Carbon economy and mineral nutrition in a sustainable peach orchard

Orchard ecosystems may represent a key factor of carbon (C) cycle, contributing to store atmospheric CO2. Among other, nutrient management is a challenge for low-input farming techniques, which are oriented to improve soil organic carbon (SOC) content. Increased SOC is a crucial step for soil fertility remediation and it is also beneficial for soil water holding capacity, being significant to improve water use efficiency. This paper mainly reports the effects of a set of alternative environmental-friendly orchard management practices (no-tillage, pruning residues and cover crop retention, compost application) on nutrients availability and soil C reserves. That alternative practices were compared against the locally conventional (soil tillage, burning of pruning residues, mineral fertilization). It is shown that a 7-year period of changed practices significantly increased SOC concentration up to 1.8% and soil microbial biomass in a Mediterranean peach orchard. Incidentally, the yield was improved on average by 30% as compared with conventional managed plot. The effects of carbon addition on the budget of soil nutrients (N, P, K, Ca, Mg) are discussed.