Effects Of Composting And Long-term Located Fertilization On The Contents And Structural Characteristics Of Humus Fractions

This paper studied the effect of chicken manure composting for 0 to 26 days on the contents and structural characteristics of soil humus fractions,which was analyzed from the organic carbon andâ–³logK.According to the compositions' element analysis,differential thermal analysis and infrared spectrometry analysis,the structural characteristics of humic acid were studied.By Pallo method,meanwhile this paper also studied the content andâ–³logK of humus fractions from the brown soil fertilized with the different Fertilizers located for 8 and 28 years,include CK,O1,O2,NPK,O1+NPK and O2+NPK The effects of long-term located fertilization on contents and optical property of humus fractions was analyzed,especially on the humin fractions.The major results are as follows:(1) On the whole,the rule of effects of composting on humus fractions was similar.Earlier composting,it helped to the formation and accumulation of humus fractions.Later composting,the rate of decomposition was speedier obviously.The effecs of dissolved organic matter(WSS) and fulvic acid(FA) were more obvious. Earlier composting,the rate of formation of HA was speedier than FA.The rate of formation of HA and FA was speedier than the rate of decomposition.Then the rate of formation of FA became slower than decomposition gradually with later composting,and the rate of formation and decomposition of HA and FA went to equilibrium went with time of composting gradually.(2) In the process of composting,the structure of humic substance extracted(HE) was more complicated than FA and simpler than HA.The compost helped to simplification of the structure of HE.Earlier composting, the ratio of simplification was raised gone with time of composting and went to equilibrium.When it became the simplest,the ratio became to reduce gone with time of composting.It means that,later composting,the development trend of structure became complicated went with time of composting.Earlier composting,the structure of FA became a little complicated.But later composting,it helped to the simplification of FA and reduced the oxidation & aromatization obviously.Earlier composting,the grade of simplification was higher, but later composting,the oxidation & aromatization tended to become enhanced.(3) From the map of differential thermal analysis and infrared spectra,the condensation grade of loose united humic acid(HAâ… ) and steady united humic acid(HAâ…¡) was increased went with the time of composting.But middle composting(composting from 2 to 10 days),the condensation grade was reduced a little.The C/N was increased went with time of composting,but it was reduced obviously at the end of composting.Compost helped to reduced the aliphatic structure and increased the aromatic structure of HAâ… . The effect of HAâ…¡was periodical,earlier composting helped the structure to become aliphatic and aromatic,but it was reduced instead with later composting,and the reducing rate of the aliphatic hydrocarbon was higher than the aromatic hydrocarbon.The degree of aliphatic and aromaticity of HA was increased obviously went with the time of composting.And the degree of aromaticity was higher than aliphatic,but it was opposite rule instead when composting for 3 days.The aromatic hydrocarbon of HA was increased and the degree of aromaticity was stronger.(4) The order of the content of humus fractions is:HMr＞FAf＞HAs＞HMi＞HAp＞HMc.The fertilization helps the organic carbon contents of the brown soil to increase,the effect is evident when the amount of organic fertilizer increased,and the fertilization influence on organic carbon of the 28-year soil samples is more evident than the 8-year sample.Effecs of organic or chemical fertilizer on free fulvic acid(FAf) is more visible than chemical fertilizer plus orgnic-fertilizer The amount of FAf of the 8-year soil samples is reduced by organic-fertilizer or chemical fertilizer,Quite the reverse,it is increased of the 28-year sample.The abstraction rate of HE(fulvic acid plus humic acid) with Na₄P₂O₇ is increased after fertilization was applied to 8-year sample.It is reduced of 28-year sample instead.To 8-year soil samples,the abstraction rate of HE is increased obviously with chemical fertilization,but it is reduced obviously of 28-year sample.The Na₄P₂P₇-extractable humic acid(HAp) is increased with fertilization,but the NaOH-extractable humic acid (HAs) is reduced.Chemical fertilizer plus organic-fertilization helped to the formation and accumulation of humic acid(HA).And organic fertilization is the best helpful to accumulation of HAp and HAs.The effects of long-term fertilization on iron-bound humin(HMi) and clay-bound humim(HMc) were similar.And the effects of chemical fertilization plus organic-fertilization applied to soil on HMi and HMc were obvious.The increasing rate of HMi and HMc of 8-year sample is the highest with more organic-fertilization plus chemical fertilization.And the increasing rate of 28-year sample is the highest with few organic-fertilization plus chemical fertilization.After fertilization was applied to soil,HMi/HMc was reduced,videlicet;the formation rate of HMi was lower than HMc.Chemical fertilization helped to decomposition of HMr of the 8-year soil samples.But organic-fertilization helped to decomposition of HMr of the 28-year soil samples.(5) The order,structure of humus fractions,from simple to complicated,is:FAf＜HMi＜HAs＜HAp＜HMc. The structure of FAf of the 8-year samples was simpler than 28-year sample.And fertilization went against to decomposition of FAf.With fertilization structure of NaOH-extractable humus was simpler than Na₄P₂P₇-extractable humus.The effect of chemical fertilization plus organic-fertilization on the structure of the extractable humus was more visible,and with more organic-fertilization its structure was easy to become complicated.The structure of fulvic acid(FA) was simpler than HA,so FA was easier to be decomposed.Fertilization helped to simplification of structure of HMi,and the effect of organic-fertilization or chemical fertilization plus organic-fertilization on HMi was more visible.The organic-fertilization and chemical fertilization plus organic-fertilization helped to simplification of structure of HMc.With single application of more organic-fertilization in,the structure of HMc was simpler.But with mixed application of more organict-fertilization,the extent of simplification was reduced instead.The structure of HMi was simlpler than HMc obviously,and effect of fertilization on structure of HMi was more obvious than HMc.To sum up, fertilization helped to simplification of structure of HMi and HMc.