Tillage erosion and controlling factors in traditional farming systems in Pinar del Río, Cuba

Abstract

Traditionally, research on soil degradation focused on water erosion. Recent studies, however, point to the importance of tillage operations as a source of soil translocation in traditional animal-powered farming systems comparable to those applied in the Cuyaguateje watershed, Cuba. Together with the effect of some controlling factors, the extent of tillage erosion on a Ferralsol (Ferralítico Rojo) caused by the traditional ox-drawn mouldboard plough, the ‘arado americano’, and a harrow, the ‘rastrillo’, were studied with a tracer experiment on a Ferralsol with 30 plots on moderate slopes ranging from 4% to 16.5%. Two tillage directions were considered: (i) parallel to the contour and (ii) up and down the slope. Due to the shallow average tillage depth of tillage with the ‘rastrillo’ (3.8cm), net mean downslope displacement could not be observed. Average tillage depth with the ‘arado americano’ was relatively shallow (11.5cm) as well and resulted only in the up and downslope direction in a significant downslope soil flux. This downward movement showed no significant relation with the slope gradient, nor with tillage depth, tillage speed and plant cover. While the potential for tillage erosion is considerable with the ‘arado americano’, actual erosion rates in our study were low compared to previous tillage erosion studies. Single soil movements up to 44cm were detected, but taking crop rotation and tillage frequencies into account, soil transportation rates of accumulated tillage operations only ranged from 8.78 to 26.34kgm−1yr−1. This is mainly due to the moderate slope range, the low tillage depth and the good farmers' practice of tilling alternately in opposing direction.