Changes in fertility parameters of gray forest-steppe soils in garden agricultural landscapes of the south of Russia

Abstract

Data on the dynamics of changes in fertility parameters of gray forest-steppe soils of the Krasnodar territory under perennial plantings are presented. Significant species diversity of soils, characteristic of these soil and climatic conditions of the region, which are classified according to the recommendations of soil scientists in southern Russia, is noted. Systematic ecological and agrochemical monitoring of the soil was carried out within the boundaries of a 200-hectare test site located in the Seversk district of the Krasnodar territory. The analysis of monitoring data is given for the period from 1993 to 2018. The most detailed analysis was made of the upper part of the soil profile-horizons Aa (0- 25 cm), A (26-43 cm) and AB (43-55 cm). Scientific research was accompanied by generally accepted methods and State standards. In 1993, the soil sections were laid in connection with the laying of fruit plantations. The main parameters of garden suitability and soil fertility were determined. The duration of the first rotation of fruit stands is 16 years. During this period, 12 commercial fruit harvests were received. After the gardens were uprooted, row crops were cultivated on the site for 3 years, and in 2012, perennial plantings were restored within the boundaries of the monitoring site. The leading crop is the apple tree of winter maturation. Already in 2013, as a result of intensive use, a significant decrease in the availability of soil organic matter was found; its losses in the arable horizon (Aa) amounted to 0.18-0.81%, depending on the type of soil. Losses of mobile phosphorus compounds during the study period were in the horizons: Aa – 2.2 mg/kg, A – 7.2 mg/kg, AB – 5.8 mg/kg, which is probably due to its alienation from the crop of row crops for 3 years and non-compliance with the rules for fertilization. The contents of metabolic potassium, the amount of absorbed bases, hydrolytic acidity, soil reaction pHwater over time, and the exploitation of soils for various crops has not changed much. Identified in the dynamics of change in chemical parameters of soil fertility were the basis for the development of erosion control measures, including mechanized tillage across slopes (steepness of slopes on the site does not exceed 3.5°) and regulation of surface runoff by slitting and construction waste channels, and the introduction of high doses of organic fertilizer (50 t/ha manure). In 2016-2017, “traces” of mobile phosphorus and mineral nitrogen (N-NO3) were detected in the soil horizon in areas without organic fertilizers on the background of apple trees entering the commercial fruiting season) determined in the range of 1.0-1.9 mg/kg (Aa); 1.1- 1.2 mg/kg (A) and 1.2 mg/kg (AB). The nitrification capacity of soils in the arable horizon decreased to 11.7-12.0 mg/kg, and in the AB horizon – to 0.1-0.2 mg/kg.