新疆农田和荒漠生态系统土壤有机碳储量及其影响因素

基于中国生态系统研究网络 (CERN) 长期监测数据,选取新疆维吾尔自治区代表暖温带干旱区的绿洲农田生态系统 (阿克苏站)、代表暖温带荒漠区 (策勒站) 以及温带荒漠区 (阜康站) 的绿洲农田和荒漠生态系统综合观测场、辅助观测场和农户调查点2005-2020年0-100 cm土层的土壤有机碳 (SOC) 储量数据,分析新疆农田和荒漠生态系统SOC储量的影响因素。研究结果表明,2005-2020年0-100 cm土层SOC总储量平均值为阿克苏站 (5.17 kg/m²)>阜康站 (4.20 kg/m²)>策勒站 (2.96 kg/m²)。0-20 cm、20-40 cm、40-60 cm土层的SOC分别约占0-100 cm土层储量的27.3%-35.3%、23.1%-24.6%和15.8%-17.5%。在阿克苏站,施肥量最高、灌溉量最低的农户调查点SOC储量最高;而在策勒站和阜康站,农户调查点和辅助观测场的施肥和灌溉措施分别最有利于提高SOC储量。总体来看,土壤含水量、地上生物量与SOC储量呈正相关关系;年平均气温与0-40 cm土层的SOC储量呈负相关关系。在单一生态站的生态系统尺度,年平均气温与SOC储量相关性不显著;地上生物量与策勒站和阜康站的SOC储量呈正相关关系,但是与阿克苏站0-40 cm土层的SOC储量呈负相关关系;施纯钾量与策勒站0-60 cm土层的SOC储量呈正相关关系,但与阜康站40-100 cm土层的SOC储量呈负相关关系。总之,与自然状态下的荒漠和农田不施肥相比,灌溉和施肥的农田管理措施有利于增加干旱区SOC储量。不同生态站要根据自身区域特点制定合理的农田管理模式,以维持较高的SOC储量。

Soil organic carbon storage and its influencing factors in farmland and desert ecosystems in Xinjiang

To understand the influencing factors of soil organic carbon (SOC) storage in farmland and desert ecosystems in Xinjiang, the SOC storage data of 0-100 cm soil layer in Comprehensive observation field, Auxiliary observation field, and Household survey field from 2005 to 2020 were selected from the oasis farmland ecosystem in a warm temperate arid areas (Aksu), and the oasis farmland and desert ecosystem in a warm temperate desert area (Cele), and a temperate desert area (Fukang) in Xinjiang Uygur Autonomous Region. The results demonstrated that the average SOC storage in 0-100 cm soil layer from 2005 to 2020 was Aksu (5.17 kg/m²)>Fukang (4.20 kg/m²)>Cele (2.96 kg/m²). The SOC in 0-20 cm, 20-40 cm, and 40-60 cm soil layers accounted for 27.3%-35.3%, 23.1%-24.6%, and 15.8%-17.5% of 0-100 cm soil layer reserves, respectively. The SOC storage was the highest in the Auxiliary observation field with the highest fertilizer application and the lowest irrigation at Aksu. The fertilization and irrigation measures of the Household survey field and Auxiliary observation field were the most beneficial to increase SOC storage at Cele and Fukang, respectively. In general, the soil water content and the aboveground biomass were positively correlated with the SOC storage in the 0-100 cm soil profile. The annual mean temperature was negatively correlated with the SOC storage in the 0-40 cm soil layer. There was no correlation between annual mean temperature and the SOC storage when different ecological stations were considered separately. The aboveground biomass was positively correlated with the SOC storage at Cele and Fukang, but was negatively correlated with the SOC storage in the 0-40 cm soil layer at Aksu. The amount of pure potassium applied was positively correlated with the SOC storage in the 0-60 cm soil layer at Cele, but was negatively correlated with the SOC storage in the 40-100 cm soil layer at Fukang. In conclusion, farmland management measures of irrigation and fertilization are beneficial to increase SOC storage in arid areas, when compared with natural deserts and farmland without fertilization. Reasonable agricultural management should be developed in different ecological stations according to their regional characteristics to improve SOC storage.