Early development characteristics of different clover species during establishment

Abstract

Maximizing the proportion of legumes in dryland pasture swards is important to provide N to the soil through nitrogen fixation and for large animal live weight gains. The establishment and early seedling characteristics of legumes has a major effect on legume survival in a pasture. The aim of this experiment was to quantify some seedling development characteristic to gain an understanding, of which species would be best suited to grow in dryland pasture mixes in the east coast of New Zealand. The seedling and early development characteristics of many legumes species were analysed in two separate experiments. In experiment one four annual legumes and two perennial control species were direct drilled into a dryland pasture at four different sowing dates in autumn. Seedling and leaf counts were done at emergence and the dry matter production was measured the following spring. In experiment two 10 different clover species and two subterranean clover cultivars were grown in a pot trial. The time to 50% emergence, leaf appearance over time, shoot weights and shoot: root ratios were measured. ‘Bolta’ balansa was the fastest species to emerge, it required a thermal time of 102.6 °Cd to reach 50% emergence. ‘Endura’ Caucasian clover was a very slow developing species, it required 179.1 °Cd to reach 50% emergence and 145.4 °Cd until first leaf appearance. It had a phyllochron of 106.5 °Cd and only produced an average of 8 leaves throughout the trial. Annual legume species had more rapid emergence, leaf appearance and greater shoot growth rates in early establishment than perennials. Subterranean clover had the greatest shoot weights after emergence, ‘Napier’ subterranean clover had a shoot weight of 0.052 g/plant and 0.132 g/plant 33 and 48 days after sowing respectively. Talish clover, alsike clover, white clover and strawberry all had the lowest shoot weights after emergence. The perennial legume species had a greater root: shoot ratios than the annual legume species. In the field gland clover was the most successful at establishment they produced 63% more dry matter than any other species.