Nutrient balances and management of soil fertility prior to the arrival of chemical fertilizers in Andalusia, southern Spain

Abstract

Studies on the role of nutrient balances in the socioecological transition of agriculture are scarce, particularly in the Mediterranean region where manure availability was low. The role of nutrient balance in this transition was evaluated in three representative localities of the inland Mediterranean region of southern Spain from 1750 to 1900. Changes in cropland distribution, population, manure availability and demand, and nutrient balance at cropland and aggregated scales were assessed. Data suggest that agriculture development around 1750 was limited by manpower. During this period manure availability was higher than demand and municipal balances for nitrogen were positive, whereas they were slightly negative for phosphorus and potassium. During the 19th century, the population increased while livestock numbers and manure availability decreased. Nutrient balances become negative at crop and aggregate scales, indicating that productivity was based on soil mining. This territorial imbalance and soil mining were the main reasons behind the turn-of-the-century crisis which led to the agrarian socioecological transition.