Abstract

CRUZ-RUIZ, E. et al. Edaphic characteristics of a forest temperate by effect of the land use change. Terra Latinoam [online]. 2012, vol.30, n.2, pp.189-197. ISSN 2395-8030.

In the National Park Nevado de Toluca (NPNT), located at an altitude of 3000 to 4800 m, forest mass has been lost as a consequence of land-use change (LUC) from forest to agriculture. Tillage and industrial fertilizers can favor emission of greenhouse gases. We studied how LUC impacts soil respiration and physicochemical properties, and how nitrogen fertilizer application affects the mineralization of carbon (C) and nitrogen (N). Soil samples were taken in two communities from the soil under Abies religiosa (SB), from crop soil (SC) and from soils abandoned for at least three years and used for sheep grazing (SP). Soil samples were characterized physicochemically and treated with applications of ammonium sulfate (585.36 kg ha-1) (ammonium treatment) or urea (250 kg ha-1) (urea treatment), or 2,4-D (1 L ha-1) (treatment 2,4-D), or captan (2 kg ha-1) (captan treatment) or nothing (dummy treatment). On the 56th day of an aerobic incubation CO2 emission and mineral nitrogen (NH4+ + NO3-) were quantified. Organic matter, total N, apparent density, water holding capacity, CIC and CO2 emission were found significantly modified at SC; organic carbon content was 55% less than SB. Texture and electrical conductivity were not modified by LUC. C mineralization increased in SB and SP when fertilizers and biocides were applied. The increase in N mineralization was inversely proportional to degradation when fertilizers were applied, regardless of land use. Agricultural land use in the Nevado de Toluca National Park NPNT degrades soil physicochemical properties and significantly modifies C and N cycles.

Keywords : CO₂; fertilizers; C and N mineralization.