糖厂滤泥还田对广西红壤蔗区土壤有机碳库和温室气体排放的影响

Exploring the potential of soil organic carbon stocks and finding ways to increase soil organic carbon stocks is of great importance to mitigate the current global warming issues. Farmland soil is an important source of greenhouse gas emissions, even small changes in soil carbon pool will have a great impact on the global climate. In the process of making sucrose by sulfurous acid in a sugar mill, a waste called filter mud is produced, which is rich in organic matter and many nutrient elements, and it will cause environmental pollution and waste of resources if it is discharged at will. At present, there are few studies on the influence mechanism of filter mud on soil organic carbon pool and greenhouse gas emission in Guangxi red soil sugarcane field, and the effect of filter mud replacement of chemical fertilizer is also rarely. Based on this, the project takes the sugar mill filter mud as the research object, applied with different application rates into the red soil sugarcane planting sugarcane which combined with chemical fertilizers, through the real-time monitoring of soil organic carbon pool, greenhouse gases, microorganisms, soil nutrient bioavailability, to obtain the dynamic changes by applying filter mud, so as to reveal the influence mechanism of filter mud on soil organic carbon pool and greenhouse gas emission in the sugarcane field of red soil in Guangxi, clarify the appropriate amount of filter mud instead of chemical fertilizer, explore the interaction mechanism between soil, soil organic carbon pool, greenhouse gas, soil nutrient bioavailability and microorganism. This project will lay a data foundation for the long-term study of the red soil organic carbon pool in Guangxi, and provide scientific and technological support for promoting the sustainable production of sugarcane industry in Guangxi.

探明土壤有机碳库存潜力及寻找增加土壤有机碳库储量的途径对缓解目前全球变暖问题具有重要意义。农田土壤是温室气体的重要排放源，土壤碳库的微小变化都有可能影响全球气候。亚硫酸法制糖产生的废弃物—糖厂滤泥富含有机质和多种营养元素，若随意排放会造成环境污染和资源浪费。当前鲜见滤泥对广西红壤蔗区土壤有机碳库变化和温室气体排放影响等方面的机理性研究及滤泥替代化肥的效果研究。基于此，本项目以糖厂滤泥为研究对象，以不同施用量配合化肥投入红壤蔗田种植甘蔗，通过对土壤有机碳库、温室气体、微生物、土壤养分生物有效性的实时监测，获取其在滤泥还田作用下的动态变化，从而揭示滤泥对广西红壤蔗区土壤有机碳库和温室气体的影响机理，明确滤泥替代化肥的适宜用量，探索滤泥、土壤有机碳库、温室气体、微生物、土壤养分生物有效性之间的相互作用机制。这将为广西红壤有机碳库的长期研究奠定数据基础，为促进广西甘蔗产业可持续发展提供科技支撑。

为研究滤泥对广西红壤蔗区土壤有机碳库变化和温室气体排放的影响机理及滤泥适宜化肥替代量，本项目对滤泥和化肥作用下的土壤碳库、温室气体排放，微生物进行监测和分析，获得三者相互间的响应机制，并通过甘蔗产量明确滤泥替代化肥的适宜用量。结果表明：滤泥和化肥均可提高土壤有机质（SOC）、微生物量碳（MBC）、土壤碱解氮（AN）、Olsen-P（AP）、速效钾（AK）的含量，施用滤泥或滤泥与化肥配施的效果更好。与不施肥处理相比，滤泥与化肥配施使SOC、MBC分别提高26.64 %~132.39 %、60.77 %~322.39 %.就红壤蔗区而言，施肥仍是甘蔗增产的有效途径；单施化肥可使甘蔗产量平均提高96.85 %，单施滤泥提高150.64 %，滤泥与化肥配施提高204.37 %。参考产投比，本项目推荐适宜的甘蔗施肥量为化肥（N:P2O5:K2O）用量为150:90:150 kg/hm2，滤泥用量为30 t/hm2。SOC、MBC、AN、AP、AK均与甘蔗产量成显著正相关，其含量的提高都有助于提高甘蔗的产量。滤泥和化肥均能促进红壤蔗区土壤CO2排放，且施肥量越高排放通量和累积排放量越高。滤泥与化肥配施使土壤CO2累积排放量含量平均提高35.59 %。旱地红壤蔗区土壤CH4和N2O排放量低，CH4年均累积排放量＜200 g/hm2，N2O＜2.00 g/hm2。SOC、MBC含量与土壤CO2和N2O的排放量密切相关。滤泥与化肥可使土壤微生物群落丰富度提高、多样性增加。SOC、MBC含量对土壤微生物群落结构有显著的影响作用，且SOC的影响效果更大。温室气体中，CH4和N2O的排放对土壤微生物群落结构亦有显著的影响作用。本研究结果为广西红壤有机碳库的长期研究奠定数据基础，为促进广西甘蔗产业可持续发展提供科技支撑。