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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    Impacts of climate change: a sensitivity analysis to understand the role of soil fertility and water on maize production in the face of climate uncertainty northwest, Zimbabwe.
    Masikati, Patricia ; Descheemaeker, K.K.E. ; Crespo, O. ; Rurinda, J. - \ 2016
    - p. 320 - 321.
    Sources of vulnerability to a variable and changing climate among smallholder households in Zimbabwe: A participatory analysis
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2014
    Climate Risk Management 3 (2014). - ISSN 2212-0963 - p. 65 - 78.
    Vulnerability analysis is essential for targeting adaptation options to impacts of climate variability and change, particularly in diverse systems with limited resources such as smallholder farms in sub-Saharan Africa. To investigate the nature and sources of vulnerability of smallholder farmers to climate variability and change, we analysed long term climate data and interviewed farmers individually and in groups in Makoni and Hwedza districts in eastern Zimbabwe. Farmers’ perceptions of changes in climate characteristics matched the recorded data. Total seasonal rainfall has not changed, but variability in the rainfall distribution within seasons has increased. The mean daily minimum temperature increased by 0.2 °C per decade in both Makoni and Hwedza. The mean daily maximum temperature increased by 0.5 °C per decade in Hwedza. The number of days with temperatures >30 °C also increased in Hwedza. Farmers indicated that livestock production was sensitive to drought due to lack of feed, affecting resource-endowed farmers, who own relatively large herds of cattle. Crop production was more sensitive to increased rainfall variability, largely affecting farmers with intermediate resource endowment. Availability of wild fruits and social safety nets were affected directly and indirectly by extreme temperatures and increased rainfall variability, impacting on the livelihoods of resource-constrained farmers. There was no evidence of a simple one-to-one relationship between vulnerability and farmer resource endowment, suggesting that vulnerability to climate variability and change is complex and not simply related to assets. Alongside climate variability and change, farmers were also faced with biophysical and socioeconomic challenges such as lack of fertilizers, and these problems had strong interactions with adaptation options to climate change. Diversifying crops and cultivars, staggering planting date and managing soil fertility were identified as the major adaptation options to stabilize yields against increased rainfall variability. There is need to evaluate the identified adaptation options on farm and with the participation of farmers to provide empirical evidence on the best options for different households.
    Vulnerability and adaptation to climate variability and change in smallholder farming systems in Zimbabwe
    Rurinda, J. - \ 2014
    Wageningen University. Promotor(en): Ken Giller, co-promotor(en): P. Mapfumo; Mark van Wijk. - Wageningen : Wageningen University - ISBN 9789461739605 - 168
    klimaatverandering - kleine landbouwbedrijven - bedrijfssystemen - klimaatadaptatie - adaptatie - klimaat - gewasopbrengst - zimbabwe - climatic change - small farms - farming systems - climate adaptation - adaptation - climate - crop yield - zimbabwe

    Keywords: Climate change; Increased climate variability; Vulnerability; Smallholder farmers; Adaptation

    Climate change and increased climate variability are currently seen as the major constraints to the already stressed smallholder farming livelihood system in southern Africa. The main objectives of this study were first to understand the nature and sources of vulnerability of smallholder farmers to climate variability and change, and second to use this knowledge to evaluate possible farm-level management options that can enhance the adaptive capacity of smallholder farmers in the face of increased climate variability and long-term change in climate. The study was conducted in Makoni and Hwedza districts in eastern Zimbabwe. Local famers’ and expert empirical knowledge were combined using research tools that mainly included detailed field observations and surveys, systems analysis and field experimentation, and simulation modelling (the Agricultural Production Systems Simulator (APSIM)). To understand the nature and sources of vulnerability, long term climate data were analysed and farmers were interviewed individually and in groups. On-farm experimentation and simulation modelling were conducted to evaluate the impacts and interactions of adaptation options namely maize cultivar choice, staggered planting dates, and variable fertilizer rates, on maize yield under both short-term climate variability and long-term climate change. Another on-farm experiment was conducted to assess whether small grains (finger millet and sorghum) perform as well as maize under variable soil and rainfall conditions.

    The long-term rainfall and temperature analyses closely supports farmers’ perceptions that the total annual rainfall has so far not changed, but variability in the rainfall distribution within seasons has increased. The number of rain days has decreased, and the frequency of dry spells within season increased. The mean daily minimum temperature increased by 0.2°C per decade in Makoni, and by 0.5°C per decade in Hwedza, over the period from 1962 to 2000. The surface air temperature is further projected to increase significantly in Makoni and Hwedza, by 2100. The impacts of rising temperatures and increased rainfall variability among smallholder households were highly differentiated because different households depend on varied farming livelihood sub-systems, which were exposed uniquely to aspects of climatic risk. For example, livestock production was sensitive to drought due to lack of feed, affecting resource-endowed farmers, who often own relatively large herds of cattle. Crop production was more sensitive to increased rainfall variability, affecting especially farmers with intermediate resource endowment. Availability of wild fruits and social safety nets were affected directly and indirectly by extreme temperatures and increased rainfall variability, impacting the livelihoods of poorer farmers. Farmers have also access to different biophysical and socioeconomic resources such as fertilizer and farm labour inputs, and as a result they respond variedly to impacts of a changing climate. Thus, alongside climate variability and change, farmers also faced biophysical and socioeconomic challenges, and these challenges had strong interactions with adaptation options to climate change.

    Experimentation in this studydemonstrated that the maize cultivars currently on the market in Zimbabwe, and in many parts of southern Africa, exhibit narrow differences in maturity time such that they do not respond differently to prolonged dry spells. The yield performance for all three cultivars is projected to be similar in future change in climates, consistent with results from the experiments.In the current cropping system farmers can select any cultivar available on the market without a yield penalty. However, with climate change none of the available cultivars will be able to compensate for the decline in yield. Greater maize grain yields were obtained with both the early (25 October – 20 November) and normal (21 November – 15 December) plantings, with no significant differences between these planting windows(e.g. on average 5 t ha-1 in Makoni, and 3 t ha-1 in Hwedza for the high fertilization rate).Contrary to previous research findings, there is a reasonably wide planting window in which good yields can be obtained if the rains start on time, but if the start of the rains is delayed until after the beginning of December planting should be done as soon as possible. Regardless of the amount of fertilizer applied, yields were reduced strongly when planting was substantially delayed by four weeks after the start of the rainy season. Maize yielded more than finger millet and sorghum even when rainfall was poor in the 2010/2011 season. For example, maize yielded 2.4 t ha-1 compared with 1.6 t ha-1 for finger millet and 0.4 t ha-1 for sorghum in the 2010/2011 rainfall season in Makoni. Finger millet and sorghum failed to emerge unless fertilizer was applied. Application of manure alone failed to address this challenge of poor emergence until fertilizer was added. Sorghum suffered critical yield losses due to bird damage. The better performance of maize over finger millet and sorghum suggested that the recommendation to substitute small grains for maize as a viable adaptation option to a changing climate, will neither be the best option for robust adaptation nor attractive for farmers in southern Africa. Alternatively spreading crops across the farm and in time can be a viable strategy to spread climatic risk as well as improve human nutrition. Poor soil fertility constrained yield more strongly than rainfall and late planting, as demonstrated by the large yield gap (> 1.2 t ha-1) between the unfertilized and fertilized cultivars even in the poor rainfall season (2010/2011).

    Fertilization increased yield significantly under both the baseline and future climates particularly when planting before mid-December.The maize response to mineral nitrogen is, however, projected to decline as climate changes, although effects only become substantial towards the end of the 21st Century. Soil fertility management is therefore likely to be a major entry point for increasing the adaptive capacity of smallholder farmers to climate change and increased climate variability. However, management of factors related to both nutrient resource access and farmers decisions to enhance resource use efficiencies are critical if agriculture is to be used as robust adaptation options to climate change by smallholder in Southern Africa.

    Comparative assessment of maize, finger millet and sorghum for household food security in the face of increasing climatic risk
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2014
    European Journal of Agronomy 55 (2014). - ISSN 1161-0301 - p. 29 - 41.
    southern africa - soil fertility - pearl-millet - sandy soil - zimbabwe - variability - management - adaptation - productivity - agriculture
    Questions as to which crop to grow, where, when and with what management, will be increasingly challenging for farmers in the face of a changing climate. The objective of this study was to evaluate emergence, yield and financial benefits of maize, finger millet and sorghum, planted at different dates and managed with variable soil nutrient inputs in order to develop adaptation options for stabilizing food production and income for smallholder households in the face of climate change and variability. Field experiments with maize, finger millet and sorghum were conducted in farmers’ fields in Makoni and Hwedza districts in eastern Zimbabwe for three seasons: 2009/10, 2010/11 and 2011/12. Three fertilization rates: high (90 kg N ha-1, 26 kg P ha-1, 7 t ha-1 manure), low (35 kg N ha-1, 14 kg P ha-1, 3 t ha-1 manure) and a control (zero fertilization); and three planting dates: early, normal and late, were compared. Crop emergence for the unfertilized finger millet and sorghum was 70% for the fertilized treatments. In contrast, the emergence for maize (a medium-maturity hybrid cultivar, SC635), was >80% regardless of the amount of fertilizer applied. Maize yield was greater than that of finger millet and sorghum, also in the season (2010/11) which had poor rainfall distribution. Maize yielded 5.4 t ha-1 compared with 3.1 t ha-1 for finger millet and 3.3 t ha-1 for sorghum for the early plantings in the 2009/10 rainfall season in Makoni, a site with relatively fertile soils. In the poorer 2010/11 season, early planted maize yielded 2.4 t ha-1, against 1.6 t ha-1 for finger millet and 0.4 t ha-1 for sorghum in Makoni. Similar yield trends were observed on the nutrient-depleted soils in Hwedza, although yields were less than those observed in Makoni. All crops yielded significantly more with increasing rates of fertilization when planting was done early or in what farmers considered the ‘normal window’. Crops planted early or during the normal planting window gave comparable yields that were greater than yields of late-planted crops. Water productivity for each crop planted early or during the normal window increased with increase in the amount of fertilizer applied, but differed between crop type. Maize had the highest water productivity (8.0 kg dry matter mm-1 ha-1) followed by sorghum (4.9 kg mm-1 ha-1) and then finger millet (4.6 kg mm-1 ha-1) when a high fertilizer rate was applied to the early-planted crop. Marginal rates of return for maize production were greater for the high fertilization rate (>50%) than for the low rate (100%) than for the high rate (
    Managing soil fertility to adapt to rainful variability in smallholder cropping systems in Zimbabwe
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2013
    Field Crops Research 154 (2013). - ISSN 0378-4290 - p. 211 - 225.
    climate-change - southern africa - sandy soil - corn production - use efficiency - food security - management - maize - farmers - yield
    Adaptation options that address short-term climate variability are likely to lead to short-term benefits and will help to deal with future changes in climate in smallholder cropping systems in Sub-Saharan Africa (SSA). In this study we combined field experimentation and long-term rainfall analyses in Makoni and Hwedza districts in eastern Zimbabwe to evaluate cropping adaptation options to climate variability. Analyses of long-term rainfall data closely supports farmers’ perceptions that the mean annual total rainfall has not changed, but the pattern of rainfall within-season has changed: the number of rainfall days has decreased, and the frequency of dry spells has increased at the critical flowering stage of maize. On-farm experiments were conducted over two cropping seasons, 2009/10 and 2010/11 to assess the effects of planting date, fertilization and cultivar on maize production. Three maize cultivars were sown in each of the early, normal and late planting windows defined by farmers. Each of the nine cultivar-planting date combinations received N, P, K and manure combinations at either zero, low or high fertilization rates. Overall, there were no significant differences in maize development or grain yield among cultivars. Maize grain yield was increased by increasing the amount of nutrients applied. Average yield was 2.5 t ha-1 for the low rate and 5.0 t ha-1 for the high rate on early planted cultivars on relatively fertile soils in Makoni in 2009/10 season. Yields on poorer soils in Hwedza were small, averaging 1.5 t ha-1 for the low rate and 2.5 t ha-1 for the high rate. Maize grain yields for the early and normal planted cultivars were similar for each fertilization rate, suggesting there is a wide planting window for successful establishment of crops in response to increased rainfall variability. Yield reduction of >50% was observed when planting was delayed by 4 weeks (late planting) regardless of the amount of fertilizer applied. Soil nutrient management had an overriding effect on crop production, suggesting that although the quality of within-season rainfall is decreasing, nutrient management is the priority option for adaptation in rain-fed smallholder cropping systems.
    Comparative productivity of maize, finger millet and sorghum for household food security in the face of increasing climatic
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2013
    Managing soil fertility to adapt to climate variability in smallholder systems of Zimbabwe
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2012
    Managing soil fertility to adapt to climate variability in smallholder systems of Zimbabwe
    Rurinda, J. ; Mapfumo, P. ; Wijk, M.T. van; Mtambanengwe, F. ; Rufino, M.C. ; Chikowo, R. ; Giller, K.E. - \ 2012
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