Biomass Production and Nutrient Consumption of the Sprouts of Alnus incana

1991

25 S.

5 Abb., 10 Tab., 6 Anh., zahlr. Lit. Ang.

Bandaufführung

37274

The effect of harvesting, both stemwood and whole-tree, on the sprouting of Alnus incana and the effect of fertilization on the biomass production and nutrient consumption of the sprouts are examined in this study. In addition, the biomass production and nutrient consumption of a coppiced and uncoppiced reference stand are also compared. Part of a 17-year-old A. incana stand growing on a site of the Oxalis-Myrtillus type was cut. The rest of the stand, surrounding the cut area, was retained in order to follow the future development of an uncoppiced stand (reference stand). The treatments were: 1. stemwood harvesting, 2. whole-tree harveting, 3. whole-tree harvesting and fertilization (wood ash at the beginning of the 1st growing season and PK with micronutrients at the beginning of the 6th growing season), 4. whole- tree harvesting and fertilization (wood ash and superphosphate at the beginning of the 1st growing season and PK with micronutrients at the beginning of the 6th and 7th growing seasons). The sprouting capacity of the alders was good. The amount of sprout biomass obtained after stemwood harvesting was greater than that after whole-tree harvesting without fertilization after both the 5th and 8th growing seasons. Fertilization increased the amount of sprout biomass. The sprouts on the whole-tree harvested plots produced 14 t/ha of stem and branchwood in eight years without fertilization, and 27-32 t/ha depending on the fertilization regime, i.e. half that on the average which the reference stand produced in 25 years. Phosphorus obviously played an important role in this growth increase. The biomass of the alder roots at the end of the study period was 12 t/ha in the 0-40 cm-thick soil layer in the coppice stand, and 10 t/ha in the reference stand. On the average, the coppiced alder stand consumed the following amounts of nutrients to produce one tonne of biomass: N 13.9, P 1.2, K 6.0, Ca 4.2, Mg 0.8 kg and Mn 282, Fe 79, Cu 6, Zn 20 and B 17 g.