Nitrogen cycling in coffee plantations

Nitrogen inputs to the coffee ecosystem are dominated by additions of fertilizer-N (100–300 kg N ha^?1 yr^?1). Small nitrogen inputs from rains and variable from inputs fixation by the leguminous shade trees can amount to 1–40 kg N ha^?1 yr^?1. Organic matter mineralization can be an important nitrogen source also. Nitrogen losses from the system include removal of N in the harvest (15–90 kg N ha^?1 yr^?1), the removal of coffee and shade tree prunings for firewood, losses from erosion, leaching losses and gaseous losses. Unfortunately, very little information exists for leaching and gaseous losses and for the factors that regulate these processes. The overall nitrogen cycle in shaded coffee plantings includes three interrelated subsystems. These are the coffee, shade and weeds subcycles.