Nutrient extraction through cones in Pinus pinea L. plantations

Abstract

Nuts of stone pine (Pinus pinea L.) are considered the most valuable nuts in the world due to their culinary applications, unique nutritional composition and bioactive properties Pine nuts are traditionally harvested from native forests; management techniques are currently being developed to domesticate the species. Even though fertilization has been recognized as a tool to enhance cone and pine nut production, its application is mostly based on soil characteristics rather than on the amount of nutrients extracted from harvested cones. Information on nutrient extraction is scarce, even for stone pine producing countries. To address this gap, eight plantations were selected from a latitudinal range of the stone pine planted area in Chile, with contrasting (high and low) productivity levels. Ten healthy mature three-year-old cones were sampled in each plantation, weighed, dried, and processed to obtain three cone components: kernels, shells, and cone residues (scales and core). Cone components were chemically analyzed to quantify nutrient content (N, P, K, Ca, Mg, Cu, Mn, Zn and Na). The distribution of nutrient extraction among cone components and the amount of nutrients extracted per ton of fresh cones were calculated. Nutrient extraction from stone pine cones differed among cone components, with the highest values corresponding to kernels. Nutrient extraction was not affected by plantation productivity level. Total N extraction was 3.5 kg ton−1, P extraction was 0.6 kg ton−1, and K extraction was 2.7 kg ton−1. Management practices based on stone pine cone nutritional extraction will result in an optimized, stable and sustainable cone production.