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Ripgut brome (Bromus diandrus), prairie grass (B. willdenowii) and soft brome (B. hordeaceus) are becoming serious weed problems in arable farms of New Zealand. This paper reports results from three years of field experiments evaluating chemical treatments for brome control in cereal crops. Ripgut brome was shown to be very competitive, with moderate infestations reducing grain yields by 25-30%. A strong relationship (R 2 =0.96) was found between seedling numbers of ripgut brome and final grain yield. The study found several promising chemical treatments that offer a good degree of control. These include preemergence applications of cyanazine + terbuthylazine, chlorsulfuron + terbuthylazine, and metribuzin. The same herbicides applied postemergence were not as effective for brome grass control.

(Festuca arundinacea Schreb.), established successfully at most sites. Findlay-Wilkinson analysis of annual total herbage accumulation (THA) of four sites, found that Maru production was above average and resident production was below average. Variation in THA between sites and years was related to variation in annual rainfall (621-1484 mmI year). Wana was the most persistent grass at all sites (60% of THA after 4-6 years), followed by Nui (51 % of THA after 4-6 years). Maru was only persistent at Southland, Wairarapa, and Taupo (averaging 39% ofTHA after 4-6 years). Matua was only persistent at Wairarapa (32% of THA over 5 years), and Roa was only persistent at Taupo (58% of THA over 5 years). At most sites, at least one grass species (in many instances more) outperformed the resident sward.

The development of additional S, P, and Mo coating on rhizobia-coated legume seed for sowing in tussock grassland is described. The main response was to additional S, as elemental S, which approximately doubled establishment in coatings of 50--100% increase relative to bare seed weight. The effect was greater when seed was sown into existing vegetation than into cultivated soil, and on brown-grey soils. Response to phosphates was smaIIer and less consisteDt with coatings of 50--100%, and Calciphos and reverted super· phosphate were better than Gafsa phosphate. Responses to types or levels of Mo were generally not significant. Manufacturing problems are discussed.

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