Low pasture biomass production and fodder scarcity are among the major challenges affecting productivity of dairy cattle farms in Sri Lanka. As a potential solution to this, two Napier hybrid cultivars CO-5 and Sampoorna were recently introduced and a field experiment was conducted to evaluate their growth, dry matter production and nutritional composition during May to September 2020. Plant measurements and samples were collected at five harvest intervals (4, 6, 8, 10 and 12 weeks after planting), with the plant samples subjected to biomass and nutritional assessments. The number of tillers and leaf length differed (P=0.01) between the two cultivars at 4 weeks harvesting interval (HI) whilst number of leaves differed at 12 HI respectively. Dry matter yield increased (P=0.16) almost linearly whilst crude protein declined exponentially with CO-5 greater than Sampoorna (P=0.057; 9.3% vs 8.7%), with increasing harvesting intervals respectively. In-vitro Organic Matter Digestibility and In-vitro Metabolizable Energy contents were similar across weeks 4, 6 and 8 but then decreased. This study demonstrates that higher dry matter yields (12.54 t/ha) can be obtained by harvesting both cultivars at 12 HI, but from a nutritional perspective harvesting at 6 HI during Yala season of the year would be optimum for farmers.

Mimosa bush (Vachellia farnesiana) is an invasive woody weed widely distributed in Australia. While it can be controlled using several mechanical and chemical techniques, this study evaluated a novel new herbicide delivery mechanism that minimizes the risk of spray drift and potential non-target damage. It was developed by Bioherbicides Australia and involves the implantation of encapsulated granular herbicides into the stem of intact plants or into the stump after cutting off plants close to ground level (cut stumped). Trials were implemented near Moree (NSW, Australia) on intact (two trials) plants and cut stumped (two trials) plants. For each trial, an untreated control plus the conventional basal bark application of a liquid formulation of triclopyr/picloram mixed with diesel was included for comparison. Encapsulated glyphosate, aminopyralid/metsulfuron-methyl, hexazinone and clopyralid were also tested in all trials. In addition, triclopyr/picloram, and metsulfuron-methyl were included in at least one of the whole plant trials. Aminopyralid/metsulfuron-methyl was consistently most effective at controlling intact plants, whilst aminopyralid/metsulfuron-methyl and clopyralid provided highest mortality when applied to cut stumps of mimosa bush. Overall, highest efficacy was achieved on single stemmed plants, but with some further refinement of the technique it should be possible to achieve similar results for multi-stemmed species.