Effect of organic fertilization on nutrient concentration and accumulation in nectarine (Prunus persica var. nucipersica) trees: the effect of rate of application

The aim of the present investigation was to evaluate the effects of annual application of three rates ofcompost on nutrient concentration and accumulation in tree organs, after 11 years of continuous applica-tion of a municipal solid waste (MSW) compost in a commercial nectarine orchard. Trees were subjected,since their plantation (2001), to the following MSW compost rate: 0, 5 and 10 t dw ha−1yr−1, split in May(60%) and September (40%). In 2011/2012 biomass of pruned wood, thinned fruits, fruit pulp and stonesat harvest, and abscised leaves were weighted and analyzed for macro (N, P, K, Ca, Mg) and micro (Fe,Mn, Cu, and Zn) nutrients concentration. In addition, leaves and fruit pulp at harvest were analyzed forheavy metal (Cd, Cr, Hg and Pb) concentration. Plant part biomass (with the exception of thinned fruits) was linearly related to compost application rate. The highest rate of compost increased N and decreasedCa and Mg concentration in leaves sampled in summer, whereas no differences among treatments wereobserved for the other nutrients. At the end of the season leaf N, K and Zn were remobilized to storageplant part, while P, Ca, Mg, Fe and Mn reached the highest values in abscised leaves. Nitrogen, K, Mg, Cu,Mn and Zn accumulation in the plant part analyzed increased as a consequence of the application of com-post at 10 t ha−1when compared with compost at 5 t ha−1and control. Phosphorous accumulation wasincreased by compost at the highest rate compared with control; no differences were observed for Ca andFe accumulation. Nitrogen and P were mainly accumulated in fruit, abscised leaves and pruned wood; Kwas allocated mainly into fruits, while Ca and Mg were found highest in abscised leaves. Concentrationof heavy metals in leaves and fruits were not affected by treatments