~(-2)的产量水平平均氮肥投入量约为180 kg·hm~(~(-2))。应用不同类型新型肥料的节约氮肥潜力为9—25 kg·hm~(-2),应用磷酸二铵和硫酸铵+过磷酸钙做启动肥可以促进苗期生长。应用高地隙追肥机可以有效延长追肥的适宜期,有利于使"养分供应匹配养分需求"。滴灌施肥技术适宜在风砂质地土壤及干旱频繁发生地区推广,实现增产19%—128%,产量可达12 000—13 000 kg·hm~(-2)。地下滴灌施肥技术增产效果相同,应该大力推广。利用主动冠层传感器Greenseeker,可以在春玉米V5-V8期很好地估测叶面积指数、地上部生物量以及植株吸氮量,并应用于变量、精准的氮肥推荐。因地制宜地应用秸秆还田技术,可以节省肥料投入,提升土壤质量。其中秸秆覆盖条耕技术(Strip-till)可以协调传统耕作与免耕的优点,有很好的应用前景。未来应该从农民实际应用的角度出发,将技术研究与技术推广相结合,针对不同的栽培耕作技术模式,建立农民可应用、或在不久的将来可应用的技术规程,实现大面积应用,达到区域性减肥增效的目标。

The Ways to Reduce Chemical Fertilizer Input and Increase Fertilizer Use Efficiency in Maize in Northeast China

To enhance the competitiveness of maize production and to protect the environment, it is necessary to reduce fertilizer input and to increase fertilizer use efficiency in China. Based on maize production in Northeast China, the ways to reduce fertilizer input and to increase fertilizer use efficiency are discussed from the viewpoints of the characteristics of maize nutrient requirements, the fertilizer-saving potential of nutrient-efficient cultivars, the 4R techniques for efficient fertilizer input and the alternative approaches by organic matter applications. To get 100 kg grain yield, the requirement for N, P₂O₅, K₂O in the plant was 1.56-1.89, 0.60-0.88, and 1.27-2.3 kg, respectively. Postsilking N and P uptake is 20%-30% and 20%-40% respectively, which contributes to the grain N and the grain P by 20%-30% and 30%-38%, respectively. At the current soil productivity condition, the N fertilizer requirement for a maize grain yield level of 12 000 kg·hm^-2 is around 180 kg·hm^-2. The application of various new-type fertilizer may save N fertilizer by 9-25 kg·hm^-2. Maize seedling growth can be improved by the application of starter fertilizer Diammonium phosphate and Ammonium sulphate + Calcium superphosphate. A high-clearance fertilizer applicator is required to apply fertilizer at later growth stage so as to match nutrient supply with plant nutrient demand. Fertigation techniques can be used in the sandy soil and/or under drought climate to increase maize yield by 19%-128%, with the highest yield level of 12 000-13 000 kg·hm^-2. Subsurface fertigation has similar effect as the surface fertigation and had a great potential for application. Greenseeker technique can be used to accurately estimate leaf area index, above-ground biomass, and N uptake at maize V5-V8 stage, and therefore to realize precision and variable recommendation of in-season N fertilizer input. Based on the climate and soil conditions in northeast China, various methods can be used to return maize straw residuals to the field so that fertilizer input can be reduced and soil quality is improved. Strip-till technique is expected to be applied greatly in this area because it combines both the advantages of traditional cultivation and no-till. The research in the future should take into account the farmers’ requirement and combines technique development with extension. The researchers should develop applicable technique protocols which target the specific cultivation and/or planting patterns and can be used in a large area now or in the future, so as to reduce fertilizer input and increase fertilizer efficiency in a regional level.