Modelling Nitrogen Fertiliser Demand in New Zealand

In New Zealand, the demand for nitrogen fertiliser has increased markedly since the early 1980s. Potentially, this trend has significant environmental and climate change implications. While many factors could contribute to this trend, little work has been done to examine the drivers of increased use of nitrogen fertiliser in New Zealand. In this paper, we review the international literature and discuss a theoretical framework for modelling fertiliser demand. Using a national data set, we develop an empirical cointegration model for New Zealand. The results suggest that, in the long run, nitrogen fertiliser use is elastic (2.3) to output prices and unit elastic to its own price.Nitrogen fertiliser demand, New Zealand, Cointegration, Demand and Price Analysis,

Use of shallow samples to estimate the total carbon storage in pastoral soils

Using data from pastoral soils sampled by horizon at 56 locations across New Zealand, we conducted a meta-analysis. On average, the total depth sampled was 0.93 ± 0.026 m (± SEM), and on a volumetric basis, the total C storage averaged 26.9 ± 1.8, 13.9 ± 0.6 and 9.2 ± 1.4 kg C m⁻² for allophanic (n=12), non-allophanic (n=40) and pumice soils (n=4), respectively. We estimated the total C storage, and quantified the uncertainty, using the data for samples taken from the uppermost A-horizon whose depth averaged 0.1 ± 0.003 m. For A-horizon samples of the allophanic soils, the mean C content was 108 ± 6 g C kg⁻¹ and the bulk density was 772 ± 29 kg m⁻³, for non-allophanic soils they were 51 ± 4 g C kg⁻¹ and 1055 ± 29 kg m⁻³, and for pumice soils they were 68 ± 9 g C kg⁻¹ and 715 ± 45 kg m⁻³. The C density —a product of the C content and bulk density —of the A-horizon samples was proportional to their air-dried water content, a proxy measure for the mineral surface area. By linear regression with C density of the A-horizon, the total C storage could be estimated with a standard error of 3.1 kg C m⁻², 19% of the overall mean

Modelling Nitrogen Fertiliser Demand in New Zealand

In New Zealand, the demand for nitrogen fertiliser has increased markedly since the early 1980s. Potentially, this trend has significant environmental and climate change implications. While many factors could contribute to this trend, little work has been done to examine the drivers of increased use of nitrogen fertiliser in New Zealand. In this paper, we review the international literature and discuss a theoretical framework for modelling fertiliser demand. Using a national data set, we develop an empirical cointegration model for New Zealand. The results suggest that, in the long run, nitrogen fertiliser use is elastic (2.3) to output prices and unit elastic to its own price

Toward In-Field Determination of Nitrate Concentrations Via Diffusive Gradients in Thin Films-Incorporation of Reductants and Color Reagents

Diffusive gradients in thin films (DGTs) have been established as useful tools for the determination of nitrate, phosphate, trace metals, and organic concentrations. General use of DGTs, however, is limited by the subsequent requirement for laboratory analysis. To increase the uptake of DGT as a tool for routine monitoring by nonspecialists, not researchers alone, methods for in-field analysis are required. Incorporation of color reagents into the binding layer, or as the binding layer, could enable the easy and accurate determination of analyte concentrations in-field. Here, we sought to develop a chitosan-stabilized silver nanoparticle (AuNP) suspension liquid-binding layer which developed color on exposure to nitrite, combined with an Fe(0)-impregnated poly-2-acrylamido-2-methyl-1-propanesulfonic acid/acrylamide copolymer hydrogel [Fe(0)-p(AMPS/AMA)] for the reduction of nitrate. The AuNP-chitosan suspension was housed in a 3D designed and printed DGT base, with a volume of 2 mL, for use with the standard DGT solution probe caps. A dialysis membrane with a molecular weight cutoff of <15 kDa was used, as part of the material diffusion layer, to ensure that the AuNP-chitosan did not diffuse through to the bulk solution. This synthesized AuNP-chitosan provided quantitative nitrite concentrations (0 to 1000 mg L-1) and masses (145 mu g) in laboratory-based color development studies. An Fe(III)-impregnated poly-2-acrylamido-2-methyl-1-propanesulfonic acid/acrylamide copolymer hydrogel [Fe(III)-p(AMPS/AMA)] was developed (10% AMPS, and 90% AMA), which was treated with NaBH4 to form an Fe(0)-p(AMPS/AMA) hydrogel. The Fe(0)-p(AMPS/AMA) hydrogel quantitatively reduced nitrate to nitrite. The total nitrite mass produced was similar to 110 mu g, from nitrate. The diffusional characteristics of nitrite and nitrate through the Fe(III)-p(AMPS/AMA) and dialysis membrane were 1.40 x 10(-5) and 1.40 x 10(-5) and 5.05 x 10(-6) and 5.15 x 10(-6) cm(2) s(-1) at 25 degrees C respectively. The Fe(0)-hydrogel and AuNP-chitosan suspension operated successfully in laboratory tests individually; however, the combined AuNP-chitosan suspension and Fe(0)-hydrogel DGT did not provide quantitative nitrate concentrations. Further research is required to improve the reaction rate of the AuNP-chitosan nitrite-binding layer, to meet the requirement of rapid binding to operate as a DGT

The new age of global health governance holds promise.

The recognition that many diseases present worldwide challenges has spurred nations and institutions to participate in the development of what is known as 'global health governance'. But this new form of governance will only succeed with strengthened country commitment, collaborations across disparate sectors and improved accountability

Integrated assessment of the environmental, economic and social impacts of land use change using a GIS format – the CLUES model

The CLUES model is an integrated catchment based model that designed to assist policy makers in understanding the implications of land use scenarios for water quality and a range of other indicators. CLUES integrates a number of existing models from several research providers, including SPARROW (catchment hydrology), OVERSEER and SPASMO (nutrient losses), ENSUS (nitrate leaching risk), and a socioeconomic model. These are combined in a GIS framework which allows scenarios of land use to be assessed in a spatial manner. Regional council staff have been trained in its use, and the model is under ongoing development in response to feedback from users. This paper discusses the overall framework of the CLUES model, and discusses in greater depth the socio-economic components and their integration with the biophysical models

Integrated assessment of the environmental, economic and social impacts of land use change using a GIS format – the CLUES model

The CLUES model is an integrated catchment based model that designed to assist policy makers in understanding the implications of land use scenarios for water quality and a range of other indicators. CLUES integrates a number of existing models from several research providers, including SPARROW (catchment hydrology), OVERSEER and SPASMO (nutrient losses), ENSUS (nitrate leaching risk), and a socioeconomic model. These are combined in a GIS framework which allows scenarios of land use to be assessed in a spatial manner. Regional council staff have been trained in its use, and the model is under ongoing development in response to feedback from users. This paper discusses the overall framework of the CLUES model, and discusses in greater depth the socio-economic components and their integration with the biophysical models.sustainability indicators, catchment models, water quality, economic impacts, land use change, Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Land Economics/Use, Political Economy,