Present Situation And Analysis Of Xiangyuan County Farmland Soil Quality

The soil texture types, physical and chemical properties of 36 521 soil samples from Xiangyuan County farmland were evaluated in this thesis. The results indicated that the majority soil was loam and the bulk density ranged in 0.90～1.32g cm-3 with 1.09g cm-3 in average. Of these types, Chisley Soil has the minimum bulk density with an average of 1.08g cm", and the maximum value was for Alluvial Soil with a average of 1.30g cm-3, with Calcareous Cinnamon soil being in mediate degree averaged at 1.30g cm-1. In the textures, the proportion of loam, sandy, and clay was in 96.9,2.10, and 1%, respectively in plough layer of. In brief, the soil body configuration is classified into light loam, heavy loam, bottom sand mold, and gold covered type. Of these types, light loam with the biggest area widely distributed in the areas of upper mountains and hills around Xiangyuan County, while heavy type was mainly concentrated in hilly gully and second terrace of red loess parent material. The soil of bottom sand mold distributed in the first-terrace along rivers, whereas gold covered type soil was in the second terrace of Xiadian plain in Xiangyuan County and at the lower part of the mountains hilly gullies.The cementation of calcium carbonate is mainly in soil structure, and generally the content of water stable aggregate was between 20 and 40%. Soil hardening and schistose structure are mainly adverse structures in the soil of Xiangyuan County. Most soil possessed of relatively high porosity, moderate density, and good ventilation. The value of pH ranged from 7.1 to 8.6 with an average of 7.9 in all soil. Of the different soil types, Calcareous Cinnamon soil has the maximum value of pH with 7.95 in average, followed by Chisley soil with an average of 7.90, whereas Cinnamon soil and Fluvoaquic soil are in the minimum value with 7.85 in average. The cation exchange capacity of the soil varied from 13 to 23 cmol kg-1 with an average of 17.99 cmol kg-1 belonging to the second level in classification. Of the various soil types, Chisley soil has the highest content of cation exchange capacity with 21.01 cmol kg-1 in average, followed by Cinnamon soil with an averaged value of 18.90 cmol kg-1, while Alluvial soil was the minimum value with 15.03 cmol kg-1.The mean content of soil organic matter, total N, available P, available K was 18.26g kg-1, 0.81g kg-1,8.96mg kg-1, and 179mg kg-1, respectively, and belonged to the second, the fourth, the fourth and the second level, respectively by the Shanxi province classification. The average contents of organic matter, total N, available P and K were increased by 2.46g kg-1, 0.06g kg-1,0.66mg kg-1, and 51mg kg-1 when compared with the second soil survey results,which were 15.8g kg-1,0.75g kg-1,8.3mg kg-1, and 128mg kg-1 respectively. The classification of S, Fe, Cu and Mn is the third level and that of Zn and B is the fourth.The result showed that, compared with second soil survey results, the soil quality, especially soil organic matter was increased significantly. However, the soil nutrient contents in many areas still belonged to third or fourth level. It was necessary to improve further.