施肥对我国农田土壤基础呼吸的影响

Response of soil basal respiration to fertilization across China’s croplands

【目的】基础呼吸是反映土壤质量的重要指标,采用整合分析研究施肥对我国不同种植制度和气候带农田基础呼吸的影响程度及其关键控制因素,为探究土壤肥力提升提供科学依据。【方法】通过以“施肥”、“土壤呼吸”、“有机碳矿化”、“soil CO_(2)efflux/soil CO_(2)emission”、“农田”为关键词,在Web of Science、中国知网、万方数据库,收集2000-2020年发表的相关文献,建立了586组配对试验数据,对肥料类型、施肥年限、施氮量、气候带、种植制度、利用方式等条件下的土壤基础呼吸数据进行标准化,采用Meta-analysis分析了土壤理化性状和生产条件指标对土壤基础呼吸的影响程度。【结果】与不施肥相比,施肥对土壤基础呼吸的提高幅度平均为60.20%,其中,施用有机肥的提高幅度为81.45%,显著高于施用化肥的47.78%。当施肥年限大于30年时,施用有机肥对土壤基础呼吸的提升幅度是施用化肥处理的1.38倍。适宜氮肥投入量[N 100~200 kg/(hm^(2)·a)]引发的土壤基础呼吸增幅(72.56%)大于高量[>200 kg/(hm^(2)·a)]和低量[<100 kg/(hm^(2)·a)]氮肥投入的增幅(44.65%和55.21%)。中温带地区施肥导致的土壤基础呼吸增幅(93.71%)显著高于亚热带(37.11%)和暖温带(40.64%)地区,施用化肥和有机肥对中温带地区土壤基础呼吸的提升效果(73.88%和110.91%)显著高于对亚热带地区(28.99%和45.00%)。施肥对旱地土壤基础呼吸的提升幅度(105.01%)显著高于对水田(28.90%)和水旱轮作(46.90%)。轮作模式下施肥对基础呼吸的提升幅度(101.60%)显著高于连作模式(50.63%)。相关性分析结果表明,土壤基础呼吸与土壤有机碳、全氮及微生物生物量碳、氮呈显著正相关。此外,施用有机肥处理下,土壤基础呼吸与碱解氮和微生物熵呈显著正相关。【结论】施肥对农田土壤基础呼吸的作用受到施肥年限、氮肥投入量、气候带、土地利用类型、种植制度、土壤质地等因素的共同影响。施肥能够显著提升土壤有机碳含量,并提高土壤基础呼吸。在较长时间(>30年)尺度上,施用有机肥相较于化肥能够显著提高土壤微生物生物量碳以及微生物熵,进而提高土壤基础呼吸,表明施用有机肥对土壤质量提升有积极的促进作用。

【Objectives】Soil basal respiration(SBR)is an important indicator for soil quality.We investigated the SBR differences caused by fertilizer types,dosages,and by other factors,trying to quantitatively define the influence degree and key factors in farmland of China.【Methods】The references were searched in keywords“fertilization”,“soil respiration”,“SOC mineralization”,“soil CO_(2) efflux/soil CO_(2) emission”,“farmland/cropland”that were published during 2000 and 2020 in the Web of Science,CNKI and CSCD database.Total of 586 pairs of experimental data were extracted and standardized to quantify the effects of fertilization(chemical and organic fertilizer)on SBR in different fertilization years,N application rates,climate zones,cropping systems,and land use types.The key factors related to the variation of SBR were analyzed by Meta-analysis.【Results】Fertilization significantly increased SBR by 60.20%,compared to no fertilization.The increase of SBR caused by organic fertilizer was 81.45%,which was significantly higher than that by chemical fertilizer(47.78%).When fertilizer was applied consecutively for more than 30 years,the SBR increase by organic fertilizer was 1.38 times of that by chemical fertilizer.The range of SBR increase under N application rate of 100−200 kg/(hm^(2)·a)(72.56%)was higher than those under>200 kg/(hm^(2)·a)and under<100 kg/(hm^(2)·a)(44.65%and 55.21%).Higher SBR by fertilization was recorded in mid-warm temperate zone(93.71%)than in subtropical and warm temperate zones(37.11%,40.64%).The effects of mineral and organic fertilizers on soil basal respiration in mid-warm temperate zone(73.88%and 110.91%)were significantly higher than those in subtropical zone(28.99%and 45.00%).Fertilization led to higher range of SBR increase in dry land(105.01%)than in paddy field(28.90%)and drought-flood rotation feild(46.90%).Higher SBR occurred in soils under rotation system(101.60%)than under continuous cropping system(50.63%).Correlation analysis showed that SBR was positively correlated with organic carbon,total N,microbial biomass carbon and nitrogen.In addition,there was a significant positive correlation between SBR and alkali-hydrolysable N and microbial quotient under the treatments of organic fertilizers.【Conclusions】Fertilization can significantly increase soil organic carbon content and soil basic respiration,the increment is impacted by fertilizer type,duration of fertilization,nitrogen input rate,climate,land use type,cropping system and soil texture.On a longer time scale(>30 years),organic fertilizer could significantly increase soil microbial biomass carbon and soil microbial quotient,thereby improve soil basal respiration more intensively than chemical fertilizers,and improve soil quality more efficiently.