Estimating plant density using a modified Carter ring method

AbstractThe 'Carter ring' method assesses potential legume plant density in regenerating annual pastures. Steel rings are forced into the ground, watered and germination counts recorded in the field. The requirement to water sites regularly until emergence can be restrictive. A modified method was used to overcome the difficulty of widely distributed sites, and to estimate potential density of non-legume pasture species.Paddocks throughout the Victorian Mallee were sampled during late February 2001. In each of nine paddocks, ten PVC rings were driven 5 cm into the soil. A spade was inserted underneath and the ring and intact soil cores secured into a plastic bag. These 'pots' were placed in a glasshouse, and watered. Plant counts were recorded after four weeks. In late June plant counts were made in the field from 30 quadrats each 0.1m2, and botanical composition assessed in July, for each of the paddocks previously sampled.The density of legumes, grasses and broadleaf plants in pots was closely related to field counts (r2 = 0.82 to 0.95; P<0.001). The percentage of grass and broadleaf plants in pots were related (P<0.10) to field composition, but legume content was not (P=0.24). The modified method reported here adequately assesses potential germination of grasses and broadleaf species as well as legumes. It is a more efficient method than watering sites at multiple distant locations.