Growth, nutrition and production of dry matter of rubber tree (Hevea brasiliensis) in function of K fertilization

Abstract

The rubber tree crop (Hevea brasiliensis) is raw material used for the production of rubber. However, the Brazilian production accounts for only a third of the demand, resulting in large cultivation areas concomitantly concerned with aspects related to production system. Hence, this study aims to evaluate the effects of potassium fertilization on the growth, nutrition and dry matter production of Hevea brasiliensis seedlings up to 35 days after planting. Potassium rates were 0 (control), 0.25, 0.5, 0.75 and 1 kg m-3 of K2O soil. Biometric evaluations such as rootstock diameter, leaf number and plant height, as well as dry matter production and potassium accumulation in shoots and roots of rubber tree seedlings were evaluated up to 85 days after transplanting. The efficiency of absorption, transport and use of potassium by rubber tree seedlings were also assessed. Potassium rates influenced plant height, stem diameter and number of leaves. However, with the increase in rates these parameters decreased. Plants obtained a maximum production of total dry matter of 141.72 g plant-1 at a rate of 0.2 kg m-3 of K2O, suggesting that it is the best rate to be applied to plants during seedling stage. Absorption and transportation efficiencies were not affected by potassium application in the soil, while the use efficiency was lower as the rate applied was higher.