DairyMod and EcoMod: biophysical pasture-simulation models for Australia and New Zealand

2008 ◽  
Vol 48 (5) ◽  
pp. 621 ◽  
Author(s):  
I. R. Johnson ◽  
D. F. Chapman ◽  
V. O. Snow ◽  
R. J. Eckard ◽  
A. J. Parsons ◽  
...  
Keyword(s):  
New Zealand ◽  
Nutrient Dynamics ◽  
Irrigation Management ◽  
Management Strategies ◽  
Simulation Models ◽  
Nutrient Status ◽  
Pasture Management ◽  
Management Options ◽  
Recent Developments ◽  
Fertiliser Application

DairyMod and EcoMod, which are biophysical pasture-simulation models for Australian and New Zealand grazing systems, are described. Each model has a common underlying biophysical structure, with the main differences being in their available management options. The third model in this group is the SGS Pasture Model, which has been previously described, and these models are referred to collectively as ‘the model’. The model includes modules for pasture growth and utilisation by grazing animals, water and nutrient dynamics, animal physiology and production and a range of options for pasture management, irrigation and fertiliser application. Up to 100 independent paddocks can be defined to represent spatial variation within a notional farm. Paddocks can have different soil types, nutrient status, pasture species, fertiliser and irrigation management, but are subject to the same weather. Management options include commonly used rotational grazing management strategies and continuous grazing with fixed or variable stock numbers. A cutting regime simulates calculation of seasonal pasture growth rates. The focus of the present paper is on recent developments to the management routines and nutrient dynamics, including organic matter, inorganic nutrients, leaching and gaseous nitrogen losses, and greenhouse gases. Some model applications are presented and the role of the model in research projects is discussed.

Systemic modelling of soil functions under the impact of agricultural management

2020 ◽  
Author(s):  
Sara König ◽  
Ulrich Weller ◽  
Birgit Lang ◽  
Mareike Ließ ◽  
Stefanie Mayer ◽  
...  
Keyword(s):  
Soil Structure ◽  
Water Distribution ◽  
Management Strategies ◽  
Simulation Models ◽  
Crop Growth ◽  
Soil Productivity ◽  
Soil Functions ◽  
Management Options ◽  
Soil Organic Matter Turnover ◽  
The Impact

<p>The increasing demand for food and bio-energy gives need to optimize soil productivity, while securing other soil functions such as nutrient cycling and buffer capacity, carbon storage, biological activity, and water filter and storage. Mechanistic simulation models are an essential tool to fully understand and predict the complex interactions between physical, biological and chemical processes of soil with those functions, as well as the feedbacks between these functions.</p><p>We developed a systemic soil model to simulate the impact of different management options and changing climate on the named soil functions by integrating them within a simplified system. The model operates on a 1d soil profile consisting of dynamic nodes, which may represent the different soil horizons, and integrates different processes including dynamic water distribution, soil organic matter turnover, crop growth, nitrogen cycling, and root growth.</p><p>We present the main features of our model by simulating crop growth under various climatic scenarios on different soil types including management strategies affecting the soil structure. We show the relevance of soil structure for the main soil functions and discuss different model outcome variables as possible measures for these functions.</p><p>Further, we discuss ongoing model extensions, especially regarding the integration of biological processes, and possible applications.</p>

Simulation of legume-cereal systems using APSIM

1998 ◽  
Vol 49 (3) ◽  
pp. 317 ◽  
Author(s):  
M. E. Probert ◽  
P. S. Carberry ◽  
R. L. McCown ◽  
J. E. Turpin
Keyword(s):  
Cropping Systems ◽  
Management Strategies ◽  
Simulation Models ◽  
Cereal Crops ◽  
Status Report ◽  
Management Options ◽  
Modelling Framework ◽  
Stylosanthes Hamata ◽  
Scenario Analyses ◽  
Simulation Scenario

A major issue for the sustainability of cropping systems is the maintenance of soil fertility and especially the supply of nitrogen to cereal crops. Choice of appropriate management strategies, including the role of legumes, is problematic, especially where climatic variation is large. Simulation models provide the means of extrapolation from the site- and season-specific bounds of experimental data to permit scenario analyses that can explore alternative management options. This paper is a status report on the capabilities of the APSIM modelling framework to simulate legume-cereal systems. APSIM deals with water and nitrogen constraints to crop growth and is well suited to the task of modelling whole systems involving crop rotations. The components that are not yet fully developed are modules for growing the legume crops and coupling these with the module describing the dynamics of soil organic matter to obtain sensible predictions of nitrogen supply to subsequent crops. Evidence is provided that those parts of the system that can be represented by current APSIM modules are predicted satisfactorily. The closest approach to a whole system that has been simulated to date is grass or legume (Stylosanthes hamata cv. Verano) leys followed by crops of maize or sorghum grown in experiments at Katherine, NT. Predictions of the yields of the leys and the cereal crops, especially the benefit from the legume leys to a second crop, were sufficiently close to measured yields to suggest that there are good prospects for developing useful models of other systems involving legumes and cereals. A simulation scenario exploring a chickpea-wheat system demonstrates how models can be used to analyse both productivity and sustainability aspects of the system.

scholarly journals PREVISÃO DA PRODUÇÃO DE MILHO SUBMETIDO A DIFERENTES NÍVEIS DE MANEJO DE IRRIGAÇÃO VIA MODELO DE SIMULAÇÃO

Irriga ◽  
1998 ◽  
Vol 3 (2) ◽  
pp. 36-47
Author(s):  
Marcia Xavier Peiter ◽  
Fazal Hussain Chaudhry
Keyword(s):  
Agricultural Production ◽  
Water Status ◽  
Irrigation Management ◽  
Management Strategies ◽  
Simulation Models ◽  
Growth And Yield ◽  
Corn Yield ◽  
Yield Model ◽  
Area Index ◽  
Plant Available Water

PREVISÃO DA PRODUÇÃO DE MILHO SUBMETIDO A DIFERENTES NÍVEIS DE MANEJO DE IRRIGAÇÃO VIA MODELO DE SIMULAÇÃO[1]  Marcia Xavier PeiterCurso de Engenharia Agrícola - Universidade Regional do Alto Uruguai e Missões - URI Campus Santiago - Tel.(055)251-1715 - Rua 20 de setembro, 2410 - Santiago, RSFazal Hussain ChaudhryDepartamento de Hidráulica e Saneamento - Escola de Engenharia de São Carlos - USPTel.(016)274-3444 - Av. Dr. Carlos Botelho, 1465 - São Carlos, SP  1 RESUMO O advento de modelos simuladores de crescimento e produção de culturas agrícolas vem permitir que as quantidades de água aplicadas e o momento de rega possam ser testados com significativas reduções de custo, tempo e mão-de-obra, além do que, a estimativa da produção não é influenciada por eventuais fatores externos, alheios ao tratamento aplicado. Desta forma, o presente trabalho tem como objetivo a avaliação, calibração e validação de um modelo de simulação de produção para a cultura do milho quando submetido a diferentes níveis de irrigação, a fim de disponibilizar uma ferramenta que permita a análise desta cultura com maior rapidez e redução de custos. Para a validação do modelo, a cultivar de milho Pioneer 3069 foi submetida a quatro níveis de manejo de irrigação com três repetições em um conjunto de lisímetros de drenagem. Procedeu-se as irrigações sempre que a fração de água disponível fosse igual ou inferior a 0,90; 0,75; 0,60 e 0,45. Através dos resultados obtido, pode-se concluir que o modelo de simulação apresenta uma aceitável estrutura de rotinas para previsão da produção de massa seca total de milho quando a cultura é submetida a diferentes níveis de manejo de rega. Desta forma, o modelo pode ser utilizado para a avaliação das conseqüências produtivas e econômicas de diferentes estratégias de irrigação. UNITERMOS: Simulação, milho, manejo de irrigação  PEITER, M.X., CHAUDHRY, F.H. Corn yield predicted when submitted to different irrigation management levels by simulation model  2 ABSTRACT The advent of simulation models for growth and yield of crops makes it possible to test the influence of irrigation depths and their timings on the economy of agricultural production. This paper calibrates and validates a corn yield model for different irrigation management strategies to obtain a tool for rapid analysis of crop response without having to conduct repeated experiments. Thus, the corn cultivar Pioneer 3069 was submitted to four irrigation management levels with three replications in a number of drainage lysimiters. Irrigations were applied when the plant available water reaches 0,90; 0,75; 0,60 and 0,45. The results show that the calibrated model has an acceptable conceptual structure of computational routines to predict corn dry matter when the crop is irrigated according to different management levels. It is concluded further that the model is capable of predicting correctly the temporal variation of the observed leaf area index and soil water status. KEY-WORDS: Simulation, corn, irrigation management 

scholarly journals Weed Management in New Zealand Pastures

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 448 ◽  
Author(s):  
Hossein Ghanizadeh ◽  
Kerry C. Harrington
Keyword(s):  
New Zealand ◽  
Weed Management ◽  
Management Strategies ◽  
Cost Effective ◽  
Integrated Weed Management ◽  
Meat Production ◽  
Weed Species ◽  
Pasture Management ◽  
Pasture Production ◽  
Important Approach

In New Zealand, pastoral farming for dairy and meat production is the major land use. As with any agricultural production system, weeds are a threat to efficient pasture production in New Zealand. In this review, we outline the problems caused by weeds in New Zealand pastures, and the management strategies being used to control them. There are currently 245 plant species from 40 plant families that are considered to be troublesome weeds in New Zealand pastures. The application of herbicides is an important approach to manage weeds in New Zealand pastures; however, a key to the success of these pastures is the use of clovers in combination with the grasses, so the challenge is to find herbicides that selectively control weeds without damaging these legumes. The use of spot spraying and weed wiping are often required to ensure selective control of some weed species in these pastures. Non-chemical agronomic approaches such as grazing management and using competitive pasture species often play a more important role than herbicides for weed management in many New Zealand pastures. Thus, integrated weed management using a combination of herbicides and good pasture management strategies leads to the most cost-effective and efficient control of pasture weeds in New Zealand.

Addressing on-farm management to enhance pasture productivity and persistence

2013 ◽  
pp. 241-244
Author(s):  
W.N. Reynolds
Keyword(s):  
Management Strategies ◽  
Dairy Farm ◽  
Stocking Rate ◽  
Pasture Management ◽  
Pasture Production ◽  
Operating Profit ◽  
The North ◽  
The Cost ◽  
On Farm ◽  
Attention To Detail

Following the 2007/08 drought, we experienced poor pasture production and persistence on our dairy farm in north Waikato, leading to decreased milksolids production and a greater reliance on bought-in feed. It is estimated that the cost of this to our farming operation was about $1300 per hectare per year in lost operating profit. While climate and black beetle were factors, they did not explain everything, and other factors were also involved. In the last 3 years we have changed our management strategies to better withstand dry summers, the catalyst for which was becoming the DairyNZ Pasture Improvement Focus Farm for the north Waikato. The major changes we made were to reduce stocking rate, actively manage pastures in summer to reduce over-grazing, and pay more attention to detail in our pasture renewal programme. To date the result has been a reduced need for pasture renewal, a lift in whole farm performance and increased profitability. Keywords: Focus farm, over-grazing, pasture management, pasture persistence, profitability

Near infrared spectroscopy of Eucalyptus pellita for foliar nutrients and the potential for real-time monitoring of trees in fertiliser trial plots

2021 ◽  
pp. 096703352110079
Author(s):  
Agustan Alwi ◽  
Roger Meder ◽  
Yani Japarudin ◽  
Hazandy A Hamid ◽  
Ruzana Sanusi ◽  
...  
Keyword(s):  
Near Infrared ◽  
Acacia Mangium ◽  
Nir Spectroscopy ◽  
Nutrient Status ◽  
Significant Loss ◽  
Eucalyptus Pellita ◽  
Operational Decision Making ◽  
Fertiliser Application ◽  
Planting Distance

Eucalyptus pellita F. Muell. has become an important tree species in the forest plantations of SE Asia, and in Malaysian Borneo in particular, to replace thousands of hectares of Acacia mangium Willd. which has suffered significant loss caused by Ceratocystis manginecans infection in Sabah, Malaysia. Since its first introduction at a commercial scale in 2012, E. pellita has been planted in many areas in the region. The species replacement requires new silvicultural practices to induce the adaptability of E. pellita to grow in the region and this includes relevant research to optimise such regimes as planting distance, pruning, weeding practices and nutrition regimes. In this present study, the nutritional status of the foliage was investigated with the aim to develop near infrared spectroscopic calibrations that can be used to monitor and quantify nutrient status, particularly total foliar nitrogen (N) and phosphorus (P) in the field. Spectra acquired on fresh foliage in situ on the tree could be used to predict N and P with accuracy suitable for operational decision-making regards fertiliser application. If greater accuracy is required, spectra acquired on dry, milled foliage could be used to predict N and P within a relative error of 10% (R2c, r2CV, RMSEP, RPD = 0.77, 0.71, 0.02 g 100/g, 1.9 for foliar P and = 0.90, 0.88, 0.21 g 100/g, 3.0 for foliar N on dry, milled foliage). The ultimate application of this is in situ nutrient monitoring, particularly to aid longitudinal studies in fertiliser trial plots and forest operations, as the non-destructive nature of NIR spectroscopy would enable regular monitoring of individual leaves over time without the need to destructively sample them. This would aid the temporal and spatial analysis of field data.

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