Soil capacity to biomass production in sandy loam soils following cover crop farming systems in tropical conditions in the Northeast region of Brazil

Abstract

Context Soil capacity to biomass production (SC) sheds light on soil health and its capacity to sustain high primary production. However, the currently existing models are based on rather local data, and thus there is a lack of predictive tools to monitor SC. Aims Our aim was to assess the influence of cover crops on soil chemical properties by considering their different behaviours (biomass production and root density). Methods We characterised soil chemical properties, and plant biomass production during 6 years in field conditions at a tropical soil. Key results Our findings suggest that: (1) green manure practice improved Ca2+, K+, and soil organic carbon (SOC) stock, but none of the studied cover crops were able to improve soil P content; and (2) we found three groups of green manure by considering the SC reduction, namely G1 (low SC reduction) that comprises Crotalaria ochroleuca and Neonotonia wightii, G2 (medium SC reduction) that comprises Brachiaria decumbens, Pennisetum glaucum, and Crotalaria juncea, and G3 (high SC reduction) that comprises Mucuna pruriens, Canavalia ensiformis, Crotalaria spectabilis, Dolichos lablab, and Stizolobium aterrimum. Conclusion We concluded that after 3 years during which soil parameters and the production of most, but not all, cover crops have increased, the deficiency in P did not allow plants to grow well anymore. Implications This study highlights the importance to consider predictive models as a tool to be used in soil management. Our study also provides a deeper view about the use of green manure and their influence on soil capacity to biomass production.