Rosselkhoznadzor has clarified the criteria for soil fertility to achieve high crop yields.

In this regard, the Russian Federal Service for Veterinary and Phytosanitary Surveillance explains that fertility means the soil's ability to meet the needs of agricultural crops for nutrients, water, air, warmth, as well as biological and physicochemical environment, contributing to obtaining a high yield of these crops.

The main indicators of soil fertility include:

• organic matter content (humus);
• soil acidity level;
• available potassium content;
• active phosphorus content.

According to the Resolution of the Government of the Russian Federation dated July 22, 2011, No. 612 "On Approval of Criteria for Significant Decrease in Fertility of Agricultural Lands", a significant decrease in fertility of such lands is considered to be a change in the values of at least three of the following criteria, which occurred as a result of land use in violation of the requirements of rational use established by the land legislation of the Russian Federation.

• decrease in organic matter content in the plow layer by 15 percent or more;
• decrease in soil acidity in acidic soils (pHkcl) by 10 percent or more;
• increase in soil alkalinity in alkaline soils (pHH200) by 10 percent or more;
• decrease in the level of available phosphorus (mg/kg of soil) by 25 percent or more;
• decrease in the level of exchangeable potassium (mg/kg of soil) by 25 percent or more.

Soil analysis based on the main fertility indicators should be carried out to evaluate the work of land users in the conservation and reproduction of resources, as land is one of the main objects of environmental protection.