| 摘要: 为探究浅埋滴灌下玉米连作秸秆连年还田土壤有机碳固存特征及其影响因素,基于连续7年的田间定位试验,设置玉米连作秸秆连年全量还田0年(0a)、3年(3a)、5年(5a)和7年(7a)4个处理,对不同秸秆还田年限玉米耕层土壤结构、胞外酶活性、不同有机碳组分含量、储量、固碳量和碳库管理指数进行对比,探讨秸秆还田年限对玉米耕层土壤有机碳固存的影响。与0a处理相比,0~30 cm土层7a广义土壤结构指数和土壤三相结构距离分别降低了3.21%、3.76%、2.99%和22.0%、12.4%、6.36%；不同处理几何平均酶活性和总体酶活性差异显著,0~30cm土层7a、5a、3a几何平均酶活性和总体酶活性分别较0a提高了20.8%、15.7%、10.0%和20.4%、16.3%、12.4%；不同处理土壤有机碳、易氧化有机碳、水溶性有机碳、微生物碳含量和储量均表现为 7a、5a 和3a 显著高于0a,0~30cm土层7a、5a土壤固碳量均显著高于3a,7a、5a分别较3a提高了221%、160%；0~30 cm土层各处理碳库指数和碳库管理指数的差异显著,7a、5a分别较3a提高了26.1%、17.0%和19.9%、7.00%；土壤β-1,4-N-乙酰氨基葡萄糖苷酶活性、液相体积分数、土壤三相结构距离、土壤纤维素酶活性和土壤β-葡萄糖苷酶活性是影响不同年限玉米秸秆还田土壤有机碳固存的主要因素,其解释率分别为 76.0%、4.10% 、3.30%、1.70%、3.40% (P<0.05)。浅埋滴灌下玉米秸秆还田通过改变土壤三相比,提高了土壤结构的稳定性,同时提高了与土壤碳素相关的土壤胞外酶活性,进而提高了土壤有机碳的固存和碳库指数。 |
| 关键词: 浅埋滴灌 秸秆还田年限 土壤特性 有机碳固存 碳库管理指数 |
| 中图分类号:S513 |
| 基金项目:国家自然科学基金(32060435、32160509)。联系方式葛选良E-mail: gexuanliang@163.com;* 通信作者杨恒山E-mail: yanghengshan2003@aliyun.com |
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| Study on soil organic carbon sequestration characteristics and influencing factors of different maize straw returning years under the shallow buried irrigation |
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GE Xuan-liang1, YANG Heng-shan1, YANG Xue-zhen1, ZHANG Rui-fu1, LIU Jing1, LI Ying-ying2
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1.College of Agronomy of Inner Mongolia Minzu University/Engineering Research Center of Forage Crops of Inner Mongolia Autonomous;2.Tongliao Horqin District Agricultural Technology Extension Center
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| Abstract: The soil organic carbon sequestration characteristics and influencing factors of maize straw returning years under shallow drip irrigation were explored. Based on seven consecutive years of field positioning experiments, treatments of 0 year, 3 years (3a), 5 years (5a) and 7 years (7a) of full straw returning were applied to compare soil structure, extracellular enzyme activity, carbon components content, storage, sequestration and pool management index, and to explore the effects of straw returning year on soil organic carbon sequestration. Compared with 0a, the generalized soil structure index and soil three-phase structure distance in the 7a 0~30 cm soil layer decreased by 3.21%, 3.76%, 2.99%, 22.0%, 12.4% and 6.36%, respectively. The geometric mean enzyme activity and total enzyme activity of different treatments were significantly different, and the geometric average enzyme activity and total enzyme activity of 7a, 5a and 3a in the 0~30cm soil layer increased by 20.8%, 15.7%, 10.0% and 20.4%, 16.3% and 12.4%, respectively, compared with 0a. The contents and storage of soil organic carbon, oxidized organic carbon, water-soluble organic carbon and microbial carbon in different treatments were significantly higher than those of 7a, 5a and 3a. The soil carbon sequestration in 0~30cm soil layer 7a and 5a was significantly higher than that in 3a, and the carbon sequestration in 7a and 5a increased by 221% and 160% respectively compared with 3a. There were significant differences in the carbon pool index and carbon pool management index of each treatment in the 0~30 cm soil layer, and the carbon pool index of 7a and 5a increased by 26.1%, 17.0%, 19.9% and 7.00% respectively compared with 3a. Soil β-1,4-N-acetylglucosaminidase activity, liquid phase volume fraction, soil three-phase structure distance, soil cellulase activity and soil β-glucosidase activity were the main factors affecting soil organic carbon sequestration at different years of field returning, and the explanation rates were 76.0%, 4.10%, 3.30%, 1.70% and 3.40%, respectively (P<0.05). Under shallow buried drip irrigation, maize straw returning improved the stability of soil structure and the activity of soil extracellular enzymes related to soil carbon by changing the soil three-phase ratio, and promoted the decomposition and transformation of returned straw by soil microorganisms, and thus improved the soil organic carbon sequestration and carbon pool index. |
| Keyword: shallow buried drip irrigation straw returning years soil characteristics organic carbon sequestration carbon pool management index |