Calculation method of cultivated land consolidation potential based on cultivated land coefficient and pre-evaluation of farmland classification

Abstract: Based on the second land investigation data and farmland classification, this article explores the quantitative and qualitative potential of cultivated land consolidation in Wuhua County in Guangdong Province. The quantitative potential of land consolidation was calculated by the cultivated land coefficient method, in which the standard cultivated land coefficient of each cultivated land parcel is decided by the mean cultivated land coefficient of the same slope grade to which the parcel belonged, and the quantitative potential of each cultivated land parcel is calculated by the multiplying the area of the parcel by the difference between its cultivated land coefficient and the standard. Based on the quantitative potential of each cultivated land parcel, the quantitative potential of each village and town was obtained. The qualitative potential was calculated by the pre-evaluation of farmland classification. Currently in many studies, the qualitative potential of cultivated land consolidation is calculated based on farmland classification, the grades of agricultural land commonly are raised 1 grade or more grade correspondingly, However, factors of farmland classification cannot completely reflect the effects that land consolidation projects produce in increasing cultivated land quality by building infrastructure such as farmland roads, farmland shelterbelts, and irrigation and drainage systems. The previous land consolidation projects in Wuhua County showed that the land parcel slope, soil thickness, irrigation condition, and drainage condition can be obviously improved by land consolidation, so these four factors were raised respectively to compute the improved land grade and the qualitative potential was obtained by subtracting the original grade from improved grade. The method for calculating qualitative potential in the article can avoid the inaccuracy brought about by the unified rising of all factors. Generally speaking, the carrying capacity can raise 100 kg per hectare if the cropland using grade raises 1 grade, and based on this, the agricultural land carrying capacity can be calculated. The result showed that the potential of cultivated land consolidation is large. The quantitative potential was 841.69 hm2 and decreased from north to south, contrary to the cultivated land use intensification. The qualitative potential showed a similar trend as the quantitative potential. The natural grade of farmland classification can be improved by 1.28 grades and the cropland using grade can be improved by 0.71. The agricultural land carrying capacity can be increased by 57862.99×104 kg. The spatial distribution of quantitative and qualitative potential was due to the difference of the agricultural structure in Wuhua County; the agriculture developed rapidly in the north region of Wuhua County relatively, and the basic condition and cultivated land coefficient was better than the south region, so the quantitative and qualitative potential of the north region was lower than the south region. The result provides successful experiences for land consolidation planning, high-standard prime farmland construction, and the layout of the land consolidation project. The quantitative and qualitative potential in this article is theoretical, and the actual potential would be affected by the cultivated land condition, the level of economic development, and the wishes of the people. Therefore, the theoretical potential must be adjusted to match the physical situation in practical application.