Comparative Productivity of Merker Grass and of a Kudzu-Merker Grass Mixture as Affected by Season and Cutting Height

The yields of a tropical kudzu-Merker grass association were compared to those of Merker grass growing alone and fertilized with 300 pounds of nitrogen per acre yearly. The effect of two heights of cutting and of season of the year on the productivity of these forages was also studied. Merker grass produced 23,652 pounds of dry matter and 1,773 pounds of crude protein per acre yearly, or about twice as much dry matter and protein as did the kudzu-Merker grass association. Kudzu contributed about 19 percent of the dry matter and almost 40 percent of the protein produced by the association. The Merker grass growing alone had a higher protein content than that growing with kudzu. Merker grass both alone and in association with kudzu yielded more when cut at a height of 2 inches from the ground than when cut at a 10-inch height. The reverse was true with tropical kudzu. Because of this compensating effect cutting height had no significant effect on yields of the kudzu-Merker grass mixture. Because of a higher proportion of kudzu, the protein content of the mixture was greater with high cutting, however. Both Merker grass and the kudzu-Merker grass association yielded about twice as much forage during the "summer" months as during the "winter" months. Lower rainfall, cooler temperature, and shorter days during the "winter" months appeared to be responsible for the reduction in growth occurring during this season. The latter two factors were apparently responsible for most of the difference in growth rates which suggest that only limited benefits may accrue from supplemental irrigation of forages during the "winter" months in the humid areas of Puerto Rico.