Composition Of Soil Humin And It's Responding To Different Concentrations Of Oxygen And Carbon Dioxide

Constitutive and biological characterization is the nature of soil. Soil organic matter (SOM) is the constitutive and biological basic substance of soil, is the condition and product of vital activity. Humic substance is major in SOM. It was divided into three fractions by the traditional method, including Humic acid (HA), Fulvic acid (FA) and Humin (HM). HM, as a very important fraction, possesses more than 50% in Soil organic carbon (SOC). But HA and FA were studied more than HM in the past. This paper presented the conception and studying methods of HM, and compared the composition and optical property of Humus and HM in different soils. It will offer new data for researching organic matter.In this paper, it is the first time to study the influence of different O₂ and CO₂ concentrations on HM's composition and optical property. Laboratory simulated method was used. The treatments of O₂ concentrations included 0%, 4-7%, 18-23% and 82-87%; the treatments of CO₂ concentrations included <2%, 8-12% and 48-52%. Dynamic sampling time is 0, 35, 70, 105, 140 and 210 days.Modified humus composition method was adopted to divide Humus into Water floating substance (WFS), Water soluble substance (WSS), HA, FA and HM; Later, Using modified Pallo method to separate HM involves Humin linked to iron (HMi), Humin linked to clay(HMc), Humin indissoluble (HMr). The results are stated in the following parts:(1) HA, FA and HM are main parts of Humus. The PQ of various soils is different. It's range is from 32.21 to 67.40%. The PQ of Black soil and Meadow soil is higher than that of Aeolian soil and Brown earth.(2) The HM varies in different soils. The relative amount of HMi, HMc and HMr respctively is 20.90-52.03%, 9.23-18.54% and 3.28-5.64%, except Chernozem; every fraction referred differs in different soils. The relative amount of HMi extracted from black...