Abstract:It is a pivotally strategic measure for China to carry out the rural land consolidation and construct a large-scale well-facilitied farmland which gives stable production despite drought or excessive rain. Because of the different topography, landform, specific factors that restrict agricultural production, the key to solve the well-facilitied farmland construction is also different. Therefore, the most urgent and the prominent obstacle factors that affect the improvement of soil fertility in the well-facilitied farmland construction project must be grasped, so as to eliminate the barrier factors and solve the main problems in the process of land consolidation. The research on the diagnosis of farmland construction obstacle factors was carried out based on Xinzheng City. The research was based on the theory of ecological niche. In the process of diagnosis, the niche suitability evaluation model and the thought of index deviation degree were combined to construct disorder factor diagnosis model based on ecological niche. The index deviation from the optimal niche and the niche deviation of each evaluation factor were calculated by using the model, and the barrier degree of each index was got. Then, the obstacle degree of each evaluation unit was obtained according to the Shefold restriction law. Finally, the factor of the barrier factor value Oi more than 0.4 of each evaluation unit in the region was screened out. The frequency of these factors was calculated and sorted according to the order from large to small, so as to dig out the main obstacle factors affecting the construction of well-facilitied farmland in Xinzheng City. The model not only overcame the limitations of the subjective weighting in the current diagnosis model of obstacle factors, but also replaced the 100% values in the index deviation model with the optimal niche value, providing theoretical and scientific basis to determine the 100% degree model values of deviation. The model made up for the deficiency of the barrier factor diagnostic model, and made the barrier factor diagnosis model more scientific and reasonable. It provided a new approach for the diagnosis of obstacle factors, and expanded the application of niche theory at the same time. The results showed that the overall obstacle degree was not so high in Xinzheng City. The total farmland area below obstacle degree score of 0.5 was 22741.14hm2, which accounted for 41.98% of the total farmland area in the study area;the total farmland area whose obstacle degree score was in interval of ［0.51,0.65] was 22493.79hm2, which accounted for 41.53% of the total farmland area in the study area;the total farmland area whose obstacle degree score was in interval of ［0.66,0.8] was 3873.96hm2, and the total farmland area above obstacle degree score of 0.8 was 5059.05hm2, separately accounted for 7.15% and 9.34% of the total farmland area in the study area. The overall natural endowment of cultivated land in Xinzheng City was pretty good, so the main limiting factors to well-facilitied farmland construction in Xinzheng City were guaranteed rate of irrigation and drainage conditions as well as part of low soil organic matter and high soil pollution index. By using this model, the spatial distribution information of main barrier factors of well-facilitied farmland construction in Xinzheng City was obtained, which was consistent with the results of field investigation and analysis, so that the validity of the model was verified. The model reliably provided a basis for the design of well-facilitied farmland construction plan.
