Hardness of podzolized chornozem under different cultivation methods in the agrocenosis of short-term crop rotation

Abstract

Goal. To identify the regularities of the profile distribution of soil hardness, to conduct a typology of its values, and to establish correlation links with the moisture content of podzolized chornozem under the influence of systematic ploughing, surface tillage to a depth of 10–12 cm for 10 years, as well as for the transition to No-till after ploughing for 5 years and surface tillage for 5 years in the agrocenosis of 5-field grain rotation in the conditions of Central Forest-Steppe. Methods. Field (establishing the influence of different cultivation systems on the content of organic matter in the podzolized chornozem), analytical (determination of humus content by the Tiurin method), calculation (calculation of humus balance in the 5-field crop rotation), and statistical dispersion analysis using the Statistica 10 computer program. Results. The study was conducted in 2021–2025 on an experimental basis at the Cherkasy State Agricultural Experimental Station of the NSC «Institute of Agriculture of the NAAS» in the conditions of a field stationary experiment laid down in 2010. The geographical coordinates of the vil. Kholodnianske (Cherkasy oblast) are 49°11’14’’N and 31°51’58’’E. The soil cover of the field is strongly graded low-humus middle carbonaceous on carbonate loess podzolized chornozem. In the spring period (maximum moisture level), the soil hardness in the soil thickness of 0–20 cm for ploughing and No-till after ploughing was < 10 kg/cm2. At the same time, for surface tillage and No-till after surface tillage, it reached the upper limit of the optimal value. In the soil thickness of 0–40 cm, the soil hardness, regardless of the method of tillage, was within the optimal values, 11.5–16.7 kg/cm2. At a depth of 35–60 and 0–60 cm for surface tillage and No-till, the hardness met satisfactory growth conditions (20–21 kg/cm2), for ploughing, unfavorable plant growth conditions (> 21.0 kg/cm2). In July, at the lowest level of moisture in the soil layer of 0–20 cm for ploughing, the hardness corresponded to the optimal conditions for plant growth, and for surface tillage and No-till, the growth conditions were satisfactory (> 21.0 kg/cm2). In the soil thickness of 0–40 cm, regardless of the method of cultivation, the growth conditions were unsatisfactory, its hardness reached critical values (> 30.0 kg/cm2), as well as at a depth of 35–60 and 0–60 cm, 47.5–54.2 and 41.2–44.0 kg / cm2, respectively. The calculation showed that between the hardness and humidity of the soil in the soil thickness of 0–30 cm, an inverse correlation was found at the level of strong correlation, regardless of the method of soil tillage: R = –0.74...0.79 ± 0.02, R2 = 0.55–0.62. For ploughing and surface tillage, an increase per unit of soil moisture corresponded to an increase or decrease in its hardness by 0.21 kg/cm2. At the use of No-till after ploughing and No-till after surface tillage, a decrease per unit of soil moisture corresponded to 0.25 kg/cm2 of its hardness, which was 1.19 times higher than for ploughing. Conclusions. With the use of No-till after ploughing and surface tillage, compared with ploughing and surface tillage in the semi-thickness of the soil 0–30 cm, 30–60, and 0–60 cm, the hardness of the soil was in the range of optimal and satisfactory values for high indicators of its humidity. In the spring period, with the use of No-till, both for ploughing and for surface tillage, optimal conditions for plant growth were formed, and in the summer period, the conditions for the growth of crops by hardness were unsatisfactory for all soil tillage systems. Most of all, they deteriorate during surface tillage.