| To the problem found in the investigation--different profile morphologicalcharacteristics ("flat type" section and " wavy type" section ) under continuous cultivation of corn formed under different tillage conditions have significant influence to corn yield, this paper systemically studied the phaeozem physical fertility characteristics of the different soil profile constitutions of the corn belt in Jilin and discussed the relationship between the soil physical properties and soil erosion under different tillage conditions. At the same time, by making use of concrete experimentation, we clear moisture characteristics and influences under different profile morphological characteristics. The results show that:(1) Soil construction of " flat type" section is better than that of " wavy type" section. In " flat type" section, the proportion of aggregates is more appropriate, which doesn't only have the coordination relation between soil water and air and soil fertility, but also has more benefit to the soil organic matter's maintaining. Physical fertility of soil is higher.Based on the relative analysis: The soil physical properties marking the soil fertility are significantly relative with both corn yield and soil organic matter. These properties include contents of >0.25 mm water stable aggregates, contents of micro-aggregates, pore space, and soil texture, specific surface area, etc. In addition, since the partial correlation to the contents of physical clay, specific surface area, available water content is highly significant, the regressive equation is: yY=-8.6197+0.3145xp.c+0.0649xs.A+0.0021xA.w and coefficient is R=0.8005, and it shows the significant the single relativity. Better soil physical properties are beneficial to enhance the soil fertility and promote the higher yield of corn.(2) The unreasonable farming system is an important reason that result in soil erosion, and the soil erosion is a main reason that result in soil quality's degradation. There are more differences of the soil anti-erosion in the different farming system: the average rate of " flat type" section is 2.88, and the average rate of " wavy type" section is 3.17. Different soil profile constitution has more intensive influences to water holding capability of soil and soil lateral rate. Because of the structurecharacteristics, " wavy type" section is bad. Wind erosion under northern spring weather and water erosion in the rainy season easily happen. But "flat type" section has better soil structure and appropriate pore ratio, which improved the soil permeability, reduced soil erosion, and increased soil water storage capability. All of these will make "flat type" section accept more rainfall and form the bigger "natural soil reservoir".(3) The capability of holding and sluicing the water in "flat type" section is larger than that in "wavy type" section. At the same time, accepting the rainfall ability is stronger. The corn water-consumption of "wavy type" section cultivated horizon is bigger than that of "flat type" section. Soil water could appear shortage in "wavy type" section, especially in the post period. Through measuring rainfall contents of growing the season, the rain of the "flat type" section is slightly surplus, but that of the "wavy type" section is shortage. Therefore, "wavy type" section cultivated horizon may occur drier phenomenon much easier than "flat type" section. This may be the main reason why drier phenomena easily happen in phaeozem. Under this kind of the phenomena, corn growth excessive depends on the rainfall of a year, and it will appear the high motion to the year's yield.(4) Soil specific gravity of the corn belt phaeozem is smaller. We suggest that the value of cultivated horizon is 2.53, and the value of plow pan is 2.65.(5) Pass to compare the analysis, physical fertility of cultivated horizon in the "flat type" section and the "wavy type" section have no a too much difference, such as soil structure, soil bulk density, pore space, etc, The real reason of different fertility is different...
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