添加石灰和秸秆对土有机碳固持的影响  

Effects of Lime and Straw Addition on SOC Sequestration in Tier Soil

作　　者：曹彬彬 朱熠辉 姜禹含 师江澜[1] 田霄鸿[1] CAO BinBin;ZHU YiHui;JIANG YuHan;SHI JiangLan;TIAN XiaoHong(College of Natural Resource and Environment,Northwest A&F University/Key Laboratory of Plant Nutrition and the Agro-environment in Northwest China,Ministry of Agriculture and Rural Affairs,Yangling 712100,Shaanxi)

机构地区：[1]西北农林科技大学资源环境学院/农业农村部西北植物营养与农业环境重点实验室,陕西杨凌712100

出　　处：《中国农业科学》2020年第20期4215-4225,共11页Scientia Agricultura Sinica

基　　金：国家重点研发计划(2016YFD0200308);陕西省重点研发计划(2019ZDLNY01-05-01);“十二五”国家科技支撑计划(2012BAD14B11)。

摘　　要：【目的】研究作物秸秆与石灰配施对土壤CO2排放、土壤有机碳(SOC)固持、土壤无机碳(SIC)转化的影响机制,以及SOC固持对初始SOC含量的响应。【方法】采用室内恒温培养试验及稳定同位素技术(13C),选用经16年不同碳氮水平管理,且长期进行冬小麦-夏休闲种植的2个供试土壤样品:S0N0土壤(不进行秸秆还田+不施用氮肥)和S1N1土壤(高量秸秆还田+高量施用氮肥:240 kg·hm-2),将S0N0土壤和S1N1土壤分别在添加秸秆(12g·kg-1)或不添加秸秆以及添加石灰(3 g·kg-1)或不添加石灰的情况下于25℃黑暗条件中培养120 d。【结果】未添加秸秆和石灰时,S1N1土壤的CO2累积释放量比S0N0土壤高出42.9%;添加等量秸秆不仅提高了S0N0土壤和S1N1土壤的CO2累积释放量(81.6%,70.4%),而且S0N0土壤CO2累积释放量的增加幅度高于S1N1土壤,这说明秸秆的添加对初始SOC含量低的土壤即S0N0土壤的原SOC矿化影响更大。但是无论添加秸秆与否,石灰的加入使S0N0土壤和S1N1土壤的CO2累积释放量分别降低了428.11和528.52 mg·kg-1。与空白土壤相比,添加秸秆使S0N0土壤和S1N1土壤的SOC含量分别提高了2.95和3.19 g·kg-1;但是与单独添加秸秆相比,同时添加秸秆和石灰使S1N1土壤的SOC显著降低了1.36 g·kg-1,而对S0N0土壤的SOC含量没有影响。利用13C稳定同位素技术发现,添加秸秆能促使新形成SOC;其中,S0N0土壤中新形成的SOC含量比S1N1土壤高出0.77 g·kg-1;然而与单独添加秸秆相比,同时添加石灰和秸秆后新形成的SOC与其相差无几,说明石灰的加入对秸秆的腐解不会造成影响。在S0N0土壤和S1N1土壤中,添加秸秆使SOC净固持量分别提高了3 066.3和2 480.53 mg·kg-1;同时添加石灰和秸秆对S0N0土壤的SOC净固持量无显著影响,但是S1N1土壤的SOC净固持量则呈现下降的趋势。石灰的加入使S0N0土壤和S1N1土壤的CO2释放量分别降低了469和529 mg·kg-1,同时使SIC含量分别提�【Objective】Soil organic carbon(SOC) sequestration is crucial for improving soil fertility and agricultural production sustainability. The soil inorganic carbon(SIC) is closely related to SOC with regarding with inter-transformation, which has also great effect on carbon sequestration. Crop straw return has been recognized as one of the most important organic amendment improving soil organic carbon sequestration in farmland. Meanwhile, the addition of lime also contributes greatly to increasing SIC,thereby affecting the SOC sequestration. However, the mechanism of simultaneous incorporation of crop straw and lime affecting on the CO2 emission, SOC and SIC dynamics are not well understood, and how the SOC sequestration responds to the initial level of SOC is not clear, particularly after straw return. 【Method】 The incubation experiment and stable isotope technique(13 C) were used in the study. The two tested soils were collected from a field with continuously cropping of winter wheat for 16 years, which was subjected to differential crop residue and nitrogen managements over long-term, including(1) S0N0 soil(no straw return+ nitrogen fertilizer application: 0);(2) S1N1 soil(high amount of straw return+ nitrogen fertilizer application: 240 kg·hm-2). And then the two soils were both incubated with or without addition of straw and lime for 120 days under 25℃. 【Result】 The study showed that the soil cumulative CO2 emission was observed 42.9% higher in S1N1 soils than that in S0N0 soils, when without straw and lime addition. In both soils, the straw addition alone increased the soil cumulative CO2 emission by averages of 81.6% and 70.4%, respectively, compared with straw absence. Meanwhile, the increase of the cumulative CO2 emission in S0N0 soils was higher than in S1N1 soils. This showed that straw addition had a greater impact on the native OC mineralization in soil with low initial SOC. Lime addition decreased soil cumulative CO2 emission in both soils whether straw addition or not. Straw addition inc

关 键 词：土壤碳 土壤呼吸 添加秸秆 施用石灰 同位素技术 

分 类 号：S156[农业科学—土壤学]