Effects Of The Same Quality Corn Stover As Well As Its Humified And Carbonized Materials On The Characteristics Of Organic Matter In Soil And Aggregates

Corn stover,as an important renewable biological energy,industrial and agricultural resources,is rich in nutrients and available chemical resources.In order to solve the problem of corn stover utilization,scholars at home and abroad have done a lot of research in recent years.However,most studies are based on corn stover returned to the field at equal mass of carbon.There are few studies on the same quality of corn stover and its humified and carbonized materials.In the current study,there is no specific comparison of which material has the most significant effect on the improvement of soil composition and structure.Therefore,the effects of corn stover and its humified and carbonized materials on soil humus and aggregate humus were studied by the laboratory incubation.In order to provide theoretical basis and scientific basis for actual production.Results show that:1.Changes on the composition and structure of corn stover during humified and carbonized process.During the humified and carbonized process of corn stover,the composition and structure of humus-like substances changed significantly.HCS and Bc treatments could improve the organic carbon content and PQ of humic-like substances.Compared with CS,the aromaticity of humified corn stover increased,aliphatic decreased,aliphatic enhanced,aromaticity decreased and molecular structure simplified.The humified and carbonized process enhance the structural stability.2.Effects of adding different organic materials on the composition of aggregates.Regardless of the incubation time,the addition of organic materials promoted the increase of granular content of > 2mm,0.25~0.053 mm,and the aggregate content of 0.25~0.053 mm in each treatment was the highest,reaching 31.29%-49.75% after three months of incubation,48.79%-53.12% after 12 months of incubation,and the minimum granular content of > 2mm was 1.85%-4.52% and 2.86%-5.10%,respectively.3.Effects of adding different organic materials on SOC.The changes of SOC content were similar in all treatments,showing: Bc>HCS>CS>CK,and there was significant difference among treatments.With the increase of cultivated time,SOC content decreased.Compared with 90 days,the organic carbon content decreased by 5.04%,5.78%,6.30% and10.23% respectively in 180 days.Compared with 180 days,the decrease rate of soil organic carbon becomes slow,and the content of each treatment decreased by 4.79%,3.22%,4.27% and1.12% respectively in 360 days.After adding organic materials,the total organic carbon content of soil aggregates was higher than that of the control,and gradually decreased with the increase of cultivated time.The total organic carbon content of aggregates in different treatments was significantly different with the increase of cultivated time.The total organic carbon content of soil aggregates in CS and HCS treatments increased with soil aggregate diameter,showing:>2,2~0.25,0.25~0.053 mm and <0.053,while Bc treatments decreased first and then increased with the diameter of soil aggregates,showing as: >2,2~0.25,<0.053,0.25~0.053 mm.4.Effect of adding different organic materials on the composition of humus in soil and aggregates.Due to different cultivated time,the carbon content of each component in soil organic matter changed with the application of different organic materials.The PQ values of CS,HCS and Bc treatments increased by 5.44%,9.10% and 11.95% respectively in soils for 90 days;and increased by 6.40%,10.50% and 12.52% respectively in soils for 180 days;and increased by 11.38%,12.97% and 13.94% respectively for 360 days.After cultivated for 90 days,HCS treatment had the greatest effect on the carbon content of HA in soil aggregates.The carbon content of HA in aggregates with different particle fraction was 3.50g/kg,3.80g/kg,3.49g/kg and 3.90g/kg,respectively.The HA content of aggregates with different particle fraction decreased relatively at 360 days.The HA content was still the highest in CS and HCS treatments,but with the increase of cultivated time,the difference between Bc and HCS treatments was not significant.5.Effects of different organic materials on the structure of HA.The ratio of C/N increased,H/C and O/C decreased,and the oxidation degree of HA decreased after adding organic materials.CS and HCS treatments increased heat release and weight loss at medium temperature,but heat release and weight loss decreased at high temperature,while Bc treatment increased heat release and weight loss at medium temperature,and the ratio of 2920/1620 of Bc treatment decreased with the increase of cultivated time.The results showed that the addition of CS and HCS increased the aliphatic degree of soil HA,decreased the aromatization degree and made the structure more simpler.However,the aromatization degree of soil HA structure was enhanced and the aliphatic degree was weakened by Bc treatment.6.Effects of different mixing modes of corn stalk and soil on the composition and structure of humus.Compared with CK,t the total organic carbon content of soil and the carbon content of humus components all increased in different degrees under different treatments,among which corn stover and soil mixed treatments were the most significant;the ratios of I2920/I1720 and I2920/I1620 were higher than CK,and the high/medium calorific ratio and the high/medium weight loss ratio are less than CK.The results showed that the aliphatic degree of HA increased,the aromatization degree decreased,the oxidation degree decreased,and the structure tended to simplify,among which corn stover and soil mixing had the most significant effect.