Effects of tree species and planting density on the total productivity of an agroforestry system

Abstract

Abstract The agroforestry system consists of crop, forest, and pasture cultivation in combination, succession, or rotation, with the goal of increasing resource-use efficiency and, consequently, productivity. This system is an important strategy to recover degraded land. Our goal with this study was to assess the effects of the spacing and stand density of three Eucalyptus species on the total productivity of an agroforest system. For this purpose, an agroforest was planted in a degraded pasture in the central-eastern region of Brazil. The system consisted of three Eucalyptus species alongside maize and Crotalaria juncea in the first year, maize and grass-to-silage production in the second year, and pasture during the third and fourth years. The increase in tree density led to greater wood production; however, it decreased the productivity of the other system compounds, indicating that the prioritization of one compound decreased the productivity of the others. Despite this negative correlation between tree growth and the growth of the other compounds, the most productive treatment (simple rows of E. urophylla) during the four years after the system implantation was 3 Mg ha− 1 of maize, 15.6 Mg ha− 1 of Crotalaria juncea for soil enhancement, 6.2 Mg ha− 1 of silage (maize with grass), 13.8 Mg ha− 1 of pasture, and 180 m3 ha− 1 of wood.