不同类型外源碳添加对灰漠土土壤碳储量的影响

为探究不同类型外源碳长期施用对耕层灰漠土土壤碳储存及固碳潜力的影响。通过田间定位试验设置秸秆不还田处理,即NPK处理(CK);NPK+1.5 t秸秆(NPKS);NPK+1.5 t有机肥(NPKM);NPK+1.5 t棉秆炭(NPKB1);NPK+3.0 t棉秆炭(NPKB2),选取2013—2021年采集的土壤为研究对象。对耕层灰漠土土壤容重(BD)、有机碳密度(SOCD)、有机碳累积速率、有机碳储量(SOCR)和施用年限与有机碳储量之间相关性进行分析。经过9年定位试验结果表明:(1)从2013—2021年BD变化趋势来看,施用NPKS、NPKM、NPKB1、NPKB2与NPK相比,均呈现降低趋势,与NPK相比平均分别降低1.84%,0.86%,5.03%,6.66%。(2)相比NPK,NPKS、NPKM、NPKB1、NPKB2处理中土壤SOCD提升幅度平均分别为12.21%,11.04%,24.14%,46.95%,其中,棉秆炭提升效果显著;累积速率分别提高73.16%,66.95%,133.52%,247.18%。(3)NPKS和NPKM处理相比SOCR增幅分别为11.67%~30.88%,12.2%~33.24%;NPKB1和NPKB2处理SOCR提升效果最为显著,相较于2013年最高提升幅度分别为29.28%,45.44%。 综合来看,秸秆还田、施用有机肥和棉秆炭均是提高灰漠土土壤碳储量的有效措施,其中,添加施棉秆炭处理更有利于灰漠土短期快速提高土壤有机碳固存,棉秆炭自身含有丰富的营养物质,长期添加棉秆炭提高土壤碳固存以及改善土壤肥力、缓解温室效应,从而作为实现碳中和的一种有效途径。

Effects of Different Types of Exogenous Carbon Addition on Soil Carbon Storage in Grey Desert Soil

In order to explore the effect of long-term application of different types of exogenous carbon on soil carbon storage and carbon sequestration potential of topsoil ash desert soil, the field positioning experiment, which included 5 treatment as no straw is returned to the field (NPK), NPK+ 1.5 t straw (NPKS), NPK+ 1.5 t organic fertilizer (NPKM), NPK+1.5 t cotton stalk carbon (NPKB1), and NPK+3.0 t cotton stalk carbon (NPKB2) was conducted. Soil collected from 2015 to 2021 was used as the research object. The correlation between soil bulk density (BD), organic carbon density (SOCD), organic carbon accumulation rate, organic carbon storage (SOCR), application years and organic carbon accumulation rate was analyzed. The results showed that (1) From the perspective of BD trend from 2013 to 2021, the application of NPKS, NPKM, NPKB1, and NPKB2 showed a consistent decreasing trend compared with NPK, with an average decrease of 1.84%, 0.86%, 5.03% and 6.66% compared with NPK, respectively. (2) Compared with NPK, soil SOCD increased by 12.21%, 11.04%, 24.14%, and 46.95% in NPKS, NPKM, NPKB1, and NPKB2 treatments, respectively, and cotton stalk carbon significantly improved soil SOCD. The cumulative rate increased by 73.16%, 66.95%, 133.52%, and 247.18%, respectively. (3) SOCR increased by 11.67% to 30.88% and 12.2%~33.24% in NPKS and NPKM treatments, respectively. NPKB1 and NPKB2 had the most significant SOCR improvement, with the highest improvement of 29.28% and 45.44% compared with 2013, respectively. Taken together, straw returned, cotton and organic carbon application is the effective measures to improve soil carbon of gray desert soil, in which addition of cotton carbon is more advantageous in short-term rapid increase soil organic carbon and carbon sequestration. Cotton charcoal itself contains rich nutrients. Long term cotton carbon addition increases soil carbon sequestration, improves soil fertility, alleviates the greenhouse effect, and is an effective way to achieve carbon neutrality.