Effect of grazing management on the performance of newer pasture cultivars

Abstract

A pasture containing Concord and Yatsyn ryegrass, 'Grasslands Wana' cocksfoot, 'Grasslands Pawera' red clover and 'Grasslands Pitau' white clover was established in autumn 1987. From spring 1987 this sward was grazed at 2-, 3- and 4-weekly intervals in spring, down to a mean height of 2-3 cm or 5-6 cm in one experiment, while in another trial it was grazed in summer at 3-, 4- and 5- to 7-weekly intervals to a mean residual height of 3-4 cm or 5-6 cm. The longest grazing interval applied in spring or summer increased spring and summer pasture yields for the 3-year period by 51 and 35% respectively, compared with the shortest grazing interval. Lenient grazing in spring or summer increased both spring and summer yields by an average of 16% over 3 years. Lenient spring grazing reduced summer pasture yields by 7% over 3 years, but much of this reduction was the result of a decreased proportion of summer-growing volunteer grasses. Yatsyn ryegrass established quickly and performed well, providing the major contribution to pasture production in these 3 years. Its content in the sward was depressed by frequent spring grazing and infrequent summer grazing, but it was not significantly affected by grazing intensity and it can be recommended as the basic ryegrass in a mixture. The contribution of Concord ryegrass was confined mainly to the first winter and spring. Wana cocksfoot was slow to establish and its content in the sward wax increased by frequent spring grazing and lenient spring and summer grazing. Its greater drought tolerance will make it a useful addition to a ryegrass pasture in areas of low summer rainfall. Pawera red clover made only a small contribution to the sward and this declined with time. The effects of summer grazing management differences were mainly confined to that season, but spring pasture management treatments also affected pasture yields and botanical composition in the following summer. Keywords seasonal pasture grazing management, pasture production, botanical composition, cattle grazing, grazing frequency, grazing intensity, ryegrass, cocksfoot