Agricultural and Resource Economics Commons^™

Harvesting Fertilized Rye Cover Crop: Simulated Revenue, Net Energy, And Drainage Nitrogen Loss, R. W. Malone, J. F. Obrycki, Douglas L. Karlen, T. C. Kaspar, D. B. Jaynes, T. B. Parkin, S. H. Lence, G. W. Feyereisen, Q. X. Fang, T. L. Richard, K. Gillette

Douglas L Karlen

Harvesting fertilized rye (Secale cereale L.) cover crop has been suggested as a method to increase producer revenue and biofuel feedstock production, but drainage N loss impacts are currently unknown. Using the tested Root Zone Water Quality Model (RZWQM) across several N rates, spring application of 120 kg N ha^-1 prior to winter rye harvest reduced drainage N loss by 54% compared with no cover crop and by 18% compared with planted rye that was neither fertilized nor harvested. Estimates of producer revenue and net energy were also positive, with 8.3 Mg ha^-1 of harvested rye biomass. …

Implications Of Changes (Structural And Market) On Farm Management And Marketing Research, George R. Allen, Lester S. Kellogg, G. Edward Schuh, Vernon W. Pherson, Reynold P. Dahl, Rex F. Daly, Dale E. Hathaway, Neil E. Harl, Earl O. Heady, A. Gordon Ball, Glenn L. Johnson, Dale O. Anderson, Lowell D. Hill, John C. Redman, Robert W. Rudd, B. F. Jones, A. Allen Schmid, Karl A. Fox, George D. Irwin, R. L. Kohls, John E. Lee Jr., Thomas T. Stout

Neil E. Harl

This conference was really an outgrowth of an earlier conference on Structural Changes in Commercial Agriculture (CAED Report 24) held in Chicago, April 12-14, 1965. While the earlier conference emphasized structural changes in the agricultural industry and their implications for education and extension, the 1967 conference focused on research.

Extractive Metallurgy Of Copper, Fathi Habashi

Fathi Habashi

Growth And Species Interactions Of Eucalyptus Pellita In A Mixed And Monoculture Plantation In The Humid Tropics Of North Queensland, Mila Bristow, Jerome K. Vanclay, Lyndon O. Brooks, Mark Hunt

Dr Lyndon O Brooks

This study investigated whether mixed-species designs can increase the growth of a tropical eucalypt when compared to monocultures. Monocultures of Eucalyptus pellita (E) and Acacia peregrina (A) and mixtures in various proportions (75E:25A, 50E:50A, 25E:75A) were planted in a replacement series design on the Atherton Tablelands of north Queensland, Australia. High mortality in the establishment phase due to repeated damage by tropical cyclones altered the trial design. Effects of experimental designs on tree growth were estimated using a linear mixed effects model with restricted maximum likelihood analysis (REML). Volume growth of individual eucalypt trees were positively affected by the presence …

Enhancing Chocolate Flavour Quality – Effects Of Technological Modifications During Fermentation Of Ghanaian Cocoa Beans, Dr. Emmanuel Ohene Afoakwa (Phd)

Professor Emmanuel Ohene Afoakwa

No abstract provided.

Effect Of Spontaneous Fermentation And Amylase Rich Flour (Arf) On The Nutritive Value, Functional And Viscoelastic Properties Of Cowpea-Fortified Nixtamalized Maize, Dr. Emmanuel Ohene Afoakwa (Phd), Philip Roger Aidoo, Randy Adjonu

Professor Emmanuel Ohene Afoakwa

Studied were conducted to evaluate the combined effects of spontaneous fermentation and Amylase Rich Flours (ARF) on some nutritive value, functional and viscoelastic properties of cowpea-fortified nixtamalized maize. A 2x3x3 factorial design, with fermentation medium, fermentation time and ARF level was performed. The blends were fermented for the specific times and analysed for their titratable acidity, pH, water absorption capacity, viscoelastic properties, texture, protein and mineral content. Fermentation and ARF addition influenced titratable acidity, pH, water absorption, viscoelastic properties and texture of the cowpea-fortified nixtamalized maize. Addition of ARF decreased the viscoelastic properties, texture and pH of all the blends …

Beethoven: Patriotism And Social Justice, Fathi Habashi

Fathi Habashi

Viscoelastic Properties And Pasting Characteristics Of Fermented Maize: Influence Of The Addition Of Malted Cereals, Dr. Emmanuel Ohene Afoakwa (Phd), Randy Adjonu, Justice Asomaning

Professor Emmanuel Ohene Afoakwa

Investigations were conducted on the viscoelastic properties and pasting characteristics of fermented maize with malted cereals and their suitability for infant feeding. A 3x3x2 factorial experimental design with malting time, cereal malt concentration and cereal type was used. Maize, millet, and sorghum malts were added to fermented maize to reducing its bulk density. Samples were analysed for their viscoelastic properties and pasting characteristics using Brabender Viscoamylograph. Sorghum malt in comparison to millet and maize malts was not effective in terms of lowering the hot and cold paste viscosities of the fermented maize. Maize and millet malts liquefied the dough considerably …

Acidification And Starch Behaviour During Co-Fermentation Of Cassava And Soybean Into Gari., Dr. Emmanuel Ohene Afoakwa (Phd), Edem John Kongor, George Annor, Randy Adjonu

Professor Emmanuel Ohene Afoakwa

Changes in acidification and starch behaviour were investigated during co-fermentation of cassava and soybean into gari, an African fermented product. Non-volatile acidity, pH and starch content were evaluated using standard analytical methods. Starch breakdown and pasting characteristics were also analysed using Brabender Viscoamylograph. Fermentation caused significant variations in the pH, non-volatile acidity and starch concentration. The pH decreased with concomitant increases in non-volatile acidity during co-fermentation of the cassava dough. Soy-fortification upto 20% caused only minimal effects on the pH, titratable acidity and starch content during the fermentation period. Starch content decreased from 69.8%-60.4% within the 48 h fermentation time …

Response Surface Methodology For Studying The Quality Characteristics Of Cowpea (Vigna Unguiculata)-Based Tempeh., George Amponsah Annor, Esther Sakyi-Dawson, Samuel Sefa-Dedeh, Firibu Kwesi Saalia, Dr. Emmanuel Ohene Afoakwa (Phd), Kwaku Tano-Debrah, Agnes Simpson Budu

Professor Emmanuel Ohene Afoakwa

Response surface methodology was used to optimize the processing conditions in the preparation of cowpea tempeh. The independent factors studied were boiling time (varying from 5 to 30 min), incubation time (varying from 12 to 48 h) and incubation temperatures (varying from 25 to 50°C), whereas the dependent factors were protein content, protein solubility, pH, titratable acidity and total color difference (using L, a* and b*). Regression models were generated and adequacy was tested with regression coefficients (R2) and the lack-of-fit tests. Optimum processing conditions were determined by method of superimposition. There was a strong and significant influence (P < 0.01) of the quadratic effect of the incubation time on the protein content of the cowpea tempeh, with similar significance (P < 0.01) noted in protein solubility with increasing boiling time. The optimum processing conditions observed for the preparation of cowpea tempeh were boiling time of about 20 min, incubation time of about 28 h and incubation temperature of about 37°C.

Mining And Civilization, An Illustrated History, Fathi Habashi

Fathi Habashi

Mixed Species Plantations: Prospects And Challenges, J Doland Nichols, Mila Bristow, Jerome K. Vanclay

Professor Jerome K Vanclay

About 2% of English-language literature on plantations deals with mixed-species plantations, but only a tiny proportion (<0.1%) of industrial plantations are polycultures. Small landholders are more innovative, with 12% of Australia’s farm forestry plantations under mixed-species plantings, and 80% of Queensland’s farm forestry as polycultures. We examine reasons for this discrepancy, and explore the history, silviculture and economics of polycultures. Financial analyses suggest that a yield stimulus of 10%, depending on product and rotation length, may be sufficient to offset increased costs associated with planting and managing a mixed-species plantation, a stimulus that has been demonstrated in many field …

Improving Productivity In Mixed-Species Plantations, Mila Bristow, J Doland Nichols, Jerome K. Vanclay

Professor Jerome K Vanclay

Mixed species plantations are often promoted as being environmentally preferable to monocultures, but are rarely considered operationally viable by commercial forest growers. Despite many publications documenting benefits demonstrated in research studies (e.g., Kelty 2006; Forrester et al. 2006b; Wood and Vanclay 1995), and despite continuing calls from a wide range of advocates for mixed-species plantations, polyculture remains the exception rather than the rule in industrial plantation forestry (Nichols et al 2006)...

Mixed-Species Plantation Of Eucalyptus With Nitrogen Fixing Trees: A Review, David I. Forrester, Jürgen Bauhus, Annette L. Cowie, Jerome K. Vanclay

Professor Jerome K Vanclay

Mixed-species plantations of Eucalyptus with a nitrogen (N2) fixing species have the potential to increase productivity while maintaining soil fertility, compared to Eucalyptus monocultures. However, it is difficult to predict combinations of species and sites that will lead to these benefits. We review the processes and interactions occurring in mixed plantations, and the influence of species or site attributes, to aid the selection of successful combinations of species and sites. Successful mixtures, where productivity is increased over that of monocultures, have often developed stratified canopies, such that the less shade-tolerant species overtops the more shade-tolerant species. Successful mixtures also have …

Illumination-Size Relationships Of 109 Coexisting Tropical Forest Tree Species, Douglas Sheil, Agus Salim, Jérôme Chave, Jerome K. Vanclay, William D. Hawthorne

Professor Jerome K Vanclay

Summary 1 Competition for light is a central issue in ecological questions concerning forest tree differentiation and diversity. Here, using 213 106 individual stem records derived from a national survey in Ghana, West Africa, we examine the relationship between relative crown exposure, ontogeny and phylogeny for 109 canopy species. 2 We use a generalized linear model (GLM) framework to allow interspecific comparisons of crown exposure that control for stem-size. For each species, a multinomial response model is used to describe the probabilities of the relative canopy illumination classes as a function of stem diameter. 3 In general, and for all …

Social And Ecological Issues For Private Native Forestry In North-Eastern New South Wales, Australia, V Alex Jay, J Doland Nichols, Jerome K. Vanclay

Professor Jerome K Vanclay

Forests in north-eastern New South Wales have often been the focus of controversy. The tension between production and preservation continues and hampers current negotiations for a code of practice for private native forestry. The structure of many private forests reflects past mismanagement and silvicultural intervention would benefit both conservation and production objectives, but such intervention is rarely financially viable. This paper sets out the economic and ecological basis for private native forestry. Both the timber industry and nature-based tourism are major contributors to the local economy, and both rely in part on private native forests. Draft regulations currently under negotiation …

Growth And Species Interactions Of Eucalyptus Pellita In A Mixed And Monoculture Plantation In The Humid Tropics Of North Queensland, Mila Bristow, Jerome K. Vanclay, Lyndon O. Brooks, Mark Hunt

Professor Jerome K Vanclay

This study investigated whether mixed-species designs can increase the growth of a tropical eucalypt when compared to monocultures. Monocultures of Eucalyptus pellita (E) and Acacia peregrina (A) and mixtures in various proportions (75E:25A, 50E:50A, 25E:75A) were planted in a replacement series design on the Atherton Tablelands of north Queensland, Australia. High mortality in the establishment phase due to repeated damage by tropical cyclones altered the trial design. Effects of experimental designs on tree growth were estimated using a linear mixed effects model with restricted maximum likelihood analysis (REML). Volume growth of individual eucalypt trees were positively affected by the presence …

Community Attitudes Towards Private Native Forestry In New South Wales, Jerome K. Vanclay

Professor Jerome K Vanclay

An on-line survey during August-September 2006 examined community attitudes toward private native forestry. Survey findings (n=156) confirmed prior hypotheses that attitudes would correlate with associations (e.g., professionals in favour of incentives, farmers in favour of freedom to manage, conservationists in favour of regulations), and with interest (biodiversity enthusiasts in favour of regulations; producers in favour of incentives), but refuted the prior hypotheses that urban dwellers would be more likely to favour regulations. Respondents appear to reflect different constituencies with divergent views without a shared understanding of the condition and dynamics of these forests. This indicates the need for more extension …

On The Robustness Of The H-Index, Jerome K. Vanclay

Professor Jerome K Vanclay

The h-index (Hirsch, 2005) is robust, remaining relatively unaffected by errors in the long tails of the citations-rank distribution, such as typographic errors that short-change frequently-cited papers and create bogus additional records. This robustness, and the ease with which h-indices can be verified, support the use of a Hirsch-type index over alternatives such as the journal impact factor. These merits of the h-index apply to both individuals and to journals.

Regeneration Changes In Tree Species Abundance Diversity And Structure In Logged And Unlogged Subtropical Rainforest Over A 36-Year Period, Maina Kariuki, Robert M. Kooyman, R Geoff B. Smith, Grant Wardell-Johnson, Jerome K. Vanclay

Professor Jerome K Vanclay

The long-term effects of logging treatments on rainforest regeneration are difficult to quantify due to compounding interactions with natural dynamics, site characteristics and tree species. The aim of this study was to examine regeneration differences over a 36-year period in stands subjected to various levels of disturbance ranging from natural, through an increasing intensity of individual tree removal to intensive logging. Multivariate and univariate analyses of trees ¡Ý 10 cm diameter at 1.3 m above the ground (dbh) showed that regeneration responses were generally correlated with disturbance gradient. In the undisturbed controls there were gradual changes that had no significant …

Realising Opportunities In Forest Growth Modelling, Jerome K. Vanclay

Professor Jerome K Vanclay

The world is continually changing: the emergence of new technology and new demands for pertinent information pose new challenges and possibilities for forest management. Are forest growth models keeping up with client needs? To remain relevant, modelers need to anticipate client needs, gauge the data needed to satisfy these demands, develop the tools to collect and analyze these data efficiently, and resolve how best to deliver the resulting models and other findings. Researchers and managers should jointly identify and articulate anticipated needs for the future, and initiate action to satisfy them. New technology that offers potential for innovation in forest …

Spatially-Explicit Competition Indices And The Analysis Of Mixed-Species Plantings With The Simile Modelling Environment, Jerome K. Vanclay

Professor Jerome K Vanclay

Individual-based modelling and analysis of forest experiments has been made more accessible to researchers with the advent of modelling environments like Simile from www.simulistics.com. Individual-based analyses of tree growth data offer insights not possible with plot-based analyses, especially when the original experimental design has been compromised by mortality or other unforeseen events. The paper illustrates how Simile can be used for individual-based analyses of mixed plantings, and how it can be used to explore the consequences of the resulting statistical models. A mixed-species planting of Eucalyptus pellita and Acacia peregrina is used to illustrate possibilities.

Structure And Floristic Composition Of Flood Plain Forests In The Peruvian Amazon, Ii. The Understorey Of Restinga Forests, Gustav Nebel, Jens Dragsted, Jerome K. Vanclay

Professor Jerome K Vanclay

Structure and floristic composition of small trees and shrubs (1.5 m height to 10 cm diameter at breast height was described in two flood plain forests of the lower Ucayali river, Peruvian Amazon. The forests were of the high and low restinga type, on an annual average flooded around 1 and 2 months, respectively. The soils were nutrient rich entisols, and the vegetation forms closed high canopy forests with presence of emergents. A total of 25 permanent sample plots covering 0.64 ha were established. They were nested within six quadratic 1 ha permanent sample plots where large individuals (>10 …

Sustainable Forestry In The Tropics: Panacea Or Folly?, David W. Pearce, Francis E. Putz, Jerome K. Vanclay

Professor Jerome K Vanclay

The profitability of uncontrolled logging can be a significant obstacle to sustainable forest management, especially in the tropics. Rice et al. (1997) have argued that not only does traditional selective logging provide higher returns but also incurs less damage to forests than sustainable forest management systems that involve harvesting of many species and the creation of large gaps in the forest canopy to foster regeneration of light-demanding species. They claimed that protected areas were the only viable way to conserve forest ecosystems and proposed that loggers be allowed to log forests selectively once, after which the forests should become parks. …

Forest Dynamics In Flood Plain Forests In The Peruvian Amazon: Effects Of Disturbance And Implications For Management, Gustav Nebel, Lars Peter Kvist, Jerome K. Vanclay, Hector Vidaurre

Professor Jerome K Vanclay

Forest dynamics were studied from 1993 to 1997 for individuals > 10 cm DBH in nine 1 ha permanent sample plots. They were established in natural flood plain forests located on the lower Ucayali river in the Peruvian Amazon. After inventories of three plots in each of three forest types, a light and a heavy felling treatment were applied to each of the two plots, while a third plot was kept untreated. Average annual stem mortality and recruitment rates in the untreated plots were among the highest observed in neotropical rain forests: mortality 2.2-3.2% per year, recruitment 3.0-4.6% per year. Dead …

The Effectiveness Of Parks, Jerome K. Vanclay

Professor Jerome K Vanclay

Bruner et al. examined the effectiveness of parks in the tropics, drawing on survey data to support their contention that parks 1) have been effective; 2) need more support; and 3) should remain a central component of conservation strategies. Their conclusions remain equivocal...

Experiment Designs To Evaluate Inter- And Intra-Specific Interactions In Mixed Plantings Of Forest Trees, Jerome K. Vanclay

Professor Jerome K Vanclay

A review of three mixed-species trials reveals the utility of competition indices for evaluating inter- and intra-specific interactions between trees, the desirability of experiments that span a range of tree spacing and composition to inform calibration of these competition indices, the need for extremes of species composition and stand density to calibrate response surfaces, and the far-reaching impact of edge-effects. Experiment layouts commonly used for mixed-species trials in forestry (such as replacement series) rarely provide a strong basis to calibrate competition indices and response surfaces. Alternative designs involving systematic changes in species composition may offer a better basis for calibrating …

How To Foster Good Husbandry Of Private Native Forests, Jerome K. Vanclay

Professor Jerome K Vanclay

It is generally agreed that effective conservation requires the cooperation of private landholders to complement reserve-based efforts, but there is little agreement about how this can best be achieved. Various stakeholders lobby for tough regulations, for greater landholder freedom, and for incentives for activities or outcomes. A review of these alternatives suggests an emerging consensus that incentives are the most effective approach. Policy-makers should consider incentive-based approaches such as stewardship support to foster conservation outcomes on private lands.

Why Model Landscapes At The Level Of Households And Fields?, Jerome K. Vanclay

Professor Jerome K Vanclay

Sustainable resource management relies upon many disciplines and deals with complex interactions at the landscape scale. Many of the issues at the landscape scale arise from decisions taken at the household level and affect land use in fields and in small patches of forest. Spatially-explicit modelling of these units is desirable because it enables rigorous testing of model predictions, and thus of underlying propositions. The greatest insights may be obtained by participatory modelling of these processes as we understand them. Despite this, few models simulate dynamics at the household and field level. FLORES, the Forest Land Oriented Resource Envisioning System, …

Diameter Growth Performance Varies With Species Functional-Group And Habitat Characteristics In Subtropical Rainforests, Maina Kariuki, Margaret Rolfe, R Geoff B. Smith, Jerome K. Vanclay, Robert M. Kooyman

Professor Jerome K Vanclay

We examined tree diameter growth in 20 plots subjected to various disturbance intensities (natural, low, moderate and intensive logging) in a bid to understand the general tree growth responses in relation to habitat characteristics in subtropical rainforests of north-eastern NSW, Australia. Species-specific regeneration strategy, maximum size and level of shade tolerance were used to classify species into five groups: emergent and shade tolerant main canopy (group 1), shade tolerant mid canopy (2), shade tolerant understoreys (3), moderate shade tolerant (4) and shade intolerant (5) tree species. Data series for trees ‗10 cm diameter at 1.3 m above the ground level …