Availability of elemental S fertiliser to crops grown in New Zealand

Non-Peer Reviewe

Study of heterogeneous nucleation of eutectic Si in high-purity Al-Si alloys with Sr addition

The official published version can be accessed from the link below - Copyright @ 2010 The Minerals, Metals & Materials Society and ASM InternationalAl-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodynamic calculations, and transmission electron microscopy techniques were employed to examine the effect of the Sr and P additions on eutectic undercoolings and nucleation phenomenon. Results indicate that, unlike P, Sr does not promote nucleation. Increasing Sr additions depressed the eutectic nucleation temperature. This may be a result of the formation of a Sr phase that could consume or detrimentally affect potent AlP nucleation sites.This work is financially supported by the Higher Education Commission of Pakistan and managerially supported from the OAD

FOR(CED)SALE:HlGH COUNTRY DEVELOPMENT

This is a record of the concepts included in a play 'For(ced) Sale: High Country Development' presented at the 1986 NZ Grassland Association Conference. Three pasture development options considered for high country properties were: 1 . high input nitrogen fertiliser and improved grass; 2. oversown improved legume species and an improved package of management options which are especially applicable to dry sunny faces where establishment has been traditionally difficult; and 3. low input development based on meeting the nutrient requirements of resident legumes using high analysis fertiliser. Aspects of the nitrogen option have been considered by Hall and Scott (1985); the oversown legume option was reviewed by Allan et al. (1985) and some background for the system based on resident legumes was reported by Boswell (1986).</jats:p

COMPARISONS OF CATTLE GRAZING AND SHEEP GRAZING

Controversy has surrounded the possible differences in pasture production which result from grazing by cattle or sheep. Experiments conducted over the 1972-76 period show that pasture production under grazing by sheep is greater than under grazing by cattle under similar intensive managements. A change from sheep grazing to cattle grazing can cause a rapid deterioration in pasture production, while the change in grazing from cattle to sheep brought a slo~ver improvement in pasture production. Cattle grazing restricted the production of the ryegrass component of the pastures in the five management systems considered.</jats:p

Fertiliser sulphur for North Canterbury pastures

Natural inputs of sulphur in North Canterbury are restricted to l-2 kg of sulphur(S)/ha/year in rainfall. On the limited area of irrigated land a further 7 kg of S may be added in irrigation water. These inputs are inadequate to replace losses which occur through leaching, removal in animal products, and excretal transfer, so fertiliser S is essential to maintain farming systems. The choice of form of fertiliser varies from sulphate, to mixtures of sulphate and elemental S, to elemental S forms. Focus in this paper is on the forms which will be effective in North Canterbury, other factors which influence choice of fertilisers, and recommended fertilisers for different farming situations. Keywords: elemental sulphur, fertiliser recommendations, rate constant, sulphur oxidation, sulphur superphosphate</jats:p

CHANGES IN THE PERENNIAL RYEGRASS COMPONENT OF GRAZED PASTURES

The contribution of perennial ryegrass to pasture production is dependent on the stage of development of the pasture, climate and pasture management. Although variability in the percentage of ryegrass in improved pastures is less than in developing pastures, changes in the ryegrass component in response to different managemcnts can be marked. Tiller counts demonstrated a lower population of ryegrass tillers under rotational grazing by cattle than under sheep. This was increased by changing either from cattle to sheep grazing or by hard set stocking with sheep during spring. Grazing to 3 cm produced more dense ryegrass pasture than grazing to 6 cm. Severity of grazing appeared to be particularly important in dry conditions when grazing below 3 cm is likely to reduce tiller density. A range of management options is therefore available to encourage the perennial ryegrass component, and thus total dry matter production, of improved pasture.</jats:p

Study of heterogeneous nucleation of eutectic Si in high-purity Al-Si alloys with Sr addition

The official published version can be accessed from the link below - Copyright @ 2010 The Minerals, Metals & Materials Society and ASM InternationalAl-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodynamic calculations, and transmission electron microscopy techniques were employed to examine the effect of the Sr and P additions on eutectic undercoolings and nucleation phenomenon. Results indicate that, unlike P, Sr does not promote nucleation. Increasing Sr additions depressed the eutectic nucleation temperature. This may be a result of the formation of a Sr phase that could consume or detrimentally affect potent AlP nucleation sites.This work is financially supported by the Higher Education Commission of Pakistan and managerially supported from the OAD

Friend or foe? Potential for native biodiversity in West Coast farming

The wet, warm West Coast climate favours tree production and pastures. Much of the land remains in indigenous forest under the control of Government agencies. In the more accessible parts of this land, and in land held under private ownership, we explore the feasibility of "farming" two examples of native biodiversity. Sphagnum moss production varies with location and differences in meso- and micro-climate. A climate model was used to predict where future sustainable sphagnum development may occur; i.e. within farming systems in the areas with the fastest growth rates. At its simplest and cheapest, this may involve flooding unimproved land and managing the moss. Another alternative could involve integration of moss production in the wet "hollow" of "hump and hollow" pasture systems. The West Coast retains several unique populations of kiwis and other indigenous birds. We advocate the future role of private enterprise (i.e. landholders) in protecting kiwi and, in the longer-term, the local communities profiting from ecotourism centred on them. Keywords: climate modelling, eco-tourism, kiwi, sphagnum moss</jats:p

Establishment and management of sown finishing pastures

Over the last decade at least seven improved pasture cultivars which have application in the summer moist finishing regions of Manawatu, coastal and south Otago and Southland have been released. Ryegrass and white clover are the dominant pasture components in these regions. Production from such pastures is limited by cool winter temperatures in OtagoISouthland and by summer moisture stress in Manawatu (see Chapter 7). Improved cultivars of ryegrass and white clover, alternative species and better management strategies can be used to lessen the effect of these limitations. The establishment and management aspects are discussed in this chapter.</jats:p