J.C.J. Groot

Multiphasic analysis of gas production kinetics for in vitro fermentation of ruminant feeds

Recently developed time-related gas production techniques to quantify the kinetics of ruminant feed fermentation have a high resolution. Consequently, fermentation processes with clearly contrasting gas production kinetics can be identified. Parameterization of the separate processes is possible with a suitable multiphasic model and modelling method. A flexible, empirical, multiphasic model was proposed for parameterization of gas production profiles. This equation was fitted, using a two-step method, to four gas production profiles and the maximum fractional rate of substrate digestion (RM) was calculated for each phase. In the first step, the number of phases and starting values for parameters of the multiphasic model were derived from a combination of either (1) the measured cumulative gas production profile and its first (rate of gas production) and second (change in rate of gas production) derivative or (2) a fitted monophasic curve and the residuals between this curve and the observations. In the second step, the starting values were used to fit di- or triphasic models. Using Approach 1 was complicated by frequent fluctuations in the gas production rate. However, the combined graph of the fitted monophasic curve and residuals (Approach 2) gave good results for every profile. The multiphasic model fitted the profiles well. The robustness of the model declined when the number of phases was increased, underlining the importance of accurate estimations of starting values. It is argued that the model parameters and the calculated RM are useful for feed quality evaluation. The results show that mathematical description of gas production profiles requires a two-step approach and a multiphasic model.

Exploring multifunctional agriculture. A review of conceptual approaches and prospects for an integrative transitional framework

In the last decade the multifunctional agriculture (MFA) concept has emerged as a key notion in scientific and policy debates on the future of agriculture and rural development. Broadly speaking, MFA refers to the fact that agricultural activity beyond its role of producing food and fibre may also have several other functions such as renewable natural resources management, landscape and biodiversity conservation and contribution to the socio-economic viability of rural areas. The use of the concept can be traced to a number of wider societal and political transformation processes, which have influenced scientific and policy approaches in different ways amongst countries and disciplines. This paper critically discusses various existing research approaches to MFA, both from natural and social sciences. To this aim different strands of literature are classified according to their focus on specific governance mechanisms and levels of analysis into four main categories of research approaches (market regulation, land-use approaches, actor-oriented and public regulation approaches). For each category an overview of the state-of-the-art of research is given and an assessment is made of its strengths and weaknesses. The review demonstrates that the multifunctionality concept has attracted a wealth of scientific contributions, which have considerably improved our understanding of key aspects of MFA. At the same time approaches in the four categories have remained fragmented and each has limitations to understand MFA in all its complexity due to inherent constraints of applied conceptualizations and associated disciplinary backgrounds. To go beyond these limitations, we contend, new meta-level frameworks of analysis are to be developed that enable a more integrated approach. The paper concludes by presenting the main lines of an integrative, transitional framework for the study of MFA, which analyses multifunctional agriculture against the background of wider societal change processes towards sustainability and identifies a number of key elements and research challenges for this.

Exploring the potential for improved internal nutrient cycling in dairy farming systems, using an eco-mathematical model

Nutrient management at Dutch dairy farms is changing rapidly from strong reliance on external inputs to more prudent utilization of internal resources. This paper explores opportunities and constraints arising from this shift towards eco-technological management. A mathematical model of inorganic and organic nitrogen (N) flows in a dairy farming system was formulated based on ecological concepts, integrating processes of nutrient input, recycling, immobilization and mineralization. Recycling is defined as the mineralization of N within the year of its incorporation into herbage, which occurs through release from faeces, animal urine and non-harvested biomass. We simulated changes in inorganic and organic N per hectare, and the consequent emission (E), mineralization (M s ) and recycling (R) of N for different initial amounts of inorganic and organic N. Results demonstrate that in the long term, the system evolves to equilibrium amounts of inorganic and organic N, which are strongly determined by the imposed management practices, such as fertilizer input and grassland management. In the short term, moving away from the equilibrium is possible for particular initial amounts of inorganic and organic N. In the equilibrium state, E was reduced by lowering inorganic fertilizer input rate, increasing grassland productivity and improving animal N conversion efficiency, i.e., only by production-related parameters. Only in the short term E was affected by adjustments in quality-related parameters: lower N content, lower digestibility of herbage, reduced degradability of non-harvested biomass and faeces, and parameters determining the functioning of soil biota (degradation rate, efficiency, C/N ratio). Qualityrelated parameters had no effect on internal nutrient cycling in the equilibrium state, because adjustments in M s were completely compensated by changes in R. A comparison of farming systems demonstrated that farming systems can be designed in such a way that improvement of internal nutrient cycling supports the same production with lower inputs and lower emissions.

Bridging the gaps between design and use: developing tools to support environmental management and policy

Abstract Integrated assessment models, decision support systems (DSS) and Geographic Information Systems (GIS) are examples of a growing number of computer-based tools designed to provide decision and information support to people engaged in formulating and implementing environmental policy and management. It is recognised that environmental policy and management users are often not as receptive to using such tools as desired but that little research has been done to uncover and understand the reasons. There is a diverse range of environmental decision and information support tools (DISTs) with uses including organisational and participatory decision support, and scientific research. The different uses and users of DISTs each present particular needs and challenges to the tool developers. The lack of appreciation of the needs of end-users by developers has contributed to the lack of success of many DISTs. Therefore it is important to engage users and other stakeholders in the tool development process to help bridge the gap between design and use. Good practice recommendations for developers to involve users include being clear about the purpose of the tool, working collaboratively with other developers and stakeholders, and building social and scientific credibility.

Composition and digestibility during ageing of Italian ryegrass leaves of consecutive insertion levels

Organic matter digestibility (OMD) is determined from the proportion of indigestible cell wall (ICW) in the total plant organic matter. To improve understanding of processes governing the proportion of ICW, plant morphological development, and leaf composition and digestibility were studied for Italian ryegrass (Lolium multiflorum Lam). Since grass is usually grown in swards, a comparison was made between spaced and sward grown plants. The time course of ICW accumulation in individual leaves on the main stem (MS) could be described by a negative exponential saturation curve. Remarkably, the curvature and the asymptotic ICW as a proportion of total leaf cell wall mass were the same for all leaves in both the spaced and the sward plants. Under both conditions, leaves consecutively formed on the MS had lower cell wall digestibility (CWD) at leaf appearance and lower rate of CWD decline during ageing, which could be explained from the longer period between the estimated start of ICW formation and the moment of leaf appearance. The higher cell wall content for consecutively formed leaves and for leaves of the sward plants enhanced the effect of lower CWD on OMD at leaf appearance, but counteracted the lower CWD decline rate, so that all leaves had the same rate of OMD decline with age. The observed trends clearly demonstrate the close link between morphological development and leaf composition and digestibility.

On the contribution of modelling to multifunctional agriculture: Learning from comparisons

In this paper a set of criteria is proposed for the evaluation of the potential contribution of modelling tools to strengthening the multifunctionality of agriculture. The four main areas of evaluation are (1) policy relevance, (2) the temporal resolution and scope, (3) the degree to which spatial and socio-institutional scales and heterogeneity are addressed and (4) the level of integration in the assessment of scientific dimensions and of the multiple functions of agriculture. The evaluative criteria are applied to the portfolio of modelling approaches developed and applied in a joint project of the French research institute INRA and the Dutch Wageningen University & Research Centre. The CLUE-S model focuses on prediction of changes in multifunctional land-use at regional scale, given a set of predetermined scenarios or policy variants, e.g. for ex-ante policy assessment and initiation of discussions on regional development. The two other modelling approaches are complementary and aim to address multifunctional farming activities. The Landscape IMAGES framework generates a range of static images of possible but sometimes distant futures for multifunctional farming activities in a small region or landscape. It supports the exploration of trade-offs between financial returns from agriculture, landscape quality, nature conservation and restoration, and environmental quality. Co-Viability Analysis generates trajectories of states and farming decisions fulfilling a given set of ecological and productive constraints representing a desired and sustainable future. The three modelling approaches differ in their policy relevance, in the ways that spatial and socio-institutional scales are addressed and in their degree of explicitation of interaction between the various functions of agriculture, but jointly cover most of the desired capabilities for assessment of multifunctionality. Caveats were particularly identified in the integration of the socio-institutional dimension and the related heterogeneity. Although the model portfolio did not completely satisfy the demands of the set of evaluative criteria, it is concluded that, due to their complementarities, in combination the three models could significantly contribute to further development and strengthening of multifunctionality.

Landscape character assessment using region growing techniques in geographical information systems.

Landscape character can be defined as the presence, variety and arrangement of landscape features, which give a landscape a specific identity and make it stand out from surrounding landscapes. Landscape character contributes to the esthetical and perceptional value of an area, which is important for the development of non-production functions in the countryside as demanded by society. In this paper we present a new methodology for landscape character assessment using the pattern of landscape features as stored in a GIS to delineate, characterize and evaluate landscapes using a region growing algorithm. We have applied this methodology in a case study area in the north of The Netherlands and compared the results with a series of expert classifications of the study area. The results of the region growing algorithms were good and interpretable in relation to the underlying data. The resemblance between the expert classification and the classification based on the region growing results varied between 34% and 100% for the different landscape types. The differences between the two data sets can be explained in terms of input data and knowledge about the study area. The classification of the region growing algorithm was more consistent than the expert classification throughout the study area. The presented methodology for landscape character assessment is proposed as support for spatial planning processes and policy development for landscape conservation by providing a quantitative tool to analyze landscape patterns, to discriminate between the various landscapes in a study area and by elucidating features that are important for the identity of a region.

Farm models and economic valuation in the context of multifunctionality: a review of approaches from France, Germany, The Netherlands and Portugal

Multifunctionality of Agriculture (MFA) is a concept that supports the recognition of complex interdependencies between different resources, production processes and outputs of agricultural land use. Political decision making within a sustainable development frame requires extensive information about these interrelationships in order to analyse the impact of implemented policies and to assess future policy effects. This paper presents selected results of the EU FP6 supported MultAgri project, such as a comparative overview of models, techniques and tools that have been applied to the assessment of various agricultural outputs. In detail, multidimensional modelling tools and economic valuation instruments have been inspected and valuated. Examples from France, Germany, The Netherlands and Portugal – the countries reviewed within the MultAgri workpackage 3 – are used to highlight specific instrumental strengths and weaknesses. Conclusions are drawn with respect to further methodological research needs on multifunctionality of agriculture.

Interpretation of results from on-farm experiments: manure-nitrogen recovery on grassland as affected by manure quality and application technique. 1. An agronomic analysis

This article discusses the outcomes of a re-analysis of a grassland experiment, by locating it within the wider institutional context composed of well-established routines used in agronomic research and the dominant epistemological tradition of agricultural sciences. It is argued that both, research routines and epistemological tradition, are strategic pillars of the reigning socio-technical regime. They contribute to path-dependency, thus reinforcing the uni-lateral development tendency centring on technological solutions that fit within the dominating regime. An important, albeit probably unintended consequence is that promising novelties are obscured within and through research, thus blocking a potentially highly effective road towards sustainability.

The role of farmers’ objectives in current farm practices and adaptation preferences: a case study in Flevoland, the Netherlands

Abstract The diversity in farmers’ objectives and responses to external drivers is usually not considered in integrated assessment studies that investigate impacts and adaptation to climate and socio-economic change. Here, we present an approach to assess how farmers’ stated objectives relate to their currently implemented practices and to preferred adaptation options, and we discuss what this implies for assessments of future changes. We based our approach on a combination of multi-criteria decision-making methods. We consistently assessed the importance of farmers’ objectives and adaptation preferences from what farmers say (based on interviews), from what farmers actually do (by analysing current farm performance) and from what farmers want (through a selected alternative farm plan). Our study was performed for six arable farms in Flevoland, a province in the Netherlands. Based on interviews with farmers, we reduced the long list of possible objectives to the most important ones. The objectives we assessed included maximization of economic result and soil organic matter, and minimization of gross margin variance, working hours and nitrogen balance. In our sample, farmers’ stated preferences in objectives were often not fully reflected in realized farming practices. Adaptation preferences of farmers largely resembled their current performance, but generally involved a trend towards stated preferences. Our results suggest that in Flevoland, although farmers do have more objectives, in practical decision-making they focus on economic result maximization, while for strategic decision-making they account for objectives influencing long-term performance and indicators associated with sustainability, in this case soil organic matter.