EFFECT OF FIVE TILLAGE SYSTEMS ON SOIL EROSION OF A HAPLUSTAND VITRIC SOIL SOWN WITH POTATO (Solanum tuberosum L.)

Soil erosion and loss of physical and chemical attributes have influence on the instability of soil resource in hillside areas. This research project was conducted in the experimental farm Botana, University of Nario, located at 2870 masl, with the purpose of evaluating the effect of five tillage systems on the loss of soil and the changes of some physical and chemical properties. The tillage systems were: LC, conventional tillage for slope; LCC, conventional tillage along contour lines; LB, conventional tillage with oxen, along contour lines; LBR, reduced tillage with oxen along contour lines and LG, guachado tillage. Tillage systems were used as treatments in a complete randomized block design with three replications; soil movement was determined by the microrelievemeter. Results showed that systems LG, LB and LBR with average values of 6,27 cm, 5,88 cm and 5,87 cm, respectively, were lower regarding to soil removal; respect to aggregate stability, WMD values ranked from 1,68 mm and 1,44 mm for LC and LBR systems, respectively, corresponding to a moderately stable ranking. Finally, it was observed that penetrability ranked from extreme values of 4,34 Mpa and 10% moisture, in meadowlands to low values of 1,49 Mpa for LBR and 1,47 Mpa for LG with 6% of moisture, in the time after harvest; with the other systems no significant changes were observed. The season had effect on penetrability that increased with soli depth before and after tillage in conventional system, with more evidence in guachado system.