Soybean Root Growth and Water Uptake

Rainfall is usually marginal for optimum crop production in the North Central Great Plains. As a result many farmers in this region are installing irrigation systems to supplement rainfall. The most common system installed is the center pivot. However, while this system has a low labor requirement it is costly. Economic reports from South Dakota State University indicate marginal to negative comparisons of irrigated crop production to dryland production. Sprinkler irrigation systems such as side roll, tow lines, hand move, side move with trail lines etc. and surface irrigation depend on root zone soil water storage to extend intervals between irrigations to gain advantages of reduced costs in system design and labor requirements, lower soil evaporation and reduce weed germination. Large root zone water storage is also needed when center pivot systems are towed between two fields with growing crops. The most significant parameters about which information is lacking in making design and associated management decisions concerning the above irrigation options are root zone depth in specific South Dakota soils and root activity in the lower part of the root zone. Questions arise such as: How rapidly and to what depth do roots penetrate in different South Dakota soils? Does root growth cease with flowering? What root density is required in a soil horizon to be significant in water uptake? It was with these questions in mind that a study was initiated into the root length density and water uptake pattern of soybeans in three South Dakota soils

Identifying the major variables controlling transport of water and analytes from an alluvial aquifer to streams

Reliable information on groundwater (GW) lateral flow characteristics is required for estimation of GW extraction, environmental flow requirements, contaminant loading from GW to surface water bodies (SWB), and aquifer remediation purposes. Lateral flow from a shallow alluvial aquifer was investigated applying parametric and non-parametric statistics to flux-theory based outputs obtained using time series hydraulic head (HH) and analyte concentration data. The emphasis of the investigation was to identify the major variables that control the export of contaminants from GW to SWB. Point measurements from 4 shallow wells (10-12 m deep) installed along a 1.1 km transect perpendicularly crossing a creek were undertaken at 7 - 12 day intervals from January through June (wet season) over 3 years in a wet tropical catchment in north-eastern Australia. The HH during two wet seasons at north upslope varied from 4.84 m to 12.37 m with mean, median, and coefficient of variation (CV) of 8.86 m, 8.73 m, and 17% respectively. At the downslope the corresponding values were 3.59-6.21 m, 4.81 m, 4.58 m, and 13%, respectively. Similar temporal trends were observed at the south upslope and downslopes. Nitrate-N concentrations at the north upslope varied from 23 to 1340 µg L-1 with mean, median, and CV of 691 µg L-1, 609 µg L-1 and 23%, respectively. Similar trends were observed at north downslope and at up- and down-slopes of southern transect. The lateral hydraulic gradient (LHG) from north upslope to downslope varied from 4.12 x 10-3 to 9.92 x 10-3 m m-1 and the corresponding flow velocity (Vx) from 3.63 x 10-3 to 3.48 x 10-2 m d-1. Nitrate-N flux from north upslope to downslope varied from 1.0 x 10-4 to 4.4 x10-3 g m-2 d-1, similar trends were observed for EC and Cl and also along southern transect. These suggest that analyte fluxes followed the LHG indicating conservative transport of the former from upslopes to downslopes. The conservative transport was reconfirmed by significant associations between HH and analyte fluxes; R2 18-70% for EC, 24-52% for Cl, and 52-76% for nitrate. Travel time for 650 m, computed using mean Vx varied from 5.8 to 69 yrs and the variations depended on the values of saturated soil hydraulic conductivity (Ks) used. The results indicate contaminant export extrapolations from point measurements to landscape scales depended on our ability to incorporate spatial and temporal variabilities in Vx and analyte fluxes, reliable information in Ks, and macropore bypass flow. We believe this is one of the few studies that have coupled flux-theory and statistics to identify and assess the major variables that control contaminant export from GW to SWB

Modeling of Soil Water Flow and Root Uptake

The soil water pressure head, h, versus soil water content, 9, and the hydraulic conductivity, K, versus θ, relationships appear as functional coefficients in the non-linear partial differential water flow model. Before the flow equation can be used to simulate the flow of water through soils, the h versus θ and K versus θ relationships must be established. This requires the estimation of the parameters that describe the h versus θ and K versus θ functional relationships. In-situ water retention and hydraulic conductivity measurements were determined from the knowledge of initial and boundary conditions and water content profiles during drainage. This information obtained in the greenhouse was used to estimate the parameters of the non-linear h(θ) and K(θ) empirical functions. The estimates were obtained through the first and second order least square best fit procedures for the logarithmically linearized h(θ) and K(θ) functions. The estimates, when combined with the flow model, SWATRE, estimated soil moisture content profile, θ, which did not agree well with the observed data. In the second method, the flow model was linearized using the Taylor series expansion. The same parameters mentioned above were estimated using two iterative procedures, Marquardt (1964) and Taylor. The simulations, θ, for the fitted estimates from both procedures, agreed well with the observed data. The convergence of the estimates in Marguardt\u27s maximum neighborhood method of iterative fitting was more stable than that in the Taylor method. Marquardt\u27s method converged more slowly. Similar procedures were followed for fitting the root uptake function parameters. The parameters in the root uptake function, estimated and fitted individually for each compartment, produced better solutions than when single function parameters were defined for the whole profile. To obtain a satisfactory solution from the flow model, including root uptake, the parameters in the h(θ) and K(θ) functions were estimated for the range of θ in which the root water uptake took place

The economic antecedents of human well being: a pooled mean group estimation of dynamic heterogeneous panel

This study seeks to investigate the economic antecedents of happiness by employing the Mean Group (MG), Pooled Mean Group (PMG) and the Dynamic Fixed Effects (DFE) estimators to analyse a set of macro panel data on selected OECD countries for 40 years from 1973 to 2012. The results show evidence that income and unemployment have a favourable impact on happiness, while happiness is hindered by inflation and income inequality. Surprisingly, the study revealed that institutional quality is not a significant antecedent of happiness. It is worth noting the importance of the reference group theory or relative theory of happiness and the set-point theory of happiness in explaining the role played by income, unemployment, inflation, income inequality and institutional quality in explaining human well-being

Evaluation of Health and Safety performance in Brunei Construction Industry

An evaluation of Health and Safety (H&S) performance in the Brunei Darussalam construction industry (BDCI) is not only important; but integrating the concept based on Total Quality Management (TQM) would greatly enhance and improve the industry practices. H&S of any workforce in any part of the world is an important issue deserving the attention of engineers and safety officers in the construction industry. The need for good quality management in any good construction site is crucial for the overall success of achieving H&S. The present trend where the rates and frequency of accidents arising from poor implementation or non-compliance on H&S code based on TQM principles in the industry is relatively higher. The research paper seeks to evaluate the significance and existence of H&S performance in the BDCI with regards to TQM. Questionnaires form an important method of data collection in this research paper. From the survey conducted, it can be seen that the implementation of H&S and TQM develop and reinforce a positive impact and environmental values in the organization. In the current performance of BDCI, there is still need for continuous development in terms of enhancing H&S based on TQM. Keywords: Health and Safety, Total Quality Management, Accidents, Construction Industr

Firm size, technological capability, exports and economic performance: the case of electronics industry in Malaysia

This paper examines the joint effects of technology and exports on the economic performances of electronics firms in Malaysia. The empirical results based on the Partial Least Square (PLS) estimate procedure show that technological capability plays a multiple role in that it influences both the exports and performance of a firm simultaneously. More importantly, we find evidence that exports act as a mediating variable between technological capability and firm performance. Size is found to influence all three: product capabilities, exports and firm performance but not process capabilities. This paper concludes that researchers, in future studies, need to examine the dynamism between size, technology, exports and performance

Malaysian Manufacturing Systems of Innovation and Internationalization of R&D

The study of innovation and technological upgrading experienced a significant interest in the academic literature, especially within the developing countries (Lall, 1998, 2001; Kim and Nelson, 2000; Ariffin and Figueiredo, 2004). The lack of involvement by developing countries in radical innovative capabilities (Rasiah, 1994; Hobday, 2005) and the interest of scholars in learning technological capability building and technological catch up processes has directed researchers to analyze various mechanisms or drivers that contribute to technological upgrading, especially in developing countries, more so in the manufacturing sector. This study aims to investigate the R&D activities and the internationalization of these activities undertaken by foreign firms within the Malaysian manufacturing sector. The study aims to provide answers to the following questions: 1. What is the status of the systems of innovation within the Malaysian manufacturing sector? 2. What is the role played by the agents of innovation, in particular TNCs or MNCs, in relation to R&D activities and its internationalization? and, 3. How is the Malaysian manufacturing (local and foreign) technological and R&D progress to date? This study confirms that the Malaysian manufacturing systems of innovation is weakly positioned but shows limited evidence of process innovation and not product innovation. However, evidence of innovation differs among states and sectors owing to differences in the systems of innovation. Although, Malaysia has not been chosen as a site for offshoring or outsorcing of R&D activities to a significant degree, it is found that one very important driver of innovation is the central role that multinational enterprises play in the Malaysian manufacturing systems of innovation. Process innovation is conducted by foreign subsidiaries and is on the rise in key the electronics industry. It is also found that technological learning by local firms is mainly through linkages, sub-contracting and technological transfer

Development of key soil health indicators for the Australian banana industry

To improve the sustainability and environmental accountability of the banana industry there is a need to develop a set of soil health indicators that integrate physical, chemical and biological soil properties. These indicators would allow banana growers, extension and research workers to improve soil health management practices. To determine changes in soil properties due to the cultivation of bananas, a paired site survey was conducted comparing soil properties under conventional banana systems to less intensively managed vegetation systems, such as pastures and forest. Measurements were made on physical, chemical and biological soil properties at seven locations in tropical and sub-tropical banana producing areas. Soil nematode community composition was used as a bioindicator of the biological properties of the soil. Soils under conventional banana production tended to have a greater soil bulk density, with less soil organic carbon (C) (both total C and labile C), greater exchangeable cations, higher extractable P, greater numbers of plant-parasitic nematodes and less nematode diversity, relative to less intensively managed plant systems. The organic banana production systems at two locations had greater labile C, relative to conventional banana systems, but there was no significant change in nematode community composition. There were significant interactions between physical, chemical and nematode community measurements in the soil, particularly with soil C measurements, confirming the need for a holistic set of indicators to aid soil management. There was no single indicator of soil health for the Australian banana industry, but a set of soil health indicators, which would allow the measurement of soil improvements should include: bulk density, soil C, pH, EC, total N, extractable P, ECEC and soil nematode community structure

Does economic development and democracy translate to happiness? a global perspective

This paper explores the relatively intriguing area of research on the “economics of happiness”. The present study was designed to determine the effects of economic development and democratic freedom on happiness. A cross-sectional econometric analysis is employed to examine the impact of the economic variables of income and democracy on happiness across thirty eight countries in 2011. Democracy and economic development were found to contribute positively to happiness. The findings also indicate a bi-directional relationship between happiness and its dual determinants of income and democratic freedom. It was found that countries reporting higher levels of well-being tend to enjoy higher incomes and seem to choose democracy over other political overtures. Institutions of democracy were found to enhance economic development and this relationship is bi-directional. The study concludes with an examination of policy implications of the findings