Growth of tropical and temperate grasses at Palmerston North

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Abstract
Warm-season yields of 14 C4-photosynthetic pathway tropical grasses were compared with yields of 6 C3-pathway temperate grasses, and observations were made on the extent of flowering and on frost sensitivity. Plants were grown in mono culture in small swards at Palmerston North for two seasons. Plant spacing, cutting frequency and height, fertiliser dressings, and disease and pest control measures were selected to encourage each variety to express its growth potential both with and without irrigation. During the first season Setaria introductions produced the highest dry matter yields (14–16000 kg/ha); the temperate grasses yielded 8 500–12 000 kg/ha. : In the second summer Digitaria decumbens, Cynodon dactylon, Paspalum dilatatum, and Setaria splendida produced 16 000–18 000 kg/ha without irrigation and the temperate grasses 4 250–12 400 kg/ha. Tropical grasses yielded as well as or better than the temperate grasses during the warm season. Irrigation did not increase yields in the first summer. Only 4 out of 20 grasses yielded more under irrigation during the second summer. Tropical grasses had a wide range in sensitivity to late autumn frosts before all swards were covered with large plastic-covered frames for frost protection. Most Setaria introductions, paspalum, and three Digitaria lines flowered strongly in both seasons, whereas S. splendida, two Digitaria introductions, Pennisetum clandestinum, ‘Grasslands Apanui’ cocksfoot, and the ryegrasses flowered more profusely in the season after establishment.