Evaluation Of The Farmland Productivity In The Ecotone Of Guanzhong Plain And Loess Plateau

As significant resources for survival, arable land is of great strategic significance formaintaining national food security and sustainable agricultural development. Yintai district ofTongchuan City located in the transition zone between Guanzhong Plain and Loess Plateau,contains complex and diverse landforms, understanding the fertility in this area, andaccurately assessing the soil fertility levels, has very important guiding significance to localagricultural production planning and management, in parallel providing a reference to arableland fertility evaluation of similar areas, in order to promote agricultural development in theregion. In this study, Yintai district of Tongchuan City as the evaluation object, using Analytichierarchy program (AHP), Fuzzy comprehensive evaluation method and in combination withDelphi research methods, evaluated the soil nutrients, arable soil fertility and crop suitabilityof study area. Results are as follows:(1) Soil organic matter and available phosphorus content of arable land in Yintai districtof Tongchuan City are at intermediate level, the average content are14.83g/kg and12.18mg/kg separately; available nitrogen content of55.08%arable land are relatively low at35mg/kg~45mg/kg, and the average content is41.89mg/kg; over70%of the region’s arableland contains relatively high available potassium content, with an average content of193.97mg/kg, mainly between150mg/kg~250mg/kg, while arable land with less than100mg/kgavailable potassium content, only takes less than6%of the whole district.(2) Soil phosphorus and nitrogen levels of the study area are generally low, unable tofully meet the needs of wheat, maize and apples growth. In the future nitrogen andphosphorus fertilizer should be reasonable increased, and pay more attention to soil building;while soil potassium is relative sufficient for wheat, maize and apples growth, it is possiblethat in the future agricultural production, to apply less or even not to apply correspondingfertilizer in potassium-rich area.(3) Total arable land area is19177.85hm2, takes31.50%of the total land area, contains3692.66hm2first level land,4991.53hm2second level land,2644.04hm2third level land, 6568.90hm2fourth level land,1280.72hm2fifth level land. High quality first and secondlevel land accounted for45.28%of arable land, and third level land takes13.79%, whilefourth, fifth level land with poor quality account for more than40%of arable land. Overall,fertility of this district stands in the lower-middle level of national standards. Main limitingfactor of arable land fertility levels including relative high fluctuation terrain, catechesis landdistribution, poor irrigation level and low infrastructure level; therefore in future, theprotection of limited arable land resources, land consolidation, construction of waterconservancy projects, and infrastructure improvement should be strengthened, in order tobuild a number of high standard arable lands.(4) Wheat (maize) and apple share similar cultivation suitability, arable land highlysuitable and suitable for wheat (maize) or apple cultivation accounted for more than50%ofthe total arable land area, mainly in central and eastern regions of Yintai district; arable landbarely suitable for wheat (maize) and apple cultivation are majority, mostly located in theYintai’s northwestern and southern regions, with the area of7648.60hm2and8289.42hm2,take39.88%and43.22%of total arable land; only less than5%of the arable land are notsuitable for wheat (maize) and apple cultivation, scattered in different areas.(5) Arable land fertility levels have a close relationship with local landforms, altitude,slope, etc. in Yintai district of Tongchuan City, and with the transition from flat-lying valleyterraces to steep mountainous region with high altitude, the quality of arable land decreasedgradually, fertility level dropped from first level to fifth level.