Plant-parasitic nematode community and enzyme activities in soils under no-till soybean crops in Brazil

Abstract

Soybean is Brazil's largest agricultural crop, grown across a variety of climates and soil conditions, and it is subjected to a large number of pests, including plant-parasitic nematodes. In general, the occurrence of plant-parasitic nematodes in soybean is influenced by various soil physicochemical properties, such as the pH, texture, and nutrient content. These soil properties may determine the nematodes community composition and affect soil quality and functioning, which can be monitored by analysing of soil enzyme activity. In this sense, the analysis of β-glucosidase and acid phosphatase enzymes can provide valuable information to assist decisions in the sustainable management of soybean cultivated soils in Brazil. In this study, we used 216 samples collected from no-till soybean fields across Brazil. The samples were used to investigate the influence of soil physical and chemical properties on the plant-parasitic nematode community and enzymatic activity. We identified seven genera of plant-parasitic nematodes including Meloidogyne, Pratylenchus, Heterodera, Rotylenchulus, Helicotylenchus, Scutellonema, and Xiphinema. Our results indicate that clay content and soil pH were the main properties modulating the plant-parasitic nematode community. We observed a higher abundance of plant-parasitic nematodes in highly acidic soils when compared to slightly acidic. In addition, soil organic matter content, available P, and pH were the main properties modulating microbial activity in the soil. No significant correlations were observed between enzymatic activity and nematode population density. This is the first study to provide insights into plant-parasitic nematode community composition and soil enzymes activity in soybean cultivated soils on a national scale in Brazil.