Green manuring: sustainable practices for soil fertility and environmental conservation

Abstract

The intensification of agriculture and environmental challenges have led to soil degradation, compromising agricultural sustainability. About 33% of global soils are moderately or highly degraded, compromising soil quality and agricultural sustainability. In this context, green manure emerges as an essential technique, promoting soil fertility and environmental conservation. Therefore, the aim of this study is to characterize the benefits of green manure in improving soil quality and promoting agricultural sustainability. This study adopted a methodological approach based on integrative literature review to analyze the role of green manure in improving soil quality and promoting agricultural and environmental sustainability. The research problem was defined by the central question: "How can green manure contribute to improving soil quality and promoting agricultural and environmental sustainability?" To ensure the relevance and quality of the included studies, inclusion and exclusion criteria were established, and data were collected from recognized academic databases. The selected studies were analyzed qualitatively, focusing on objectives, methodologies, results, and conclusions, as well as identifying gaps and areas for future research. The synthesis of the studies was organized around emerging themes, including the effects of green manure on soil structure and fertility, impact on biomass and microbiological activity, effectiveness in nutrient cycling and weed suppression, and recommended practices and ideal plant species for green manure. Green manure, using cover crops such as legumes and grasses, presents significant benefits for soil physical structure, biomass, microbiological activity, nutrient cycling, and weed suppression. Studies demonstrate that green manure improves soil porosity, aggregation, and water infiltration, which are essential for soil health and erosion reduction. The biomass of cover crops enriches the soil with organic matter, stimulating microbiological activity and promoting efficient nutrient cycling, reducing the need for chemical fertilizers. Legumes, such as pigeon pea and velvet bean, are particularly effective in biological nitrogen fixation, increasing the availability of this nutrient in the soil. Green manure also contributes to the cycling of phosphorus and potassium, which are essential for plant growth. The ability of cover crops to suppress weeds, through competition for resources and allelopathic properties, reduces dependence on chemical herbicides, benefiting the environment and soil health. Considering these benefits, green manure stands out as a sustainable agricultural practice, promoting healthier and more productive soils. The adoption of this technique can lead to more resilient and sustainable agriculture, capable of facing the challenges of soil degradation and climate change. It is crucial to encourage the adoption of green manure through public policies, continuous research, and farmer training. The practice should be adapted to local conditions and specific crop needs to maximize its benefits and promote agricultural sustainability on a large scale.