| The Northeast Plain has fertile land and its grain output is at the forefront of our country.It has become an important commodity grain base and a ballast for food security in our country.Since the implementation of the rural household contract responsibility system in the early 1980 s,with the transfer of labor,the development of small-scale mechanization,and the large-scale use of fertilizers and pesticides,problems such as irrational soil profile structure and deterioration of physical properties have arisen,which have become the improvement of soil fertility and food.Constraints on yield.In response to the long-term irrational farming machinery and production management methods in the rice production process,the rice soil has become shallower,poorer cultivability,soil compaction,water retention and fertilizer retention,and reduced fertility buffer capacity,and the resulting rice The root distribution becomes shallow,the range of nutrient absorption decreases,fertilizer and water use efficiency decreases,rice is easy to lodging,and rice yield is not high and unstable.This paper uses the method of field investigation and sampling analysis to develop a research on the construction of a reasonable plough layer index system for paddy fields.It is of great significance to implement high-standard farmland construction,improve fertility,ensure high and stable rice production and national food security.This paper takes two typical saline areas in the Northeast Plain(inland saline areas in Jilin Province and coastal saline areas in Liaoning Province)as the research objects.According to the principle of index selection and the principle of using Norm values,the minimum data is adopted Set method(MDS)and redundancy analysis method(RDA)are used to construct a reasonable arable layer index system for paddy fields,and the fuzzy comprehensive evaluation method is used to compare and verify the systems established by the two methods.The main conclusions are as follows:(1)The comparison of the minimum data set method(MDS)and the redundancy analysis method(RDA)established by the fuzzy comprehensive evaluation method to establish an index system found that the redundancy analysis method(RDA)is more suitable for constructing a reasonable plough layer of paddy fields in the saline area of Northeast Plain Index system.(2)The four index systems constructed(Reasonable plough layer index system for high-yield paddy fields and overall paddy fields in Jilin inland saline areas and Liaoning coastal saline areas)include soil physics and chemistry Three aspects of biological attributes;the impact of these three attributes should be considered when constructing a reasonable plough layer index system for paddy fields,instead of only one or two attributes.(3)Whether it is the indicator system constructed by the minimum data set method(MDS)or the redundancy analysis method(RDA),the rice yield increases with the increase of the index comprehensive index IFI,and the correlation between them is significant.(4)The three indexes of tillage depth,plow bottom thickness,and organic matter exist in each index system,and they are important parameters for constructing a reasonable tillage index system for paddy fields.(5)The reasonable plough layer index system for high-yield paddy fields in the inland saline area of Jilin is: bulk density,plough layer depth,plow bottom thickness,phosphatase,urease,microbial biomass nitrogen,microbial biomass phosphorus,available phosphorus,available potassium,and organic matter;The reasonable plough layer index system for high-yield paddy fields in the coastal saline area of Liaoning is: <0.01 mm micro-aggregates,plough layer depth,plow layer thickness,phosphatase,urease,microbial biomass phosphorus,and organic matter;... |
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