Agroclimatic and soil risks in organic farming

Abstract

The article considers current agroclimatic and soil risks in organic farming using the example of walnut cultivation in the Central Forest-Steppe of Ukraine. Particular attention is paid to the role of organic carbon, humus content, soil acidity and assessment of the condition of dark gray podzolized soils. Soil risk analysis showed that the process of dehumification and reduction of microbial activity in the studied soils occurs constantly, since the lack of sufficient organic matter is critically low for soil microorganisms, and a humus level of less than 2 % is a sign of a critical loss of soil fertility and a decrease in its water-holding capacity. A sharp drop in humus levels in 2025, caused by insufficient organic fertilizers and prolonged drought, which reduced their effectiveness and affected the work of the microbiological association of bacteria. During the period 2023–2025, a slow rate of humus formation was observed in the absence of an additional source of organic matter, but turfing helped protect the soil from overheating, erosion, and compaction.The Corg content (1.0 %) indicates a low organic matter content in the soil (optimal Corg content: 1.8–2.5 % for wal-nut); low Corg causes deterioration of soil structure, moisture retention, and reduces microbial activity. Potentially mineralized nitrogen (14 kg N/ha) is critically low (optimum for nut orchards: 60–100 kg N/ha) – a sign of nitrogen starvation. The C:N ratio = 12.5 shows that the carbon to nitrogen ratio does not yet block mineralization (norm for mineralization: 10–15), but due to the general deficiency of C and N, even a favorable ratio does not guarantee sufficient microbiological activity. Dark gray podzolized soils are at risk under organic production conditions. The prospects for preserving soil fertility through a sustainable management system are analyzed: annual monitoring of humus, C, N; systematic sodding of rows using legumes + cereal grasses, not only ruderal flora; increasing biological activity through biological products with effective microorganisms and mulching with plant residues with low C:N (legumes); adding organic matter – humus, compost, green manure (sideration with legumes).