生物炭对农田土壤氨挥发的影响机制研究进展

Effects of biochar on ammonia volatilization from farmland soil:A review

降低土壤氨挥发量是农田生态系统中减少土壤氮素损失、提高氮肥利用率的关键途径之一。生物炭具有独特的理化性质,施入土壤后可改变土壤理化性状,影响土壤氮素循环,并对农田土壤中氨挥发产生重要的影响。本文首先介绍了稻田和旱田两种土地利用方式下农田氨挥发过程及其影响因素(气候条件、土壤环境、施肥管理等);其次,重点综述了生物炭对农田生态系统氨挥发影响的研究进展,并从物理吸附机制、气液平衡机制、生物化学过程调节机制等方面探讨了生物炭介入下农田土壤氨挥发的响应机制,认为土壤氨挥发减排的响应主要是基于生物炭表面含氧官能团对土壤NH4+和NH3的吸附作用及促进土壤硝化作用;而生物炭增加土壤氨挥发排放主要与生物炭提高土壤pH值和透气性、增强土壤有机氮矿化微生物活性有关。最后,对生物炭减少土壤氨挥发、提高氮肥利用率的研究方向进行了展望。

Reducing soil ammonia volatilization is one of the key ways to reduce soil nitrogen loss and improve nitrogen utilization efficiency in farmlands.Biochar has unique physico-chemical pro-perties,which can change soil physical and chemical properties,affect soil nitrogen cycle,and affect ammonia volatilization in farmland soil.Firstly,we reviewed the ammonia volatilization process and its influencing factors(climatic condition,soil environment,and fertilization management,etc.)in paddy fields and upland fields.Then,research progress on the impacts of biochar on ammonia volatilization from farmland ecosystem was reviewed.Furthermore,the mechanisms underlying the responses of ammonia volatilization to biochar intervention were discussed from the aspects of physical adsorption,gas-liquid equilibrium,and biochemical progress regulation.The reduction of soil ammonia volatilization is mainly based on the adsorption of soil NH4+and NH3 by oxygen-containing functional groups on the surface of biochar and the promotion of soil nitrification.How-ever,the increases of soil ammonia volatilization are mainly related to the increases of soil pH,air permeability,activities of microorganisms related with soil organic nitrogen mineralization.Finally,the research direction of reducing soil ammonia volatilization and improving nitrogen utilization efficiency by biochar was prospected.