A survey was undertaken among farm advisory officers of the Ministry of Agriculture and Fisheries to determine the distribution of, production from, and attitudes to Paspalum dilatatum in New Zealand. Paspalum is widespread throughout most of Northland, Auckland. Bay of Plenty, Waikato, and Poverty Bay. It is present in most of the remainder of the North Island and in northwestern South Island. Abundance is decreasing in Northland and is static in most other districts except Waikato where some increase was noted. Factors such as site, soil type, and kind and intensity of farming system influence abundance. Distribution limits are set by winter temperatures, but summer temperatures influence its ability to compete with other pasture components. Growth normally begins in November, reaches a maximum in January, and declines quickly in April and May. Animal consumption is high over the whole growth period and highest from December to March. Attitudes to paspalum were related to its abundance in 8 district. Ability to produce herbage during summer was the characteristic considered most desirable, and exclusion of other pasture components by becoming sod-bound was regarded as the most undesirable feature.

Pasture and soil cobalt (Co) concentrations weremonitored for 8-9 yearson six properties that had been developed in pasture for periods ranging from 15 to 24 years on yellowbrown pumice soils in the Rotorua-Taupo area, NewZealand Allsiteshadbeentopdressedannually withCo beforethe survey beganin 1979, but from then the amount and frequency of Co applied was reducedconsiderably.Despitethisreduction, pasture Co concentration remained adequate for grazing livestock and soil Co extracted with EDTA was maintained at satisfactory values throughout the survey period. Serum vitamin B 12 inlambs grazed on the sampled pastures confirmed that they all had adequate Cointake. Ina fieldtrialnearTaupo, small plotsofwhiteclover, perennialryegrass, andlucerne wereestablished on a site previously in permanent pasturewhich had received 16applications of Co. Ryegrass had thehighest Co concentration, lucerne the lowest, and white clover intermediate but the outstandingresultwasthatCoconcentrationremainedhighinryegrass andwhitecloverandtherewasno decrease for 12yearsevenwherenofurther Co was applied. Conclusions are that pastures on yellowbrown pumice soils, where soil Co reserves have been increased by repeated annualCo application, A89085Received 30 November 1989; accepted 23 March 1990 canbemaintained as Co-sufficient for livestock by much lowerrates than the traditional 350 g/ha per yearofcobaltsulphate. Thisworkindicates that175 g/ha applied every third year or 100 g/ha annually are satisfactory and that the accumulated soil Co reserves can last for 10 years or more.

Three trials in the Waikato and Northland examined the effects of applying a range of grazing pressures at various times of the year on mixed pastures of ryegrass (Lolium perenne), paspalum (Paspalum dilatafum), and white clover (Trifolium repens). The effect of lax grazing or hay and silage making in spring was to reduce paspalum content in the immediate following summer, with an associated increase in ryegrass content. These effects persisted for at least 12 months. Lax grazing with sheep in each season increased paspalum content. Lax summer grazing with she&p and very hard summer grazing with cattle increased paspalum and decreased ryegrass content. The latter effect was thought to be due to pulling of ryegrass. Some practical aspects of the results are discussed

No abstract

Application of gibberellic acid at 100 g a.i./ha in July resulted in rapid visual responses in both kikuyu grass and ryegrass swards in the form of elongation and a slight yellowing of foliage. Ground level cuts showed significant dry matter responses of both kikuyu grass and ryegrass to gibberellic acid, but they were smaller than the visual responses indicated. The greatest response from kikuyu was the equivalent of 11 kg DM/ha/day. In both grasses, gibberellic acid affected mainly the vertical distribution of dry matter, as reflected in either the dry matter yield or the proportion of dry matter above 3 em. There were indications that gibberellic acid reduced regrowth after trimming of both kikuyu and ryegrass.