Agrarian (Mar 2020)
Jatropha curcas growth and productivity under different phosphorus doses
Abstract
Information on the nutritional requirements of J. Curcas is extremely important in developing a fertilization manual for the species, and there are no conclusive studies with phosphorus and nutritional demand for this element is still unknown. The objective of the present study was to identify and recommend adequate phosphate fertilization for J. curcas growth and productivity. The experiments were conducted in two years using J. curcas plants four months old implanted in the spacing of 4 x 2 m. We used the randomized block design in arrangement in a split plot arrangement with five treatments (phosphorus doses of 0; 75; 150; 225 and 300 kg ha-1) in the plots and two years of evaluations (2015 and 2016) in the subplots, four replications and plot of two plants. Triple superphosphate was used as phosphorus source (P2O5) and the doses were divided into five monthly applications starting in November in the first year and in October in the second year, shortly after the first rainfall. The results justify the need to pay special attention to phosphate fertilization because it interferes decisively in vegetable growth and grain yield J. curcas. The grain yield in J. curcas plants is closely related to the foliar concentration of phosphorus. The highest yields were obtained with foliar phosphorus concentrations of 2.81 g kg -1 in the 1st year of cultivation and 3.35 g kg -1 in the 2nd year of cultivation. It is recommended the doses of 208 kg ha-1 of P2O5 in the 1st year of cultivation and 214 kg ha-1 of P2O5 in the 2nd year of cultivation to obtain plants of J. curcas with vigorous vegetative growth and maximum yield of grains.
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