| The availability of organic fertilisers plays a major role in organic farming systems. Such systems exclude the use of synthetic fertilisers, whilst aiming to optimise internal nutrient cycling. The low availability of manures, particularly in dry areas, can lead to negative nutrient balances inmany organic farming systems. Such negative nutrient balances are mainly found for P and K. In this paper,we aim to study the availability of P in irrigated and rainfed semiarid Mediterranean grassy crops with long-term organic and conventional farming practices. NaHCO3 extracts were prepared from an array of soils from 16 plots, covering organic and conventional management in rainfed and irrigated conditions. Inorganic (NaHCO3-Pi) and organic P (NaHCO3-Po)... |
