| The cultivated land is a basic resource for human survival, it is the material basis foragricultural production, economic development and social progress. Because of populationgrowth, deterioration of the environment, improper use of land, The cultivated land contractedrapidly, and the quality decline, the sustainable development of cultivated land has become animportant issue to be solved. So it is necessary for more accurate evaluation of cultivated landfertility, to the rational use of existing cultivated land resources. Providing a scientific basisfor the adjustment of agricultural structure, land improvement and agriculturaldecision-making,so as to protect our agriculture sustainable development. This study useLongxian as the research object, choose basic statistical analysis, the space kriging (onKriging), analytic hierarchy process and fuzzy mathematics, study soil nutrient spatialdistribution, abundance of the Status of Farmland and appropriate performance. The researchresults are as follows.(1) Available K content was higher in the study area, average content is157.95mg/kg．Organic matter and nitrogen content in the medium level,the averageconcentration are11.98g/kg and67.68mg/kg. Available phosphorus content is low, as10.26mg/kg.(2) Organic matter, nitrogen and available phosphorus content is higher in Valleyterraces and Loess tableland of Longxian. The soil that available potassium content is higherlocates in the northern Loess Hilly Region. the content of organic matter has an upward trendwith increasing altitude, the highest average emerged in the range of1500-1800m. Betweenavailable nitrogen, available phosphorus and the altitude was a significant negative correlation,the average levels of the highest values found in the area of higher than1800m and800-1000m. Potassium and altitude was a significant positive correlation, the correlation coefficient is0.228, the highest content in the range of1200-1500m. Slope has a great impact on soilnutrients, available nitrogen, phosphorus and potassium's Correlation reached a significantlevel. The content of organic matter, nitrogen and available phosphorus are higher below3°,the content decreases with increasing slope. The highest content of potassium appeared within the range of slope greater than25°, with the slope decreases, the content has a cleardownward trend. In addition to potassium, the content of the other three nutrient are shadyhigher than the sunny, semi-shady than half sunny.(3) Relative to the demand of wheat growth in the study area, the most content ofalkaline hydrolysis is in the middle level, and can basically meet the growing demand. Thecontent of available phosphorus is low,48.62%of the cultivated land in a "lack " state whichcan not meet the normal growth of the wheat demand, the rest of the soil available phosphoruscontent only in the "medium" level. Available K's content is high, is located in "medium"level or higher than it,5.68%of soil available K in a "very rich" level. For the growth needsof the corn, nitrogen is able to meet its growth needs. Available phosphorus's content whichis located at the21991.41hm~2can not meet the growth needs of corn, only0.01percent ofcultivated land in the rating of "very rich". The cultivated land in which available potassium'scontent in the level of "lack "is only944.65hm~2, accounting for2.09percent of cultivatedarea. The rest of the cultivated land available K were high, can meet the demand for corngrowth.(4) The area of farmland in the study area is45226.91hm~2,19.87%of the total land area.The third level of farmland has highest distribution which is18207.20hm~2, accounting for40.26%of the total cultivated area. The next is the second level of farmland,it's area is10415.13hm~2, accounting for23.03%of the total cultivated area. The area of the first levelfarmland is5101.46hm~2, accounting for11.28%of the cultivated area. The area of the forthlevel farmland is6978.06hm~2, accounting for15.43%of the cultivated area. The fifth level offarmland is least, accounting for10.01%of the cultivated area. The most of the first andsecond level of farmland placed in the slope which is less than7°, flat-lying areas of thevalley terraces and loess tableland area, the most of soil types are loess soil, damp soil andblack loam, where soil nutrient content is higher and the soil structure is almost nuclear-like,soil texture is mostly sino soil. The third level of farmland is largely distributed in alltownship, mainly in the Loess Plateau and slope between7-15°, major soil type is loess. Theforth level of farmland is distributed in Heibei township, Lijiahe township, Huoshaozhaitownship and Wenshui township, and largely distributed in the Loess Plateau and loess hillyregion, which slope mostly in the7-25°, the main soil types are loess soil, purple soil and redclay. The fifth level of farmlang major places in the Xinjichuan township and Tianchengtown, and landforms is mostly rocky hilly mountain, most of the land slope between15-25°,the content of soil nutrient. Is low.(5)The land of highly suitable and suitable for wheat is total14068.33hm~2, accountingfor31.11%of all cultivated land, mainly located in the central region of Longxian, irrigation is better, content of soil nutrient is higher, is the main body of cultivated land. The cultivatedland of barely suitable for wheat is24923.25hm2, accounting for55.11%of the total area,Were distributed in all township, lack of irrigation facilities, undulating terrain, soil erosion ismore serious. The area of no-suitable for agriculture is6235.33hm2with poor irrigation, theimprovement is extremely difficult, mainly distribute in Longxian hilly and gully region anddebris mountain areas. |
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