Traditional soil fertility management ameliorates climate change impacts on local andean crops within smallholder farming systems

Food security in traditional smallholder mountain communities across the globe is being jeopardized by multiple global changes. Rising temperatures are projected to impact the suitability of cultivation areas for many crops. To maintain yields, smallholders may need to alter the nutrient management, the timing of cultivation, or even the crops currently cultivated. In the Andean region, farmers have traditionally relocated crops to higher and cooler elevations to cope with warming climates. However, failure to relocate crops could result in increased susceptibility to warmer temperatures and a higher incidence of pests. Traditional soil fertility management practices and a focus on traditional (orphan) crops offer potential solutions to cope with rapid climate warming in the region. To test this hypothesis two side-by-side experiments were established with traditional Andean crops (Oxalis tuberosa and Lupinus mutabilis) at three elevations, each with two fertility treatments (organic or synthetic nutrient additions). Soil and climate data (i.e., temperature and precipitation) were collected throughout the growing season, and crop performance was evaluated through various indicators, including yield and plant phenotypic characterization. Two-way ANOVAs were conducted to understand the influence of site and nutrient management on crop performance. Results showed that warmer climate negatively impact the production and performance of O. tuberosa and that organic fertilizers can help increase crop yield and biomass production of O. tuberosa. In contrast, L. mutabilis showed an accelerated growth cycle with increasing temperature, but grain yield and biomass production were not significantly affected. Our findings highlight that climate warming is a serious threat to small-scale agriculture in the Peruvian Andes and could cause severe declines in production of locally important crops. The use of organic inputs instead of synthetic fertilizers may help support crop growth and improve agroecosystem resilience.