The influence of zinc and copper fertilizer application on zinc, copper and cadmium concentration in mixed pasture : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Soil Science at Massey University

There has been considerable debate about the accumulation of cadmium (Cd) in agricultural soils and its subsequent uptake by pasture plants due to phosphate fertilizer application. Ruminants grazing pastures absorb a small fraction of this Cd, and some of this is subsequently accumulated in the liver and kidney. Although tissue accumulation of Cd in grazing livestock is generally small (< 1 mg Cd kg-1 fresh tissue), but any reduction in plant uptake is beneficial in reducing such accumulation further, especially in the kidneys. Uptake of Cd by pasture may be affected by the concentration of other nutrient cations, such as zinc (Zn) and copper (Cu). In addition, since Zn and Cu are complexed by the same metal binding protein (metallothionein) as Cd, a change in the ratio of these nutrients in pasture may also reduce Cd accumulation rates by interfering with Cd accumulation. In order to assess the effects of Zn and Cu on Cd uptake by pasture, a field experiment was conducted, using three pairs of pasture plots with low ( 0.2 mg Cd kg-1) and high (0.6 mg Cd kg-1) background Cd status. Twelve sub-plots (l.44 m2) were laid out in each plot and increasing levels of Zn (0, 5, 15 and 40 kg ha-1) and Cu (0, 2, 5 and l0 kg ha-1) were added as ZnSO4. 7H2O and CuSO4.5H2O respectively. Pasture samples were collected at regular intervals and analysed for dry matter yield, botanical composition and Zn, Cu and Cd uptake. Soil samples were extracted with 0.01M CaCl2 and 0.lM HCl solution to measure the plant available Zn, Cu and Cd. It was found that the plots with a high background Cd status in the soil resulted in a higher Cd concentration in mixed pasture (0.22 mg Cd kg-1 DM) than those with a low background Cd status (0.10 mg Cd kg-1 DM) at the first harvest (after 73 days). The Cd concentration in the mixed pasture was higher during the summer (December) period than in the early spring (September). Application of Zn fertilizer increased the Zn concentration in pasture from 37 to 150 mg kg-1 DM at the first harvest. Excessive amounts of Zn lead to a decrease in DM yield. The growth of pasture was controlled principally by the amount of plant available Zn, which depended on the amount of both added Zn and added Cu. The effect of the added Cu was to increase the toxicity of the addd Zn. Application Cu fertilizer increased the Cu levels from 9 to 16 mg kg-1 DM at the first harvest. The Cu concentration in pasture continued to decrease with time following the addition of fertilizers. The legumes are more tolerant of Cu than grass. The Cu concentration in harvest 4 (after 159 days) ranged from 6.9 to 7.0 mg kg-1 DM in grass and 8.9 to 9.9 mg kg-1 DM in legumes. The Cd concentration in the pasture decreased with increasing Zn concentration in the pasture at the first harvest. The effect of Zn on Cd uptake was more pronounced on plots with a high background Cd status in the soil. The effect of Zn on Cd concentration depends on the external Zn concentration levels. There was no consistent effect of Cu concentration on Cd concentration. The effect of the addition of Cu and Zn in fertilizer was to lower the Cd:Cu and Cd:Zn ratios in the herbage. There was a good relationship between soil available Zn as extracted by 0.1M HCl and Zn concentration in the herbage. A similar observation was obtained for Cu. But there was no consistent relationship between 0.01M CaCl2 extractable Cd and the Cd concentration in pasture. The results indicated that pasture and soil analysis for Cd and Zn may provide useful guides to situations where Cd concentrations in pasture may be decreased by Zn applications

Prediction distribution for linear regression model with multivariate Student-t errors under the Bayesian approach

[Abstract]: Prediction distribution is a basis for predictive inferences applied in many real world situations. It is a distribution of the unobserved future response(s) conditional on a set of realized responses from an informative experiment. Various statistical approaches can be used to obtain prediction distributions for different models. This study derives the prediction distribution(s) for multiple linear regression model using the Bayesian method when the error components of both the performed and future models have a multivariate Student-t distribution. The study observes that the prediction distribution(s) of future response(s) has a multivariate Student-t distribution whose degrees of freedom depends on the size of the realized sample and the dimension of the regression parameters’ vector but does not depend on the degrees of freedom of the errors distribution

Globalisation, Liberalisation, and Equitable Growth: Lessons from Contemporary Asian Experience

Since the beginning of the 1980s the less developed countries (LDCs) have been getting integrated with the global economy at a rapidly accelerating rate. The impetus for the process came from the need to make adjustment in the unsustainable imbalance in the external account that most of these countries experienced in the aftermath of the oil shocks of the 1970s and the declining demand for their exports due to the recession in the OECD countries during the 1980s. Many of these countries had to subject themselves to structural adjustment programmes at the behest of the multilateral donor agencies, led by the World Bank and the International Monetary Fund, who emphasised the urgency of reforming the protectionist trade regimes of these countries. Simultaneously, these countries came to realise the inefficiency of resource use fostered by their past strategy of import-substituting industrialisation (ISI) characterised by a trade and investment regime that enshrined overvalued exchange rates, quantitative import controls, high and non-uniform rates of effective protection, discrimination against export and strong impediments to foreign direct investment. The reform programme that these countries gradually implemented during the 1980s and the early 1990s dismantled many of the components of the ISI strategy. The extent of dependence on quantitative import controls was sharply curtailed. The exchange rate came to be increasingly determined by market forces. The rates of tariff were brought down. The discrimination against exports, relative to import substitutes, was reduced. There was also a sharp reduction in restrictions to which foreign direct investment had been subjected in the past.

Integration of biological data resources using image object keying.

This paper proposes a novel concept of ‘image object keying'. The work builds on earlier research in this area and shows how the 3D structure of a protein can be retrieved interactively from a gel electrophoresis protein spot. It uses intelligent image matching operations like the Hough Transform and Edge Detection techniques. Unique aspects are that searches may be initiated from multiple biological resources but with the results being integrated into a single page. A significant outcome of this work is that it enables researchers to search the database without the need to write and complex script