Sustainable orchard management in semi-arid areas to improve water use efficiency and soil fertility

Due to the impact of climate changes (mainly increased temperature and precipitation changes) as combined with poor orchard management (e.g., continuous tillage, use of mineral fertilisers) on soil fertility, orchard management should be revised. Improvement of orchard management practices aimed at increasing soil fertility traits (e.g., soil organic carbon, microbial community, soil porosity) will be beneficial for soil conservation and also for improvement of water use efficiency at farm scale through improved soil water holding capacity. This paper mainly focuses on some effects on orchards grown under semi-arid environment of changed soil management practices from conventional (soil tillage, mineral fertilisers, burning of pruning residues) to sustainable (no-tillage, pruning residues and cover crop retention, compost application) on soil microbial biomass, organic carbon (SOC), mineral nutrients availability and water use efficiency. Results show that a 7/10-year period of changed practices significantly increased SOC concentration and soil microbial biomass at Mediterranean fruit tree orchards and that yield was improved by 30-50% as compared with that recorded in conventional managed orchards. The positive effect of carbon addition on reserves of soil nutrients (N, P, K, Ca, Mg) is also reported. Seasonal volumes of irrigation water are reduced by ∼30% in orchards under sustainable management practices, contributing to improve water use efficiency.