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Earthworm Populations in Savannas of the Orinoco Basin. A Review of Studies in Long-Term Agricultural-Managed and Protected Ecosystems
Laboratory of Environmental Studies, Institute of Tropical Zoology and Ecology, Central University of Venezuela, Apdo 47058, Caracas 1041A, Venezuela
Received: 1 February 2012; in revised form: 24 March 2012 / Accepted: 26 March 2012 / Published: 10 April 2012
Abstract: Earthworm biomass and production in savannas are limited by seasonal precipitation and the lack of organic and nutrient resources; I hypothesize that after a long-term protection of savanna from fire and agricultural activities drastic changes in the physical and chemical characteristics of the soil occur with a concomitant increase in earthworm abundance and activities. Similar changes might occur after a long-term fertilization of savannas with manure. This review article considers the earthworm communities and other soil quality indices in Trachypogon savannas of the Orinoco Basin in an organic agricultural forestal savanna (OAFS) amended with compost over forty years in Puerto Ayacucho, Venezuela, and in an Experimental Station long-term protected (PS) from fire and cattle raising from more than four decades in Central Llanos, Venezuela, comparison is made with results from similar savannas. Long-term additions of organic manure or a long protection have induced significant changes in the soil physical and chemical properties of the natural savanna (NS) soils that induce a significant increase in the density and biomass of earthworm populations. On the other hand, the protection of the savanna promotes an improvement in the physical and chemical properties of the soil, which favors an increase in the density and biomass of earthworms in the PS compared with the NS subjected to recurrent burning and grazing. The results emphasize the importance of appropriate organic matter management and the relevance of earthworms in such agroecosystems.
Keywords: protected savanna; organic farms; soil quality; microbial biomass; enzymatic activities; Amazonia; pedofauna
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MDPI and ACS Style
López-Hernández, D. Earthworm Populations in Savannas of the Orinoco Basin. A Review of Studies in Long-Term Agricultural-Managed and Protected Ecosystems. Agriculture 2012, 2, 87-108.
López-Hernández D. Earthworm Populations in Savannas of the Orinoco Basin. A Review of Studies in Long-Term Agricultural-Managed and Protected Ecosystems. Agriculture. 2012; 2(2):87-108.
López-Hernández, Danilo. 2012. "Earthworm Populations in Savannas of the Orinoco Basin. A Review of Studies in Long-Term Agricultural-Managed and Protected Ecosystems." Agriculture 2, no. 2: 87-108.