Management of grassland on the sunny aspect of North Canterbury dry hill country: environment and quantity and quality of herbage

Abstract

The climate during the year from April 1979, the soil, and the unimproved vegetation (predominantly Rytidosperma = danthonia/striated clover grassland) of a site in North Canterbury at 500 m altitude, with north-westerly aspect are described. Soil moisture was below wilting point from late November to late February. The block was grazed by 11 hoggets/ha for a week in mid July and with 7.5 ewes/ha plus their lambs from early August to early October. Herbage mass varied throughout the year between 4000 and 1000 kg DM/ha with in vitro digestibility of less than 600/0. Dead herbage was the main component for most of the year and its digestibility of less than 40% depressed herbage quality. Regrowth from quadrats clipped at 3-weekly intervals was 2630 kg DM/ha/a. Although minimum soil temperatures at 20 mm depth in winter exceeded 10°C, herbage regrowth was less than 20 kg DM/ha/day. Differences in herbage regrowth during the moist seasons were related best to seasonal variation in soil temperature at 300 mm depth. It is suggested that grazing management to reduce dead herbage in early winter could improve subsequent herbage quality and possibly reduce the carryover of dead herbage to the autumn.

Key Words:

• Rytidosperma (= danthonia) grassland
• digestibility
• microclimate
• grassland soils
• grasslands
• grazing lands
• management
• environmental conditions
• productivity
• feed crops