Phosphorus and silicon fertilization in potato crop (Solanum tuberosum L.)

Abstract

Due to high nutrient demand and higher production costs, typically are used high rates of phosphate fertilizers in the potato (Solanum tuberosum L.) cultivation. However, due to increased concern with phosphate pollution and the higher production costs of potato crop in recent seasons, it becomes necessary to study techniques that improve the efficiency of phosphorus fertilization in this crop. Silicon fertilization promotes several benefits to potato crop, besides being a promising technique to improve the utilization of phosphorus applied, because it may increase the P availability in soil by competition from silicon (Si) with the same adsorption sites. The aim of this study is to evaluate the effect of silicon fertilization, in form of Fertisilica product, about the P availability in soil, potato nutrition, yield and quality of potato tubers, grown under different P rates. Furthermore, we seek to establish in field of potato producing, responses to phosphorus fertilization, in combination with silicon rates, therefore, propose the possible reduction of P rates applied by Si inclusion in fertilization of this crop. An experiment will be carried out in greenhouse and other in commercial field of potato production. Both experiments will be carried out in the experimental design of randomized blocks in 4x3 factorial scheme, with four replications. In greenhouse, the treatments will be constituted by application of 10, 50, 100 and 200 mg dm-3 of P, combined with 0, 50 and 200 mg dm-3 of Si. In field, the treatments will be constituted by application of 0, 125, 250, and 500 kg ha-1 of P2O5, combined with 0, 75 and 300 kg ha-1 of Si. In greenhouse, will be evaluated: a) leaf diagnosis, b) number, mean weight and yield of tubers; c) dry matter accumulation in roots, tubers, shoots and whole plant, d) P and Si concentration and accumulation, e) P fractions in plant; f) use efficiency of P absorbed and g) Si and P concentrations in soil after potato harvest. In field, will be evaluated: a) leaf diagnosis, b) dry matter, P and Si accumulation, c) number, yield and classification of potato tubers, d) appearance of the skin and occurrence of defects in tubers, e) mean tuber weight, f) tubers dry matter percentage, g) use efficiency of P applied. The data will be submitted to analysis of variance. The effects of phosphorus fertilization will be evaluated by regression analysis and the effects of silicon fertilization will be assessed by LSD test (p<0,05).