Internal nutrient translocation in chestnut tree stemwood. III. Dynamics across an age series of Castanea sativa (Miller)
1996
Colin-Belgrand, M. | Ranger, J. | Bouchon, J.
Nutrient translocation in chestnut tree stemwood was calculated from the distribution of nutrient content throughout the tissue life-span. The dynamics of internal translocation were followed during the crop rotation by means of an age series of five coppiced stands (2-19 years). N, P, K, Ca and Mg contents in tree rings were estimated from the concentrations along a vertical and radial gradient and from the ring volume obtained using stem ring analysis. Real nutrient translocation was calculated stepwise between successive stages in the age series; apparent translocation was computed on a complete tree rotation by comparing the initial content just after the ring was formed with the mineral content in the oldest stand. There was a marked translocation of N, P, K and Ca when the rings were physiologically-active tissues. Real translocation of N, P and K (but not Ca) increased with stand age, obviously in parallel with the enlarged stemwood biomass reaching 23.2 and 20.6 kg ha-1 for K and N in the last years of rotation, nearly 5 kg ha-1 for Mg and about 3 kg ha-1 for Ca and P. Potassium was the most mobile element since translocation reached 60% of the total amount immobilized in the stemwood at the end of the rotation, whereas values for N, P and Mg were approximately 25% and 10% for calcium. Total apparent translocation reached respectively 39.2 and 32.4 kg ha-1 for K, N, approximately 12 and 7 kg ha-1 for Mg and Ca and only 4.4 kg ha-1 for P. Total apparent translocation as a percentage of total wood immobilization was 114% for K, 83% for Mg, 63% for P, but only 39% for N and 24% for calcium.
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