Abstract:

In order to further system further in-depth system of Songliao Plain corn with black soil farming area high-yield cropland of soil quality management and evaluation to provide theoretical support and learn from , and the black soil resources utilization and protection, as grain yield income soil structure theory has important practical significance, and the black soil resources utilization and protection, for grain yield income in the exploration of the theoretical aspects of soil structure, the high-yield cropland of the low-yield cropland and comparative method, under freezing conditions, through the analysis of bulk density, porosity, aggregate distribution and stability, compared to three index determination and analysis of different frequencies, different water content of frozen, the high yield cropland and cropland of the low yield in 0-20 cm soil structure characteristics, the different water 5%, 10%, 15%, 20%, 25% and different freezing frequency 0, 2, 4, 6, the results showed: the different water content after freezing and thawing soil pore space characteristics change with significant influence. The results showed that, freeze-thaw cycle could significantly increase the number of Songliao Plain Corn Belt yield cropland and low-yield cropland of 0-20 cm top soil porosity, high-yield cropland to increase the percentage of 32.58. The percentage of 17.95 increased in low-yield cropland. Significantly reduced the average pore size of Feret-diameter in the range of 0-20 cm soil layer of low-yield cropland and soil Feret-diameter by 2.31 before freezing to frozen 1.92 percentage reduction of 16.88, average pore size of the low-yield farmland soil freeze before the 8.91 lower to 4.65 of the frozen, reducing the percentage of 47.81 (P<0.05). In addition to the rate of the soil pores into round aggregates in pore number of freeze-thaw cycle on the high-yield cropland and low-yield cropland of all classes, with an average pore size, the average Feret-diameter have different impact on the degree of difference (P<0.05). Yield field >5 mm average pore size of the aggregates by freeze before the 37.08 to 23.84 of the frozen lower percentage of 38.4, the change significantly different (P<0.05), which was a unique variation of high-yield cropland and compared to low-yield cropland. Yield cropland of the other size of the aggregates and the low-yield cropland of all grain size aggregates the average pore size of the freeze response was not obvious. High-yield cropland and low-yield cropland had > 5 mm aggregates of pores round rate changes significantly, high-yield cropland reduced to 0.27 from 0.36 before freezing, the percentage change of 25. Low-yield cropland increased from 0.25 before freezing to frozen 0.34, the 36 change in the percentage of the difference was significant (P<0.05) between the changes in the law was the opposite, also reflects the high-yield cropland large particle aggregates pores round rate freeze the law's response was different from the particularity of the low-yield cropland, the above conclusions on system management and evaluation of the Songliao Plain corn with black soil farming area high-yield cropland of soil quality to provide theoretical support a certain significance.