Seasonal changes in the mineral nutrient content of persimmon leaves

Abstract

Changes in the concentration and content of macro- and micronutrients in youngest-mature-leaves on fruiting and non-fruiting shoots from persimmon ( Diospyros kaki cultivar ‘Fuyu’) were recorded over two seasons in a commercial orchard. Additional samples were collected during a national survey of 50 orchards. There were no major differences between concentrations in leaves sampled from fruiting or non-fruiting shoots at individual harvests throughout the season. Concentrations of Cu, N, P and S declined during early growth, but reached values which remained constant by mid season. The trends for Fe and Zn were similar to that for N, although the concentrations of both elements increased towards the end of one season. Concentrations of B, Ca, Mg and Mn, on the other hand, generally increased steadily. In the case of K, concentrations remained relatively constant (or increased only gradually) until mid season, before declining. There was no apparent seasonal pattern for Cl or Na. Developing fruit had a pronounced effect on all leaves, not just those closest to fruit. Significant quantities of K, N and P (18–63% of the maximum accumulated) were remobilized from leaves in the 12 weeks prior to leaf-fall, sufficient to meet all of the N and K, and about 70% of the P requirements of fruit during this period. Depletion of other nutrients was negligible. Use of the survey and seasonal composition data to improve the effectiveness of tissue analysis of this crop is discussed.