Effect of Maize Conservation Crops Associated with Two Vegetal Covers on the Edaphic Macrofauna in a Well-Drained Savanna of Venezuela

Abstract

Conventional agricultural in the Venezuelan Llanos has generated gradual soil degradation. Therefore, conservationist agriculture has been proposed. According to several works, this type of management favors soil macrofauna. To test this hypothesis, the response of soil macrofauna to the establishment of conservationist maize crops, associated with Brachiaria dictyoneura (Bd) and Centrosema macrocarpum (Cm), was evaluated. The samples of soil and soil macrofauna were taken per vegetation cover at different climatic season over 2 years and 10 months. For this period and under the conditions studied, the results partially refute the hypothesis; on the one hand, they showed that the soil macrofauna of a natural savanna (NS) is the most diverse and equitable (N1 = 4.5 ± 2.8), followed by the cultivation of maize associated with Cm (N1 = 3.2 ± 1.9) and the least diverse with Bd (N1 = 2.6 ± 2.1). Additionally, some taxonomic groups apparently did not tolerate soil intervention, while Termitidae was favored. On the other hand, the temporal variation of the soil macrofauna did not differ between vegetation covers (F: 1.18; p = 0.37). This variation could be due to the decrease in TP (r = −0.55) and increased BD (r = 0.56).

Keywords

• soil macrofauna
• community analysis
• agroecology
• maize
• improved pastures
• tropical savannas