Improving the McCall herbage growth model

Romera, Álvaro J.; McCall, D. G.; Lee, J. M.; Agnusdei, M. G.

doi:10.1080/00288230909510529

Cited by 46 publications

(41 citation statements)

References 36 publications

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“…A model was constructed by integrating whole-system environmental impact and economic production cost modules , a pasture module (Romera et al, 2009) and a module estimating social acceptability using a meta-regression estimating consumer WTP (White and Brady, 2013). The model is depicted in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…To describe the variety of pasture management systems available, pasture yield and nutrient contents were therefore simulated by the McCall pasture model (McCall and Bishop-Hurley, 2003) as updated by Romera et al (2009). The McCall model was parameterized and validated for U.S. pasture production as described in Appendix A.…”

Section: Crop and Pasture Production Parametersmentioning

confidence: 99%

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Optimizing diet and pasture management to improve sustainability of U.S. beef production

White

Brady

Capper³

et al. 2014

Agricultural Systems

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a b s t r a c tSystem sustainability balances environmental impact, economic viability and social acceptability. Assessment methods to investigate impacts of enterprise management and consumer decisions on sustainability of beef cattle operations are critically needed. Tools of this nature are especially important given the predictions of climate variability and the dependence of beef production systems on forage availability. A model optimizing nutritional and pasture management was created to examine the environmental impact of beef production. The model integrated modules calculating cradle-to-farm gate environmental impact, diet cost, pasture growth and willingness to pay (WTP). Least-cost diet and pasture management options served as a baseline to which environmental-impact reducing scenarios were compared. Economic viability was ensured by a constraint limiting change in diet cost to less than consumer WTP. Increased WTP was associated with improved social acceptability. Model outputs were evaluated by comparing to published data. Sensitivity analysis of the WTP constraint was conducted. A series of scenarios then examined how forecasted changes in precipitation patterns might alter forage supply and opportunities to reduce environmental impact in three regions in the United States. On a national scale, single-objective optimization indicated individual reductions in greenhouse gases (GHG), land use and water use of 3.6%, 5.4% and 4.3% were possible by changing diets. Multi-objective optimization demonstrated that GHG, land and water use could be simultaneously reduced by 2.3%. To achieve this change, cow-calf diets relied on grass hay, continuously-or rotationally-grazed irrigated and fertilized pasture as well as rotationally-grazed pasture. Stocker diets used rotationally-grazed, irrigated and fertilized pasture and feedlot diets used grass hay as a forage source. The model was sensitive to consumer WTP. When alternative precipitation patterns were simulated, opportunities to decrease the environmental impact of beef production in the Pacific Northwest and Texas were reduced by precipitation changes; whereas opportunities in the Midwest improved. Economic viability, rather than biological limitations, reduced the potential to improve environmental impact under future precipitation scenarios. Decreased spring rainfall resulted in lower pasture yields and required greater use of stored forages. Related increases in diet cost reduced opportunities to appropriate funds toward investment in environmental-impact reducing pasture management strategies. The model developed in this study is a robust tool that can be used to assess the impacts of enterprise management and consumer decisions on beef production sustainability.

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Section: Methodsmentioning

confidence: 99%

Section: Crop and Pasture Production Parametersmentioning

confidence: 99%

Optimizing diet and pasture management to improve sustainability of U.S. beef production

White

Brady

Capper³

et al. 2014

Agricultural Systems

View full text Add to dashboard Cite

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“…There are several advantages of such long-term trials, including the ability to highlight the effectiveness of slow-release fertiliser products, long-term changes in C, N, S and P cycling (Nguyen et al 1989, Murata et al 1995, Blake et al 2000, P accumulation and losses (Condron & Goh 1990, McDowell et al 2003, losses and cycling of fertiliser contaminants such as Cd (McDowell 2010), and the ability to account for nutrients in the soilÁplantÁanimal system via a mass balance approach (Williams & Haynes 1992). Datasets from long-term trials such as that at Winchmore have also been used successfully to construct, modify and validate both nutrient cycling and pasture growth models (Metherell et al 1995, Romera et al 2009). …”

mentioning

confidence: 99%

Pasture production from a long-term fertiliser trial under irrigation

Smith

Moss

Morton³

et al. 2012

New Zealand Journal of Agricultural Research

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New Zealand pastoral farming has benefited greatly from the application of phosphorus (P) and sulphur (S) fertilisers supplied in the main by superphosphate (SSP). The long-term fertiliser trial at Winchmore, mid-Canterbury, New Zealand was set up in 1952 and has yielded a wealth of data on the effect of fertiliser, grazing by sheep and flood irrigation on pasture production. The trial was initially (1952Á1958) designed to measure the effect of no fertiliser and SSP applied each year at 188, 376 and 564 kg ha . The cessation of fertiliser decreased clover content and increased the proportion of weeds and low-fertility grasses. The decline in production once fertiliser application ceased followed a curvilinear pattern, but never reached the low production of the no fertiliser treatments even after 20 years. In 1980, the residual treatments were changed to compare a reactive phosphate rock (RPR)/S treatment as well as an intermediate (250 kg (1 y (1 treatments have shown that without any nitrogen fertiliser, ryegrass and clover will persist in irrigated pastures and result in high levels of pasture production (11Á12 t ha

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“…Se basó en definir todas las variables posibles que puedan afectar el resultado de los sembríos, teniendo presente medidas de tiempo, cantidad y temperatura que influyen en el producto sea del agrado para su venta (Romera, 2009). Así mismo, en México se implementó en un proyecto de aplicación de un modelo colaborativo para el desarrollo ágil de software, con base en los factores del modelo de McCall se evalúa la calidad del software a partir de listas de comprobación de las características operativas, aceptación del cambio, y adaptabilidad a nuevos ambientes (Cedejas et al, 2015).…”

Section: Mccallunclassified

Modelos de calidad del software, un estado del arte

2017

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R e s u m e nExisten diferentes modelos de calidad del software que permiten un proceso de mejora continua con su implementación. En el presente escrito se exponen características de los modelos investigados a través de una revisión de información, se realiza una clasificación de los mismos de acuerdo con el nivel de proceso o de producto; cada modelo cuenta con unas características y una estructura la cual se enuncia brevemente en el escrito. Las diferentes empresas, con el fin de verse inmersas en una mejora continua de sus procesos, han identificado la importancia de hacerse a la implementación de modelos que permitan certificar y garantizar la calidad de sus productos y procesos, se encontraron algunos casos de éxito de la implementación de los modelos estudiados, los cuales permitieron a las empresas posicionarse o destacarse por mejorar los procesos de su negocio. PalabRas c l av eCalidad, modelo, estándar, software, evaluación, calidad de software Software quality models, a state of the art a b s t R a c tThere are many software quality models that allows a process of continuous improvement with its implementation. In this paper some characteristics of the investigated models are exposed, through an information revision, a classification of these models is performed according to the level of the process or product; each model count with some characteristics and a structure that is briefly stated in the written. The different enterprises in order to be immersed on a continuous improvement of their processes have identified the importance of getting the implementation of models that allows to certify an guarantee the quality of their processes and products, some success cases were found for the implementation of the studied models, which allowed the enterprises to position or stand by the improvement of their business process.

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Improving the McCall herbage growth model

Cited by 46 publications

References 36 publications

Optimizing diet and pasture management to improve sustainability of U.S. beef production

Optimizing diet and pasture management to improve sustainability of U.S. beef production

Pasture production from a long-term fertiliser trial under irrigation

Modelos de calidad del software, un estado del arte

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