The investigation, monitoring and evaluation of cultivated land quality is of great significance.

Cultivated land is a precious and limited natural resource. the quality of cultivated land is related to national food security, quality safety of agricultural products and ecological security. it is a necessary basis to ensure sustainable social and economic development and meet the growing material needs of the people. The rigidity of cultivated land in China is decreasing, the population is increasing rapidly and the contradiction between supply and demand of grain is becoming increasingly prominent. improving the quality of cultivated land in China is the strategic decision of national food security. However, the basic fertility of farmland in China is about 20% lower than that in developed countries; the highly intensive planting of farmland and the utilization mode of high intensity and high input, especially the intensive mode of nutrient disequilibrium, not only lead to the degradation of farmland fertility. it also causes some eco-environmental problems, which leads to the great fluctuation of grain production in our country, and the potential of high-yield crop varieties can not be brought into full play. Therefore, to master the changing characteristics and laws of cultivated land quality in different regions and different utilization patterns, and to carry out long-term monitoring, evaluation and early warning of cultivated land quality, it is of great significance to improve the quality of cultivated land, guide the quality management of cultivated land, and ensure national food security and sustainable development of agriculture.

In China, the degradation of cultivated land such as secondary gullification, secondary salinization, desertification, nutrient depletion, soil erosion and environmental pollution caused by unreasonable use has been very serious. The task of transforming the quality characters of degraded cultivated land is arduous, which requires complex technology, a lot of investment and long-term labor. The productivity and other quality traits of reclaimed cultivated land can not be compared with high-quality cultivated land in the short term. However, at present, the dynamic monitoring of cultivated land quality is generally carried out after the degradation of cultivated land quality, at this time, the production performance and utilization benefit of cultivated land have been harmed to a certain extent. By monitoring the quality of cultivated land, we can dynamically monitor the quality of cultivated land, warn the changing situation, and take preventive measures according to the early warning, so that the quality of cultivated land can be maintained at a high level with less investment. Therefore, cultivated land quality monitoring is an important foundation to carry out cultivated land quality construction and improve the goal and benefit of cultivated land quality construction.

The monitoring and evaluation of cultivated land quality is a basic and long-term work. In order to fully grasp the situation of cultivated land quality and the law of dynamic changes of soil fertility in China, since the 1980s, agricultural departments at all levels across the country have established a number of long-term positioning monitoring points for cultivated land quality. According to incomplete statistics, there are about 3000 provincial monitoring sites, 2000 prefecture-level monitoring sites and 9000 county-level monitoring sites for a long time. These long-term positioning monitoring play an important role in finding out the base number and changing trend of cultivated land quality in China. However, the number of these monitoring sites is too small, monitoring projects focus on soil fertility and productivity, and do not pay enough attention to soil environmental factors. Therefore, in the near future, the Ministry of Agriculture will standardize the monitoring and evaluation of cultivated land quality and issued the "measures for investigation, Monitoring and Evaluation of cultivated Land quality". On the basis of this work, the monitoring and evaluation of cultivated land quality will further expand the monitoring points and monitoring contents, and carry out network monitoring and early warning of cultivated land quality changes in China. We will promote the construction of a long-term monitoring network for the change of cultivated land quality in China, promote the standardized collection of monitoring data and in-depth analysis of a large number of data, and make full use of the long-term positioning test of soil fertilizer and the "3414" experiment of soil testing and formula fertilization. To carry out the study on the evolution law of cultivated land fertility, driving factors and their coupling relationship with productivity, and put forward countermeasures and suggestions for soil improvement and scientific fertilization for middle and low yield fields in China, so as to provide basic data and theoretical basis for realizing the sustainable increase of grain production and the improvement of cultivated land quality in China.

The measures for investigation, Monitoring and Evaluation of cultivated Land quality (hereinafter referred to as "measures") fills the gap in the lack of special legislation on cultivated land quality management and protection at the national level in the form of departmental regulations. it has the characteristics of systematicness, overall situation, specialization and maneuverability. The measures provide an important basis for agricultural departments at all levels to improve the investigation and monitoring system of cultivated land quality, carry out investigation, monitoring and evaluation of cultivated land quality, and publish cultivated land quality information. it is of milestone significance to improve the level of cultivated land quality management and protection in our country under the new situation.

The "measures" will promote the management of cultivated land quality investigation, monitoring and evaluation data, ensure the integrity, authenticity and accuracy of the data, promote the research on cultivated land quality, and put forward countermeasures and measures for the protection and improvement of cultivated land quality. we will earnestly promote new achievements in China's cultivated land quality management and protection, and promote the implementation of the strategy of "storing grain in the land and storing grain in technology"!