PENDIMETHALIN HERBICIDE AS AN ALTERNATIVE TO S-METALOCHLOR IN THE ESTABLISHMENT OF FODDER BEET IN NORPATAGONIA ARGENTINA

Abstract

Fodder beet is a crop of interest in the Norpatagonia Argentina, since it is used for feeding cattle in winter. Although it offers nutritional advantages and significant yields, its slow establishment and competition with weeds pose challenges to producers, and thus the application of herbicides is essential for proper crop management. The objective of this study was to evaluate the effect of replacing the pre-emergent herbicide S-metolachlor by pendimethalin on the establishment of fodder beer. Pot and field experiments were carried out. The pot experiment consisted of 3 treatments of pre-emergent herbicides (PRE): S-metolachlor 1 L ha^-1 (M) and pendimethalin in two doses: 4 and 6 L ha^-1 (P4 and P6), and a post-emergent herbicide (POS): Betanal 1 L ha^-1 (B). The field experiment was conducted using a split-plot design, with PRE (P4, P6 and M) as the main factor, and with and without POS (B) as the secondary factor. Crop emergence dynamics and weed control were evaluated by comparing richness, abundance and diversity between treatments. In the pot trial, treatment P4 showed crop emergence dynamics similar to the control treatment (T), being less phytotoxic than M. In both experiments, the treatments did not show significant differences in weed species richness, while P4 without POS was the treatment exhibiting the highest abundance and diversity of species. The replacement of M by P4 would be a suitable alternative for the establishment of fodder beet crop accompanied by a post-emergence herbicide.