Edafic fauna under different straw levels in sugarcane crop

Abstract

The organisms that constitute the soil fauna are highly relevant to the litter-soil compartments, because they act in important processes, such as fragmentation of the plant material, decomposition and nutrients cycling. This study aimed to evaluate the invertebrate fauna community in soil cultivated with sugarcane harvested without burning, considering the maintenance of different straw levels on the soil surface. Treatments consisted of different amounts of sugarcane straw: T0% (0 Mg ha-1); T25% (2.2 Mg ha-1); T50% (5.1 Mg ha-1); T75% (7.8 Mg ha-1); and T100% (12.0 Mg ha-1). Samples were collected in the dry season and late wet season, with "Pitfall" traps. The number of individuals per trap per day during the dry period ranged from 11.1 (T0%) to 14.7 (T25%) and, in the rainy season, from 15.11 (T0%) to 33.15 (T75%). The highest Shannon values were observed during the rainy season, and the lowest values for diversity and equitability resulted in a higher incidence of Araneae and Formicidae groups. The amount of straw on soil showed no significant influence on ecological indices and total and average wealth. The harvest time affected the number of individuals, species wealth and Shannon and Pielou's indices. The maintenance of straw on the soil surface benefitted the soil fauna, concerning the conventional crop management.

Keywords

• Araneae
• Formicidae
• epigeal fauna
• biological indicator