Assessing the options for upland livestock systems under CAP reform: Developing and applying a livestock systems model within whole-farm systems analysis

This paper presents a scenario-based analysis of the impacts of Common Agricultural Policy (CAP) reform for upland agriculture using a Welsh case-study. Specifically the paper examines the impacts of the introduction of the single-farm payment (SFP), the modulation of direct payments under Pillar I of the CAP and the increase in agri-environment payments under Pillar II. Three enterprises are examined, upland sheep rearing with lamb finishing, spring- and autumn-calving suckler-cattle with calf rearing. These enterprises are modelled under conditions in 2002/3, 2004/5 and for the reformed CAP in 2005/6. To support this analysis a livestock system model (LSM) was implemented. The model assesses alternative management regimen using a flexible state-transition approach. This simplifies the realisation and parameterisation of potentially complex management regimen. The model tracks fodder requirements to achieve targets based on defined diets. The LSM underpins whole-farm analyses of stocking-rates, labour and other resource requirements and net-farm income. From the case study the paper concludes that the impacts of the introduction of the CAP reform on the financial performance of the systems are small but negative (a net reduction of around 5% in support). The larger reduction in direct payments (15–18%) is partially offset by agri-environment measures. The paper concludes that while SFP encourages a more market-oriented outlook, the adaptive capacity within systems as they stand is very limited. There are a range of possible adaptation strategies, but for the uplands the extensification of cattle systems by reducing stock numbers and cutting back on labour seems most probable.     

Towards sustainable farming systems: Effectiveness and deficiency of the French procedure of sustainable agriculture

There is a widespread consensus about the importance of sustainable agriculture. In France, the Farming Orientation Law of July 1999 has set down a precise procedure for the implementation of sustainable agriculture: the contrat territorial d’exploitation – or territorial farm contract (TFC). This paper aims to analyse the TFC effectiveness. An analysis has been made of the TFCs signed in the Midi-Pyrenees Region in south-western France, using statistical analysis and qualitative surveys of a sample of farms. The results show that the most valuable effects have been mainly economic. Effects regarding social and environmental aspects were very limited. But from the point of view of an integrated approach, indirect effects of TFCs can be observed on social and environmental aspects. These results are explained, on the one hand, by farmers’ motivations guided by economic objectives, and on the other hand, by the dominance of professional farming organisations in the implementation of TFC’s procedure. Given these results, two ways of improving the elaboration procedure for TFCs are proposed. Firstly, technical improvements can be made to the diagnostic assessment of farms, and to the choice of actions addressed by the contract. Secondly, organisational improvements can be applied to TFCs elaboration and implementation process, in order to adopt a participatory approach which would involve all rural stakeholders.     

Hydraulic-hydrological simulations of canal-command for irrigation water management

A modelling system that combines the hydraulic simulations of the canal and hydrological simulations of the irrigated command is introduced. It uses MIKE 11 and MIKE SHE, two well-established modelling systems, for the hydraulic and hydrological simulations respectively. In addition, it also has an irrigation scheduling module and a crop growth module. The modelling system is applied to the Mahanadi Reservoir Irrigation Scheme, a large irrigation project in Central India. The results show that presently a significant amount of water is wasted in the command during the monsoon season. It is demonstrated that the minimization of this wastage could lead to a substantial crop production in the subsequent dry season. Furthermore, the simulations illustrate the versatility of the modelling system for planning and analysing the various aspects of an irrigation project.     

我国植保机械及施药技术现状与发展趋势

阐述了我国植保机械及施药技术的现状,分析了我国施药技术中存在的问题以及与国外植保机械发展水平的差距,并提出了发展趋势。     

From on-farm solid-set sprinkler irrigation design to collective irrigation network design in windy areas

In this paper, a contribution to the design of collective pressurised irrigation networks in solid-set sprinkler-irrigated windy areas is presented. The methodology is based on guaranteeing minimum on-farm performance, using a historical hourly wind speed database and a ballistic solid-set irrigation simulation model. The proposed method was applied to the Montesnegros Irrigation District (central Ebro basin, Spain). The district irrigates an area of 3493 ha using an on-demand schedule. The average wind speed in the area is 2.8 m s⁻¹. An analysis of district water records showed that farmers often reduce water demand when the wind speed is high, but their irrigation decision making is limited by the capacity of the irrigation network and by the unpredictable character of local winds. Simulations were performed for 11 irrigation seasons, 2 triangular sprinkler spacings (18 m × 18 m and 18 m × 15 m), and 2 sprinkler models. The percentage of monthly suitable time for irrigation was determined for four management strategies. The first one was based on a wind speed threshold (3 m s⁻¹), while the other three were based on three levels (standard, relaxed and restrictive) of two irrigation performance parameters: the Christiansen Uniformity Coefficient (CU) and the Wind Drift and Evaporation Losses (WDEL). The standard strategy classified the time as suitable for irrigation when CU ≥ 84% and WDEL ≤ 20%. The thresholds limits of the irrigation parameters for the relaxed strategy were CU ≥ 80% and WDEL ≤ 25%. Finally, the restrictive strategy used thresholds of CU ≥ 90% and WDEL ≤ 15%. The suitable time for the first strategy (56%) was always lower than for the standard and the relaxed strategies (with respective average values of 75 and 86%), and higher than for the restrictive strategy (30%). In order to design the collective network, the hydrant operating time was equalled to the suitable time for irrigation. The differences in the cost of the collective network plus the on-farm equipment were particularly relevant between the restrictive strategy and the other three. Differences in suitable operating time were clear between sprinkler spacings, and less evident between sprinkler models. The application of the proposed methodology may be limited by the availability of historical wind speed records and CU estimates for different combinations of sprinkler models, sprinkler spacings and wind speed.     

Suitability of Multi-Agent Simulations to study irrigated system viability: application to case studies in the Senegal River Valley

It is assumed that Agent-Based Modeling is a useful technique for water management issues. In particular, it may provide a suitable framework for representing irrigated systems. The objective of this paper is to demonstrate its potential for a specific use: research on irrigated systems’ viability in the Senegal River Valley. The main assumption to be verified is that Multi-Agent Systems constitute a suitable architecture to study theoretically irrigated systems’ viability using simulations. By using Multi-Agent Systems, virtual irrigated systems can be designed that might then be used as virtual laboratories. These virtual labs constitute an alternative when real labs cannot exist for some reason.

In this paper we report on experiments we have conducted using such virtual labs for exploring an Agent-Based Model through the simulation of scenarios. A scenario is defined as a triplet: an environment, a set of individual rules, a set of collective rules. It is evaluated according to the longevity of the irrigated system. An index is defined, based on the ratio of long-enduring simulations among a set of repetitions of a given scenario. Even if simulation results display significant diversity for a given scenario due to random factors in the processes simulated, the ratio of long-enduring simulations is repeatable. This entails to explore the overall behavior of the virtual irrigated system and to build theories concerning the viability of Senegalese irrigated systems. An example is given showing the need for strong coherence for a given environment among individual rules and collective rules.     

三阶开环控制系统根轨迹图形的研判

利用根轨迹极坐标方程对三阶系统根轨迹进行了研究，得出了三阶系统根轨迹的基本图形为双曲线的结论，并对图形的各种具体情况进行了进一步的讨论。     

大田作物非充分灌溉实施效果分析评价

将现有非充分灌溉技术研究成果应用于大田作物中,从作物耗水量、单产、产量要素、水分生产率、节水量与总效益等方面进行了综合评价。结果表明,与充分灌溉相比,非充分灌溉(Ⅰ)节水增效显著,非充分灌溉(Ⅱ)总产量或总效益下降较大,实际应用中应把握好非充分灌溉度的问题。     

Agricultural practice changes with cultivating genetically modified herbicide-tolerant oilseed rape

To facilitate weed suppression, oilseed rape or canola (Brassica napus) has been genetically modified (GM) over the last two decades to incorporate herbicide tolerance (HT). The introduction of oilseed rape in commercial agriculture raises concerns about potential adverse agronomic and environmental effects linked to both the genetic modification and altered agricultural practice. How will this new crop modify the existing cropping practice? What are the potential agro-environmental implications of its introduction? This paper analyses and schematises recorded and conceivable agricultural practice changes with GMHT oilseed rape introduction and its likely agro-environmental effects. It develops a conceptual systematics of influencing factors, subsequent practice changes and likely agro-environmental effects. The results can be used to design the mandatory monitoring of adverse GM crop effects.     

杨凌区降雨对作物生长适应性的模糊分析

依据模糊数学理论 ,采用模糊综合评判方法 ,从降雨“适量”、“适时”和“有效程度”3个指标出发 ,就杨凌区降水资源对农作物生长发育适应性做了评价分析 ,并提出降雨对作物生长的适宜度模型。通过实地调查与计算分析 ,该模型较好地反映了杨凌区主要作物对该区降雨特征的适宜能力 ,同时也较好地反映了本区降雨资源的地域特征 ,为该地区农作物合理布局决策提供了科学依据