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

MOREIRA, M., RODRÍGUEZ, MP, DOMÍNGUEZ, A, WALL, L ; BEDANO J.C.

Congreso; 7th World Congress on Conservation Agriculture; 2017

A new alternative called sustainable intensifi cation of agriculture has recently emerged in thecontext of conventional agriculture. Its goal is to use environmental resources more intensely forincreasing crop yields, through the reduction of fallow?s time and the increase of crop numberper unit of area. Nevertheless, it eff ect on soil fauna is still unknown. The aim of this contributionis to assess the eff ect of diff erent degrees of intensifi cation and diversifi cation of crop rotationson earthworm communities in the Pampas Region. Agricultural systems were also comparedwith 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 fi eld withthe same land use history and soil type. Five crop systems with diff erent intensifi cation degrees(soybean monoculture, typical intensifi cation, high intensifi cation with legume, high intensifi cationwith 100% grass, pasture) and a natural grassland were sampled in each farm. The treatments haddiff erent indexes of crop rotation calculated as: days of the year with plants/365 days, from 0,43 fortypical crop rotation (wheat/soybean-corn-soybean) to 1 in pasture. For earthworm sampling, fi ve25x25x20 cm soil monoliths were extracted from each site and hand-sorted in-situ. All the collectedindividuals were identifi ed till species level. We observed that all crop systems had a negative eff ecton earthworms comparing with natural systems. However, the legume intensifi cation system had apositive eff ect on earthworm abundance, regarding the other crop rotations; probably related to thegreater percentage of nitrogen fi xing crops