Tropical Grasslands (1982) Volume 16, 112–117

DRY MATTER AND NITROGEN CHANGES IN FIVE TROPICAL GRASSES AS INFLUENCED BY CUTTING HEIGHT AND FREQUENCY

C.H. MIDDLETON

Queensland Department of Primary Industries, South Johnstone, Qld. 4859

Abstract

A clipping experiment to examine the effect of cutting height and frequency on dry matter yield and nitrogen concentration of five tropical grasses was carried out (1973–75) in a high rainfall, humid environment at South Johnstone in north-eastern Queensland. The grasses examined were common and Makueni guinea (Panicum maximum), setaria (Setaria sphacelata var. splendida), Basilisk signal grass (Brachiaria decumbens) and pangola grass (Digitaria decumbens). Cutting frequencies were 3, 6 and 12 weeks with cutting heights of 5, 10 and 15 cm (stoloniferous 1 grasses) and 10, 20 and 30 cm (tufted grasses) in 1973–74 and 5, 10 and 20 cm for all grasses in 1974–75.
During two consecutive 48-week periods, cutting frequency was the major factor to influence the dry matter yield and nitrogen concentration of grasses. Increasing the frequency decreased yield but increased the nitrogen concentration. Cutting height had no effect on the nitrogen concentration of grasses and only a small effect on dry matter yield. In 1973–74 the yield of tufted grasses cut at the 12-week frequency declined with increasing cutting height. However, in 1974–75 the inclusion of 5 cm cutting reduced the yield of setaria, common guinea and signal relative to 20 cm cutting.
The yield perjormance of Makueni guinea and S. sphacelata var. splendida confirm their potential as useful grasses in the wet tropics of Australia.

Download full article (437 KB PDF)  

  Return to Contributed Articles