Growth of Jatropha seedlings in response to single superphosphate and rock-flour fertilization

Abstract

Research into rock-flour have shown the potential of some of these residues in promoting the mineral enrichment of soils; a practice defined as stonemeal soil. Such practice aims to increase soil fertility and provide good productivity and greater agricultural sustainability. The present study had as objective to evaluate the growth of jatropha seedlings (Jatropha curcas L.) in response to fertilization of the substrate with single superphosphate and rock-flour. The experiment was setup and conducted from September to November, 2007, in a greenhouse at the Institute of Agricultural Sciences/UFMG. The treatments, in a 2 x 5 factorial design of randomized blocks, with three replications, corresponded to two doses of rock-flour (0 and 20 kg m-3 of substrate) and 5 doses of single superphosphate (1.25, 2.5, 5.0, 7.5 and 10.0 kg m-3 of substrate). Plant height, stem diameter, plant height/stem diameter ratio, number of leaves per plant, leaf area, fresh and dry matter of root and shoot, total fresh and dry matter, shoot/root dry-matter ratio, dry matter content and the Dickson quality index- IQD, were all evaluated. The results show no significant interaction between the levels of phosphorus and rock-flour applied and the variables studied. The application of single superphosphate was significant for plant height, stem diameter, leaf area, root, shoot and total fresh matter, with a positive response up to the maximum applied phosphorus dosage.