Abstract:

The Yunnan’s dry-hot valleys represent one of China’s core coffee production areas. However, the traditional sun-grown monoculture system has induced a series of problems under extreme climatic conditions of high temperature and drought, including premature aging of coffee trees, unstable quality, soil erosion, and biodiversity decline, severely constraining sustainable industrial development. To address these challenges, this paper systematically presents the theoretical foundations, synergistic mechanisms, and technical specifications of agroforestry systems combining shade cultivation with grass cover as a solution. Research indicates that traditional monoculture exposes coffee trees to prolonged intense light and high-temperature stress, resulting in reduced photosynthetic efficiency and physiological dysfunction, thereby affecting coffee quality improvement. Simultaneously, exposed soil surfaces exacerbate soil erosion, while excessive dependence on chemical fertilizers and pesticides triggers soil acidification, environmental pollution, and food safety risks, disrupting ecological balance. The introduction of shade and grass cover technologies can effectively mitigate these issues. Shade trees reduce canopy temperature and transpiration rates, creating more suitable microenvironments for coffee cultivation. Grass cover effectively maintains soil moisture, increases organic matter, improves soil structure, and forms effective three-dimensional systems for soil and water conservation in conjunction with shade trees. The integrated shade-coffee-grass system formed by their combination constructs stable three-dimensional composite agricultural ecosystems through synergistic management of water, nutrients, soil health, and biodiversity. This paper further proposes practical implementation guidelines for this technology in dry-hot valley regions, including: (1) scientific selection of drought-resistant, deep-rooted shade tree species and nitrogen-fixing, drought-tolerant grass species; (2) optimized three-dimensional spatial planning to achieve 40% to 50% shade coverage; (3) precision water and fertilizer management combined with drip irrigation technology and ecological integrated pest management. Finally, four key development directions for promoting this model are outlined: (1) increasing scientific research investment and technology transfer; (2) enhancing policy support and incentives for green production; (3) strengthening technical training and demonstration extension; (4) developing ecological coffee brands to enhance product value-added. This study aims to provide practical pathways for transforming Yunnan’s coffee industry towards ecologically sound, high-quality, and efficient sustainable development.

Key words: dry-hot valley, coffee, agroforestry system, sun-grown monoculture system, shading, grass cover, soil erosion