Trends in nutrient reservoirs stored in uppermost soil horizons of subantarctic forests differing in their structure

PEÑA RODRIGUEZ, S.; A. MORETTO,; X. PONTEVEDRA-POMBAL,; N. ORO ; E. GARCIA RODEJA,; J. GAYOSO, ; J. ESCOBAR,; J. NOVOA MUÑOZ

AGROFORESTRY SYSTEMS

SPRINGER

Lugar: Berlin; Año: 2013 vol. 87 p. 1273 - 1281

0167-4366

Macro- (C, N, P, K, Ca and Mg) and micronutrient (Fe, Mn, Cu and Zn) reservoirs wereestimated in theO(Oi?Oe?Oa) and in theA(0?10 cm depth) soil horizons of four stands of Nothofagus pumilio (lenga) from Tierra del Fuego which differ in their forestry characteristics. The type of soil layer (O and A) and the forest structure, as related to aboveground biomass storage, were assessed as a factor of variation in the nutrient reservoirs of both soils layers.Nutrient reservoirs showed similar ranges in both soil layers for total organic C (34?65 Mg ha-1), total N (1.5?3.5 Mg ha-1), rapidly available Ca (1.3?2.7 Mg ha-1) andMg(0.18?0.36 Mg ha-1). Rapidly available K, available P, and medium-term available Fe and Cu were accumulated preferentially in A the horizons, whereas medium-term available Mn and Zn weremainly stored in the O horizons. The forest structure was not a statistically significant factor of variation on the nutrient reservoirs in the O horizons, although a legacy effect of the accumulated above-ground biomass on nutrient reservoirs in this soil layer can not be discarded. On the contrary, the pools of total organic C, total N, rapidly availableKand medium-term availableCu and Zn in the A horizons varied significantly with the different forest structure. In terms of lenga forests sustainability, uppermost soils layers should be preservedas they accumulate most of the soil fertilitywhich is essential for lenga regeneration after logging.The inclusion of the assessment of soil fertility in themanagement plans of the lenga forests in the ecotone ofthe Argentinean Tierra del Fuego is strongly recommended,as it will contribute to ensure a successfulregeneration of lenga in logged areas.