The degradation area of cultivated land accounts for more than 40% of the total area in China, and the pollution problem is more serious.

A few days ago, the Ministry of Agriculture held a national on-the-spot meeting on cultivated land quality construction in Yangzhou, Jiangsu Province, which revealed that at present, the area of cultivated land degradation accounts for more than 40% of the total cultivated land area. What factors can not be ignored behind the decline in the quality of cultivated land? How to protect the quality of cultivated land and ensure national food security?

"Red Line" and "bottom Line":

Establish the concept of "attaching equal importance to quantity and quality" of cultivated land resources

"Ten years ago, the land was so good that anything could be grown. But over the past few years, I do not know why, 'sunny days are hard, rainy days do not seep soup', now we can only grow some good living potatoes, and then crop some corn. " After the autumn harvest, Chen Wanfu, a villager from Zhangguan Village, Xiaoguan Township, Xuanen County, Hubei Province, was ready to level several acres of farmland in his family. He grabbed a handful of hardened clods and sighed.

At the soil and fertilizer workstation of the Hubei Provincial Department of Agriculture, researcher Liang Huadong produced a chart of "soil investigation and soil fertility evaluation." The chart shows that at present, among the cultivated land in Hubei, high-yield fields with an annual grain yield of more than 800 kg per mu account for only 26.1%, and medium-and low-yield fields account for 73.9%. 30 years ago, according to the ninth-class cultivated land classification, of the 50 million mu of regular cultivated land in Hubei, the area of first-and second-class land was more than 60%. Now the area of first-class land has decreased by 28.14%, while the area of inferior cultivated land has increased rapidly, and the area of sixth-class land has more than tripled.

Behind the data is the reality of the decline in the quality of cultivated land in our country. The results of national cultivated land quality monitoring show that in the northeast black soil area, the soil organic matter content of cultivated land has dropped significantly, with an average content of 26.7 grams per kilogram, a decrease of 31% compared with 30 years ago. the black soil layer has dropped from 80 cm to 100 cm at the beginning of reclamation to 20 cm to 30 cm, and loess has been exposed in many places.

"at present, the secondary salinization in the Huang-Huai-Hai Plain in China is serious, the fertility of the black soil in Northeast China is declining, and the soil organic matter is declining rapidly. the farmland soil degradation, barren red soil, acidification and soil heavy metal pollution caused by soil erosion in Northwest China are serious, and the quality of new cultivated land is low." Zhou Wei, a researcher at the Institute of Agricultural Resources and Agricultural regionalization of the Chinese Academy of Agricultural Sciences, pointed out.

The decline in the quality of cultivated land has posed a certain threat to the stable grain production, and also sounded the alarm for the national food security. In order to ensure China's food security in the future, the state has clearly proposed to control the 'red line' of no less than 1.8 billion mu of arable land, but this is only a quantitative concept, which is far from enough. While ensuring the quantity of cultivated land, it is of great significance to vigorously strengthen the construction of the quality of cultivated land and keep the 'bottom line' of the quality of cultivated land. " Chen Wenfu, academician of the Chinese Academy of Engineering, said so.

Insufficient soil fertility and increased pollution:

Control non-point source pollution to realize "storing grain in soil"

On the one hand, the basic capacity of cultivated land in China is insufficient, on the other hand, the problem of land pollution is becoming more and more serious.

According to statistics, the area of arable land in China is less than 10% of the world, but it uses nearly 40% of the world's chemical fertilizer. At present, the use of pesticides in China has reached 1.3 million tons, which is 2.5 times the world average.

From a scientific point of view, 70% to 80% of grain output depends on basic soil fertility, and 20% to 30% on water and fertilizer input, while the contribution rate of cultivated land basic soil fertility to grain production in China is only 50%. Land degradation caused by industrial waste pollution, chemical fertilizer and pesticide pollution and seed product pollution is serious. " Zhou Wei said.

Experts said that at present, the level of chemical fertilizer consumption in China is already very high, and due to the decreasing rate of returns, the output growth caused by increasing the input of chemical fertilizers is close to the limit, and the model of increasing the input of agrochemicals and energy should be changed in the future. By controlling agricultural non-point source pollution, improving the basic soil fertility of cultivated land and storing grain in the soil, it is the inevitable choice to establish a long-term mechanism of food security in the future and to realize food security.

In order to promote the protection and improvement of cultivated land quality, it was proposed at the national cultivated land quality construction site meeting that the level of field facilities and the basic fertility of cultivated land should be comprehensively improved in the future, and the quality environment of cultivated land should be improved. to ensure the construction of 800 million mu of high-standard farmland with drought and waterlogging by 2020, the content of soil organic matter will be increased by 0.5%, the utilization rate of organic fertilizer resources will be increased by 20%, and the straw will be returned to 80%. Achieve zero growth in the use of pesticides and chemical fertilizers.

Co-ordinate the present with a long-term perspective:

Establish a long-term mechanism for quality protection of cultivated land

Before 2011, 1300 mu of homestead, roads, potholes and other abandoned facilities were left behind after the relocation of four villages. after three years of reclamation and renovation, these lands have been reclaimed into farmland, and 10500 mu of concentrated connected areas have been formed together with the surrounding farmland. After comprehensive management and the application of improved varieties and good methods, they have become high-standard farmland for drought and waterlogging, and the yield of rice here has reached 1300 jin per mu this year. " In Hanjiang District, Yangzhou City, Jiangsu Province, Huai Si Town Reclamation Land Rapid Fertilizer Project area, District soil Fertilizer Station Deputy Director Liu Yan said.

Zeng Yande, director of the planting Department of the Ministry of Agriculture, said that to improve the quality of cultivated land, we should pay attention to the overall planning of current and long-term, production and ecology, engineering and technology, agricultural machinery and agronomy. Efforts should be made to improve acidification, salinization and other obstacles, improve soil fertility, preserve water and fertilizer, and control pollution restoration.

Chen Wenfu pointed out that in the future, we should also explore and promote the establishment of cultivated land construction and protection compensation policies to provide financial guarantee for the construction of cultivated land quality. It is suggested that the state should set up a special fund to improve the quality of existing cultivated land on the basis that the income from land transfer is not less than 15% for agricultural land development, and that it should be used to improve soil fertility by returning straw to the field, increasing the application of organic fertilizer and soil improvers.

At present, there are no special laws and regulations on the quality management of cultivated land in our country, but some provisions in principle have been made in the Land Management Law and the regulations on the Protection of basic farmland. Due to the lack of corresponding laws and regulations on cultivated land quality management, it is difficult to check the quality of cultivated land, and it is difficult to timely and effectively punish the behavior that destroys cultivated land or causes the decline of cultivated land quality. In this regard, experts suggest that while implementing the action of cultivated land quality construction, we should do a good job in the delineation of permanent basic farmland, strengthen the construction of cultivated land quality monitoring system, strengthen the legislative process of cultivated land quality protection, and bring cultivated land quality protection into the track of normalization, legalization and standardization.