| 摘要: |
| 【目的】研究长期不同管理措施和作物轮作体系下，不同施肥处理土壤剖面中无机碳含量分布和无机碳储量及其与耕层土壤有机碳含量的关系。【方法】采用长期定位试验（1990－2014年），以土娄土为供试土壤，设置裸地休闲、自然撂荒及冬小麦 夏玉米轮作体系（以下简称作物轮作体系）3种土壤管理措施，其中作物轮作体系设9个施肥处理，分别为不施肥（对照，CK）、氮肥（N）、氮钾（NK）、磷钾（PK）、氮磷（NP）、氮磷钾（NPK）、秸秆+氮磷钾（SNPK）、低量有机肥+氮磷钾（M1NPK）和高量有机肥+氮磷钾（M2NPK），共计11个处理，测定耕层（0～20 cm）有机碳含量、不同土层（0～300 cm）无机碳含量，并计算0～100 cm、0～300 cm土层无机碳储量，然后分析不同土层无机碳储量与耕层有机碳含量的关系。【结果】不同土壤管理措施显著影响了0～20 cm土层有机碳含量，其中长期撂荒与作物轮作体系的土壤有机碳含量相近，且显著高于裸地休闲处理。在作物轮作体系下，不同施肥处理对0～20 cm 土层有机碳含量也有明显影响，其中有机物和N、P、K配施的SNPK、M1NPK、M2NPK处理的有机碳含量显著高于CK。不同土壤管理措施和作物轮作体系下各施肥处理0～300 cm土层的无机碳含量分布均呈类似“S”形曲线， 其中0～40 cm土层较高，随着土层深度的增加无机碳含量下降较快，在80～140 cm土层最低，然后逐步升高到160～180 cm达到最高值，之后一直呈缓慢下降趋势。对于0～100 cm土层无机碳储量，裸地休闲处理显著高于自然撂荒和作物轮作体系处理；作物轮作体系中M2NPK处理显著高于其他处理。对于0～300 cm土层无机碳储量，裸地休闲处理显著高于自然撂荒处理；作物轮作体系中施用有机肥处理则显著低于其他施肥处理，其他施肥处理均提高了0～300 cm土层无机碳储量，其中PK、NP、NPK、SNPK处理显著高于CK。0～100 cm土层无机碳储量与耕层土壤有机碳含量之间呈显著正相关，但0～300 cm土层无机碳储量与耕层土壤有机碳含量呈负相关。【结论】在干旱、半干旱地区，如果有灌溉条件，建议用0～300 cm土层无机碳储量来研究无机碳与有机碳的关系较为准确。另外在研究区施用有机肥可显著提高土壤有机质含量，但不能同时提高土壤无机碳固存。 |
| 关键词: 土娄土 长期试验 土壤有机碳 土壤无机碳 |
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| 基金项目:公益性行业（农业）科研项目（201203030） |
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| Effect of long-term soil management and fertilization on storage of soil inorganic carbon and its relationship with soil organic carbon content in plough layer of manual loess soil |
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YANG Wenjing,ZHANG Shulan,YANG Xueyun
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| Abstract: |
| 【Objective】The storages of soil organic carbon (SOC) and inorganic carbon (SIC) under soil management and fertilization were investigated.【Method】This study was based on a 24-year long experiment (1990－2014) in manual loess soil.There were three soil management regimes,i.e.bare fallow (Fallow),cropland abandonment (Set aside),and winter wheat and summer maize rotation system (Cropping).Under Cropping, there were nine nutrient management regimes,i.e.un-amended (control,CK),nitrogen (N),nitrogen and potassium (NK),phosphorus and potassium (PK),nitrogen and phosphorus (NP),nitrogen,phosphorus and potassium (NPK),wheat/maize straw (S) with NPK (SNPK) and two dose of dairy manure (M) with NPK (M1NPK and M2NPK).A total of eleven treatments were included.The contents of SOC in plough layer and SIC in different depths were measured and the correlation between SIC stock in different soil depths and SOC content in plough layer (0－20 cm) was analyzed.【Result】Set aside had significantly higher SOC content than Fallow in depth of 0－20 cm.Under Cropping system,the organic matter with N,P,and K fertilizers (SNPK,M1NPK,and M2NPK) had significant higher SOC contents than CK.Under different management and fertilization regimes,the distribution of SIC in soil profile of 0－300 cm showed the a “S” pattern.The content of SIC was high in topsoil (0－40 cm),then rapidly declined with the increase of soil depth and reached the lowest value at the depth of 80－140 cm before gradually increasing and reaching the maximum value at the depth of 160－180 cm.Fallow had significant higher SIC stock than Set aside and Cropping in the depth of 0－100 cm.Under cropping system,SIC stocks in depth of 0－100 cm in M2NPK treatment was significantly higher than others.Fallow had higher SIC stocks in depth of 0－300 cm soil than Set aside and SIC stocks in M1NPK and M2NPK treatments were significantly lower than other fertilizer treatments.The other fertilizer treatments increased SIC stocks in depth of 0－300 cm,and SIC stocks of PK,NP,NPK,and SNPK treatments were significantly higher than that of CK.SIC stocks in the depth of 0－100 cm were significantly and positively correlated with topsoil SOC content,while SIC stocks in the depth of 0－300 cm was negatively correlated with topsoil SOC content.【Conclusion】It is suggested to use the soil layer of 0-300 cm for investigation of the relationship between SOC and SIC in arid and semiarid areas.Applying organic manure could increase SOC content in soil but could not increase SIC sequestration. |
| Key words: lou soil long-term field experiment soil organic carbon soil inorganic carbon |
