| In this study,the meadow paddy soil in Toudao Town,Ji’an City,Jilin Province was used as experimental materials to study the effects of single chemical fertilizer(rice straw leaving the field after harvest)treatment(CF),full returning of rice straw and chemical fertilizer treatment(OCF),organic fertilizer and chemical fertilizer treatment(OF),rice specific bio organic fertilizer treatment(OMF)on the physical and chemical properties of paddy soil,organic carbon and its component content,aggregate composition The influence of the composition of aggregate organic carbon and humus and the structural characteristics of organic carbon provides a theoretical basis for the effects of different fertilization treatments on soil nutrient changes and soil organic carbon characteristics.The research results are as follows:1.Compared with chemical fertilizer alone,chemical fertilizer combined with organic fertilizer can significantly increase the percentage of physical clay particles of<0.01 mm grain size,increase the content of hygroscopic water,reduce soil pH,increase electrical conductivity,and increase the content of available N,P,K and total N,total P,total K.2.The content of particulate organic carbon,easily oxidized organic carbon,recombined organic carbon and light organic carbon in the treatment of chemical fertilizer combined with organic fertilizer was significantly higher than that in the treatment of chemical fertilizer alone;Compared with CF treatment,OCF,OF,OMF treatment increased the humus content in soil,in which the HE content increased by21.72%,34.11%,44.75%,HA content increased by 20.25%,30.88%,55.62%,FA content increased by 12.18%,42.13%,17.26%,and HM content increased by 6.50%,74.21%,54.76% respectively.3.In paddy soil with different fertilization treatments,the large aggregate>2mm is the main component of the aggregate.Compared with CF,organic fertilizer significantly increased the content of large aggregates>2mm,decreased the content of micro aggregates 0.25-0.053 mm,and the content of silt and clay particles<0.25 mm significantly decreased.The average weight diameter and geometric average diameter of aggregates in organic fertilizer treatment were significantly higher than those in chemical fertilizer treatment alone,and the damage rate decreased.4.In paddy soil with different fertilization treatments,the organic carbon content in aggregates>2mm is the highest.The treatment of chemical fertilizer combined with organic fertilizer significantly improves the organic carbon content in aggregates at all levels compared with the treatment of chemical fertilizer alone,and can improve the ratio of large aggregate to micro aggregate organic carbon,as well as the contribution rate of large aggregate organic carbon content to soil.In the soil of different fertilization treatments,the content of HE and HA in the large aggregates>0.25 mm in the treatment of chemical fertilizer combined with organic fertilizer was significantly higher than that in the treatment of chemical fertilizer alone;However,FA content in aggregates>2mm decreased by 4.10%,10.66% and 21.31% respectively.The slope of absorption spectrum of humus solution of chemical fertilizer combined with organic fertilizer increased,the degree of aromatization decreased,the hue coefficient increased,the molecular structure tended to be simple,and the molecular weight was smaller than that of chemical fertilizer alone.5.Compared with chemical fertilizer alone,the content of dissolved organic carbon in soil can be increased by applying organic fertilizer in combination;The percentage of the integral value of each region in the total integral value of DOM fluorescence components in the four treatments was mainly humic acid,with the least tyrosine like protein,the most tyrosine like protein in CF treatment,and the more humic acid in OMF treatment;The metabolites of dissolved microorganisms treated with CF and OCF were higher than those of fulvic acid;Fulvic acid substances treated with OF and OMF were higher than dissolved microbial metabolites;Compared with CF,the alkyl carbon content in OCF,OF and OMF treatment decreased by 1.06%,5.57% and 4.11%respectively,and the alkoxy carbon content increased by 1.60%,7.29% and 2.51%respectively;Compared with CF,the aromatic carbon content of OF and OMF treatment increased by 0.88% and 3.30% respectively,the carboxyl carbon content decreased by2.59% and 1.71% respectively,and the aromaticity increased by 0.06% and 3.02%respectively.To sum up,in different fertilization treatments,compared with the single fertilizer application,the full amount of rice straw returned to the field with chemical fertilizer,the organic manure with chemical fertilizer,and the special organic fertilizer for rice with chemical fertilizer all improved the soil quality,among which the combination of organic manure with chemical fertilizer and the special organic fertilizer for rice with chemical fertilizer had better soil fertility. |
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