Spacing and fertilization effects on Eucalyptus camaldulensis growth and diameter distribution at the savanna region in Minas Gerais State, Brazil

Abstract

Eucalyptus camaldulensis plants were established under four spacing and fertilization levels at the savanna region in Minas Gerais State (17º00’S, 45º54’W and 440 m high). The study aimed to test the hypothesis that by changing the distance between plants in the row a change in fertilization levels would be required. Spacing consisted of a fixed distance between rows (3 m) varying the distance between plants in the planting line (2, 3, 4 and 5 m). Fertilization consisted of increasing proportional levels, named 0, 1, 2, and 4. Linear and quadratic regression models were fitted for DBH (diameter at breast height) and height after 32 months since plantation, as a function of fertilization level and plant unit area. Diameter distribution was analyzed using the Weibull distribution. Linear models were more efficient to describe the relationship between diameter growth and area per plant, while a quadratic model described better the effect of the fertilization levels; the maximum diameter growth was observed at the 2.8 level. Both, level of fertilization and plant unit area presented a quadratic effect on height growth; the maximum height was observed with 12 m² per plant and level 2.5 of fertilization. The diametric distribution varied in function of the spacing and fertilization level.