| Study of soil nutrient depletion in cultivated land of Heilongjiang Province |
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| DOI：10.7606/j.issn.1000-7601.2018.06.33 |
| Key Words: soil nutrients infertility index organic matter total nitrogen farmland ecology obstacle type region Heilongjiang Province |
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| Abstract: |
| With the support of Arcgis spatial analysis function and SPSS mathematical statistics function, using the methods of membership model, analytic hierarchy process, comprehensive index model, obstacle degree diagnosis model, superposition method and so on, this study analyzed the status of soil nutrient depletion and regional ecological problems in the cultivated land of Heilongjiang Province, diagnosed and identified soil nutrient barrier factors and optimal quantification indicators, spatially expressed regions with soil nutrient obstacle. The results are as follows: (1) 70.58% of the whole province is in slight or above soil nutrient deficiency, which is gradually weakening from the southwestern to the northeastern regions, in that the severe barren area is mainly distributed in the west of Songnen Plain accounting for 2.95% of the cultivated land, and the ecological problem of farmland is the severe desertification of the soil. The moderate infertile area is mainly distributed in the central sag area of fault in the middle part of Songnen Plain. The northwestern Sanjiang Plain is located in the transitional zone from the Piedmont Plain to the Plain. This accounts for 41.09% of the cultivated land. Soil salinization also exists in the Songnen Plain, the mildly infertile areas are mainly distributed in the eastern, northeastern, and southeastern region of the Songnen Plain and a small portion is in the western area, northwest and southwest of Sanjiang Plain accounting for 26.54% of cultivated land in the region. The ecological problem of farmland is soil erosion; (2) Organic matter content and total nitrogen are the main limiting factors of soil nutrient depletion in the region that accounted for 88.37%; (3) Organic matter content is the best quantitative indicator of soil nutrient depletion and nutrient quantification index; (4) 47.92% of the cultivated land have moderate or greater obstacle factors, and 14 types of obastacle region were found. The factors of MC-MN-MP, MC-MN-MK and MC-MN accounted for the largest portion, 39.84%, of the areas. |
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