Track 2-12: Control and Management of Weeds and Diseases of Grass and Forage Systems
Description
Undesirable C4 annual grasses such as summer grass (Digitaria sanguinalis, (L.) Scop., SG) and yellow bristle grass (Setaria pumila (Poir.) Roem. et Schult., YBG) are prevalent in dairying regions in the North Island of New Zealand. Field surveys of 39 dairy pastures in the central North Island demonstrated that their percentage ground cover has tripled over the last four years (Tozer et al. 2012). The prolific seed production of these species is thought be facilitating this increase in ground cover. However, little information is available on their fecundity in dairy pastures. Counting the number of seeds in a panicle is slow and laborious, therefore a rapid and robust method to assess fecundity is required. In USA crops, Forcella et al. (2000) found a significant curvilinear relationship between YBG seeds per panicle and panicle length, regardless of crop identity, year and weed density. A study was therefore established to determine if panicle length or weight could be used to estimate YBG and SG fecundity in intensively managed dairy pastures in New Zealand.
Included in
Methods for Estimating Seed Production of Two Summer-Active Grass Weeds, Setaria pumila and Digitaria sanguinalis, in New Zealand Dairy Pastures
Undesirable C4 annual grasses such as summer grass (Digitaria sanguinalis, (L.) Scop., SG) and yellow bristle grass (Setaria pumila (Poir.) Roem. et Schult., YBG) are prevalent in dairying regions in the North Island of New Zealand. Field surveys of 39 dairy pastures in the central North Island demonstrated that their percentage ground cover has tripled over the last four years (Tozer et al. 2012). The prolific seed production of these species is thought be facilitating this increase in ground cover. However, little information is available on their fecundity in dairy pastures. Counting the number of seeds in a panicle is slow and laborious, therefore a rapid and robust method to assess fecundity is required. In USA crops, Forcella et al. (2000) found a significant curvilinear relationship between YBG seeds per panicle and panicle length, regardless of crop identity, year and weed density. A study was therefore established to determine if panicle length or weight could be used to estimate YBG and SG fecundity in intensively managed dairy pastures in New Zealand.
