The degraded area of cultivated land in China is more than 40% of the long-term high intensity and overload utilization.

The Ministry of Agriculture issued a national bulletin on the quality of cultivated land on the 17th, which is the first time that cultivated land has been graded and graded in China.

According to the Bulletin, the quality of 1.826 billion mu of arable land (land data before the second national land survey) is divided into one to ten from high to low.

Zeng Yande, director of the planting Management Department of the Ministry of Agriculture, said that in order to find out the soil background, the Ministry of Agriculture launched a nationwide fertility survey and quality evaluation of cultivated land in 2002. After years of data accumulation, from 2013 to 2014, experts were organized to analyze the site conditions of cultivated land, physical and chemical properties of plough layer, soil management, soil profile characteristics and other aspects, and divided the quantity and distribution of cultivated land from one to ten grades.

According to the Communique, the area of cultivated land rated as first-to third-class is 498 million mu, accounting for 27.3% of the total cultivated land. The basic fertility of this part of cultivated land is relatively high, and there are basically no obstacle factors. Agricultural production should be carried out in accordance with the combination of use and cultivation to ensure that the quality of cultivated land increases steadily.

The area of cultivated land rated as fourth to sixth grade is 818 million mu, accounting for 44.8% of the total cultivated land. The environmental and climatic conditions of this part of cultivated land are basically suitable, the construction of farmland infrastructure has a certain foundation, and the potential to increase production is the greatest. It is estimated that by 2020, according to the average increase of one grade in the basic fertility of cultivated land, this part of cultivated land can achieve an increase of more than 160 billion jin of comprehensive grain production capacity.

The area of cultivated land rated as 7 to 10 is 510 million mu, accounting for 27.9% of the total cultivated land. The basic soil fertility of this part of cultivated land is relatively poor, and the production obstacles are prominent, so it is difficult to improve fundamentally in a short time, so the construction of farmland infrastructure and the internal quality of cultivated land should be carried out continuously.

What are the current problems in the quality of cultivated land in China? Xu Minggang, a researcher from the expert guidance group on cultivated land quality construction and management of the Ministry of Agriculture, said: "in recent years, China's agricultural production has always adhered to the model of high input and high output, and cultivated land has been used with high intensity and overload for a long time. The quality of cultivated land shows a trend of 'three major' and 'three low'."

Among them, the "three big" refers to a large proportion of medium-and low-yield fields, a large area of cultivated land quality degradation, and a large area of polluted cultivated land. According to the survey, among the existing cultivated land in China, medium-and low-yield fields account for 70% of the total cultivated land. Extensive farming methods, especially excessive application of chemical fertilizers, have led to the degradation of cultivated land quality. at present, the degraded area of cultivated land in China accounts for more than 40% of the total cultivated land, soil acidification in the south and shallower plough layer in North China Plain. The problem of salinization and desertification of cultivated land in Northwest China is also very prominent. The over-standard rate of soil pollution in cultivated land has reached 19.4%. There are eutrophication of surface water in the south and nitrate pollution of groundwater in the north, and there are more agricultural film residues in the northwest and other places.

"three low" refers to low content of organic matter, low grade of supplementary cultivated land and low basic soil fertility. For a long time, the so-called "occupation-compensation balance" of construction land in China only refers to the balance of quantity. According to experts, generally speaking, the fertility of supplementary cultivated land and occupied cultivated land is also different from that of occupied cultivated land by two levels, one of which is equivalent to a production capacity of 100 kilograms per mu of land.