| As the country's major grain production areas, the middle and lower reaches of the Yellow River under typical farm land is vital for the production of food security. In view of this situation, we analyze the fertility statistical characteristics and spatial distribution in soil of the Fengqiu, based on the GS +, Arc GIS, SPSS software,in the full use of geostatistics theory. The results prove that:(1) In the study area, the results show that soil nutrient content and fertility levels are in good condition. There are 16 kinds of indicators to represent soil properties and nutrient, which are included: water content, bulk density, silt content, clay content and sand content that represent the physical properties; and p H value, organic matter, total nitrogen, total phosphorus, total potassium, ammonium nitrogen, nitrate nitrogen, available phosphorus, total sulfur, total calcium, total magnesium, total sodium, total iron and manganese that represent the chemical property. The p H value is between 7.15-9.02, appeared alkaline. Soil organic matter content in the range between 2.55-30.36 g / kg, and 69.32% of samples are above average level. Bulk density is between 1.01-1.56; the moisture is 0.86-36.77%; total nitrogen content of 40.94- 1698.74 mg/kg. Total phosphorus content of 300.83-1283.66 mg/kg; total potassium content of 20.27-34.79 g/kg; available phosphorus range of 3.88-52.06 mg/kg; total iron content in the range is 12.48-36.99 g/kg; total sulfur content 33.22-1645.28 mg/kg; the whole range of calcium content is 28.38-72.88 g/kg; total magnesium content is 5.38-18.96 g/kg; the full content of manganese is 283.56-793.46 mg / kg. Ammonium and nitrate content range from 2.6 ~ 13.50 mg / kg and 11.49 ~ 141.87 mg / kg, respectively. Clay content range of 1.75-30.69%; silt content of 6.29-66.24%; sand content of 12.52-91.96%.(2) Between the indicators, there was a significant correlation. Soil organic matter was extremely significantly correlated with the integrated fertility index(IFI), ammonium, total manganese, total sodium, total magnesium, total calcium,total iron and total sulfur. Soil moisture was extremely significantly correlated with the total potassium, total iron, total sulfur, total calcium, total magnesium, total sodium,total manganese, the ammonium, p H value and bulk density, except total nitrogen, nitrate and total phosphorus. Also, between available phosphorus and total calcium, total magnesium, total sodium, total manganese, ammonium nitrogen, total phosphorus and total iron density have a significant correlation.The integrated fertility index(IFI) distributed ranged from 0.26 to 0.8. The average, standard deviation and coefficient of variation was 0.448, 0.139 and 31.03%, respectively. There are two-thirds of the research area where the IFI index is at a low level(0.362 ~ 0.629).The low areas of IFI stand for low soil fertility levels, that need to reinforce the cultivation measure. North of the research area is the high level areas of IFI. From south to north is decreased. The lowest is located in the middle. The high and low areas IFI coincide to a certain extent with organic matter.(3)Based on the results of statistical characteristics, the interpolation method in geostatistics is used in the analysis of indicators spatial distribution in soil. The distribution of organic matter content in the study area is the highest value appeared in paddy-fields in southern, and decreasing to the north. The lowest value appeared in dry land distribute in the middle and southern. Both of ammonium nitrogen and nitrate nitrogen have a maximum value in the southernmost and have a minimum value in the northernmost area. From south to north is decreased step by step. In the vertical cross section, ammonium nitrogen and nitrate nitrogen are accumulated and gathered in the depth of 0-20 cm, gently within the depth of 20-100 cm. Nitrogen content of the soils, on the whole, is low, and with only minute changes. The phosphorus content level is high, and it is content spatial distribution vary widely. Available phosphorus content is decreasing from south to north, but the total phosphorus content first increased, and then decreased. Along the vertical direction, both of them are accumulated and gathered in the depth of 0-20 cm, gently within the depth of 20-100 cm. The soil of research area is rich in potassium.(4)Results indicated the level of potassium content in north is higher than the south. The law is more related to human activities. The minor elements content were moderate in soil with only minute changes. They were more affected by human life and tillage method, while have a little relationship with soil properties.As the content of salt and alkali in the soil of Fengqiu was high, applying organic fertilizer is an effective way to regulating acid-base equilibrium. During the process of cultivation, it's essential to increase thickness of the plough layer, to prevent the loss of nutrients. Combine with type of crop, appropriate increase fertilizers and irrigation are effective ways to improve nutrient preserving capability.Under the background of the increasing pressure of farmland production and the growing seriousness of food production security in China, this thesis evaluates the spatial distribution of nutrient and the soil fer tility characteristic of Fengqiu agricultural land, then analyses the fertility spatial variability, which provide s theoretical support to the protection of local farmland and the promotion of precision agriculture. This the sis also provides certain theoretical reference and practice guidance to food production security, the efficie nt use of land resources, the sustainable development in small scale and the ecological environment protect ion of Fengqiu as well as the surrounding plains. |
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