The response of earthworms to the diversification and intensification of crop rotation in no-till systems of the pampa region of argentina

MOREIRA FERRONI M; RODRÍGUEZ MP; DOMINGUEZ A; ORTIZ C; WALL LG; BEDANO JC

Rosario

Congreso; 7th World Congress on Conservation Agriculture; 2017

CAAPAS-AAPRESID

A new alternative called sustainable intensification of agriculture has recently emerged in the context of conventional agriculture. Its goal is to use environmental resources more intensely for increasing crop yields, through the reduction of fallow?s time and the increase of crop number per unit of area. Nevertheless, it effect on soil fauna is still unknown. The aim of this contribution is to assess the effect of different degrees of intensification and diversification of crop rotations on earthworm communities in the Pampas Region. Agricultural systems were also compared with natural ecosystems. A total of 24 sites were sampled in 4 farms located near Pergamino city (Buenos Aires province) where a DICR essay was established 3 years before sampling, in a field with the same land use history and soil type. Five crop systems with different intensification degrees (soybean monoculture, typical intensification, high intensification with legume, high intensification with 100% grass, pasture) and a natural grassland were sampled in each farm. The treatments had different indexes of crop rotation calculated as: days of the year with plants/365 days, from 0,43 for typical crop rotation (wheat/soybean-corn-soybean) to 1 in pasture. For earthworm sampling, five 25x25x20 cm soil monoliths were extracted from each site and hand-sorted in-situ. All the collected individuals were identified till species level. We observed that all crop systems had a negative effect on earthworms comparing with natural systems. However, the legume intensification system had a positive effect on earthworm abundance, regarding the other crop rotations; probably related to the greater percentage of nitrogen fixing crops.