CRITICAL PERIOD OF COMPETITION BETWEEN WEEDS AND IRRIGATION BEANS IN PABELLON, AGS.

Abstract

Competition by weeds is one of the main constraints in increasing dry-beans yields. The critical period for weed competition was studied using the variety Flor de Mayo, sin­ce it is the most extensively grown in the area covered by the Pabellon Experiment Station at Aguascalientes.
The study was conducted during 1976 and 1977. The ex­periments involved 6 competition periods (10, 20, 30, 40, 50 and 60 days) plus 2 levels of weed infestation (with and without weeds) and 2 checks (clean, ano weedy during the full growing cycle). A randomized complete block design was used with 14 treatments and 6 replications. The analysis of variance showed significant differen­ces among treatments and years as well as for the treatment x year interaction.

Based on grain yield reductions due to weed competition, the critical period for this variety was established between the first 30-40 days after emergence, since from this time on yield reduction became greater. Therefore, for bean varieties of similar maturity to that of Flor de Mayo, it is recommen­ded to keep them weed free during a period of about 40-50% of the crop cycle.