Investigation on the influence of some natural organic complex fertilizers of boron for increasing the metabolic activity and quantitative and qualitative yield in the peach tree, on psamosols from Southern Oltenia [Romania]

Natural organic complex fertilizers of boron are bioactive substances, having many biological activities, especially properties of increasing metabolic activity and production. The obtained results in the Redhaven peach variety have shown the favourable effects of treatments on fruit tree growth and development according to the phenological phase and the number of treatments. The chlorophyll content (a+b) has increased once with the number of treatments, while the highest values were obtained at the stage of shoot maturation, at the variant fertilized with complex boron, 5 l/ha, in four treatments (5.99 mg/g fresh matter). The determinations on the NPK content of leaves at the stage of intense shoot growth pointed out better results at the variants treated with natural complex fertilizers of boron, where four treatments were applied (3.06%Nt, 0.64%Pt, 1.63%Kt at the variant treated with complex boron, in four treatments). The DM content of leaves has shown higher values at all the variants where natural complex fertilizers of boron were applied. It also increased once with the number of treatments. The best results were obtained at the variants treated with Cupribor and Boron complex, in four treatments (41.23%). At all the studied variants, the DM quantity accumulated in leaves through photosynthesis was higher at the variants treated with natural complex fertilizers of Boron in four treatments (43.7mg DM/dm2/8h at the variant treated with Cupribor and 47.2mg DM/dm2/8h at the variant treated with Boron complex). As concerns the fruit production, there were significant yield increases at all the variants fertilized with Boron, but the best results were obtained at the variants where four treatments with Folibor (12.2t/ha) and Boron complex (11.5t/ha) were applied. The fruit quality was favourably influenced by boron. The obtained fruits had a higher content of DM, glucose, vitamin C and a lower content of nitrates.