A Study of Soil Aggregates Distribution Characteristics in Representative Tobacco Fields under Tobacco-Rice Rotation Cropping Systems and Their Relationships with Soil Nutrients and Crop Yields
[Objective]This study utilized a combination of field surveys and soil sampling analyses during tobacco-rice cropping seasons to evaluate the distribution characteristics of soil aggregates and examine their relationships with soil nutrient levels and crop yields.[Method]Ten normal tobacco fields and ten obstacle tobacco fields,all situated on the same parent material,were selected.Field investigations and soil sampling were conducted at these sites.Surface soil samples(0-20 cm depth)were collected and analyzed for aggregate composition,nutrient content,and biological characteristics.The aim was to examine the relationship between soil aggregate distribution patterns and edaphic properties over the course of tobacco-rice crop rotations.[Result]Soil organic carbon,total nitrogen,alkaline-extractable nitrogen,ammonium nitrogen,and readily available potassium as well as soil microbial basal respiration,microbial biomass carbon,microbial biomass nitrogen,microbial biomass phosphorus,β-glucosidase,cellulase,aminoacylglucosidase,and β-D-xylylglucosidase,acid phosphatase,and polyphenol oxidase in normal tobacco field were significantly higher than those in the barrier tobacco field(P<0.05).The proportion of macroaggregates(2-8 mm)during the tobacco and rice seasons in normal tobacco field was significantly higher than those in the barrier tobacco field,which were respectively 35.09%and 31.75%,with high aggregate stability.Tobacco growth parameters and crop yield were also substantially higher in normal tobacco field.There was a significant positive correlation between macroaggregates and soil organic carbon and total nitrogen during the rice season within tobacco fields.[Conclusion]The proportion of soil macroaggregates(2-8 mm)was higher in normal tobacco field compared to the barrier tobacco field,and differences in soil nutrient levels and aggregate distribution were clear.Long-term tobacco-rice crop rotations markedly enhanced soil aggregate formation.The development of soil structure through macroaggregate stabilization represents an important mechanism for improving soil fertility and physical properties over time under this cropping system.
万方数据
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