不同施肥模式下黄壤旱地土壤碳氮储量分布特征
Spatial Distribution of Carbon and Nitrogen Storage in Yellow Soil with Different Fertilization Practices

以长期定位试验为基础，研究不同施肥模式（不施肥CK、单施有机肥M、氮磷钾配施NPK、氮磷钾配施有机肥NPKM）对黄壤旱地土壤碳氮储量的影响。结果表明：与不施肥相比，施肥均能显著提高表层（0~20 cm）土壤碳氮质量分数，碳表现为M＞NPKM＞NPK,氮表现为NPKM＞M＞NPK,其质量分数均随土层增深而递减；CK、M、NPK、NPKM模式下黄壤旱地0~100 cm土层碳储量依次为122.55、218.57、161.95和177.76 t·hm-2，氮储量依次为11.55、15.08、12.25和13.19 t·hm-2，其施肥模式下耕层（0~20 cm）土壤碳氮储量占总储量的38.31%～42.95%和33.64%～38.20%。有机肥、化肥及有机无机配施能够显著提高耕层土壤有机碳、氮质量分数，有利于提升土壤养分供应能力，但同时也增加了农田系统碳氮损失的潜在风险。因此，从长远来看，有机物料的输入可以提高黄壤旱地土壤碳氮贮量，维持并提高土壤肥力和养分供应能力，更有利于黄壤区农业的可持续发展。
This study investigated the impacts of different fertilizing modes on the spatial distribution of carbon and nitrogen storage in yellow soil.Long-term fertilizing experiment (> 20 years) was performed with four treatments,denoted as control (i.e.no fertilization),M (i.e.organic fertilizer),NPK (i.e.nitrogen phosphorus and potassium fertilizer),and NPKM (i.e.blend of organic and inorganic fertilizer).The results showed that fertilization increased the contents of both carbon and nitrogen in the surface soil.In specific,the carbon content of three fertilizing treatments was M＞NPKM＞NPK and the nitrogen content was NPKM＞M＞NPK.Both carbon and nitrogen contents decreased with the depth of soil.At the soil depth of 0-100 cm,the carbon content was 122.55,218.57,161.95 and 177.76 t·hm-2 for the control,M,NPK,and NPKM treatment,respectively.On the other hand,their nitrogen content was 11.55,15.08,12.25 and 13.19 t·hm-2,respectively.It was noteworthy that the major storage of carbon and nitrogen was in the topsoil (0-20 cm),accounting for 38.31%-42.95% and 33.64%-38.20%,respectively.These results suggest that fertilization could increase the carbon and nitrogen contents in the plough layer,thereby improving nutrient supply in soil,but potentially increasing the loss of carbon and nitrogen from farmland system.Thus,the blend of organic fertilizers can potentially increase their economic viability and agricultural production as well as facilitate the storage and immobilization of carbon and nitrogen in soil for the sustainable development of agriculture in regions featured with yellow soil.