Almacenamiento y dinámica de carbono orgánico en uso de suelo pasto y bosque en el cantón Chilla

Abstract

The changes in land use are the second source of the emission of greenhouse gases such as CO2 product of anthropogenic interventions, such as deforestation. This implies that land use has a direct effect on global climate change, ecosystem services and biodiversity. In this context, agricultural expansion plays a decisive role, because the population continues to increase and with them the increase of foods rich in protein such as meat. From this point of view, it is essential to increase the reserves of organic carbon in the soil in the pastures, as an option to mitigate CO2 emissions. On the other hand, forest ecosystems play a fundamental role in climate change, with tropical forests storing 32% of the organic carbon in the soil (SOC), while in temperate and boreal forests they store around 60% of SOC. With the above the objectives were: a) analyze the main physical-chemical properties in two land use, b) determine a set of minima data that affect the levels of organic carbon by land use, c) compare the level of COS and apparent density of the soil by layers of 0 - 10 cm, 10 - 20 cm and 20 - 30 cm and d) quantify the total of COS by land use. For this purpose, two properties were selected in the commune of Cune, Canton Chilla. The first farm cultivated with Brachiaria sp, and the second was a forest. Samples were taken from undisturbed soils with a cylinder to determine the apparent density (Da) of the soil and sample altered to determine: texture, pH, nutrients and organic carbon. The statistical analysis was through ANOVA and Tukey HDS Test (P <0.05) and a principal component analysis to determine the set of nutrients that affected the storage of COS. The results indicated acidic sandy loam soils in both land uses, with Da ranges between 1.12-1.02 g cm3 in grass and 1.11-1.27 g cm3 in forest. The minimum set of data were the K, Ca and Mg bases, P, C and N that were expressed in the first two components> 60% of the total variance. The use of pasture soil accumulates greater COS between 20-30 cm with 3.37 Mg C ha-1 and the manor value with 3.05 Mg C ha-1 between 0-10 cm. In forest, the values were between 1.91 Mg C ha-1 at 20 cm depth and 2.97 Mg C ha-1 at 30 cm. the greatest accumulation of COS was in the use of pasture soil (90.90 Mg C ha-1) and in forest the soil captured 83.94 Mg C ha-1. The values of stored COS are lower than those determined for mountain soils in the highlands of Ecuador. It is recommended to continue with this study but in other regions of the country, to establish a policy of ecosystem services of organic carbon for the current agrarian systems.