长期施肥对设施土壤活性有机碳含量及碳库管理指数的影响

Effects of Long-term Fertilization on Soil Labile Organic Carbon Content and Carbon Pool Management Index in Greenhouse

以连续8年设施定位施肥田间试验为依托,选择不施肥(CK)、4个单施化肥(N0PK、N1PK、N2PK、N3PK)、有机肥(M)和4个化肥与有机肥配施(MN0PK、MN1PK、MN2PK、MN3PK)共10个处理,研究长期定位施肥对设施土壤总有机碳、活性有机碳及其组分(高、中和低活性有机碳)含量和碳库管理指数及其剖面分布的影响。研究结果表明,在0~50 cm土层,各施肥措施土壤总有机碳、活性有机碳含量均随土层深度加深呈逐渐下降趋势。与CK相比,单施化肥对土壤总有机碳含量影响不显著,单施有机肥和化肥与有机肥配施均可显著提高0~20 cm土层土壤总有机碳含量(P<0.05),增幅分别为104.9%~135.3%和97.6%~139.6%,也可显著提高0~50 cm土层土壤活性有机碳含量(P<0.05),增幅分别为33.8%~235.5%和33.8%~251.3%。在0~20 cm土层,与施用相同化肥相比,化肥与有机肥配施显著提升了土壤总有机碳含量(P<0.05),增幅分别为76.8%~174.7%;有机肥与中量化肥配施(MN2PK)处理施入有机肥中有机碳固定率为最大,平均为26.6%。在0~20 cm土层,与施用相同化肥相比,化肥与有机肥配施显著提升了土壤活性有机碳和高活性有机碳含量(P<0.05),增幅分别为99.6%~259.4%和122.2%~330.7%;土壤活性有机碳及其组分与总有机碳含量之间呈显著线性正相关(P<0.05),其中高活性有机碳与总有机碳含量的相关系数最大(r=0.953)。与施用相同化肥相比,化肥与有机肥配施可显著提高0~20 cm土层土壤活性有机碳及其高和中活性组分的碳库管理指数(P<0.05),土壤活性及其高和中活性组分的碳库管理指数随施氮量的增加而增加。综上,在设施番茄栽培条件下,连续8年化肥与有机肥配施可显著提高0~20 cm土层土壤总有机碳、活性有机碳及其高活性组分含量,进而显著提高了0~20 cm土层土壤活性有机碳及其高活性组分的碳库管理指数,提高了设施土壤肥力,改善了设施土壤质量;有机肥与中量化肥配施(MN2PK)是设施番茄可持续生产较为合理的管理措施。

In this study,a located fertilization experiment was conducted in a greenhouse for eight years,in which different treatments were set up as follows,no fertilization treatment(CK),four treatments of chemical fertilizer(N0PK,N1PK,N2PK,N3PK),manure treatment(M),and four treatments of chemical fertilizer combination with manure(MN0PK,MN1PK,MN2PK,MN3PK).The effects of long-term fertilization on soil total organic carbon(TOC),labile organic carbon(LOC)and its components(highly,moderately and lowly LOC)contents,and carbon pool management index(CPMI)and their profile distribution were studied.In the 0–50 cm layer,soil TOC and LOC contents of all fertilization measures showed a gradual decrease with the depth of soil layer.Compared with CK,the effects of application of chemical fertilizer(N0PK,N1PK,N2PK,N3PK)on soil TOC contents were not significant.The application of manure and the chemical fertilizer combination with manure(MN0PK,MN1PK,MN2PK,MN3PK)significantly increased soil TOC contents in the 0–20 cm layers(P<0.05),increased by 104.9%–135.3%and 97.6%–139.6%,respectively,and significantly increased the soil LOC contents in 0–50 cm soil layers(P<0.05),increased by 33.8%–235.5%and 33.8%–251.3%,respectively.In the 0–20 cm layer,the chemical fertilizer combination with manure significantly increased soil TOC contents compared with application of chemical fertilizer by 76.8%–174.7%,fixation ratios of organic carbon from manure under the medium application of chemical fertilizer combination with manure(MN2PK)treatment was the largest,with an average of 26.6%.In the 0–20 cm layer,the chemical fertilizer combination with manure significantly increased soil LOC and highly LOC contents compared with application of chemical fertilizer by 99.6%–259.4%and 122.2%–330.7%,respectively.The contents of soil LOC and its components were significantly linearly positively correlated with soil TOC content(P<0.05),the correlation coefficient between contents of highly LOC and TOC was the largest(r=0.908).Compared with the application of the same chemical fertilizer,the chemical fertilizer combination with manure significantly increased CPMI of soil LOC and its highly and moderately components in the 0–20 cm layer(P<0.05),CPMI of LOC,highly and moderately LOC increased with the increase of nitrogen application rate.In summary,under the condition of greenhouse tomato cultivation for eight years,the chemical fertilizer combination with manure significantly increased the contents of soil TOC,LOC and its highly components in the 0–20 cm layer,and CPMI of soil LOC and its highly components were significantly improved.The chemical fertilizer combination with manure increased soil fertility and improved soil quality.Medium-weight treatments of chemical fertilizer combination with manure treatments(MN2PK)is a reasonable management practice for sustainable production of tomatoes in greenhouse.