长期施肥砂姜黑土微生物学特征差异及评价

Difference and assessment in microbial characteristics of lime concretion black soil affected by long-term fertilization

【目的】作为安徽省主要中低产土壤类型之一,砂姜黑土不良属性严重制约旱地粮食作物稳产增产,因此本研究利用长期定位试验研究砂姜黑土微生物特征对不同施肥模式的响应,为改善砂姜黑土生态功能、提高地力可持续性等提供理论依据。【方法】基于安徽省杨柳长期定位试验（始于1981年）,研究5种施肥模式不施肥（CK）、单施化肥（NPK）、单施有机肥（M）、有机肥与化肥配施（等氮）（MNPK）、有机肥与化肥配施（高氮）（HMNPK）砂姜黑土耕层土壤可培养微生物数量、微生物生物量及酶活性等微生物学性状的变化规律,并通过主成分分析方法对不同施肥模式下的土壤微生态进行综合评价。【结果】与不施肥相比,长期施用有机肥（M、MNPK和HMNPK）可显著增加土壤微生物总数量（15.68~22.80倍）,尤其是细菌和放线菌数量二者分别于M、MNPK处理达最高值（30.50×10~5cfu/g和15.50×10~4 cfu/g）;长期单施有机肥对土壤真菌有明显抑制作用,单施化肥有利于土壤真菌数量的增加。施用有机肥（M、MNPK和HMNPK）可有效增加土壤微生物生物量碳、氮含量,其中MNPK处理微生物量碳含量增幅最高,达119.74%但与M、HMNPK处理差异不明显,微生物量氮含量增幅达88.46%,显著高于M、HMNPK处理;长期单施化肥仅对微生物量碳含量有提增作用（38.87%）对微生物量氮作用不明显,其对微生物量碳的提增作用显著低于其他施肥处理。长期单施有机肥可显著提高土壤脲酶与转化酶活性,抑制磷酸酶活性,长期单施化肥的作用则相反。用主成分分析方法将9个生物指标降维提取出2个主成分,第一主成分以细菌、放线菌、微生物量碳、微生物量氮、脲酶和转化酶为主要影响因子,第二主成分以为真菌、酸性和中性磷酸酶为主要影响因子分别代表了与碳、氮和磷循环密切相关微生物影响因子。通过综合得分把不同施肥模式下砂姜黑土微生物生态划分为3个等级,一等包括长期有机肥与化肥配施（等氮与高氮）,二等包括长期单施有机肥,三等为长期单施化肥与不施肥。【结论】通过综合评价可得砂姜黑土的微生物生态状况在长期有机肥与化肥配施条件下最佳单施有机肥次之而长期单施化肥与不施肥的较差。

[Objectives]Being a major part of low-yielding soil types in Anhui province,lime concretion black soil restrains crop yields from increasing and stabilizing owing to its intrinsic properties.Based on a long-term fertilization experiment,responses of soil microbial properties to different fertilizer application were explored,which can provide a theoretical mechanism and support for improving lime concretion black soil ecological function and enhancing soil productive sustainability.[Methods]The long-term fertilization experiment,located in Yangliu Village of Anhui Province,was started since 1981,wheat and corn have been rotationally planted,all the straws are removed out of the plots after harvest.Five treatments were designed：non-fertilized（CK）,mineral fertilizer（NPK）,organic fertilizer（M）,mineral plus organic fertilizer（mineral N：organic N = 1：1,MNPK）,and mineral plus organic fertilizer with higher amount of nitrogen（HMNPK）.We investigated number of bacteria,fungi and actinomycete,microbial biomass-carbon（SMBC） and microbial biomass-nitrogen（SMBN）,and activities of urease,invertase,acid and neutral phosphatase.Principal components analysis was used to evaluate soil micro-ecosystem quality in different fertilization.[Results]1） Compared with CK,the organic fertilizer treatments（M,MNPK and HMNPK） significantly increased soil culturable microbes by 15.68-22.80 times,especially bacteria and actinomycete,the maxima were in treatment of M and MNPK with value of 30.50 X 105 and15.50 x 10 cfu/g,respectively.The fungi was inhibited by M,but increased obviously by NPK.2） The SMBC and SMBN were reinforced by the organic fertilizers（M,MNPK and HMNPK）,in which the maximal increments in SMBC and SMBN appeared in treatment of MNPK（119.74%and 88.46%）;NPK treatment enhanced the SMBC significantly（38.87%）,but affected SMBN slightly.3） The activities of soil urease and invertase were increased significantly by long-term application of organic fertilizer,while that of acid phosphatase was not.The effects of the NPK treatment on these enzyme activities were opposite to organic fertilizer.4） Two principal components were extracted from the initial 9 indicators.The major contributors of primary component were bacteria,actinomycete,SMBC,SMBN,urease and invertase,and the secondary contributors were fungi,acid and neutral phosphatase.Being evaluated comprehensively by principle components analysis,the micro-ecosystem qualities in treatments of MNPK and HMNPK were in the 1st level,M in the 2nd level and NPK and CK in the 3rd level.[Conclusions]The comprehensive best microbial ecological function in lime concretion black soil is found in the long-term organic plus inorganic fertilization condition,then is the mere organic fertilizer application and worst is the pure mineral fertilizer application and non-fertilization.