Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Cash-Based Versus Water-Based Payment for Environmental Services in the Uplands of Northern Vietnam : Potential Farmers' Participation Using Farm Modeling
Jourdain, D. ; Boere, E. ; Berg, M. van den; Dinh Quang, D. ; Phuc Thanh, C. ; Affholder, F. - \ 2016
In: Upland Natural Resources and Social Ecological Systems in Northern Vietnam Elsevier Inc. Academic Press - ISBN 9780128054536 - p. 43 - 62.
Payment for environmental services - Poverty alleviation - Swidden agriculture - Terraces - Vietnam - Whole farm modeling
The forested areas of northern Vietnam, mostly located in mountainous areas, have important watershed regulating functions. However, current land-use changes pose a threat to the continuing provision of environmental services. This chapter investigates two alternative payment for environmental services (PES) programs tailored to reestablish natural or productive forests in the uplands of northern Vietnam: "Payments for Forest" (PFF) and "Terraces for Forest" (TFF). Both programs involve setting aside sloping land for reforestation but they differ in the type and amount of compensation offered. PFF offers annual payments per area of retired land. TFF offers to convert a certain amount of the current sloping land into a terraced area, combined with annual payments per area of retired land. The main objective of the chapter is to compare the two types of programs in terms of potential participation (what type of farmers will likely participate?), and what impact it would have on their revenues. Using mathematical programming, we developed a set of farm models corresponding to typical farms of a mountainous district of northern Vietnam. We simulated the level of participation of different types of farms for the two types of PES programs. For each specific PES, we analyzed participation, measured by the area of land converted into forest land and its impacts on land use and household revenues. Results show that, given the assumptions of the models, increasing access to irrigated terraces as a way to compensate for land conversion to forest increases the participation of the poorest farmers. Therefore, our research suggests that PES schemes, when fine-tuned to a Southeast Asian context, may not only be used as a way to restore ecosystem services but also as a way to alleviate poverty.
Cotton as an entry point for soil fertility maintenance and food crop productivity in savannah agroecosystems - Evidence from a long-term experiment in southern Mali
Ripoche, A. ; Crétenet, M. ; Corbeels, M. ; Affholder, F. ; Naudin, K. ; Sissoko, F. ; Douzet, J.M. ; Tittonell, P.A. - \ 2015
Field Crops Research 177 (2015). - ISSN 0378-4290 - p. 37 - 48.
organic-matter - nitrogen-fertilization - chemical-properties - nutrient dynamics - semiarid tropics - use efficiency - pearl-millet - burkina-faso - dry-matter - management
Given the scarcity of manure and the limited land available for fallowing, cotton cultivation with its input credit schemes is often the main entry point for nutrients in cropping systems of West Africa. In an experiment carried out during 25 years in southern Mali, the crop and soil responses to organic fertilizer (=OF), inorganic fertilizer (=IF), and a combination of both (=OIF) were quantified and compared to a control treatment for a typical cotton-sorghum-groundnut rotation. From 1965 to 1979 (15 years, period 1), fertilizers were only applied on cotton and the control treatment was not fertilized. From 1980 to 1989 (10 years, period 2), the amount of manure applied was split between cotton and sorghum, and inorganic fertilizers were applied to the three crops. Inorganic fertilizers were also applied to plots with cotton and sorghum that were previously unfertilized control treatments. In favorable rainfall seasons maximum yields of fertilized treatments reached ca. 3.5 t ha-1 in the case of cotton and groundnuts, and ca. 2 t ha-1 in the case of sorghum. During period 1, cotton yields were steady (ca. 1 t ha-1) when no fertilizers were added. Cotton yields were 20% higher in the OF and OIF treatments than in the IF treatment. Sorghum and groundnut benefited from residual effects of fertilizer application on cotton leading to a 200% and 50% yield increase respectively compared to the control treatment. During period 2, yields of the three crops were similar across fertilized treatments. Groundnut yields in the OF treatment, and cotton yields in the OF and IF treatments were respectively 45%, 30% and 20% significantly higher than those in the respective control treatments. No added benefit on crop yields was observed from the combined use of inorganic and organic fertilizer. Soil nutrient contents (SOC, N, P, K) did not significantly change in any of the treatments after 25 years. Soil pH decreased in treatments receiving inorganic fertilizer. Despite low level of soil organic matter, crops responded to organic or inorganic fertilization and crop productivity over time was mostly influenced by the interaction between fertilization and rainfall variability. Our results highlight the role of cotton in West African landscapes as an entry point of nutrients via fertilization, which impacts positively on the productivity of the other crops in the rotation. Credit schemes by the cotton company for farmers to purchase fertilizer to which they would otherwise not have access are thus crucial for sustained crop productivity.
Water for forests to restore environmental services and alleviate poverty in Vietnam: a farm modeling approach to analyze alternative PES programs
Damien, J. ; Boere, E.J.M. ; Berg, M.M. van den; Dang, D. ; Cu, T.P. ; Affholder, F. ; Pandey, S. - \ 2014
Land Use Policy 41 (2014). - ISSN 0264-8377 - p. 423 - 437.
sustainable land-use - ecosystem services - southeast-asia - agricultural intensification - payments - impact - issues - deforestation - technologies - population
Most forested areas in South East Asia are located in mountainous areas, where they are reservoirs of biodiversity and have important watershed regulating functions. However, the continuing provision of these environmental services may be jeopardized by land use changes. To re-establish natural or productive forests, programs are being proposed in which participating farmers can set aside some of their cultivated sloping land and receive payment for maintaining the newly forested land. This paper compares two types of payments for ecosystems services (or PES)-type programs designed to favor reforestation by farming households: “Payments for forests” (PFF) and “Terraces for forests” (TFF). Both programs involve setting aside sloping land for reforestation but differ in the type and amount of compensation offered. PFF offers annual payments per area of retired land. TFF offers to cover the cost of converting a certain amount of a farm's sloping land into terraces, combined with annual payments per unit area of retired land. The main objective of the paper is to compare the two types of programs in terms of cost-efficiency – can we get the same amount of forest at lower cost? – and equity – will the poorest farmers participate? Using mathematical programming, we developed a set of farm models corresponding to typical farms in a mountainous district in Northern Vietnam. We simulated participation rates of different types of farms in the two types of PES programs. For each PES, we assessed the amount of land converted into forest, the cost of the program, and its impacts on land use and household revenues, at individual farm and village level. Results of our simulations showed that increasing access to irrigated terraces as a way of compensating for converting land to forest increased the participation of the poorest farmers and was more cost efficient than pure cash payments. This suggests that existing PFF programs are biased against the smallest landholders in the region whereas they could be transformed into win–win programs likely to increase forested areas and reduce inequalities among farm households. Our paper demonstrates that PES schemes, when fine-tuned to the South East Asian context, could not only be used to restore ecosystem services, but also to alleviate poverty.
The yield gap of major food crops in family agriculture in the tropics: Assessment and analysis through field surveys and modelling
Affholder, F. ; Poeydebat, C. ; Corbeels, M. ; Scopel, E. ; Tittonell, P.A. - \ 2013
Field Crops Research 143 (2013). - ISSN 0378-4290 - p. 106 - 118.
pennisetum-typhoides s - tillering pearl-millet - nitrogen balances - simulating growth - central brazil - generic model - northern laos - burkina-faso - grain-yield - water-use
Yield gaps of major food crops are wide under rainfed family agriculture in the tropics. Their magnitude and causes vary substantially across agro-ecological, demographic and market situations. Methods to assess yield gaps should cope with spatio-temporal variability of bio-physical conditions, management practices, and data scarcity under smallholder conditions. Particularly challenging is to determine the most relevant methods for estimating potential (Yp) and water-limited (Yw) yields against which actual yields (Ya) are compared. We assessed yield gaps of main staple rainfed crops across contrasting family farming systems in Senegal (millet, subsistence oriented systems), central Brazil (maize, market oriented systems) and Vietnam (maize, market oriented systems and upland rice, subsistence oriented systems). In each region, actual aboveground biomass, Ya and yield components were measured over 2–3 agricultural seasons in a network of farmers’ fields, covering the diversity of soils and farmers’ management practices. Yp and Yw were calculated using a simple ad hoc crop simulation model (potential yield estimator, PYE) that was calibrated for each situation with observed and secondary data. Maize yields measured on farmers’ fields were on average relatively high in market oriented systems, but extremely variable (4.14 ± 1.72 Mg ha-1). In contrast yields of crops of subsistence oriented systems were very low (0.80 ± 0.54 Mg ha-1 and 0.80 ± 0.47 Mg ha-1 for millet and upland rice, respectively). Ya - Yp was 0.15 for millet in Senegal, 0.33 for upland rice in Vietnam, 0.26 for maize in Vietnam, and 0.46 for maize in Brazil. In Vietnam, there was little difference between Yw and Yp suggesting a low incidence of water constraints. The gap between Ya and Yw was equal to (millet in Senegal) or twice (maize in Vietnam and Brazil) the difference between Yw and Yp, indicating that yield gaps depend strongly on factors other than global radiation, temperature, rainfall and soil water holding capacity. Previous studies in the case study areas showed that the main causes of yield gaps were poor soil fertility and weed infestation related to the inability of farmers to access chemical inputs. Simple methods to estimate Yw and Yp, such as the values at the 90th percentile of Ya, or a bilinear boundary function fitted between seasonal rainfall and the best farmers’ yield both led to strongly underestimated yield gaps. Yw and Yp estimated with a crop simulation model appeared to be more accurate, even in situations of relative scarcity of field data to calibrate cultivar-specific model parameters.
Can more irrigation help in restoring environmental services provided by upper catchments? A case study in the Northern Mountains of Vietnam
Jourdain, D. ; Boere, E.J.M. ; Berg, M.M. van den; Dinh Quang, D. ; Phuc Thanh, C. ; Affholder, F. - \ 2012
In: Conservation Agriculture and Sustainable Upland Livelihoods: Innovations for, with and by Farmers to Adapt to Local and Global Changes, Hanoi, Vietnam, 10 - 15 December, 2012. - Hanoi : CIRAD - ISBN 9782876146877 - p. 161 - 163.
Ad hoc modeling in agronomy: What have we learned in the last 15 years?
Affholder, F. ; Tittonell, P.A. ; Corbeels, M. ; Roux, S. ; Motisi, N. ; Tixier, P. ; Wery, J. - \ 2012
Agronomy Journal 104 (2012)3. - ISSN 0002-1962 - p. 735 - 748.
systems simulation-model - crop growth simulation - soil-water deficit - agricultural systems - environmental-models - maize production - decision-making - carbon-dioxide - use efficiency - climatic risk
The “Use and Abuse of Crop Simulation Models” special issue of Agronomy Journal published in 1996 ended with the myth of the universal crop model. Sinclair and Seligman consequently recommended tailoring models to specific problems. This paper reviews the fate of the idea of such ad hoc approaches to crop simulation modeling during the past 15 yr. Most crop modelers have since adhered to the principles formulated by Sinclair and Seligman, but yet their practice faces two major issues: (i) how to define the structure of the model as depending on the question to be addressed (model conceptualization) and (ii) how to minimize efforts in software development (model computerization). Progress in model conceptualization as reported in the literature concerns (i) inferring a conceptual model from what is known of the problem to address, (ii) deriving summary models from comprehensive ones, and (iii) using multivariate methods to analyze the hierarchy of drivers of variability in the variable to be predicted. Considerable effort has been invested in the development of frameworks to facilitate model computerization, and the commercial modeling software is constantly improving. But there are limits in the flexibility permitted by these tools. Acquiring basic skills in coding a model using a scientific programming language is preferred by scientists wishing to keep the fullest understanding and control on their crop models. Connecting the model to commercial database software may facilitate this strategy. However, the computerization issue may still lead to tensions between modeling teams concerning the legitimacy to develop their own model.
A research agenda to explore the role of conservation agriculture in African smallholder farming systems
Giller, K.E. ; Corbeels, M. ; Nyamangara, J. ; Triomphe, B. ; Affholder, F. ; Scopel, E. ; Tittonell, P.A. - \ 2011
Field Crops Research 124 (2011)3. - ISSN 0378-4290 - p. 468 - 472.
western kenya - soil-erosion - cover crops - no-tillage - emissions - residues - brazil - shift
Controversy surrounds the promotion of conservation agriculture (CA) in smallholder farming systems in sub-Saharan Africa. The introduction of CA is a profound change in farm management. Benefits in reduced erosion and stabilized crop production may be obtained, but technical performance at field level is but one of the determinants of adoption. For various reasons, all of the CA principles are not always fully implemented by farmers and results not as favourable as expected. As with other approaches to increasing agricultural productivity, the production constraints, farmers’ objectives, and the expected benefits and costs of implementing CA are important aspects that influence adoption. At farm and village levels, trade-offs in the allocation of resources become important in determining how CA may fit into a given farming system. At a regional level, factors such as the market conditions, interactions among stakeholders and other institutional and political dimensions become important. At each level, opportunities or difficulties emerge that enhance or impede development, adaptation and adoption of CA. The ex-ante identification of situations for where CA (and which form of CA) is appropriate demands research from a multi-stakeholder, multi-level, and interdisciplinary perspective. Recommendations are made where research is required to address key knowledge gaps
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