Water-physical properties of the soil under multi-component grass mixtures on the eroded slope lands of the Pre-Carpathian region

Abstract

The soil cover of Pre-Carpathians is represented mainly by sod-podzolic surface-gleyed soils. These soils have low fertility due to unfavourable physicochemical properties with a relative richness of gross forms of nutrients. Withdrawal of sloping lands with a steepness of more than 3^o from intensive agricultural use and their transfer to sown forage lands is the main direction of optimization of nature management in Ukraine. One of the effective measures to improve the agro-ecological condition, improve agrophysical indicators and increase the fertility of sloping sod-podzolic surface-gleyed soils is their liming with multi-component grass mixtures

The aim of the research was to establish the influence of multicomponent grass mixtures on agrophysical properties (composition density, moisture and total porosity) of the soil in the Pre-Carpathian conditions.

Higher humidity in the soil layer 0–30 cm, on poorly washed soils both at the beginning of vegetation recovery (by 0.7–1.8%) and after the first mowing (by 1.2–8.9%) and medium-washed (by 0.7–1.6% and 0.4–5.7%, respectively) was observed under semi-complex (5–6 components) and complex (7–12 components) perennial legume-cereal grass mixtures compared to simple (three-component) herbal mixture (perennial fenugreek, meadow thyme, meadow clover). After the second mowing a similar pattern was observed on poorly washed soils, while on moderately washed soils the soil moisture was almost the same under all grass mixtures.

The reserves of productive moisture in the soil layer 0–30 cm at the beginning of spring vegetation were 44.1–45.4 mm, after the first mowing – 28.8–34.8 mm on poorly washed soils, 56.1–57.3 mm and 34.9–38.2 mm on medium-washed and were higher under 5–12 component grass mixtures in comparison with simple three-component grass mixture (perennial fenugreek, meadow thyme, meadow clover). After the second cut, such a pattern is not observed.

The bulk density in the soil layer 0–30 cm under multi-component perennial legume-cereal grass mixtures was 1.31–1.32 g/cm³ on poorly washed soils, 1.32–1.33 g/cm³ on medium-washed perennial soils at the beginning of spring vegetation, after the first mowing 1.32–1.33 g/cm³ and 1.34–1.35 g/cm³, after the second mowing 1.36–1.37 g/cm³ respectively.

The overall porosity of slightly washed and medium washed soils, both at the beginning of spring vegetation and after the first and second mowings was satisfactory (46.5–49.2% on slightly washed and 45.4–49.6% on medium washed) under all grass mixtures. The air capacity of the soil on slightly washed soils was 23.9–24.8% at the beginning of spring vegetation, after the first mowing 27.5–30.0% and after the second mowing 17.7–18.9%. A similar pattern is observed on moderately washed soils.

The structural condition of the soil layer 0–10 cm according to the content of agronomically valuable aggregates (0.25–10 mm), both on slightly washed (76,7–78,7%), and on medium washed (73.7–78.2 %) soils is good (structurality coefficient – K = 3.29–3.69), on medium-washed soils – 73.7–78.2% (K = 2.92–3.30), and by the number of water-resistant aggregates (48.5– 51.3 and 47.7–49.9%) is satisfactory. It should be noted that the highest rates on both slightly washed and moderately washed soils were obtained under complex (7–12 components) perennial legume-cereal grass mixtures.