Response of Desmanthus to clipping on a phosphatic clay mine-spoil

Defoliation treatments of 1, 2 and 3 harvests annually were imposed on 3 Desmanthus accessions. Total dry matter yields from 2 and 3 harvests annually were 26.2 and 16.0 t per ha respectively across all accessions. The proportion of leaf decreased from 50 to 10 percent with decreasing frequency of harvest. Contrary to the expected trend, leaf in vitro organic matter digestibility of all accessions was low (34-41 percent) and increased with decreasing harvest frequency. Differential clipping schedules are required to optimize forage quality and seed production from the various accessions. Both temperate and tropical Desmanthus species were productive on this subtropical phosphatic clay site, with herbage and seed production occurring during the warm season for both species.