摘要
为了解生物质炭的施用对土壤本身碳、氮、磷循环的影响,选择不同酸碱度的3种土壤,设置对照(不施生物质炭和肥料)、施生物质炭、单施肥料及同时施生物质炭和肥料等4个处理,研究了施用生物质炭对土壤碳、氮、磷的转化与形态的影响。结果表明,施用生物质炭增加了土壤的pH值,在酸性土壤上尤为明显。施用生物质炭显著地提高了供试3种土壤的有机碳积累,降低了酸性和中性土壤中的水溶性有机碳,促进了土壤微生物生物量碳的提高,降低了易氧化有机碳占总有机碳的比例,轻微增加了土壤中胡敏酸与富里酸的比值(humic/fulvic acids,H/F)。施生物质炭可降低土壤中的NH4+-N含量,有利于氮素向缓效态转化,防止氮素淋失;但它可增加土壤中NH3的挥发损失,对NH3挥发损失的影响在酸性土壤中小于中性和石灰性土壤。施生物质炭可提高土壤中的总磷含量,在未施肥料磷的土壤施用生物质炭增加了土壤水溶性磷的比例,但在施肥料磷的土壤中施用生物质炭却降低了土壤水溶性磷的比例;施生物质炭可增加土壤中NaHCO3-IP和NaHCO3-OP等生物有效态磷在总磷中的比例,降低了NaOH-IP和残余态磷的比例,明显增加了HCl-P的比例。研究认为,施用生物质炭可促进土壤碳的固定,可在一定程度上改善土壤氮、磷等养分的有效性;可考虑优先用于酸性土壤。
Soil organic matter has an important role in soil fertility and agricultural productivity.Many practices have been used to increase organic carbon in soil,particularly nitrogen fertilization,zero-tillage agriculture,and the addition of large amounts of manure to soil.These practices do not sequester significant quantities of C into soil because most of the organic matter is not stable and is mineralized very fast.Many factors contribute to soil organic C stabilization,including soil clay content,rainfall,and temperature regimes.In recent years,there has been considerable interest in the use of biochar from pyrolysis of renewable biomass to sequester C and improve soil productivity.Much of the stimulus for this interest comes from research on the soils of the Amazon basin,known as Terra Preta de Indio,that contain variable quantities of organic black carbon considered to be of anthropogenic origin.Biochar can improve nutrient availability,cation exchange capacity,bulk density,and water-holding capacity,but these effects depend on the feedstock,prolysis conditions.It is important to evaluate the effects of biochar on soil fertility under different soil and climatic regimes to increase our understanding of potential interactions before widespread use of biochar in agricultural systems.Although biochar has been shown to increase soil fertility and productivity in the tropics,there is limited information about influences of biochar on transformation and chemical forms of C,N and P in soils.Therefore,an incubation experiment was conducted to study the effects of biochar application on transformation and chemical forms of C,N and P in soils with different pH.
The experiment included four treatments,i.e.,control without application of any chemical fertilizers and biochar, conventional fertilization with application of chemical fertilizers,biochar treatment with application of biochar but without any chemical fertilizers,and conventional fertilization + biochar treatment with application of both biochar and chemical fertilizers.The treated soils were incubated at temperature of 20 35 ℃ for 12 months,and the incubated soils were characterized for different forms of C,N,and P and potential capacities of N leaching and volatilization loss.
The results showed that application of biochar increased soil pH,particularly for acidic soil.Application of biochar increased significantly the accumulation of organic C,microbial biomass C and humic/fulvic acids(H/F)of the soils,and decreased water soluble C in both acidic and neutral soils,and proportion of total organic C in easily oxidized organic carbon.Addition of biochar could promote the transformation of rapidly available N into slowly available N, and thus decrease potential of N leaching loss. However, application of biochar increased the volatilization loss of NH 3 in the soils,and the effect on volatilization loss was less in the acidic soil than that in both neutral and calcareous soils.The application of biochar increased total P in the soils.The application of biochar increased proportion of water soluble P for the soils without addition of chemical fertilizers,but it decreased the proportion for the soils with addition of chemical fertilizers.Application of biochar increased proportions of bio-available P such as NaHCO 3-IP and NaHCO 3-OP in the soils,and decreased the proportions of NaOH-IP and residual P.Proportion of HCl-P increased when biochar was applied.
It is concluded that application of biochar is benefit to increasing fixation of organic carbon and modifying availability of N and P in soils.It is recommended that biochar could be preferentially applied in acidic soil.
出处
《浙江大学学报(农业与生命科学版)》
CAS
CSCD
北大核心
2014年第3期303-313,共11页
Journal of Zhejiang University:Agriculture and Life Sciences
基金
国家科技支撑计划资助项目(2012BAD05B04
2014BAD14B04)