Potential Suitability Distribution For Building Agriculture And Forestry Land And Soil Fertility Background In Shaanxi Province

As the focus of the construction of modern high efficient agriculture and forestry,the potential distribution of building agriculture and forestry can be a guide for its scientific planning and rational layout.Based on 220 geographical distribution points data of building agriculture and forestry in Shaanxi Province,together with 10 environment factors and the maximum entropy(Maxent)model and the spatial analysis of ArcGIS,the potential distribution of building agriculture and forestry in Shaanxi Province and its dominant environment factors were studied in this paper.Soil fertility of building agriculture and forestry land in Shaanxi Province was evaluated on determing weight of factors by means of the correlation coefficient and normalization of factors through membership function.The results are as follows:(1)The AUC(area under curve)value for training data predicted by Maxent was 0.964 and for the test data was 0.915.The training accuracy and fitting precision of the model are excellent.(2)The top three cities with great development potential of building agriculture and forestry in Shaanxi Province were Weinan,Xi’an and Xianyang city.The last three cities with small development potential were Shangluo,Baoji and Tongchuan city.The total potential area can reach 124700 hectares.Weinan located in central Shaanxi Province had the greatest potential.The area was 49577 hectares,accounting for 9.8 percent of the city’s total commonly used arable land.(3)The night lights brightness data,elevation,slope and the annual average temperature were the main environmental factors to affect the potential distribution of building agriculture and forestry.(4)Soil fertility in Shaanxi Province was divided into 4 grades.The integrated fertility index(IFI)of the building agriculture and forestry land at the first grade was bigger than 0.6181;the IFI of the building agriculture and forestry land at the second grade was 0.3216~0.6181;the IFI of the building agriculture and forestry land at the third grade was 0.1203~0.3216;the IFI of the building agriculture and forestry land at the forth grade was less than 0.1203.(5)The building agriculture and forestry land at the second grade had the greatest potential,the second is the third land and the forth land.The potential of the first land is minimal.They respectively account for 72.7%、21.3%、5.8%、0.2%。(6)It is good for the building agriculture and forestry when the content of effective potassium of soil was 25.8~387.5 mg/kg,the content of effective phosphorus was 0.4~30 mg/kg,the content of total nitrogen was 0.025~0.701 g/kg,the content of soil organic matter was 0.25~9.23 g/kg,the content of total potassium was 0.45~4.16 mg/kg,the content of sand was 7.67~89.04%,the content of clay was 3.54~59.76%,pH was between 4.3 and 9.9.