Modelling the productivity of naturalised pasture in the North Island, New Zealand: a decision tree approach

Zhang, Baisen; Valentine, Ian; Kemp, Peter

doi:10.1016/j.ecolmodel.2004.12.016

Cited by 26 publications

(26 citation statements)

References 24 publications

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“…The total amount of C fixed or assimilated through photosynthesis (TCA) and the net amount of C accumulated in above ground herbage (NCA) in any grazing system is dependent on climate, slope, soil fertility and grazing management (Zhang et al 2005). In a grazed pasture TCA has been measured/estimated to be approximately four times NCA (Saggar et al 1999;Soussana et al 2004).…”

Section: Inputs Of C To the Terrestrial Pool Photosynthesismentioning

confidence: 99%

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Simple models of carbon and nitrogen cycling in New Zealand hill country pastures: exploring impacts of intensification on soil C and N pools

Hoogendoorn

Bowatte

Tillman

2011

New Zealand Journal of Agricultural Research

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Concerns about climate change and water quality make it necessary to have a better understanding of the cycling of carbon (C) and nitrogen (N) within landscapes. In New Zealand, pastoral farming on hill country is a major land use, and there is little information available at a landscape level on the cycling of C and N within these systems, particularly the impacts of land use intensification. Published information on the individual components of C and N cycles in hill country pastoral systems was used to construct simple C and N models for two notional hill country paddocks with contrasting amounts of annual net herbage accumulation (NHA). These simple models of C and N cycling were used to explore the potential impacts of intensification on soil C and N pools. The C and N models constructed illustrate that both the C and N cycles in hill country pastoral farming are characterised by large fluxes in and out of the system and relatively small annual accumulations or depletions of their respective soil pools. The mechanisms by which these inward and outward fluxes are generated differ greatly between C and N. Most of the C cycling through the soil/plant/animal system in a year is sourced from the atmosphere through photosynthesis in that same year and the annual quantity of C ingested by grazing animals is only approximately 25% of that fixed annually. In contrast, the annual quantity of N ingested by grazing animals is 300Á400% of that added to the system annually by fixation, and most of this ingested N (!80%) is returned to the soil in animal excreta. This contrasts with B25% of ingested C returned in animal excreta. Grazing animals, with their propensity to exhibit camping behaviour, are therefore much more influential in the spatial redistribution of N than C in hill country pastures. The simple C and N models presented in this paper indicate that while land use intensification results in increased inputs of both C and N to the soil, intensification is also likely to result in increased losses of C and N from the soil pool. Which of these processes dominates in a given situation determines whether intensification will result in an increase or decrease of soil C and N. Based on a simple C model, we postulate that if intensification increases NHA by one unit there is likely to be an increase in soil C unless at the same time increased grazing pressure results in at least a three-unit increase in dry matter eaten/harvested. Keywords: carbon; nitrogen; hill country; grazing; intensification Introduction Two environmental issues of major concern are increasing concentrations of greenhouse gases in the atmosphere and increased concentrations of nitrogen (N) in receiving waters. These are affected by global carbon (C) and N cycles, and soil C and N are major components of these cycles. Hill country farmers are intensifying *Corresponding author. Email: coby.hoogendoorn@agresearch.co.nz Hill country pastoral landscapes occupy a large area of New Zealand, but compared with flat land, relatively little is known of nut...

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Section: Inputs Of C To the Terrestrial Pool Photosynthesismentioning

confidence: 99%

“…The corresponding data for the 'summer dry' paddock are taken from Blennerhassett (2002) for a hill country site near Waipawa in Central Hawke's Bay. The differences in measured annual NHA between these two sites result mainly from differences in annual rainfall (Zhang et al 2005). …”

Section: System Boundaries Definitions and Scenariosmentioning

confidence: 99%

Simple models of carbon and nitrogen cycling in New Zealand hill country pastures: exploring impacts of intensification on soil C and N pools

Hoogendoorn

Bowatte

Tillman

2011

New Zealand Journal of Agricultural Research

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“…The fascination with the promise of analysis of large volumes of data has led to an increasing number of successful applications of data mining in recent years. For instance, Zhang et al (2005) showed how data mining techniques can be used to model native pasture productivity. The results revealed that data mining techniques were very efficient to predict the main critical points and pasture productivity.…”

Section: Introductionmentioning

confidence: 99%

Data mining to estimate broiler mortality when exposed to heat wave

Vale

Moura

Nääs

et al. 2008

Sci. agric. (Piracicaba, Braz.)

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Heat waves usually result in losses of animal production since they are exposed to thermal stress inducing an increase in mortality and consequent economical losses. Animal science and meteorological databases from the last years contain enough data in the poultry production business to allow the modeling of mortality losses due to heat wave incidence. This research analyzes a database of broiler production associated to climatic data, using data mining techniques such as attribute selection and data classification (decision tree) to model the impact of heat wave incidence on broiler mortality. The temperature and humidity index (THI) was used for screening environmental data. The data mining techniques allowed the development of three comprehensible models for estimating specifically high mortality during broiler production. Two models yielded a classification accuracy of 89.3% by using Principal Component Analysis (PCA) and Wrapper feature selection approaches. Both models obtained a class precision of 0.83 for classifying high mortality. When the feature selection was made by the domain experts, the model accuracy reached 85.7%, while the class precision of high mortality was 0.76. Meteorological data and the calculated THI from meteorological stations were helpful to select the range of harmful environmental conditions for broilers 29 and 42 days old. The data mining techniques were useful for building animal production models.

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“…Observa-se elevada porcentagem de instâncias classificadas corretamente (96,9%) e baixa porcentagem classificadas incorretamente (3,1%), distribuição da acurácia (precision) e taxa de acertos (recall) por classe na grande maioria próximo de 1, e ainda matriz de confusão bastante consistente. Os resultados estão próximos aos obtidos em outros trabalhos de Mineração de dados utilizando a árvore de decisão (YANG et al, 2002;PIETERSMA et al, 2003;ZHANG et al, 2005).…”

Section: Algoritmo Resultante Da Base De Dados Do íNdice De Temperatuunclassified

“…Mineração de dados utilizando a árvore de decisão (YANG et al, 2002;PIETERSMA et al, 2003;ZHANG et al, 2005).…”

Section: Algoritmo Resultante Da Base De Dados Do íNdice De Temperatuunclassified

Sistema inteligente aplicado ao acionamento do sistema de climatização em instalações para bovinos leiteiros

Perissinotto¹

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A Deus, que me iluminou e me deu forças nos momentos em que mais precisei para vencer os obstáculos surgidos durante esse percurso. À Escola Superior de Agricultura "Luiz de Queiroz", pelas tantas oportunidades oferecidas.À Universidade de Évora, por ter aberto suas portas para a realização do meu estágio de doutorado.À Professora Dra. Daniella Jorge de Moura, pela orientação atenciosa, pela amizade, confiança, incentivo e entusiasmo na execução deste trabalho, responsável pelo meu crescimento pessoal e científico.Ao Professor Vasco Fitas da Cruz, pela orientação durante o estágio de doutorado, a quem devo todo meu respeito, minha consideração e gratidão, pela confiança, pelos bons conselhos e pela amizade sincera.Aos professores do Programa de Pós-Graduação em Física do Ambiente Agrícola, pelos ensinamentos e oportunidade de realização do curso.Aos professores Iran José Oliveira da Silva, Flávio Augusto Portela Santos e Paulo César Sentelhas, pelos ensinamentos, sugestões para a melhoria e engrandecimento deste trabalho.Aos amigos Soraia, Sérgio e Murilo pelo apoio na instalação e execução do experimento.Aos colegas da FEAGRI/UNICAMP, pela amizade e apoio direto e indireto na realização deste trabalho.Aos colegas do Curso de Pós-Graduação em Física do Ambiente Agrícola, pelo convívio e amizade durante a realização do curso. Aos meus irmãos Marcello, Márcio e Mariana e aos meus sobrinhos Marcello Júnior eLorena, pela amizade, apoio e carinho.Aos meus Avós Ézio e Clara pelo incentivo, e carinho.Aos meus Tios (as) e primos (as), que tanto me incentivaram e me apoiaram durante a realização do curso.À Coordenação de Aperfeiçoamento de Pessoal de Nível Superior -CAPES, pela concessão da bolsa de estudos para a realização do curso e do estágio de doutorado. O objetivo deste estudo foi desenvolver um sistema especialista para controlar o acionamento do sistema de climatização em instalações para bovinos leiteiros. A modelagem foi desenvolvida a partir de dados fisiológicos dos animais (temperatura retal e freqüência respiratória) em função dos dados climáticos do interior das instalações (temperatura e umidade relativa do ar, e índice de temperatura e umidade). O banco de dados foi formado em dois ambientes distintos: clima subtropical (município de São Pedro, SP) e clima mediterrâneo (cidade de Évora, Portugal). Para a formação do banco de dados fisiológicos foram utilizadas vacas Holandesas multíparas, em lactação, selecionadas de acordo com o peso e a produção de leite. As vacas permaneceram durante todo o dia com livre acesso às baias e demais áreas do abrigo, mas sem acesso à pastagem. A temperatura retal foi obtida por um termômetro clínico digital, inserido no reto, e a freqüência respiratória pela contagem dos movimentos da região do flanco, durante 15 s. Para a análise física do ambiente no interior e exterior das instalações utilizou-se de estações meteorológicas, com leituras de temperatura e umidade relativa do ar realizadas a cada 30 min ao longo das 24 horas. No processo inicial de análise dos dados foi u...

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Modelling the productivity of naturalised pasture in the North Island, New Zealand: a decision tree approach

Cited by 26 publications

References 24 publications

Simple models of carbon and nitrogen cycling in New Zealand hill country pastures: exploring impacts of intensification on soil C and N pools

Simple models of carbon and nitrogen cycling in New Zealand hill country pastures: exploring impacts of intensification on soil C and N pools

Data mining to estimate broiler mortality when exposed to heat wave

Sistema inteligente aplicado ao acionamento do sistema de climatização em instalações para bovinos leiteiros

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