Effect Of Reduced Slow/controlled Release Fertilizer Input And Increased Efficiency Of Spring Maize In South Central Liaoning

Northeast China is the largest maize producing area,which plays an important role in guaranteeing national food security.In recent years,due to the shortage of agricultural labor force,one-time fertilization has gradually become a common phenomenon in maize production,which makes the application of slow/controlled release nitrogen fertilizers,stable fertilizers and other new nitrogen fertilizers gradually increased.However,at present,there are a wide variety of slow/controlled release fertilizers,most of which have unclear fertilizer efficiency.Fertilization recommendations for slow/controlled release fertilizers are seldom available for different regions and crops.Therefore,in view of the soil and climate characteristics in the central and southern part of Liaoning province,four kinds of slow/controlled release nitrogen fertilizers,which are widely used and representative in production,were selected.Field plot experiments were conducted in 2016 and 2017 to study the matching characteristics of spring maize yield,benefit and nitrogen release of slow/controlled release fertilizers with nitrogen absorption of Maize under different application conditions.Based on these,two kinds of slow/controlled release nitrogen fertilizers were screened out.The slow-release and controlled-release fertilizers suitable for local spring maize production were studied on the basis of these two kinds of slow-release and controlled-release fertilizers for reducing nitrogen and increasing efficiency of spring maize in central and southern Liaoning province,in order to provide guidance for the scientific application of new slow-release fertilizers in spring maize production in this area.The main research contents and results are as follows:1.Study on matching characteristics between nitrogen release of different slow and controlled release fertilizers and nitrogen absorption of spring maize in central and southern Liaoning provinceIn this study,nitrogen-free treatment?CK?,conventional urea application rate?CK1?and 10%nitrogen-reducing control treatment?CK2?,10%nitrogen-reducing treatment?F1,F2,F3 and F4?,F1:stable fertilizer?SU?,F2:urea-formaldehyde mixed fertilizer?UF?,F3:carbon-based corn slow-release fertilizer?BF?and F4:resin coated urea?RCU?were set up.The results showed that the yield of maize was F1>F3>F2>F4>CK2?2016?and F1>F4>CK2>F3>F2?2017?,among which the fertilizer efficiency of F1 and F4 was stable,and the nitrogen accumulation of Maize at different growth stages,especially after anthesis,was significantly increased by the treatments of slow/controlled release fertilizer and nitrogen reduction,F1>F2>F3>F4?the same results in two years?;In terms of fertilizer nitrogen supply,the inorganic nitrogen content in soil from maize heading stage to filling stage was the highest in the stable fertilizer treatment,and the inorganic nitrogen content in soil from maturity stage period was the highest in coated urea treatment.The correlation between nitrogen release of slow release fertilizer and nitrogen absorption of spring maize was significantly higher than that of ordinary urea,and both showed significant positive linear correlation.The correlation coefficients were F1>F2>F3>F4?2016?and F4>F1>F3>F2?2017?.Taking all the above factors into consideration,during the whole corn growth period the stable fertilizer and resin-coated urea had the best matching between nitrogen release and nitrogen absorption of spring corn in the one-time fertilization area of spring corn in the central and south of Liaoning province.2.Effects of reduced application of stabe fertilizer on soil inorganic nitrogen content and nitrogen utilization of spring maize.In this study,no-nitrogen treatment?CK?,conventional nitrogen application?CK1?and control treatment?CK2?of common urea and stable fertilizer treatment?S?were set.Three gradients?S1,S2,S3?were set for stable fertilizer nitrogen reduction treatment in shenyang test area,and two gradients?S1,S2?were set in haicheng test area.Nitrogen reduction in S1,S2 and S3 treatment was 10%,15%and 20%,respectively,compared with?CK1?treatment.The results showed that,compared with the treatment of fast-effect nitrogen fertilizer,the stable fertilizer could ensure the inorganic nitrogen content in surface soil to maintain a high level in the whole gr owth period of corn,meet the nitrogen demand in the growth and later stage of corn,and improve the inorganic nitrogen content in 0-40cm soil of mature stage of corn.With the increase of the reduced amount of stable fertilizer,the yield first increased and then decreased,in which the effect of S2 treatment on controlled release fertilizer was stable.Under the condition of nitrogen reduction,the yield and benefit of maize could be maintained and increased by 7.5%and 1795yuan hm^-2?compared with CK1?respectively.The apparent n utilization,agronomic n utilization and partial n productivity were 10.4%-12.4%,3.4%-6.2%and 6.5%-10.8%respectively?compared with CK1 treatment?.Considering the above factors,the one-time fertilization area of spring maize in the middle and south of Liaoning province is recommended to reduce nitrogen by about 15%,with the best effect.3.Effects of soil inorganic nitrogen and nitrogen absorbing by maize under the reduced nitrogen fertilizer application of resin coated ureaIn this study,no nitrogen treatment?CK0?,conventional nitrogen application?CK?and nitrogen reduction control treatment?CK1?and resin coated urea nitrogen reduction treatment?T0?were set.In shenyang test area,3 resin-coated urea and common urea were treated with nitrogen abatment in different proportions?T1,T2,T3?,and 2 treatments?T1,T2?were applied in haicheng test area.The ratios of T1,T2and T3 treatment with coated urea and ordinary urea were 8:2,6:4 and 4:6,respectively.The results showed that the yield of coated urea was 3.89%-25.76%higher than that of ordinary urea.The application of coated urea significantly promoted the nitrogen supply capacity in the early stage of soil and the nitrogen accumulation in the later stage of maize tasseling and spinning,and increased the nitrogen utilization rate and agricultural efficiency by 2.4%-6.2%and 2.5%-7.3%,respectively.Among them,the ratio of coated urea to ordinary urea was 6:4?T2treatment?showed the best effect.Regression analysis of different proportion of coated urea and maize yield data showed that 62%of coated urea and 38%of common urea combined application,can make the local corn yield and nitrogen apparent utilization and economic benefit is the highest and the most reasonable,and can give full play to the ordinary urea coated fertilizer,effectively increasing the mid and late spring corn soil inorganic nitrogen supply capacity,obtain significantly increase yield,improve the economic benefit..