This plot cut study, conducted on the subtropical north coast of New South Wales, evaluated the effect of defoliation interval, seeding rate and application of nitrogen and lime on production and survival over summer of a Lolium perenne/Trifolium repens pasture. There was a 117% or 12 781 kg DM/ha difference in DM yield between the worst and best treatment combinations over the 17 month period of the study. The best treatment combination for yield also gave the highest rate of ryegrass survival and lowest levels of 'summer grass' ingression over the first summer. Defoliation at 4 weeks or 'when ready' (before onset of senescence, 'lodging' or rust), compared to at 2 weeks, increased DM yield by 18 and 32% in year 1 and 41 and 59% in year 2 respectively. The larger difference in year 2 was primarily due to a greater ingression of 'summer grass' (winter dormant) and a lower survival of ryegrass plants over the first summer in the most frequently cut plots. The lower root DM in summer at the more frequent cutting interval may have been one factor responsible for the defoliation effect. DM yields of a 'clover dominant' sward (nil N except at sowing and 8 kg ryegrass/ha; clover = 53%) was 85% in year 1 and 50% in year 2 (up to August) of that of a 'ryegrass dominant' sward (100 kg urea ha-1 mo-1 and 35 kg ryegrass/ha; clover = 8%). The lower yield of the 'clover dominant' pasture in year 2 was partly due to a greater level of 'summer grass' infestation. Application of N increased plant survival over summer, but under grazing, many plants may have been lost through sod pulling by stock, as roots were more restricted to the surface. Application of lime increased DM yield in both years.

The effects of 5 foliar-applied fungicides on seed yield of faba bean (Vicia faba) cv. Fiord were studied over 3 years at Tamworth in northern New South Wales. In 2 seasons when the diseases chocolate spot (Botrytis fabae) and rust (Uromyces viciae-fabae) were significant, 5 applications of foliar fungicides after flowering increased yield, by up to 1.6 t/ha in 1990 and nearly 0.9 t/ha in 1992, compared with the unsprayed treatment.Mancozeb, dichlofluanid, and tebuconazole were the most effective fungicides for preventing yield reduction, and vinclozolin and procymidone had little or no effect. Mancozeb and tebuconazole were effective in reducing the severity of both diseases, whereas procymidone was only active against chocolate spot. Differences between the most effective fungicides when applied 5 times or twice (at early and mid flowering) were seldom significant. Seed yields following 2 applications of tebuconazole were significantly higher than from 1 application, but for mancozeb, 2 applications were better than 1 in 1992 only. It was estimated that rust accounted for most of the yield loss in 1990 and 1992, and did so mainly by reducing seed size. Application of mancozeb early and during late flowering provided an effective and economical increase in grain yield in 1990 and 1992.

The effect of the narrow-leafed lupin (Lupinus angustifolius L.) on growth and production of subsequent cereal crops was studied at three sites on the acidic, N-infertile soils of the Pilliga Scrub region of northern New South Wales.Beneficial effects of lupins on dry matter production were evident in either one (Kamala, Florida A) or two subsequent crops of wheat (Florida B). In the absence of fertilizer N, wheat following lupins outyielded wheat following wheat by an average of 57%. At Florida B, the second wheat crop following lupins outyielded the wheat only plots by 35%. The response to lupins was established early in vegetative growth and was essentially maintained. Effects of lupins on grain yields, evident at all sites in the first crop, were maintained at the two Florida sites for a second crop. Increases in the absence of fertilizer-N were between 0.29 and 1.22 t ha-1 (55 and 145%) (crop 1) and as great as 0.39 t ha-1 (38%) in year 2. Barley responded similarly with increases of 127 and 47% in years 1 and 2, respectively. Amounts of fertilizer required to raise the yields of wheat following wheat to those of wheat following lupins ranged between 40 and 80 kg ha-1. Effects of lupins on protein concentration of cereal grains were inconsistent; largest effects were achieved through N fertilization. Both the incidence and severity of root diseases at Florida A were reduced in the rotation plots; the effect persisted into the third wheat crop following lupins. Disease control was not a factor in the lupin effect at Kamala. Nitrogen budgets for the unfertilized wheat-wheat and lupinwheat sequences at Kamala and Florida A indicated that lupin cropping (i) resulted in potential net gains of soil N of 128 (Kamala) and 29 kg ha-1 (Florida A), and (ii) increased N yields of the following wheat crops by 37 (Kamala) and 20 kg ha-1 (Florida A).

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