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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    Bioenergy potential and greenhouse gas emissions from intensifying european temporary grasslands
    Wicke, Birka ; Kluts, Ingeborg ; Lesschen, Jan Peter - \ 2020
    Land 9 (2020)11. - ISSN 2073-445X - p. 1 - 18.
    Biomass - Biorefinery - Integral emission assessment - Intensification - Permanent grasslands

    Agricultural intensification is considered essential for meeting growing demand for food and biomass for energy purposes. Intensifying grasslands is under-represented, although it is a promising option given their large land area and relatively low management levels. This study quantifies the bioenergy potential from intensifying temporary grasslands in Europe and the integral greenhouse gas emission effects in 2030. We first conducted a literature review of intensification options for European grasslands and then applied the environmental impact assessment model MITERRA-Europe to implement the key intensification option of using multi-species grass mixtures. The results showed that 853 kha (or 8%) of temporary grassland could be made sustainably available for additional biomass production. This can be translated into a bioethanol potential of 23 PJ yr−1 and an emission mitigation potential of 5.8 Mt CO2-eq yr−1 (if conventional grass mixture from surplus temporary grassland is used for energy) or 72 PJ yr−1 and 4.0 Mt CO2-eq yr−1 (if surplus temporary grassland is used for grassy energy crops). Although the bioenergy potential is limited, the key advantage of intensification measure is that it results in a better environmental performance of temporary grasslands. This makes it a key option for sustainably producing bioenergy in areas with high shares of temporary grasslands.

    Towards actionable farm typologies : Scaling adoption of agricultural inputs in Rwanda
    Hammond, Jim ; Rosenblum, Nathaniel ; Breseman, Dana ; Gorman, Léo ; Manners, Rhys ; Wijk, Mark T. van; Sibomana, Milindi ; Remans, Roseline ; Vanlauwe, Bernard ; Schut, Marc - \ 2020
    Agricultural Systems 183 (2020). - ISSN 0308-521X
    Adoption of agricultural innovations - Intensification - Rural development - Scaling - Smallholders - Typologies

    Rollout of development interventions using a one-size-fits-all model can achieve economies of scale but neglects to account for variability in farm and farmer characteristics. A data-driven approach to incorporate farmer diversity in scaling strategies may help to achieve greater development impact. However, interpreting the multiplicity of smallholder characteristics is complex, time-consuming, and the ways in which the insights gained can be implemented is poorly understood. Navigating these tensions, we present a farm typology study carried out in collaboration with a large development organisation (the “scaling partner”) promoting agricultural inputs in Rwanda. This study was conducted late in the scaling pathway, in order to finesse the scaling strategy, rather than to target intervention selection. Drawing on nearly 3000 interviews from 17 districts of the Western, Southern, and Eastern Provinces of Rwanda, the typology differentiates households along two axes: 1. prosperity (a cornerstone of conventional typologies), and 2. adoption of inputs (fertilisers and improved crop varieties). We used an efficient household survey tool, a minimum-variable approach, and concepts from the study of adoption of agricultural innovations. Through an action-research collaboration with the scaling organisation we adapted the methods and the findings to be “actionable. Approximately two-thirds of the study population were using fertilisers and improved seed to some extent. Along each prosperity stratum, however, there were multiple degrees of adoption, demonstrating the value of including adoption information in typology constructions. Ten farm types were identified, where the key differences along the prosperity axis were land area cultivated and livestock owned, and the key differences along the adoption axis were perceptions of input efficacy, access to training, and education level. We also present a simple decision tree model to assign new households to a farm type. The findings were used in three ways by the scaling organisation: (i) characterisation of the population into discrete groups; (ii) prioritisation, of farm types for engagement, and geographical locations for further investment; and (iii) design of decision support tools or re-design of packages to support technology adoption for specific farm types. The need for field-level validation of the typologies was also stressed by the scaling organisation.

    Exploring social preferences for ecosystem services of multifunctional agriculture across policy scenarios
    Bernués, Alberto ; Alfnes, Frode ; Clemetsen, Morten ; Eik, Lars Olav ; Faccioni, Georgia ; Ramanzin, Maurizio ; Ripoll-Bosch, Raimon ; Rodríguez-Ortega, Tamara ; Sturaro, Enrico - \ 2019
    Ecosystem Services 39 (2019). - ISSN 2212-0416
    Abandonment - Agrienvironmental policy - Economic values - Intensification - Social-ecological systems - Trade-offs

    Multifunctional agroecosystems are the result of complex adaptive interactions between humans and nature where trade-offs between food production and other ecosystem services are key. Our objective is to explore the social preferences for ecosystem services, and the associated willingness to pay, in three multifunctional agroecosystem in Europe (Mediterranean, Atlantic, Alpine) under alternative agrienvironmental policy scenarios. We use the same methodology (a choice experiment including equivalent attributes and levels) to rank and estimate the economic value of provisioning, regulating, supporting and cultural ecosystem services. We define the scenarios (current situation, abandonment and enhanced management) in biophysical terms to elucidate changing relations between social perception and level of delivery of ecosystem services. We derive some lessons. i) Value of ES: biodiversity and regulating ecosystem services always produce welfare gains; people, however, perceive trade-offs between delivery of agricultural landscapes and quality food products. Nevertheless, preferences are heterogeneous and vary across regions, scenarios and ES. ii) Policymaking: society's willingness to pay for the delivery of ecosystem service exceeds largely the current level of public support. Moreover, further abandonment and intensification of agriculture is clearly rejected by the public. iii) Methodological: monetary valuation is context dependent and extrapolation of economic values can be misleading.

    Is labour a major determinant of yield gaps in sub-Saharan Africa? A study of cereal-based production systems in Southern Ethiopia
    Silva, João Vasco ; Baudron, Frédéric ; Reidsma, Pytrik ; Giller, Ken E. - \ 2019
    Agricultural Systems 174 (2019). - ISSN 0308-521X - p. 39 - 51.
    Extensification - Farm power - Frontier analysis - Intensification - Triticum aestivum L. - Zea mays L.

    We investigated the role of labour in explaining the yield gap of cereals at both crop and farm levels on smallholder farms in Southern Ethiopia. A household survey containing detailed information of labour use at crop and farm level of ca. 100 farms in a maize-based system around Hawassa and ca. 100 farms in a wheat-based system around Asella was used for this purpose. Stochastic frontier analysis was combined with the principles of production ecology to decompose maize and wheat yield gaps. Actual maize and wheat yields were on average 1.6 and 2.6 t ha −1 , respectively, which correspond to 23 and 26% of the water-limited yield (Yw) of each crop. For both crops, nearly half of the yield gap was attributed to the technology yield gap, indicating sub-optimal crop management to achieve Yw even for the farmers with the highest yields. The efficiency yield gap was ca. 20% of Yw for both crops; it was negatively associated with sowing date and with the proportion of women's labour used for sowing in the case of maize but with the proportion of hired labour used for sowing and weed control in the case of wheat. The resource yield gap was less than 10% of Yw for both crops due to small differences in input use between highest- and lowest-yielding farms. The contribution of capital and farm power availability to crop yields, input use and labour use was analysed at the farm level. Labour calendars showed that crops cultivated in Hawassa were complementary, with peak labour occurring at different times of the year. By contrast, crops cultivated in Asella competed strongly for labour during sowing, hand-weeding and harvesting months, resulting in potential trade-offs at farm level. Oxen ownership was associated with capital availability, but not farm power in Hawassa and with both capital availability and farm power in Asella. Farmers with more oxen applied more nitrogen (N) to maize in Hawassa and cultivated more land in Asella, which is indicative of an intensification pathway in the former and an extensification pathway in the latter. Differences in land:labour ratio and in the types of crops cultivated explained the different strategies used in the two sites. In both sites, although gross margin per unit area increased linearly with increasing crop yield and farm N productivity, gross margin per labour unit increased up to an optimal level of crop yield and farm N productivity after which no further response was observed. This suggests that narrowing the yield gap may not be economically rational in terms of labour productivity. We conclude that labour (and farm power) is not a major determinant of maize yield gaps in Hawassa, but is a major determinant of wheat yield gaps in Asella.

    How to increase the productivity and profitability of smallholder rainfed wheat in the Eastern African highlands? Northern Rwanda as a case study
    Baudron, Frédéric ; Ndoli, Alain ; Habarurema, Innocent ; Silva, João Vasco - \ 2019
    Field Crops Research 236 (2019). - ISSN 0378-4290 - p. 121 - 131.
    East Africa - Intensification - Rainfed wheat - Resource-saving technologies - Yield gap - Yield-increasing technologies

    As wheat demand is increasing in sub-Saharan Africa (SSA), domestic production is being encouraged. The potential to increase the productivity and profitability of wheat appears large in the region, but little is known about the concrete interventions needed to meet that potential. In this study, we selected a site in Northern Rwanda (representative of the cool humid climatic zone which accounts for most of the spring wheat production of SSA) and analysed the determinants of wheat productivity and profitability for 130 smallholder farms during two consecutive short rainy seasons, namely 2017A and 2018A (wheat is seldom grown during long rainy seasons: potato is the preferred crop then). Although wheat yields were found to be high when compared to typical yields in SSA (means of 3469 and 3052 kg ha −1 during the seasons 2017A and 2018A, respectively), large yield gaps were also found (1.977 t ha −1 on average, or 37.6% of the highest farmer's yield, defined as the average actual yields above the 90th percentile of this variable). Evidences presented in the paper suggest that wheat productivity could be increased through increased seeding rate (a 0.14% increase in wheat grain yield was found with a 1% increase in seeding rate), increased nitrogen (N) application combined with frequent weeding (a 0.02% increase in wheat grain yield was found with a 1% increase in N application and frequent weeding), and labour-saving technologies (e.g., herbicides and mechanization). If wheat profitability would also increase with frequent weeding and labour-saving technologies, it would decrease with increased input use in many cases. Indeed, seed, fertilizer and amendments represent most of the wheat production cost in the area. These results illustrate the importance of assessing the impact of narrowing the yield gap on profitability, not only productivity, as some yield-increasing technologies may not be desirable from an economic perspective. They also demonstrate that resource-saving technologies (input-saving e.g., precision agriculture, labour-saving e.g., mechanization) may be as much in demand by African smallholders as yield-increasing technologies, calling for a more balanced approach in current research and development initiatives on the continent.

    Maize crop nutrient input requirements for food security in sub-Saharan Africa
    Berge, H.F.M. ten; Hijbeek, R. ; Loon, M.P. van; Rurinda, J. ; Tesfaye, K. ; Zingore, S. ; Craufurd, P. ; Heerwaarden, J. van; Brentrup, F. ; Schröder, J.J. ; Boogaard, H.L. ; Groot, H.L.E. de; Ittersum, M.K. van - \ 2019
    Global Food Security 23 (2019). - ISSN 2211-9124 - p. 9 - 21.
    Cereals - Crop nutrient requirements - Food self-sufficiency - Intensification - Maize - Soil fertility - Sub-saharan Africa - Yield gaps - Zea mays

    Nutrient limitation is a major constraint in crop production in sub-Saharan Africa (SSA). Here, we propose a generic and simple equilibrium model to estimate minimum input requirements of nitrogen, phosphorus and potassium for target yields in cereal crops under highly efficient management. The model was combined with Global Yield Gap Atlas data to explore minimum input requirements for self-sufficiency in 2050 for maize in nine countries in SSA. We estimate that yields have to increase from the current ca. 20% of water-limited yield potential to approximately 50–75% of the potential depending on the scenario investigated. Minimum nutrient input requirements must rise disproportionately more, with N input increasing 9-fold or 15-fold, because current production largely relies on soil nutrient mining, which cannot be sustained into the future.

    Do wealthy farmers implement better agricultural practices? An assessment of implementation of Good Agricultural Practices among different types of independent oil palm smallholders in Riau, Indonesia
    Jelsma, Idsert ; Woittiez, Lotte S. ; Ollivier, Jean ; Dharmawan, Arya Hadi - \ 2019
    Agricultural Systems 170 (2019). - ISSN 0308-521X - p. 63 - 76.
    Farmer typology - Indonesia - Intensification - Land use - Oil palm - Smallholders

    Palm oil has become a leading vegetable oil over the past 30 years and smallholder farmers in Indonesia, with more than 12 million hectare the world's largest producer of palm oil, have massively engaged in oil palm (Elaeis guineensis) cultivation. In Sumatra, where more than 60% of Indonesian palm oil is cultivated, smallholders currently cover roughly 50% of the oil palm area. The rapid expansion of palm oil however did not happen without controversy. In current efforts by the Indonesian government, NGO's and private sector to improve sector performance, smallholders are often characterized as the Achilles heel of the oil palm sector due to poor practices and low yields compared to companies. However, ‘oil palm smallholders’ is a container concept and there has been only limited research into smallholder diversity beyond the organised versus independent farmer dichotomy. This research delves into the implementation of Good Agricultural Practices (GAP) among seven types of independent smallholders in Rokan Hulu regency, Riau province. The research area consisted of a relative established agricultural area on mineral soils and a relative frontier, mostly on peat. Smallholder types ranged from small local farmers to large farmers who usually reside in urban areas far from their plantation and regard oil palm cultivation as an investment opportunity. The underlying hypothesis is that larger farmers have more capital and therefore implement better agricultural practices than small farmers, who are usually more cash constrained. A wide range of methods was applied, including farmer and farm surveys, remote sensing, tissue analysis and photo interpretation by experts. These methods provided data on fertilizer use, nutrient conditions in oil palms, planting material, planting patterns, and other management practices in the plantations. Results show that yields are poor, implementation of GAP are limited and there is much room for improvement among all farmer types. Poor planting materials, square planting patterns, and limited nutrient applications were particularly prevalent. This implies that farmers across different typologies opt for a low-input low-output system for a myriad of reasons and that under current conditions, initiatives such as improving access to finance or availability of good planting material alone are unlikely to significantly improve the productivity and sustainability of the smallholder oil palm sector.

    Agroecological integration of shade- and drought-tolerant food/feed crops for year-round productivity in banana-based systems under rain-fed conditions in Central Africa
    Blomme, G. ; Ocimati, W. ; Groot, J.C.J. ; Ntamwira, J. ; Bahati, L. ; Kantungeko, D. ; Remans, R. ; Tittonell, P. - \ 2018
    In: 10th International Symposium on Banana. - International Society for Horticultural Science (Acta Horticulturae ) - ISBN 9789462611924 - p. 41 - 54.
    Intensification - Resilience - Small-scale farming - Year-round productivity - Yield gaps
    Yield gaps in banana-based production systems have increased in the past two decades due to declining soil fertility, drought and biotic stresses. Sustainable, environmentally sound and economically viable strategies for intensification in these systems are urgently needed. Agroecological practices, such as the integration of shade- and drought-tolerant crops, nitrogen-fixing and cover crops could potentially improve soil fertility and moisture retention, reduce the weed burden, narrow yield gaps and increase overall plot/farm productivity in these systems. In Malaysia, leguminous crops like Pueraria phaseoloides, Calopogonium caeruleum and Centrosema pubescens are often cultivated as cover crops (to suppress weeds, and reduce moisture loss and soil erosion) in young rubber and oil palm plantations with low shade levels. Even in mature oil palm plantations with less than 30% light intensity, various shade-tolerant crops are grown, e.g., elephant foot yam, turmeric and arrow root. In humid tropical Africa, Colocasia (taro) and Xanthosoma (cocoyam) are reported to tolerate shade conditions and hence often planted under perennial banana/plantain plantations. Drought tolerance is a less common feature of most annual crops grown in the humid tropics. A few root and tuber crops (e.g., cassava, taro, yam and sweetpotato) remain in the field during the dry season in Central Africa and are then harvested according to household needs. This paper also reports on crops (Mucuna, lablab and chickpea) with potential for integration into banana-based systems during the dry season, if planted during the last month of the rainy season. These crops are reported to use the residual soil moisture content for continued growth during the dry season months. The paper concludes with detailed descriptions (from a literature review) on drought- and shade-tolerance characteristics of various crops which have long been integrated in Central African banana-based cropping systems, crops with a more recent cultivation history and crops with potential for system integration.
    Environmental impact of milk production across an intensification gradient in Ethiopia
    Woldegebriel, Daniel ; Udo, Henk ; Viets, Theo ; Harst, Eugenie van der; Potting, José - \ 2017
    Livestock Science 206 (2017). - ISSN 1871-1413 - p. 28 - 36.
    Dairying - Environmental impact - Intensification - LCA - Tigray
    This paper quantifies environmental performances of milk production systems differing in degree of intensification in the Mekelle milkshed area, Ethiopia. Life Cycle Assessment (LCA) methodology was used to estimate Land Use (LU), Fossil Energy Use (FEU) and Global Warming Potential (GWP) of the cattle sub-system in 8 large-scale, 8 (peri-)urban and 8 rural farms. The large-scale farms owned considerably more and other types of cattle (35.0 cattle units (cu); mainly Friesians) than the (peri-)urban (6.3 cu; mainly crossbreds) and rural farms (4.1 cu; mainly local breeds). The milk production per average cow per year was much lower in rural farms (730 kg) than in large-scale (2377 kg) and (peri-)urban farms (1829 kg). Milk was the main contributor to the economic benefits of the large-scale (90%) and (peri-)urban (80%) farms, whereas milk (sold and consumed at home) contributed only about 40% to the economic benefits in the multifunctional rural farms. The environmental impacts per cu, reflecting the absolute impacts of cattle keeping, were considerably higher in the large-scale and (peri-)urban farms than in the rural farms. LU and FEU were for the great majority caused by the land use for hay, straws and grasses, and harvesting, transport and processing of feeds, in particular wheat bran. On-farm emissions from enteric fermentation and manure storage were the main contributors to GWP. The impacts per kg milk did not differ significantly between the three systems. The LU per kg milk estimates (9.4, 11.2 and 8.8 m2 in the large-scale, (peri-)urban and rural farms, respectively) were relatively high compared to LCA studies of milk production in developed countries due to large amounts of low-quality forages and wheat bran fed, whereas the FEU values per kg milk (7.5, 11.1 and 6.6 MJ in the large-scale, (peri-)urban and rural farms, respectively) were relatively low compared to studies of milk production systems in developed countries. The GWP estimates per kg milk (1.75, 2.25 and 2.22 kg CO2-equivalents per kg milk in the large-scale, (peri-)urban and rural farms, respectively) were slightly higher than GWP values for the same types of farms in other developing countries, due to the relatively large amounts of low quality feeds fed. The quality of cattle management practices seems more important than the choice for a specific cattle keeping system in reducing environmental impacts of milk production.
    Sustainable intensification in agriculture : the richer shade of green. A review
    Struik, Paul C. ; Kuijper, Thomas - \ 2017
    Agronomy for Sustainable Development 37 (2017)5. - ISSN 1774-0746
    Agronomy - Intensification - Resilience - Resource use efficiency - Sustainability - Trait-based agroecology - Values
    Agricultural intensification is required to feed the growing and increasingly demanding human population. Intensification is associated with increasing use of resources, applied as efficiently as possible, i.e. with a concurrent increase in both resource use and resource use efficiency. Resource use efficiency has agronomic, environmental, economic, social, trans-generational, and global dimensions. Current industrial agriculture privileges economic resource use efficiency over the other dimensions, claiming that that pathway is necessary to feed the world. Current agronomy and the concept of sustainable intensification are contested. Sustainable intensification needs to include clarity about principles and practices for priority setting, an all-inclusive and explicit cost-benefit analysis, and subsequent weighing of trade-offs, based on scientifically acceptable, shared norms, thus making agriculture “green” again. Here, we review different forms of intensification, different principles and concepts underlying them, as well as the norms and values that are needed to guide the search for effective forms of sustainable and ecological intensification. We also address innovations in research and education required to create the necessary knowledge base. We argue that sustainable intensification should be considered as a process of enquiry and analysis for navigating and sorting out the issues and concerns in agronomy. Sustainable intensification is about societal negotiation, institutional innovation, justice, and adaptive management. We also make a plea for at least two alternative framings of sustainable intensification: one referring to the need for “de-intensification” in high-input systems to become more sustainable and one referring to the need to increase inputs and thereby yields where there are currently large yield (and often also efficiency) gaps. Society needs an agriculture that demonstrates resilience under future change, an agronomy that can cope with the diversity of trade-offs across different stakeholders, and a sustainability that is perceived as a dynamic process based on agreed values and shared knowledge, insight, and wisdom.
    Yield gaps in oil palm : A quantitative review of contributing factors
    Woittiez, Lotte S. ; Wijk, Mark T. van; Slingerland, Maja ; Noordwijk, Meine van; Giller, Ken E. - \ 2017
    European Journal of Agronomy 83 (2017). - ISSN 1161-0301 - p. 57 - 77.
    Intensification - Management - Palm oil - Perennial - Physiology - Yield
    Oil palm, currently the world's main vegetable oil crop, is characterised by a large productivity and a long life span (≥25 years). Peak oil yields of 12 t ha−1 yr−1 have been achieved in small plantations, and maximum theoretical yields as calculated with simulation models are 18.5 t oil ha−1 yr−1, yet average productivity worldwide has stagnated around 3 t oil ha−1 yr−1. Considering the threat of expansion into valuable rainforests, it is important that the factors underlying these existing yield gaps are understood and, where feasible, addressed. In this review, we present an overview of the available data on yield-determining, yield-limiting, and yield-reducing factors in oil palm; the effects of these factors on yield, as measured in case studies or calculated using computer models; and the underlying plant-physiological mechanisms. We distinguish four production levels: the potential, water-limited, nutrient-limited, and the actual yield. The potential yield over a plantation lifetime is determined by incoming photosynthetically active radiation (PAR), temperature, atmospheric CO2 concentration and planting material, assuming optimum plantation establishment, planting density (120–150 palms per hectares), canopy management (30–60 leaves depending on palm age), pollination, and harvesting. Water-limited yields in environments with water deficits >400 mm year−1 can be less than one-third of the potential yield, depending on additional factors such as temperature, wind speed, soil texture, and soil depth. Nutrient-limited yields of less than 50% of the potential yield have been recorded when nitrogen or potassium were not applied. Actual yields are influenced by yield-reducing factors such as unsuitable ground vegetation, pests, and diseases, and may be close to zero in case of severe infestations. Smallholders face particular constraints such as the use of counterfeit seed and insufficient fertiliser application. Closing yield gaps in existing plantations could increase global production by 15–20 Mt oil yr−1, which would limit the drive for further area expansion at a global scale. To increase yields in existing and future plantations in a sustainable way, all production factors mentioned need to be understood and addressed.
    Can intensification reduce emission intensity of biofuel through optimized fertilizer use? Theory and the case of oil palm in Indonesia
    Noordwijk, Meine van; Khasanah, Nimatul ; Dewi, Sonya - \ 2017
    Global change biology Bioenergy 9 (2017)5. - ISSN 1757-1693 - p. 940 - 952.
    Biofuel policy - Carbon emission - Fertilizer price - Intensification - Land sparing/sharing - Net emission saving - Palm oil

    Closing yield gaps through higher fertilizer use increases direct greenhouse gas emissions but shares the burden over a larger production volume. Net greenhouse gas (GHG) footprints per unit product under agricultural intensification vary depending on the context, scale and accounting method. Life cycle analysis of footprints includes attributable emissions due to (i) land conversion ('fixed cost'); (ii) external inputs used ('variable cost'); (iii) crop production ('agronomic efficiency'); and (iv) postharvest transport and processing ('proportional' cost). The interplay between fixed and variable costs results in a nuanced opportunity for intermediate levels of intensification to minimize footprints. The fertilizer level that minimizes the footprint may differ from the economic optimum. The optimization problem can be solved algebraically for quadratic crop fertilizer response equations. We applied this theory to data of palm oil production and fertilizer use from 23 plantations across the Indonesian production range. The current EU threshold requiring at least 35% emission saving for biofuel use can never be achieved by palm oil if produced: (i) on peat soils, or (ii) on mineral soils where the C debt due to conversion is larger than 20 Mg C ha-1, if the footprint is calculated using an emission ratio of N2O-N/N fertilizer of 4%. At current fertilizer price levels in Indonesia, the economically optimized N fertilizer rate is 344-394 kg N ha-1, while the reported mean N fertilizer rate is 141 kg N ha-1 yr-1 and rates of 74-277 kg N ha-1 would minimize footprints, for a N2O-N/N fertilizer ratio of 4-1%, respectively. At a C debt of 30 Mg C ha-1, these values are 200-310 kg N ha-1. Sustainable weighting of ecology and economics would require a higher fertilizer/yield price ratio, depending on C debt. Increasing production by higher fertilizer use from current 67% to 80% of attainable yields would not decrease footprints in current production conditions.

    Identifying determinants, pressures and trade-offs of crop residue use in mixed smallholder farms in Sub-Saharan Africa and South Asia
    Valbuena Vargas, Diego ; Tui, Sabine Homann Kee ; Erenstein, Olaf ; Teufel, Nils ; Duncan, Alan ; Abdoulaye, Tahirou ; Swain, Braja ; Mekonnen, Kindu ; Germaine, Ibro ; Gérard, Bruno - \ 2015
    Agricultural Systems 134 (2015). - ISSN 0308-521X - p. 107 - 118.
    Biomass - Conservation agriculture - Crop-livestock farms - Intensification - Intensity - Sustainable intensification

    Crop residues (CR) have become a limited resource in mixed crop-livestock farms. As a result of the increasing demand and low availability of alternative resources, CR became an essential resource for household activities, especially for livestock keeping; a major livelihood element of smallholder farmers in the developing world. Farmers' decisions on CR use are determined by farmers' preferences, total crop production, availability of alternative resources and demand for CR. Interaction of these determinants can result in pressures and trade-offs of CR use. Determinants, pressures and trade-offs are shaped by the specific socio-economic and agro-ecological context of these mixed farms. The objective of this paper is to provide a comparative analysis of the determinants of CR use and to examine some options to cope with pressures and trade-offs in 12 study sites across Sub-Saharan Africa and South Asia. Drawing on socio-economic data at household and village level, we describe how cereal intensification and livestock feed demand influence use, pressures and trade-offs of CR use across study sites, specifically cereal residue. Our results show that in low cereal production and livestock feed demand sites, despite a low demand for CR and availability of alternative biomass, pressures and trade-offs of CR use are common particularly in the dry season. In sites with moderate cereal production, and low-moderate and moderate livestock feed demand, alternative biomass resources are scarce and most residues are fed to livestock or used to cover household needs. Subsequently, pressures and potential trade-offs are stronger. In sites with low cereal production and high livestock feed demand, pressures and trade-offs depend on the availability of better feed resources. Finally, sites with high cereal production and high livestock feed demand have been able to fulfil most of the demand for CR, limiting pressures and trade-offs. These patterns show that agricultural intensification, better management of communal resources and off-farm activities are plausible development pathways to overcome pressures and trade-offs of CR use. Although technologies can largely improve these trends, research and development should revisit past initiatives so as to develop innovative approaches to tackle the well-known problem of low agricultural production in many smallholder mixed systems, creating more sustainable futures.

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