SEASONAL FORAGE YIELD OF ALFALFA AT DIFFERENT AGES OF REGROWING IN THE SOUTHEAST OF COAHUILA

The forage yield of an alfalfa meadow depends on the cutting interval, since it influences the growth dynamics. Therefore, the optimal cutting time after regrowth should be identified, where the greatest amount of biomass can be harvested and the correct structure of the meadow can be achieved according to its morphological components. The objective was to evaluate the seasonal productive behavior of alfalfa variety Premium at different ages of regrowth and to identify the point of greatest biomass accumulation in southeastern Coahuila, Mexico. The eight treatments were evaluated using a randomized complete block design with three replications. The treatments consisted of weekly successive cuts, during eight weeks of regrowth, in each season of the year. Forage yield (FY) increased from 7 to 56 days of regrowth (DR), with an average of 1071 to 12,125 kg ha(-1). The highest yield was recorded in spring with 3226 kg ha(-1) (P <= 0.05); leaf had the highest contribution with 50 %. The ratio: leaf/stem decreased (P <= 0.05) at higher DDR, but in winter it was higher, with 1.6. Maximum plant height (PH) was 61 cm at 42 DR in spring (P <= 0.05). The maximum correlation (R-2 = 0.99) between FY and PH was recorded in winter. In conclusion, the best productive performance of the Premium variety was recorded in spring, with higher forage yield and plant height, variables that increased with days of regrowth; therefore, the correlation between these two variables is a reliable indirect method to estimate forage yield.