Effect of nitrogen and boron fertilisation on chemical composition of <i>Pinus pinea</i> L. nut kernels

The Mediterranean pine nut is the seed of the stone pine tree ( Pinus pinea L.). The kernel primarily comprises protein and fat, being an excellent source of mono and polyunsaturated fatty acids. It is also rich in vitamin B complex, vitamin C, and various minerals. The present study investigated the effects of N and B fertilization on the chemical composition of pine nut kernels. The trial was established in 2018 in a stone pine stand of Ribatejo, Portugal, and four levels of N (0, 30, 60 and 90 kg/ha annually) and two levels of B (0 and 2 kg/ha every two years) were tested. The results obtained from 2018/2019 to 2020/2021 show that fertilization with N and B did not significantly influence the levels of moisture, ash, protein, and total fat, the fatty acid composition (except for myristic acid), as well as the concentrations of P, K, Ca, Mg, Zn, and Cu in pine nut kernels. However, Fe, Mn, and B concentrations decreased with N application. Overall, kernel composition varied over the three years.