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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Using yield gap analysis to give sustainable intensification local meaning
Silva, João Vasco - \ 2017
University. Promotor(en): Martin van Ittersum, co-promotor(en): Ken Giller; Pytrik Reidsma. - Wageningen : Wageningen University - ISBN 9789463437141 - 361
crops - yields - crop yield - modeling - simulation models - cereals - farming systems - yield losses - gewassen - opbrengsten - gewasopbrengst - modelleren - simulatiemodellen - graansoorten - bedrijfssystemen - oogstverliezen

Yield gap analysis is useful to understand the relative contribution of growth-defining, -limiting and -reducing factors to actual yields. This is traditionally performed at the field level using mechanistic crop growth simulation models, and directly up-scaled to the regional and global levels without considering a range of factors intersecting at farm and farming system levels. As an example, these may include farmers' objectives and resource constraints, farm(er) characteristics, rotational effects between subsequent crops or decisions on resource allocation and prioritization of crop management. The objective of this thesis is to gain insights into yield gaps from a farm(ing) systems perspective in order to identify opportunities for sustainable intensification at local level.

Three contrasting case studies representing a gradient of intensification and capturing a diversity of agricultural systems were selected for this purpose, namely mixed crop-livestock systems in Southern Ethiopia, rice based-farming systems in Central Luzon (Philippines) and arable farming systems in the Netherlands. A theoretical framework combining concepts of production ecology and methods of frontier analysis was developed to decompose yield gaps into efficiency, resource and technology yield gaps. This framework was applied and tested for the major crops in each case study using crop-specific input-output data for a large number of individual farms. In addition, different statistical methods and data analyses techniques were used in each case study to understand the contribution of farmers' objectives, farm(er) characteristics, cropping frequency and resource constraints to yield gaps and management practices at crop level.

Yield gaps were largest for maize and wheat in Southern Ethiopia (ca. 80\\\\% of the water-limited yield), intermediate for rice in Central Luzon (ca. 50\\\\% of the climatic potential yield) and smallest for the major arable crops in the Netherlands (ca. 30\\\\% of the climatic potential yield). The underlying causes of these yield gaps also differed per case study. The technology yield gap explained most of the yield gap observed in Southern Ethiopia, which points to a lack of adoption of technologies able to reach the water-limited yield. The efficiency yield gap was most important for different arable crops in the Netherlands, which suggests a sub-optimal timing, space and form of the inputs applied. The three intermediate yield gaps contributed similarly to the rice yield gap in Central Luzon meaning that sub-optimal quantities of inputs used are as important in this case study as the causes mentioned for the other case studies.

Narrowing the yield gap of the major crops does not seem to entail trade-offs with gross margin per unit land in each case study. However, the opposite seems to be true for N use efficiency and labour productivity particularly in Southern Ethiopia and Central Luzon, and to a less extent in the Netherlands. This means that (sustainable) intensification of smallholder agriculture in the tropics needs to go hand-in-hand with agronomic interventions that increase land productivity while ensuring high resource use efficiency and with labour-saving technologies that can reduce the drudgery of farming without compromising crop yields.

Other insights at farm(ing) system level were clearer in Southern Ethiopia than in Central Luzon or in the Netherlands. For example, alleviating capital constraints was positively associated with intensification of maize-based farming systems around Hawassa and increases in oxen ownership (an indicator of farm power) was associated with extensification of wheat-based farming systems around Asella. In Central Luzon, farm and regional factors did not lead to different levels of intensification within the variation of rice farms investigated and the most striking effect was that direct-seeding (and thus slightly lower rice yields) was mostly adopted in larger farms, and used lower amounts of hired labour, compared to transplanting. In the Netherlands, the analysis of rotational effects on crop yields provided inconclusive results but confounding effects with e.g. rented land do not allow to conclude that these are not at stake in this farming system.

This thesis broadens the discussion on yield gaps by moving from the technical aspects underlying their estimation towards the broader farm level opportunities and constraints undermining their closure. Overall, insights from contrasting case studies support conventional wisdom that intensification of agriculture needs to occur in the 'developing South', where yield gaps are large and resource use efficiency low, while a focus on improving sustainability based on sustainable intensification (or even extensification) is more appropriate in the 'developed North', where yield gaps are small and resource use efficiency high.

A comprehensive assessment of agriculture in lowlands of south Brazil: characterization and comparison of current and alternative concepts
Theisen, Giovani - \ 2017
University. Promotor(en): Niels Anten, co-promotor(en): Lammert Bastiaans. - Wageningen : Wageningen University - ISBN 9789463436380 - 234
cropping systems - farming systems - crop management - lowland areas - wetlands - pampas - brazil - intensification - sustainability - productivity - indicators - soil management - rice - flooded rice - oryza sativa - maize - zea mays - glycine max - cover crops - livestock - rotation - mixed farming - seedbed preparation - farm machinery - teeltsystemen - bedrijfssystemen - gewasteelt - laaglandgebieden - pampa's - brazilië - intensivering - duurzaamheid (sustainability) - productiviteit - indicatoren - bodembeheer - rijst - natte rijst - maïs - dekgewassen - vee - rotatie - gemengde landbouw - zaaibedbereiding - landbouwwerktuigen

Agriculture in the lowlands of south Brazil is of strategic importance at the national level, since it supplies around 80% of the rice consumed by the Brazilian population. In Rio Grande do Sul, the southernmost state in Brazil, three million hectares of lowlands are ready for grain-based agriculture. Of this area, about half is fallow, partly used for cattle grazing, and irrigated rice is the predominant crop, cultivated annually on 1.1 million ha. The remaining area is used for soybean and other crops. The predominant cropping system is a combination of irrigated rice and cattle. Over the last decades, rice yields have steadily increased, but this rise in yield level has to a large extent been obtained at the expense of a continuously higher use of external inputs. The recent introduction of soybean in rotation with rice has partially improved the system, but in most areas the situation is becoming incompatible with the modern demands for sustainability. This thesis presents a long-term study (2006-2015) of five cropping systems for lowlands. Next to monocrop rice and two rice-soybean rotations conducted in either conventional or minimum tillage, the experiment contained two novel systems based on large ridges, on which soybean and maize were combined with either cover crops or crop-livestock integration in winter. In these last systems, 8-m-wide ridges were built to avoid flooding, thus allowing for diversification of cash crops and the cultivation of cover crops or pastures in winter time, as well as the use of no-tillage. All systems were evaluated at process-level, including soil preparation, seeding, plant nutrition, pest management, irrigation, harvesting, transport and cattle management, as well as regarding their performance for the different dimensions of sustainability, particularly environment, land productivity, economics, energy-use and labour. Next to system assessment, two additional experiments were conducted for the evaluation of two specific technologies for soil management in these areas. Crop livestock integration on the ridge-based system offered the best balance between food production, environmental impact and economics. This system is well suited to be used in fields that are kept fallow, thereby enlarging the agricultural productivity of the lowlands. The additional experiments revealed that a knife-roller can successfully substitute plough-and-harrow for soil preparation after rice harvest, and that germination of weed seeds can be reduced if crop seeding is conducted at a lower speed or using a no-tillage seeder equipped with an improved cutting mechanism. Overall the results show that by using alternative cropping systems that allow for diversification and new methods of field management it is possible to simultaneously attain a larger agricultural production and improved sustainability in the lowlands.

Agronomic and socioeconomic sustainability of farming systems : A case in Chencha, South Ethiopia
Dersseh, Waga Mazengia - \ 2017
University. Promotor(en): Paul Struik, co-promotor(en): Rogier Schulte. - Wageningen : Wageningen University - ISBN 9789463436830 - 157
potatoes - solanum tuberosum - ethiopia - food security - farming systems - mixed farming - sustainability - optimization - efficiency - farm surveys - household surveys - socioeconomics - self sufficiency - profits - training - agronomic characteristics - productivity - soil fertility - rotation - animal feeding - improved varieties - inorganic fertilizers - aardappelen - ethiopië - voedselzekerheid - bedrijfssystemen - gemengde landbouw - duurzaamheid (sustainability) - optimalisatie - efficiëntie - bedrijfsonderzoeken - huishoudonderzoeken - sociale economie - zelfvoorziening - winsten - opleiding - agronomische kenmerken - productiviteit - bodemvruchtbaarheid - rotatie - diervoedering - veredelde rassen - anorganische meststoffen

Potato has multiple benefits and thus can play a vital role in ensuring food security in Ethiopia. However, for diverse reasons, its productivity is low. The farming systems in Ethiopia in which potato is grown, are predominantly mixed farming systems.

Most of the research in Ethiopia is focused on crop-specific constraints and thus there is limited research in which the interrelations between crop and livestock management practices are investigated. There is also not enough research focused on combined analysis of soil nutrient and animal feed balances and agronomic and socioeconomic efficiencies at farm level.

This study assessed production constraints and agronomic and socioeconomic sustainability of the farming systems in South Ethiopia and explored the possible synergetic options to alleviate major constraints. More specifically, the study intended to quantify the variation in input and output among farms, to identify constraints hindering expansion of potato production, to evaluate the sustainability of the farming systems at farm level, to identify constraints of sustainable intensification, and to explore synergetic solutions for the major constraints. Different research approaches were used ranging from lab analysis, household surveys, group discussions, to farm surveys.

Results showed that constraints related to input and product use in potato production vary across households indicating a need for a pluriform advisory model recognizing (and building upon alleviation of) the diversity of constraints identified in this analysis. The sustainability of the farming system is constrained by low agricultural productivity, low soil fertility, poor labour efficiency and limited economic return associated with improper crop rotation, inappropriate soil fertility management practices, shortage of animal feed, labour- and economically inefficient farm practices and labour shortage. However, there is ample scope to overcome the major constraints and simultaneously to optimize farm management.

The core messages of the study can be summarized as follows:

1) the current potato production is characterized by low productivity and economic returns due to various socioeconomic, agronomic and biological factors;

2) the soil fertility is low and there is uneven distribution of nutrients over plots with relatively high fertility levels in the homestead areas;

3) the current labour shortage can be attributed to mainly inefficiency of agricultural management practices and labour migration to towns for economic reasons indicating that the farming system is not sustainable in terms of labour;

4) considering the direct return from animal production, most of the farms had very low gross margin with the current management system and this reduced the overall operating profit of farms. The low return from animal rearing was offset by the relatively high profit from crop production indicating the benefit of mixed farming system in sustaining agricultural production; and

5) each farm can have a wide range of optimized solutions mainly through introduction of improved technologies and subsequent redesigning of the farm managements.

In general, the findings of the current study indicate that it is worthwhile to assess the sustainability of agricultural production in different farming systems and agro-ecologies of Ethiopia. In addition, the combined effect of introducing improved agricultural technologies and subsequent reconfiguring the farm management is very crucial to increase and sustain agricultural production.

Impact of trophic ecologies on the whereabouts of nematodes in soil
Quist, Casper W. - \ 2017
University. Promotor(en): Jaap Bakker, co-promotor(en): Hans Helder. - Wageningen : Wageningen University - ISBN 9789463430814 - 129
nematoda - spatial distribution - soil fauna - biota - trophic levels - food webs - soil ecology - soil biology - farming systems - soil types (ecological) - geostatistics - ruimtelijke verdeling - bodemfauna - trofische graden - voedselwebben - bodemecologie - bodembiologie - bedrijfssystemen - bodemtypen (ecologisch) - geostatistiek

Soil life is highly diverse, and ecologically intricate due to myriad of biotic interactions that take place. Terrestrial nematodes have a high potential to serve as an effective and policy-relevant indicator group for ecosystem functioning and soil biodiversity. The work described in this thesis contributed to the robust mapping of nematode communities at scales relevant in both agronomic and environmental contexts. The overarching aim of the work described in this thesis was to contribute to a sound exploration of the potential of nematode communities as an indicator group for the biological condition of soils. Therefore, the distributions of a wide range of nematode taxa were studied, within and between trophic groups and in soils conditioned by various plant species and/or farming systems.

In Chapter 2 nematode taxon-specific qPCR assays were used to pinpoint responses of nematode communities to invasive plant species Solidago gigantea in two invaded ecosystems: semi-natural grasslands and riparian floodplains. Nematode communities and fungal biomass were examined in adjacent invaded and uninvaded patches. The dominant presence of the invasive plant causes a decrease of plant species-richness and diversity, and an about twofold increase of fungal biomass. Only the density of a single group of fungivorous nematodes (Aphelenchoididea) increased, whereas the densities of two other, phylogenetically distinct lineages of fungivorous nematodes, Aphelenchidae and Diphtherophoridae, were unaffected by the local increase in fungal biomass. Apparently S. gigantea induces a local asymmetric boost of the fungal community, and only Aphelenchoididae were able to benefit from this change induced by the invasive plant.

In Chapter 3 the outcome is shown of a test whether farming system effects are mirrored in compositional changes in nematode communities. The long-term impact of three farming systems (conventional, integrated and organic) on nematode communities was investigated at the Vredepeel, an experimental farm in the southeastern part of The Netherlands. The results showed that organic farming causes specific shifts in nematode community composition, exceeding the usually large crop-related assemblage shifts. Strongest effects were observed for the (putative) bacterivore Prismatolaimus, which was relatively common in organic fields and nearly absent in conventional and integrated farming. A reverse effect was observed for Pristionchus; this necromenic bacterivore and facultative predator made up about 7 – 21% of the total nematode community in integrated and conventional farming, whereas it was nearly absent from organic fields. The observed farming system effects suggest that specific nematode taxa might be indicative for the impact of farming practices on soil biota. Knowledge of spatial distribution patterns of soil organisms with distinct trophic preferences will contribute to our understanding of factors that maintain and regulate soil biodiversity, and is essential information to design soil sampling strategies with predictable accuracies.

Chapter 4 deals with microscale patchiness of 45 nematode taxa (at family, genus or species-level) in arable fields and semi-natural grasslands, on marine clay, river clay or sandy soils. Contrary to our expectations, an increase of the number of cores per composite sample above 3, did not result in more accurate detection for any of the taxa under investigation (range of number of cores per composite sample: 3, 6, 12 or 24). Neither system nor soil type did influence microscale distribution. The insights in the spatial distribution of nematodes at microscale presented here, sheds light on the impact of trophic preferences on the spatial distribution of individual nematode taxa, and will allow for the design of statistically sound soil sampling strategies.

Chapter 5 shows belowground distribution patterns of 48 nematode taxa in 12 visually homogeneous fields (each 100 x 100 m) on three soil types (marine clay, river clay and sand) and two land-use types (arable and natural grasslands) across the Netherlands. Over 35,000 nematode-taxon specific qPCR assays allowed us to quantitative analyse nematode taxa at family, genus or species level in over 1,200 soil samples. A sampling scheme was optimized for Bayesian geostatistical analysis (Integrated nested Laplace approximations; INLA). Multivariate analysis show soil type and land-use related differences in the nematode community composition, which underline the effects of environmental filtering and niche partitioning of nematodes. All individual nematode taxa together show a wide range of degrees of spatial variabilities were found (expressed by the range-parameter and the spatial variance parameter (s2spatial). No general effects were detected of soil characteristics or nematode traits (cp-value, trophic group, weight) on the spatial distribution parameters. The relatively high percentages of unexplained spatial variability – 92.5% of the variation for the range-parameter and 74% for spatial variance (s2spatial) – point at a major role of stochasticity for variability of nematode densities within fields. This study adds empirical evidence that distribution patterns of terrestrial nematodes, in areas without noticeable gradients, are driven by neutral / stochastic processes, within the boundaries set by the environment.

In the final Chapter 6, I discuss the opportunities and challenges of the use of molecular tools in soil ecological research, the impact of trophic preferences on the whereabouts of nematodes, the use of nematode communities as indicator for soil condition and how this might be developed and applied to facilitate more sustainable ecosystem management.

Exploring opportunities for rural livelihoods and food security in Central Mozambique
Leonardo, Wilson José - \ 2017
University. Promotor(en): Ken Giller, co-promotor(en): Gerrie van de Ven; Henk Udo. - Wageningen : Wageningen University - ISBN 9789463431651 - 183
agricultural production systems - food security - crop production - livelihoods - small farms - biofuels - farming systems - models - intensification - mozambique - agrarische productiesystemen - voedselzekerheid - gewasproductie - middelen van bestaan - kleine landbouwbedrijven - biobrandstoffen - bedrijfssystemen - modellen - intensivering

Growing awareness of widespread hunger and poverty in many countries in the SSA is spurring a focus on productivity increase in smallholder farming systems. The rationale is that with current production systems many SSA countries are not keeping pace with population growth and changing of peoples’ lifestyles. To respond to this challenge the Government of Mozambique developed its Strategic Plan for Agricultural Development (PEDSA) aiming to improve agricultural productivity of the majority of smallholder farmers who depend on agriculture for their livelihoods. Smallholder farmers are diverse in terms of resources and aspirations. The main objectives of this study are first to understand the diversity among maize-based smallholder farms and their current constraints in improving agricultural productivity in the Manica Plateau, Central Mozambique, and second, building on that understanding to explore options for biomass production either for food, cash or biofuel at farm level and contributions to maize availability in the region. The study was conducted in the Dombe and Zembe Administrative Posts. Farmers in the two posts cultivate both food and cash crops using the same resources, however, distances to the urban market differ, with Zembe close and Dombe far away from the markets. In addition, the agroecological conditions for crop production are more favourable in Dombe compared with Zembe. Using farm surveys, direct observations and on-farm measurements, followed by Principal Components Analysis (PCA) I identified land and labour as the variables that can best explain the variability found among smallholder farms (Chapter 2). Based on these variables I categorised farms into four Farm Types (FT): FT1. Large farms (4.4 ha in Dombe and 2.2 ha in Zembe), hiring in labour; FT2. Intermediate sized farms (1.9-1.2 ha), hiring in and out labour; FT3a. Small farms (1.1-0.9 ha), sharing labour; and FT3b. Small farms (1.0-0.7 ha), hiring out labour. The maize yield and maize labour productivities were higher on large farms (2.3 t ha-1 in Dombe and 2.0 t ha-1 in Zembe; 2.5×10-3 t h-1 in Dombe and 2.6 ×10-3 t h-1 in Zembe) compared with small farms (1.5 t ha-1 in Dombe and 1.1 t ha-1 in Zembe; 1.4×10-3 t h-1 in Dombe and 0.9×10-3 t h-1 in Zembe). The hiring in labour from small farms allowed large farms to timely weed their fields. Small farms were resource constrained and hired out labour (mutrakita) for cash or food to the detriment of weeding their own fields, resulting in poor crop yields. Excessive alcohol consumption by small farms also raised concerns on labour quality. Chapter 3 explored options aiming at addressing farmers’ objectives of being maize self-sufficient and increased gross margin and the contribution to national objective of producing food. A bio-economic farm model was used to investigate two pathways to increase agricultural production: (i) extensification, expanding the current cultivated area; and (ii) intensification, increasing input use and output per unit of land.

In the extensification pathway I considered the use of animal traction, herbicides and cultivators to save labour, whereas in the intensification pathway I explored the use improved varieties of maize, sesame, sunflower, pigeonpea and fertilizers. I focused on the large farms and the small farms hiring out labour as they represent both sides of the spectrum. The simulated results showed that combining labour and labour saving technologies substantially increased both gross margin and maize yields of large and small farms in both posts. Minor trade-offs is observed on large farms between the two goals whereas for small farms we see synergies between the goals. We concluded that prospects for increasing gross margin and food production are much better for large farms in Dombe compared with other farms. In Dombe, the maximum gross margin of large farms was 7530 $ y-1 per farm and maximum maize sales of 30.4 t y-1 per farm. In Zembe, the maximum gross margin of large farms (2410 $ y-1 per farm) and maximum maize sales (9.5 t y-1 per farm) were comparable to small farms in Dombe. I further assessed the impact of two biofuel investments (jatropha plantation and sunflower outgrower schemes) on farm level food security (food availability, access to food, stability of food, utilization of food). The results showed positive impact on small farms from employment on a jatropha plantation by increasing access to food and no impacts on intermediate and large farms. Impacts on food security from the sunflower outgrower scheme were minor which may be explained by the poor yields.

The need to link smallholder farmers to markets has been increasingly recognized as important strategy to promote rural development and poverty reduction. I developed an analytical framework, the Windmill Approach that looked at decision making at farm level to grow certain crops and at transaction strategies (Chapter 5). Through this framework I showed that a farmer decision to participate in a particular (new) value chain is determined by (a) the suitability of the new crop in the farm system (including the adaptability of the current farm system), and (b) the farmer’s experience with selling in various value chains. This has major policy implications as it highlights that to support smallholder farmers access to markets a holistic approach is needed that combines farming systems analysis and transaction cost theory.

In order to explore the opportunities for smallholder development there is need to understand the diversity of farms and farmers’ social and economic context. For large farms, in Central Mozambique farms with on average 2-4 ha of land, opportunities to improve their livelihoods through crop production can follow two pathways: intensification and extensification. Smallholders continue to produce staple food crops even when working on a plantation or participating in outgrower schemes. For small farms, off-farm opportunities such as those in a biofuel plantation are the best options to improve their livelihoods.

Sustainable development of agriculture: contribution of farm-level assessment tools
Olde, Evelien de - \ 2017
University. Promotor(en): Imke de Boer, co-promotor(en): Eddy Bokkers; F.W. Oudshoorn. - Wageningen : Wageningen University - ISBN 9789463430685 - 152
sustainable agriculture - sustainability - sustainability indicators - sustainability criteria - assessment - tools - reliability - validity - farming systems - duurzame landbouw - duurzaamheid (sustainability) - duurzaamheidsindicatoren - duurzaamheidscriteria - beoordeling - gereedschappen - betrouwbaarheid - geldigheid - bedrijfssystemen

Current environmental, economic and social challenges urge agriculture to change to more sustainable modes of production. Insight in the impact of a system or a potential innovation on sustainability could support decision makers in identifying actions towards sustainable development. Over the past decade, therefore, a large number of tools have been developed to assess sustainability performance at farm level. Several concerns, however, have been raised whether assessment results provide reliable and valid conclusions about the sustainability performance of farms, and whether these conclusions can be implemented in practice. To evaluate the contribution of farm-level assessment tools to sustainable development of agriculture, this thesis analyzed current approaches to assessing sustainability. One of these approaches is the sustainability assessment tool RISE 2.0, which was used to assess the sustainability performance of 37 organic farms in Denmark. Analysis of the assessment results showed the impact of decisions, made during the development of a tool (e.g. selection of themes, indicators, reference values, scoring and aggregation method), on the assessment results. This emphasizes the importance of transparency in sustainability assessment tools to understand assessment results and identify actions to improve. Subsequently, a comparison of sustainability assessment tools in practice was made to gain insight into practical requirements, procedures and relevance perceived by farmers. Of 48 indicator-based sustainability assessment tools, only four tools (RISE, SAFA, PG and IDEA) complied to the selection criteria and were applied to assess the sustainability performance of five Danish farms. Characteristics including data requirements, assessment time, complexity, transparency and output accuracy varied between tools. Critical factors in farmers’ perception of tool relevance were context specificity, user-friendliness, complexity of the tool, language use, and a match between value judgements of tool developers and farmers. Farmers, moreover, indicated that implementing conclusions derived from sustainability assessments is challenging given the complex organization of agricultural systems. A more in-depth analysis of the four tools revealed a high diversity in selected indicators, themes, reference values, and scoring and aggregation methods. This results in different conclusions on the sustainability performance of farms, which does not only cause confusion but also affects the trust in, and reliability and implementation of, sustainability assessments. Variability in tools is caused by different perspectives on how to assess sustainability and is related to differences in context, priorities and value judgements of tool developers. These differences also play a role in the prioritization of criteria for indicator selection. To explore whether sustainability experts agreed on which criteria are most important in the selection of indicators and indicators sets for sustainability assessments, two ranking surveys were carried out. Both surveys showed a lack of consensus amongst experts about how best to measure agricultural sustainability. This thesis revealed variability in approaches to assess sustainability at farm level. This makes current assessment tools less suitable for functions that require a high reliability and validity, such as certification. Instead, current assessment tools present a useful starting point for discussion, reflection and learning on sustainable development of farming. To enhance the contribution of tools towards sustainable development of agriculture, more attention should be paid to increasing reliability and validity of tools, and improving transparency, harmonization, participation and implementation of assessments.

A generic method to analyse yield gaps in feed-crop livestock systems
Linden, Aart van der - \ 2017
University. Promotor(en): Imke de Boer; Martin van Ittersum, co-promotor(en): Simon Oosting; Gerrie van de Ven. - Wageningen : Wageningen University - ISBN 9789463430746 - 214
animal production - fodder crops - livestock feeding - crop production - crop yield - crop ecology - quantitative analysis - beef production - farming systems - dierlijke productie - voedergewassen - veevoeding - gewasproductie - gewasopbrengst - gewasecologie - kwantitatieve analyse - rundvleesproductie - bedrijfssystemen

Global livestock production is expected to increase in future decades, and expansion of the agricultural area for feed production is not desired. Hence, increasing livestock production per unit agricultural area is essential. The bio-physical scope to increase production of livestock systems with the corresponding feed crop production (feed-crop livestock systems) could not be assessed generically at the start of this research. In crop production, however, crop models based on concepts of production ecology are widely applied to assess the bio-physical scope to increase actual production. The difference between the biophysical scope and actual production is referred to as the yield gap. The objectives of this thesis were 1) to develop a generic framework to assess the scope to increase production in feed crop-livestock systems based on concepts of production ecology, 2) to develop a generic livestock model simulating potential (i.e. maximum theoretical) and feed-limited livestock production, and 3) to apply this framework and model to feed-crop livestock systems, and conduct yield gap analyses.

Concepts of production ecology for livestock were specified in more detail. Feed efficiency at herd level was a suited benchmark for livestock production only, and production of animal-source food per hectare for feed-crop livestock systems. Application of the framework showed that the yield gap was 79% of the potential beef production of a cow-calf system, and 72% of a cow-calf-fattener system in the Charolais region of France. The model LiGAPS-Beef (Livestock simulator for Generic analysis of Animal Production Systems – Beef cattle) was developed to simulate potential and feed-limited production of beef cattle using input data about animals’ genotype, climate, and feed quality and availability. The model consists of sub-models describing thermoregulation, feed intake and digestion, and energy and protein utilisation. Model evaluation under different agro-ecological conditions indicated live weight gain was estimated fairly well (15.4% deviation from measured values). LiGAPS-Beef was coupled with crop growth models to simulate potential and resource-limited production of twelve grass-based beef production systems in the Charolais region. Resource-limited production combines feed-limited production of cattle and water-limited production of feed crops. Yield gaps were on average 85% of potential live weight production per hectare, and 47% of resource-limited production. Yield gaps were attributed to feed quality and quantity limitation (41% of potential production), water-limitation in feed crops (31%), the combination of sub-optimal selling or slaughter weights, culling rates, calving dates, age at first calving, and stocking densities (9%), and the combination of prolonged calving intervals and calf mortality (2%). Improved grassland management and an earlier start of the grazing season may increase live weight production per hectare. Furthermore, the resource-limited production of bulls was simulated to increase by 6-14% from 1999-2006 up to 2050 due to climate change.

From the results of this thesis, it can be concluded that 1) a generic framework using concepts of production ecology is available now to assess the bio-physical scope to increase production in feed-crop livestock systems per unit area; 2) the mechanistic model LiGAPS-Beef simulates potential and feed-limited production of beef cattle fairly well; 3) combining LiGAPS-Beef with crop growth models allows to quantify yield gaps in feed-crop livestock systems, and to analyse these yield gaps. The method described in this thesis can be used subsequently to identify options to mitigate yield gaps, and to increase livestock production per unit area, which may contribute to sustainable intensification of agriculture.

Matching breeding goals with farming systems to enhance the sustainability of fish farming
Besson, Mathieu - \ 2017
University. Promotor(en): Imke de Boer; Hans Komen, co-promotor(en): M. Vandeputte. - Wageningen : Wageningen University - ISBN 9789463430067 - 201
fish culture - sustainability - animal production - farming systems - models - feed conversion - breeding - growth rate - feed conversion efficiency - animal welfare - visteelt - duurzaamheid (sustainability) - dierlijke productie - bedrijfssystemen - modellen - voederconversie - veredelen - groeitempo - voederconversievermogen - dierenwelzijn

Fish farming is growing but is also facing challenges regarding economic viability and environmental sustainability. Selective breeding could enhance the sustainability of fish farming by changing animal performances. Thus, our aim was to develop sustainable breeding goals by using economic (EV) or environmental values (ENV) to weigh the traits to improve. EV and ENV represent the economic and environmental impacts of improving a trait. They were calculated using a bioeconomic model combined with a life cycle assessment. We showed that the EV and ENV of traits change with the factor constraining the production of the farm. It suggests that breeding goals should be finely tuned according to the limiting factor to maximize economic or environmental responses. In addition, we showed that improving feed conversion ratio is a major trait to improve because it always increases profit and decreases environmental impacts. We conclude that it is possible to develop breeding programs enhancing the sustainability of fish farming by improving the right trait in the right production system.

Closing the nutrient loops in (peri-)urban farming systems through composting
Nigussie, Abebe - \ 2017
University. Promotor(en): Thomas Kuijper; A. de Neergaard, co-promotor(en): S. Bruun. - Wageningen : Wageningen University - ISBN 9789463430050 - 144
urban agriculture - farming systems - nutrients - composting - refuse - sewage - waste treatment - vermicomposting - soil quality - nitrogen - ethiopia - stadslandbouw - bedrijfssystemen - voedingsstoffen - compostering - vuilnis - rioolwater - afvalverwerking - vermicompostering - bodemkwaliteit - stikstof - ethiopië

Organic amendments are used to improve soil fertility and maintain agricultural fields in a productive state. Despite these benefits, the use of organic amendments is limited in many developing countries. The overall objective of this thesis is therefore to provide a better understanding of current waste management practices in developing countries and ensure sustainable crop production via the biotransformation of urban waste into a high-quality soil amendment. First, I aimed at determining the causes for the limited use of organic amendments in small-scale urban farming systems. I interviewed 220 urban farmers in Ethiopia and found that competition for agricultural waste between fuel, feed and soil amendment is a major cause for the limited use of organic amendments. I demonstrated that allocation of agricultural waste for soil amendment is linked with farmers’ livelihood strategies. I also studied variation in compost demand among different farmer groups, and the socio-economic variables which explained these variations.

Gaseous losses of ammonia and greenhouse gas (GHG) emissions occur during composting of nitrogen-rich urban waste. Several technologies could reduce these losses. However, these technologies are inadequate to fit within the broader farming systems because they are expensive. The second aim of this thesis was to develop low-cost methods to mitigate N losses and GHG emissions from composting, while retaining its fertilising value.

Composting by earthworms (vermicomposting) is proposed as a low-cost strategy for minimising N losses and GHG emissions. Using a wide range of substrate qualities (C:N ratio, labile C sources) and other factors (earthworm density, amount of input, and moisture), I showed that vermicomposting reduced N losses and GHG emissions compared with traditional thermophilic composting, but the magnitude of the earthworm effect varied between substrates. Earthworms also change the quantity and composition of dissolved organic carbon during composting. Another low-cost strategy is to delay the addition of N-rich substrates during composting. I demonstrated that addition of nitrogen-rich substrate after the thermophilic phase reduced N losses. Delayed addition of N-rich substrates increased N2O emissions, but reduced CH4 emissions. Delayed addition resulted in compost that was as stable and effective at completely eradicating weed seeds as traditional composting.

In conclusion, urban waste compost should be considered as alternative source for soil amendment, particularly in developing countries with competition for agricultural waste. Technologies such as vermicomposting and delayed addition of N-rich substrate are recommended to increase or maintain the nitrogen content of compost, reduce N losses and mitigate GHG emissions.

Met Hoofd Hart en Handen
Adelhart Toorop, R.L. de; Veluw, C. van - \ 2016
Ekoland 2016 (2016)10. - ISSN 0926-9142 - p. 24 - 25.
biologische landbouw - agrarisch onderwijs - bedrijfssystemen - modelleren - agrarische bedrijfsvoering - geitenhouderij - organic farming - agricultural education - farming systems - modeling - farm management - goat keeping
Wageningen is een van de weinige plekken in Europa waar een masterprogramma Organic Agriculture wordt aangeboden. Hoewel het binnen WUR een van de meest praktische opleidingen is, wordt het gros van de kennis binnen de collegezalen overgedragen. In het vak ‘Analyse en Ontwerp van Biologische Bedrijfssystemen’ verdiepen studenten zich in de zomer vier weken lang in de praktijk van de boeren van een biologisch bedrijf.
Sustainability of livestock production systems : a comparing conventional and organic livestock husbandry
Wagenberg, C.P.A. van; Haas, Y. de; Hogeveen, H. ; Krimpen, M.M. van; Meuwissen, M.P.M. ; Middelaar, C.E. van; Rodenburg, T.B. - \ 2016
Wageningen : Wageningen University & Research (Wageningen Economic Research report 2016-035) - ISBN 9789462577480 - 121
livestock - livestock farming - organic farming - europe - literature reviews - sustainable animal husbandry - farming systems - sustainability indicators - vee - veehouderij - biologische landbouw - europa - literatuuroverzichten - duurzame veehouderij - bedrijfssystemen - duurzaamheidsindicatoren
Sustainable livestock production systems are needed to feed the larger, more urban, richer and older world population in 2050. Quantitative information about the sustainability performance of existing livestock production systems can aid the debate of which actions could be developed and implemented. Strong points of conventional and organic dairy cattle, beef cattle, pig, laying hen, and broiler production systems were identified in peer-reviewed literature for a limited number of sustainability indicators within the subjects of economy, productivity, environment, animal welfare, and public health. This study aims to identify lessons learned for sustainable livestock production.
Agricultural intensification in Nepal, with particular reference to systems of rice intensification
Uprety, Rajendra - \ 2016
University. Promotor(en): Thomas Kuijper, co-promotor(en): Harro Maat. - Wageningen : Wageningen University - ISBN 9789462579651 - 190
rice - oryza sativa - nepal - asia - south asia - intensification - livelihoods - livelihood strategies - farming systems - farming - crop management - fertilizers - nutrients - irrigation - varieties - rijst - azië - zuid-azië - intensivering - middelen van bestaan - strategieën voor levensonderhoud - bedrijfssystemen - landbouw bedrijven - gewasteelt - kunstmeststoffen - voedingsstoffen - irrigatie - rassen (planten)

This thesis deals with agricultural intensification in Nepal. The initial focus of the study was the System of Rice Intensification (SRI), as introduced in Nepal from 2001. The multiple factors affecting SRI adoption, modification and dissemination together with the option to apply SRI in different combinations of its components result in a variety of SRI applications. For the same reason the effect of SRI on overall agricultural and livelihood development of Nepalese farmers has to be evaluated within the variety of farming systems in which it is applied.

Despite government policies to promote rice cultivation, national rice production is declining. Farmer livelihood strategies, as reflected in rice farming systems, and field management strategies were influenced by several agro-ecological and socio-economic factors. Livelihood and field management strategies of rice farmers are interconnected. In the study presented here four livelihood strategies and three kinds of field management strategies are distinguished. Two livelihood strategies can be characterized as more intensive and more productive; the other two are less intensive and less productive. Livelihood strategies are more family resource-based strategies, while farmers’ field management strategies are more context-dependent. Field management strategies were characterized by forms of nutrient management. Intensive management strategies had most similarities with SRI. But rice intensification is not achievable as a general strategy.

Government policies (fertiliser subsidies) encourage increased fertiliser use. Study results didn't show any significant effect of volume of fertilisers on rice yield but the combined use of organic manure and mineral fertilisers resulted in the highest average rice yields. Irrigation management is another important factor for rice production. Field management is influenced by the reliability of water which was better in farmers' managed irrigation system. Choice of rice varieties influenced the overall rice farming system and cropping intensity and preference of varieties for rice cultivation by scientists and by farmers were different in eastern Nepal. Most popular varieties were those not recommended by science and policy and were disseminated farmer to farmer.

The introduction of SRI in Morang district resulted in several changes in rice farming, but only part of the farmers have adopted such technologies, and adoption has been only in part of their fields. Other farmers have incorporated some SRI practices in their conventional practices. After the introduction of SRI, farmers further tested, re-packaged or hybridized SRI methods to make SRI ideas suitable for their agro-ecological and socio-economic environments. In order to reform Nepalese rice farming, we need to recognize that different farmers, with different livelihood strategies, and with access to different kinds of fields, need different forms for agricultural intensification. High-intensive farmers prefer to use modified SRI methods where there is good irrigation and drainage facilities. There are many possibilities for improvement of the existing nutrient management practices of rice farmers in Nepal. Nutrient management will be useful to increase rice production because the majority of farmers currently use fertilisers non-judiciously. The SRI-recommended practices (younger seedlings, early weeding, use of organic manure, and alternate wetting and drying (AWD) irrigation) will be useful to improve the nutrient use efficiency of rice farmers. Cost-reduction strategies and less labour-intensive cultivation practices will be appropriate options to improve existing rice farming system of Nepal. Participatory cultivar selection and dissemination will be better strategies to introduce new, promising rice cultivars among rice farmers.

Trajectories of agricultural change in southern Mali
Falconnier, G.N. - \ 2016
University. Promotor(en): Ken Giller, co-promotor(en): Katrien Descheemaeker; T.A. van Mourik. - Wageningen : Wageningen University - ISBN 9789462577596 - 209 p.
agriculture - agricultural development - farms - classification - self sufficiency - food - income - intensification - farming systems - intensive production - mali - landbouw - landbouwontwikkeling - landbouwbedrijven - classificatie - zelfvoorziening - voedsel - inkomen - intensivering - bedrijfssystemen - intensieve productie

Key words: longitudinal study, farm typology, food self-sufficiency, income, legumes, ex-ante analysis, participatory research, scenario.

Smallholder agriculture in sub-Saharan Africa provides basis of rural livelihoods and food security, yet farmers have to cope with land constraints, variable rainfall and unstable institutional support. This study integrates a diversity of approaches (household typology and understanding of farm trajectories, on-farm trials, participatory ex-ante trade-off analysis) to design innovative farming systems to confront these challenges. We explored farm trajectories during two decades (1994 to 2010) in the Koutiala district in southern Mali, an area experiencing the land constraints that exert pressure in many other parts of sub-Saharan Africa. We classified farms into four types differing in land and labour productivity and food self-sufficiency status. During the past two decades, 17% of the farms stepped up to a farm type with greater productivity, while 70% of the farms remained in the same type, and only 13% of the farms experienced deteriorating farming conditions. Crop yields did not change significantly over time for any farm type and labour productivity decreased. Together with 132 farmers in the Koutiala district, we tested a range of options for sustainable intensification, including intensification of cereal (maize and sorghum) and legume (groundnut, soyabean and cowpea) sole crops and cereal-legume intercropping over three years and cropping seasons (2012-2014) through on-farm trials. Experiments were located across three soil types that farmers identified – namely black, sandy and gravelly soils. Enhanced agronomic performance was achieved when targeting legumes to a given soil type and/or place in the rotation: the biomass production of the cowpea fodder variety was doubled on black soils compared with gravelly soils and the additive maize/cowpea intercropping option after cotton or maize resulted in no maize grain penalty, and 1.38 t ha−1 more cowpea fodder production compared with sole maize. Farm systems were re-designed together with the farmers involved in the trials. A cyclical learning model combining the on-farm testing and participatory ex-ante analysis was used during four years (2012-2015). In the first cycle of 2012-2014, farmers were disappointed by the results of the ex-ante trade-off analysis, i.e marginal improvement in gross margin when replacing sorghum with soybean and food self-sufficiency trade-offs when intercropping maize with cowpea. In a second cycle in 2014-2015 the farm systems were re-designed using the niche-specific (soil type/previous crop combinations) information on yield and gross margin, which solved the concerns voiced by farmers during the first cycle. Farmers highlighted the saliency of the niches and the re-designed farm systems that increased farm gross margin by 9 to 29% (depending on farm type and options considered) without compromising food self-sufficiency. The involvement of farmers in the co-learning cycles allowed establishment of legitimate, credible and salient farm reconfiguration guidelines that could be scaled-out to other communities within the “old cotton basin”. Five medium-term contrasting socio-economic scenarios were built towards the year 2027, including hypothetical trends in policy interventions and change towards agricultural intensification. A simulation framework was built to account for household demographic dynamics and crop/livestock production variability. In the current situation, 45% of the 99 households of the study village were food self-sufficient and above the 1.25 US$ day-1 poverty line. Without change in farmer practices and additional policy intervention, only 16% of the farms would be both food self-sufficient and above the poverty line in 2027. In the case of diversification with legumes combined with intensification of livestock production and support to the milk sector, 27% of farms would be food self-sufficient and above the poverty line. Additional broader policy interventions to favour out-migration would be needed to lift 69% of the farms out of poverty. Other additional subsidies to favour yield gap narrowing of the main crops would lift 92% of the farm population out of poverty. Whilst sustainable intensification of farming clearly has a key role to play in ensuring food self-sufficiency, and is of great interest to local farmers, in the face of increasing population pressure other approaches are required to address rural poverty. These require strategic and multi-sectoral approaches that address employment within and beyond agriculture, in both rural and urban areas.

Optimizing soil and water management in dryland farming systems in Cabo Verde
Santos Baptista Costa, I. Dos - \ 2016
University. Promotor(en): Coen Ritsema; Violette Geissen, co-promotor(en): Luuk Fleskens. - Wageningen : Wageningen University - ISBN 9789462577367 - 189 p.
water management - soil management - farming systems - dry farming - optimization - watershed management - watersheds - runoff - erosion control - cape verde - waterbeheer - bodembeheer - bedrijfssystemen - optimalisatie - beheer van waterbekkens - stroomgebieden - oppervlakkige afvoer - erosiebestrijding - kaapverdië

“Optimizing Soil and Water Management in Dryland Farming Systems in Cabo Verde”

Isaurinda Baptista

Summary

Soil and land degradation poses a great challenge for sustainable development worldwide and, in Cabo Verde, has strongly affected both people’s livelihood and the environment. Dryland food production in Cabo Verde faces steep slopes, inadequate practices, irregular intense rain, recurrent droughts, high runoff rates, severe soil erosion and declining soil fertility, leading to the inefficient use of rainwater. Despite the enormous investment in soil and water conservation measures (SWC), land degradation due to water erosion is still rife and dryland crop productivity remains low. Sustainable land management (SLM) techniques that reduce runoff, erosion and nutrient loss are the key to mitigating/preventing land degradation and assuring long-term soil productivity.

This thesis investigated soil and water management techniques for Cabo-Verdean dryland farming systems to increase the efficiency of rainwater and crop yield, combining traditional and scientific knowledge in a field-based participatory approach. Field experiments were conducted in different agro-ecological zones of the Santiago Island aiming to evaluate the effects of water conservation techniques (mulching of crop residue, soil surfactant and pigeon-pea hedges) combined with organic amendments (compost and animal or green manure) on runoff, erosion, soil nutrients and crop yield. The PESERA-DESMICE modelling approach allowed assessing the biophysical and socio-economic benefits of the promising SLM techniques against a local baseline condition and their potential application at larger scale, under climate variability.

Following the general introduction (chapter 1), chapter 2 of the thesis reviews the national strategies towards building resilience against the harsh environmental conditions, analyses the state of land degradation and its drivers, surveys the existing SWC measures, and assesses their effectiveness against land degradation and in supporting people’s livelihoods. The analysis allows inferring that the relative success of Cabo Verde in tackling desertification and rural poverty is due to an integrated governance strategy that comprises awareness raising, institutional framework development, financial resource allocation, capacity building, and active participation of rural communities. The chapter provides a panoramic view of the importance of SWC measures for Cabo Verde drylands and recommends further specific, science-based assessment of the biophysical and socioeconomic impact of SLM and potential for upscaling.

Chapter 3, first, discusses the participatory approach used in selecting the SLM techniques that are field-tested in this research and, then, evaluates the effects of the selected water conservation techniques combined with organic amendments on the generation of runoff and soil loss from rain-fed agricultural fields compared with traditional farmers’ practices. The chapter also discusses the main factors influencing runoff and soil loss in semiarid dryland hilly areas, including the degree of soil cover, rainfall amount and erosivity, slope and soil infiltration rate. Runoff was significantly reduced only with the treatments containing mulch on slopes >10% and in the treatment containing surfactant and organic amendment on slopes <10%. Observed soil erosion rates were highest for the silty-clay-loam soil, followed by the sandy-loam soil and the loamy-soil, reaching a maximum value of 17 Mg ha-1 in the traditional practice, but were reduced by more than 50% with the SLM techniques. Residue mulch and pigeon-pea combined with an organic amendment (T3) almost eliminated runoff and erosion from agricultural fields even on steep slopes, contributing to improved use of rainwater at the plot level. The chapter recommends that SLM techniques, such as T3, be advocated and promoted for the semiarid hillsides of Cabo Verde prone to erosion to increase rainwater-use and to prevent further soil degradation.

As soil erosion, runoff and related nutrient losses constitute a high risk to soil fertility in Cabo Verde drylands, chapter 4 focuses on the effects of the techniques tested in chapter 3 on erosion and runoff related nutrient losses (NO3-N and PO4-P) and on crop productivity. The traditional system lost significantly higher amounts of both NO3-N and PO4-P than the tested SLM techniques, with the T3 technology reducing soil loss, runoff and nutrient losses to nearly a 100%. Nutrient losses from the amended plots were low, while the significant losses from the traditional system could result in long-term nutrient depletion in the soil. The treatments did not consistently increase crop yield or biomass in all three sites, but the combination of organic amendment with soil surfactant increased both crop yield and biomass in some cases. T3 was the best treatment for steep slope areas, although it is crucial to manage the pigeon-pea hedges to achieve higher maize yield. For flatter areas with deeper soils, the combination of organic amendment with soil surfactant could be a less expensive and effective choice. The chapter identifies and recommends SLM techniques to prevent nutrient depletion, improve dryland crop yield and avoid further land degradation due to erosion by water, both in steep slope areas and flatter areas.

Given the potential of the SLM techniques, but also significant spatial-temporal yield variability, chapter 5 considers the PESERA-DESMICE modelling approach to capture a greater range of climatic conditions and evaluate the biophysical and socio-economic benefits of the promising SLM technique (residue mulch combined with pigeon-pea hedges and an organic amendment - T3) against the traditional baseline practice of maize-bean intercropping (T0). It also evaluates the potential for upscaling the selected technique at Island scale. From stations in semi-arid and sub humid climates, long-term historic rainfall statistics allowed construction of 50-year rainfall realizations providing a unique time-series of rainfall scenarios and an envelope of the potential biomass production. T3 elevates yield under both sub-humid and semi-arid climates with greater security for sub-humid areas even though risk of crop failure still exists. The T3 technology offered good potential to increase yields by 20% in 42% of the area and reduce erosion by 8.6 Mg ha-1, but in terms of cost effectiveness, it might be prohibitively expensive for farmers lacking inputs. Such findings can inform policy options or influence adoption of conservation measures under the climatic variability of the Cabo Verde drylands and resilience to future climate change.

The thesis ends with a synthesis chapter (6) that presents the research findings, highlights the new contributions made to the current scientific debates on Climate-Smart Agriculture (CSA) technologies for sub-Saharan Africa, sustainable intensification and land degradation neutrality. The T3 technology can be a promising CSA practice that could be widely used by smallholder farmers in semiarid regions to maintain food production and secure farmers’ livelihoods, while contributing to ecosystem services by storing water in the soil. The synthesis concludes with policy recommendations for optimizing soil and water management on hilly drylands to prevent further degradation.

Hence, the thesis presents options to support moving from degrading and low yielding land management practices towards more sustainable land intensification in hilly drylands that reduce runoff and soil loss, increase crop nutrient and crop productivity, ultimately, contributing to the mitigation/adaptation of climate change, food security and land degradation neutrality in Cabo Verde.

Integrated assessment of farm level adaptation to climate change in agriculture : an application to Flevoland, The Netherlands
Mandryk, M. - \ 2016
University. Promotor(en): Martin van Ittersum, co-promotor(en): Pytrik Reidsma; Bas Arts. - Wageningen : Wageningen University - ISBN 9789462576612 - 155 p.
climate adaptation - climatic change - agriculture - farm structure - farming systems - future - klimaatadaptatie - klimaatverandering - landbouw - bedrijfsstructuur in de landbouw - bedrijfssystemen - toekomst
The findings of the thesis allowed assessing plausible futures of agriculture in Flevoland around 2050 with insights in effective adaptation to climate change at different levels. Besides empirical findings, this thesis contributed methodologically to the portfolio of climate change impact and adaptation assessment. Overall, this thesis performed a prospective (using scenarios), multi-scale (taking into account crop, farm and regional level), integrated (notably multi-objective) and participatory assessment. The following features have been elaborated in this thesis to better assess the context of farm level impact and adaptation: analysis of long term farm structural change, assessment of farmers’ multiple objectives, assessment of contribution of crop and farm level adaptation measures to improvement of farm performance on important objectives, and an analysis on institutional feasibility of implementation of adaptation measures.
Effect of water use by smallholder farms in the Letaba basin : a case study using the SIMGRO model
Querner, E.P. ; Froebrich, J. ; Clercq, Willem de; Jovanovic, Nebo - \ 2016
Alterra, Wageningen-UR (Alterra-report 2715) - 49 p.
hydrology - models - groundwater - surface water - irrigation - farming systems - limpopo - south africa - hydrologie - modellen - grondwater - oppervlaktewater - irrigatie - bedrijfssystemen - zuid-afrika
For the Letaba basin situated in the South African part of the Limpopo basin, a hydrological study was carried out in order to quantify the effect of smallholder farming on river flows. Important was to study the consequences of improved agricultural systems on the river flows, in particular for the Kruger National Park situated in the lower part of the Letaba basin. The SIMGRO model was used in this study, which integrates groundwater and surface water. The model was calibrated, and furthermore a comparison of measured discharges and groundwater levels against calculated discharges and groundwater levels, revealed that the model is suiTable for practical analysis. For the smallholders farms different scenarios were defined with different levels of crop yield. An increase in crop yield has consequences on more water use as irrigation and crop water use. Because the area covering smallholder farming is only 0.5% of the basin, the effects of changes in water use are relatively small. In a scenario, the weather conditions for 2050 were analysed. This reveals that discharges will go down by 30% on average, which means a substantial reduction of the water resources.
Coffee certification in East Africa: Impact on farms, families and cooperatives
Ruben, R. ; Hoebink, Paul - \ 2015
Wageningen Academic Publishers - ISBN 9789086862559 - 264 p.
certification - coffee - small farms - labelling - sustainability - farming systems - east africa - certificering - koffie - kleine landbouwbedrijven - etiketteren - duurzaamheid (sustainability) - bedrijfssystemen - oost-afrika
Certification of coffee producers is frequently suggested as a promising strategy for improving the position of smallholder farmers in the market. After the launch of the first Fairtrade label in 1988, several other standards have been promoted either by voluntary agencies (Utz-certified) or by private coffee companies. Each coffee label relies on different strategies for enhancing sustainable production and responsible trade. Coffee certification in East Africa is of a rather recent nature but has been rapidly expanding, representing currently 26 percent of the world's sustainable certified coffee supply. Marketing channels, cooperative organisation and household structures show notable differences between Kenya, Uganda and Ethiopia. Empirical studies on the effects of standards for smallholders are scarce. This book intends to deepen our understanding on the role and functions of coffee certification regimes, based on three innovative approaches: (1) longitudinal field survey data capturing changes in coffee farming systems and effects on household welfare; (2) in-depth interviews and behavioural experiments regarding risk attitudes, trust and investments at cooperative level; and (3) detailed discourse analyses regarding gender roles and female bargaining power within coffee households. The chapters included in this book provide new and original evidence about the impact of coffee certification based on large-scale field surveys and in-depth interviews.
NSO-typering 2010-2012 : typering van agrarische bedrijven in Nederland
Everdingen, W.H. van - \ 2015
Den Haag : LEI Wageningen UR (LEI nota 2015-153) - 34 p.
normen - bedrijfsgrootte in de landbouw - agrarische bedrijfsvoering - landbouwstatistieken - standaardisering - nederland - bedrijfsstructuur in de landbouw - productiestructuur - landbouwbedrijven - bedrijfssystemen - landbouw - standards - farm size - farm management - agricultural statistics - standardization - netherlands - farm structure - production structure - farms - farming systems - agriculture
Binnen de agrarische sector komen zeer uiteenlopende productiestructuren en bedrijfssystemen voor. Om de structurele kenmerken en de economische resultaten gemakkelijker te kunnen beschrijven en analyseren, is een eenduidige, homogene classificatie van landbouwbedrijven noodzakelijk. Deze classificatie, gebaseerd op economische normen, is in Europees verband in de jaren tachtig ontwikkeld en sindsdien enkele malen aangepast. De actuele documentatie van de Europese Commissie is opgenomen in het Typology Handbook (RI/CC 1500 rev.).1 Het onderhoud van de typering en de normen in Nederland wordt gecoördineerd door het Centrum voor Economische Informatievoorziening (CEI). Bij elk van de aanpassingen is door Nederland gekozen om een eigen variant te gebruiken waarin meer recht wordt gedaan aan specifiek Nederlandse agrarische producten, zoals zetmeelaardappelen, bloembollen en blank kalfsvlees. Tot en met 2009 werd voor de Nederlandse variant het brutostandaardsaldo (bss), de Nederlandse grootte-eenheid (nge) en de NEG-typering gebruikt. In 2010 zijn die criteria vervangen door de Standaardopbrengst (SO) en de Nederlandse standaardopbrengst (NSO)-typering. In 2014 is voor de Nederlandse variant een nieuw kengetal geïntroduceerd: de Standaard Verdiencapaciteit (SVC) van bedrijven. Dat kengetal is ontwikkeld vanwege verschillen in marge tussen de sectoren. Met de SVC is de bedrijfsgrootte van bedrijven over bedrijfstypen heen meer gerelateerd aan arbeidsinzet en resultaat dan bij de SO het geval is.
Biophysical soil quality of tillage systems in conventional and organic farming
Crittenden, S. - \ 2015
University. Promotor(en): Lijbert Brussaard, co-promotor(en): Mirjam Pulleman; Marius Heinen. - Wageningen : Wageningen University - ISBN 9789462575981 - 135
bodemkwaliteit - bodemfysica - grondbewerking - biologische landbouw - bedrijfssystemen - bodembiologie - bodemecologie - soil quality - soil physics - tillage - organic farming - farming systems - soil biology - soil ecology
Balans in bemesting : proefbedrijf Vredepeel onderzoekt de optimale bemstingsstrategie voor bioteelt
Haan, J.J. de; Verstegen, H.A.G. - \ 2015
Ekoland 35 (2015)10. - ISSN 0926-9142 - p. 20 - 22.
biologische landbouw - bemesting - groenteteelt - vollegrondsteelt - preien - veldproeven - bedrijfssystemen - stikstofbalans - proefbedrijven - emissiereductie - groenbemesters - organic farming - fertilizer application - vegetable growing - outdoor cropping - leeks - field tests - farming systems - nitrogen balance - pilot farms - emission reduction - green manures
Juiste bemesting is essentieel voor goede gewasopbrengsten, opbouw van bodemvruchtbaarheid en het voorkomen van emissies. Onderzoekers Janjo Haan en Harry Verstegen zochten op proefbedrijf Vredepeel naar de beste bemesting voor het biologische bedrijfssysteem. Bijbemesting in de prei en het goed inschatten van de mineralisatie en stikstofbenutting blijkt het lastigst.
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