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Soil water repellency (SWR) is a common phenomenon observed throughout the world. It has a significant impact on water infiltration, altering soil hydrology and consequently the soil microbial community and nutrient cycling. Despite the importance of this phenomenon, the processes involved in the development and breakdown of SWR are poorly understood. The importance of the microbial community for SWR is becoming increasingly apparent. In this study, relationships between microbial activities and SWR were investigated by utilising the patchy occurrence of SWR to select both repellent and wettable soils in six locations of the east coast of the North Island of New Zealand. Samples were from directly adjacent locations in mid spring and late summer, and a range of soil physico-chemical properties and enzyme activities were measured. The degree and potential persistence of SWR did not change between the two sampling times, whereas actual persistence of SWR increased. Soil moisture decreased between the two times, and although there was an inverse relationship between moisture and actual persistence of SWR in late summer, unexpectedly, it was a positive relationship in spring. Phosphatase, arylsulfatase and polysaccharide degrading enzyme activities increased with increasing SWR, whereas peroxidase activity decreased. The possible effects of increasing temperature and decreasing water content were modelled, and the observed relationships were strengthened. Arylsulfatase activity was strongly correlated with the degree of SWR, as was extractable organic sulfate, suggesting that the breakdown of sulfate-esters within humic material in soil may be involved in the release and accumulation of SWR-inducing hydrophobic compounds. Additional keywords: humic material, microbial community, peroxidase, phosphatase, soil moisture, sulfatase., Introduction Soil water repellency (SWR) has been observed in a wide range of natural and agricultural environments in over 50 countries (Dekker et al. 2005). SWR is a temporary property [...]

The gas transport parameters, diffusivity and air-filled porosity are crucial for soil aeration, microbial activity and greenhouse gas emission, and directly depend on soil structure. In this study, we analysed the effect of long-term tillage and irrigation practices on the surface structure of an arable soil in New Zealand. Our hypothesis was that topsoil structure would change under intensification of arable production, affecting gas exchange. Intact soil cores were collected from plots under intensive tillage (IT) and direct drill (DD), irrigated or rainfed. In total, 32 cores were scanned by X-ray computed tomography (CT) to derive the pore network >30 [micro]m. The cores were then used to measure soil-gas diffusivity, air-permeability and air-filled porosity of pores close to the resolution of the X-ray CT scans, namely [greater than or equal to] 30 [micro]m. The gas measurements allow the calculation of pore-network connectivity and tortuosity parameters, which were compared with the CT-derived structural characteristics. Long-term irrigation had little effect on any of the parameters analysed. Total porosity tended to be lower under IT than DD, whereas the CT-derived porosity was comparable. Both the CT-derived mean pore diameter (MPD) and other morphological parameters, as well as gas measurement-derived parameters, highlighted a less developed structure under IT. The differences in the functional pore-network structure were attributed to SOC depletion and the mechanical disturbance through IT. Significant correlations between CT-derived parameters and functional gas transport parameters such as tortuosity and MPD were found, which suggest that X-ray CT could be useful in the prediction of gas transport. Additional keywords: carbon depletion, Dexter index, intensive tillage, P-parameter, soil organic carbon, soil structure., Introduction Modern agriculture associated with increased inputs of agrichemicals, irrigation and intensive cultivation has led to soil compaction and erosion, which negatively affect the delivery of soil ecosystem services. Concomitant [...]

Mass transport in soil occurs through the soil pore network, which is highly influenced by pore structural parameters such as pore-size distribution, porosity, pore tortuosity, and coordination number. In this study, we visualised the networks of meso- and macro-pores (typical pore radius r [greater than or equal to] 10 [micro]m) using micro-focus X-ray computed tomography (MFXCT) and evaluated pore structural parameters of two loamy soils from Japan and New Zealand packed at different degrees of compaction. The effect of compaction on pore structural parameters and relationships between pore structural parameters and measured mass transport parameters were examined. Results showed a clear influence of compaction on pore structural parameters, with the MFXCT-derived mean pore radii and pore tortuosities decreasing and the mean pore coordination number increasing with increasing dry bulk density. Especially, pores with r > 80 [micro]m became finer or were not well formed due to compaction. The MFXCT-derived pore structural parameters were not well correlated with the equivalent pore radii from measured water retention curves. However, volumetric surface areas and pore-network connectivity-tortuosity factors derived from MFXCT allowed a fair prediction of several important mass transport parameters such as saturated hydraulic conductivities, soil-gas diffusion coefficients, and soil-air permeabilities. Further studies are needed to link micro-pores with radii smaller than the X-ray CT resolution to meso- and macro-pores visualised by X-ray CT to improve the prediction of mass transport parameters in soil. Additional keywords: air permeability, hydraulic conductivity, microfocus X-ray computed tomography (MFXCT), pore network, soil gas diffusion coefficient., Introduction A better understanding of gas transport in soil is important to elucidate the emission of greenhouse gases (Kruse et al. 1996; Smith 2003; Kawamoto et al. 2006; Wickramarachchi et [...]

Sustainable horticulture depends on the integrity of soil functions, which directly depend on soil architecture affecting aggregation, root growth, as well as liquid and gas permeability. We hypothesised that changes in soil architecture resulting from feedback mechanisms between management, soil organic carbon contents (SOC), biota and vegetation can be captured with X-ray computed tomography (CT), and that these affect the soil filtering function, which thus, can be manipulated through orchard management. We compared the transport of copper, a widely used fungicide, through intact soil cores from vine rows of kiwifruit orchards under organic and integrated management. We first derived 3D-macropore characteristics from CT-images, followed by leaching a pulse of copper and a tracer through the same cores. The organic orchard soil had a significantly higher SOC content than the integrated orchard soil, and this was positively correlated with total porosity. Macropores (>92 [micro]m) were larger with a higher connectivity, but significantly fewer in the organic than the integrated orchard soil. This resulted in a lower macroporosity and a better copper filtering capacity of the organic than the integrated orchard soil. Copper distribution was reasonably predicted when combining SOC contents, pH and macropore characteristics. Significant relationships between soil parameters and indicators of the strength of preferential flow verified that CT-derived macropore characteristics can be used to predict functional solute transport parameters. The relevance of our results and relationships observed between macropore characteristics, functional indicators of preferential flow and the fate of copper needs verification with samples representing more soils and sites. Additional keywords: carbon, filtering function, kiwifruit orchard, soil architecture, X-ray computed tomography., Introduction Kiwifruit is the fruit of a perennial woody vine. New Zealand (NZ) is among the leading kiwifruit-producing countries worldwide. Kiwifruit production totalled ~1 412 351 MT in 2012 with [...]

Soils and their protection have been recognised of paramount importance by the Food and Agriculture Organization (FAO) by declaring 2015 as the International Year of Soils (Martin et al. 2017). [...]

Attracting and retaining competent teachers is a key concern when it comes to managing the supply and demand for teachers. This article examines the motivation that prompts people to enter or leave the teaching profession with the aim of identifying a decision framework for defining teacher policies. The results are based on the teacher workforce planning system put in place by the Education Department of the Swiss Canton of Geneva. Having identified the most influential factors affecting teacher motivation, we rated these with regard to their responsiveness to policy measures in a bid to identify levers for deriving effective teacher policies. This decision framework highlights three main issues to serve as a focus for policy measures--the characteristics of the job activities, working conditions and professional image. Finally, priority policy measures have been derived from motivational inducement systems, which include task, leadership, reward, professional development and social systems. (Contains 4 tables, 2 figures, and 4 notes.)

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1523-1739.2008.00898.x Byline: ASTRID ZABEL (*), KARIN HOLM-MULLER ([dagger]) Author Affiliation: (*)Universitaetsstr. 16, Environmental Policy and Economics (ETHZ), 8092 Zurich, Switzerland, emailastrid.zabel@env.ethz.ch ([dagger])Institute for Food and Resource Economics (ILR), Rheinische Friedrich-Wilhelms-Universitaet, Nussallee 21, 53115 Bonn, Germany Article History: Paper submitted May 14, 2007; revised manuscript accepted October 25, 2007.

Pesticides are indispensable in modern agricultural production; however, their off-site migration and detrimental effects on surface water and groundwater quality cause concern. Current pesticide usage and trend data show pesticide use is widespread in New Zealand. According to national surveys, concentrations of most pesticides in groundwater are usually low, and their occurrence has been attributed to non-point sources of contamination. Although it is well established that the environmental fate of pesticides is governed by complex interactions of many processes such as sorption, degradation, and transport, our understanding of these basic mechanisms in the vadoze zone is too far from complete to predict quantitatively the fate of trace residues of pesticides in various soil types within one geographical location. This is mainly due to the vexing issue of the complex nature of soil and its lateral heterogeneity, such as spatial and temporal variability in field-scale. The use of simulation models to predict the environmental fate of pesticides using laboratory- and field-derived parameters is discussed. The objective of this overview is to present past and recent environmental fate work on pesticides carried out under New Zealand conditions, to provide a wider perspective on the subject matter, and to give some recommendations for future research directions. Additional keywords: sorption, degradation, transport, groundwater contamination, models., Introduction It goes without saying that the use of pesticides in modern agriculture to control weeds, insects, other pests and diseases has significantly increased global food production. The term 'pesticides' [...]

Research has been conducted on PDC-109, the main component of bovine seminal plasma. The examination of the binding effect of PDC-109 to membranes on the lipid phase structure and physical properties has been conducted.

Astudy of the movement of aminophospholipids in the plasma membrane of rain sperm cells using spin- and fluorescence-labeled phospholipids shows that translocation of phosphatidylcholine and sphingomyelin to the inner cytoplasmic leaflet is slow while phosphatidylserine (PS) and phosphatidylethanolamine (PE) disappear fast from the exoplasmic monolayer. Inhibition of inward movement of PS and PE by ATP depletion or pretreatment of ram sperm cells with N-ethylmaleimide indicates the mediation of protein in aminophospholipid translocation. Distribution studies reveals a transverse distribution of phospholipids in plasma membranes.