连续7年施肥提升复垦土壤肥力提高玉米产量的驱动因子

Driving factors of improving fertility and maize yields in the reclaimed soils by seven years of applied organic manure and chemical fertilizer

研究长期施肥对玉米连作体系下采煤塌陷区复垦土壤肥力变化和玉米产量的影响,明确玉米产量提高的驱动因素和最佳施肥处理,可为该区域培肥土壤和耕地质量提升提供理论依据。该研究依托7 a(2014—2020年)复垦定位肥料试验基地,设置不施肥对照(CK)、氮磷钾平衡施肥(NPK)、单施有机肥(M)和有机肥配施无机肥(MNPK)4个处理,采集0~20 cm土层土壤样品,研究不同施肥处理对作物产量、土壤化学指标(包括有机质、全氮、有效磷、速效钾、有效铁锰铜锌含量)、土壤物理指标,即团聚体分布比例及其碳氮含量以及土壤生物指标,即与碳循环相关的土壤酶活性的影响。结果表明,施化肥及有机肥较CK均显著提高了玉米籽粒产量,且以M处理的增幅最大。M处理显著提高了土壤有机质、全氮、速效钾及有效锰含量,增幅分别为21.50%、12.50%、98.37%及20.19%;MNPK处理改善了土壤的基本性质,显著提高了大粒径团聚体(>2 mm)中有机碳和全氮含量,增幅分别达68.68%和471.43%,但是显著降低了土壤有效铜和有效锌含量,降幅分别为16.67%和16.46%。而且施加有机肥后,加速了大团聚体(0.25~2 mm)的破碎,伴随着粉黏粒组分(<0.053 mm)数量的增加。此外,NPK处理显著提高了β-葡萄糖苷酶活性,增幅为29.17%,但是显著降低了脲酶活性,降幅为29.79%,施有机肥(M和MNPK)显著提高了蔗糖酶、β-葡萄糖苷酶、脲酶和碱性磷酸酶活性,增幅分别为45.87%~73.39%、54.98%~60.73%、43.09%~80.32%和51.52%~54.97%。进一步通过主成分分析以及土壤肥力综合指数评价,表明单施有机肥是该复垦区域耕地质量提升和维持土地生产力较好的农田管理措施。结合冗余分析结果可知,β-葡萄糖苷酶是评价土壤肥力的敏感性指标,它对玉米籽粒产量和土壤有机质含量的贡献率高达72.40%。因此,在现有的农田管理条件下,单施有机肥主要通过增强β-葡萄糖苷酶活性进而促进复垦土壤肥力的形成,最终提高了作物产量,是维持该复垦区作物高产稳产和培育耕地质量的有效措施。

This study aims to clarify the effects of long-term different fertilization on the soil fertility and grain yield under the continuous maize cropping system in coal mining subsidence areas.The key soil factors were determined in the fertilization treatments for the high maize yield.Four treatments were set with no fertilization(CK),nitrogen,phosphorus and potassium fertilizer(NPK),organic manure alone(M),and organic manure combined with chemical fertilizer(MNPK).Soil samples were also collected in the 0-20 cm thickness.A systematic investigation was made to explore the effects of fertilization treatments on the crop yield,contents of soil organic matter(SOM),total nitrogen(TN),available phosphorus(AP),available potassium(AK),available iron(A-Fe),available manganese(A-Mn),available copper(A-Cu),available zinc(A-Zn),the distribution of aggregates and associated carbon and nitrogen content,as well as the enzyme activities related to carbon cycle.The results showed that the NPK,M and MNPK treatments significantly increased the maize grain yield,especially for M treatment,compared with the CK treatment.M treatment significantly increased the SOM,TN,AK,and A-Mn contents,which increased by 21.50%,12.50%,98.37%,and 20.19%,respectively.MNPK treatment was improved the properties of the reclaimed soil.There was the significant increase in the>2 mm aggregate associated with organic carbon and total nitrogen contents,which were 68.68%and 471.43%,respectively.But the soil A-Cu,and A-Zn contents were reduced by 16.67%and 16.46%,respectively.Moreover,the application of manure(M and MNPK)accelerated the crushing of large macroaggregate(0.25-2 mm),accompanied by the increase of the proportion of silt and clay fraction(<0.053 mm).In addition,NPK treatment significantly increased the activity ofβ-glucosidase by 29.17%,but the urease activity was reduced by 29.79%.M and MNPK treatment significantly increased the activities of sucrase,β-glucosidase,urease and alkaline phosphatase,with the increases of 45.87%-73.39%,54.98%-60.73%,43.09%-80.32%and 51.52%-54.97%,respectively.Furthermore,the principal component analysis showed that the application of organic manure alone was the better management measure to improve the quality of cultivated land and maintain land productivity in this reclaimed area.The redundant analysis showed thatβ-glucosidase was a sensitivity index to evaluate the soil fertility,which was contributed 72.40%to the maize grain yield and SOM content.Therefore,the application of organic manure alone can be expected to promote the formation of soil fertility of reclamation under the existing farmland management.The activity ofβ-glucosidase was enhanced to ultimately improve the crop yield.The effective measure can also be used to maintain the high and stable crop yield for the cultivated land quality in this reclaimed area.The finding can provide a theoretical basis for the improvement of soil and cultivated land quality..