Soil chemical and biological properties after long-term of spring barley monoculture under different agricultural practices
Unit of Agrotechnology Studies, Centre of Estonian Rural Research and Knowledge, J. Aamisepa 1, EE48309 Jõgeva County, Estonia
*Correspondence: elina.karron@metk.agri.ee
Abstract:
Sustainable agriculture supports soil health and the growth of microorganisms through various agricultural management practices. This multidisciplinary study connected agrotechnology, agrochemistry, and soil microbiology. A 29-year barley monoculture field trial was conducted, focusing on soil pH, soil organic carbon (Corg), dehydrogenase activity (DHA), and the abundance of bacteria, including Gram-positive (Gram+) and Gram-negative (Gram-) bacteria, Actinobacteria, and saprotrophic fungi. Three agrotechnological factors were considered: chemical plant protection (no protection (PP0), herbicides (H), herbicides, and fungicides (HF)); fertilization (only mineral fertilizer (NPK) and mineral fertilizer with cattle slurry addition (NPKS)); and tillage (autumn shallow mixing (AM), autumn ploughless tillage (APT), autumn plowing (AP), and spring plowing (SP)). All agrotechnological factors were found to have a significant effect on the measured variables, with fertilization having the strongest effect, followed by chemical plant protection and tillage practices. The application of cattle slurry six years ago with annual mineral fertilizer had a significant positive effect on all measured properties, except for saprotrophic fungi. The absence of chemical plant protection significantly increased Corg and DHA, Gram-positive bacteria, and Actinobacteria, whereas the lowest amounts of Gram-positive bacteria, Gram-negative bacteria, and Actinobacteria were found in treatments with only herbicide application, followed by herbicide and fungicide combined. Tillage is an important factor for Gram-positive and Gram-negative bacteria and fungal biomass. Tillage had the most significant effect on fungal biomass compared to plant protection and fertilization. Intensive tillage (deep plowing) in autumn had the strongest negative effect on soil microbiota.
Key words:
chemical plant protection, fertilization, long-term field trial, tillage