Linus Franke

Linus Franke
University of the Free State | ufs · Department of Soil- and Crop and Climate Sciences

PhD

About

98
Publications
42,677
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2,309
Citations
Citations since 2017
31 Research Items
1761 Citations
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20172018201920202021202220230100200300
20172018201920202021202220230100200300

Publications

Publications (98)
Article
The abilities of grain legumes to fix atmospheric nitrogen are well documented, but the non-N effects of incorporating legumes into cereal-based systems are poorly understood. Continuous cropping of maize is assumed to increase maize fungal root pathogens, but few studies have documented this in sub-Saharan Africa. In this study, it was hypothesize...
Article
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Underutilized crops, such as okra, have the potential to alleviate stress on crop production imposed by climate change and farming conditions, but their production is greatly hindered by poor seed quality. Insect pollination and seed coating with organic substances (biochar) may improve okra’s seed performance, but the beneficial effects of biochar...
Article
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The South African policy sphere hails the commercialisation of small-scale farming as the answer to a myriad of socio-economic, ecological and political challenges of rural livelihoods. Yet the low agricultural productivity of this sector challenges the realisation of this pathway. Through comparison with large-scale farmers, this review sought to...
Article
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High-density grazing is a form of rangeland management aiming to strategically mimic the ways grasslands are utilized by grazers in natural situations. It aims to regenerate grasslands by improving soil and vegetation productivity and diversity. More recently, high-density grazing systems have been promoted as a key approach to mitigating climate c...
Chapter
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Significance Statement The chapter describes the conflicting interests of water users in the uThukela catchment of the Maloti-Drakensberg (MD) mountain system, including the implications of poor management on ecosystem health and livelihoods. As this is a strategic water resource area for both Lesotho and South Africa, effective management towards...
Article
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Leguminous plants are known to require phosphorus fertilizers and inoculation with nitrogen fixing rhizobia for optimum yield but other nutrients may also be lacking. In this study, the most limiting nutrients for legume growth were determined in soils where the crops had not responded to P and rhizobial inoculation in field trials, using the doubl...
Article
Increasing nutrient loads from land use and land cover (LULC) change degrade water quality through eutrophication of aquatic ecosystems globally. The Vaal River Catchment in South Africa is an agriculturally and economically important area where eutrophication has been a problem for decades. Effective mitigation strategies of eutrophication in this...
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Research to inform a sustainable future for southern African mountains as socialecological systems requires major investment. This is needed to strengthen existing relationships, build new relationships among academia, policy, and practice, and drive a robust research capacity program. This is particularly important in disciplines where there is cu...
Article
Abstract To exploit the potential of ecological intensification during sunflower cropping, it is crucial to understand the potential synergies between crop management and ecosystem services. We therefore examined the effect of pollination intensification on sunflower yield and productivity under various levels of soil fertilization over two seasons...
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To exploit the potential of ecological intensification during sunflower cropping, it is crucial to understand the potential synergies between crop management and ecosystem services. We therefore examined the effect of pollination intensification on sunflower yield and productivity under various levels of soil fertilization over two seasons in the e...
Article
A correct estimation of crop coefficients (KC) is essential to assess water requirements of crops from weather variables and thereby optimize irrigation management. KC depends on crop type and varies with crop growth stage, and to a limited extent, with climate. KC values are often assumed to be transferable between locations and climates. KC value...
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This paper provides a systematic review of studies assessing the impact of climate change on crop yields in southern Africa. Moreover, it synthesises the current knowledge of the impact of elevated ambient CO2 levels (eCO2) and temperatures on physiological processes, and the application of this knowledge in mechanistic crop models. While eCO2 evid...
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South Africa harbours many small-scale potato growers who produce for home consumption and local markets using variable levels of inputs (seed, nutrients, water). We assessed potato production practices, input resource use and use efficiencies, farm characteristics and yield gaps on smallholder potato farms in the KwaZulu Natal and Mpumalanga Provi...
Article
In South Africa, the potato is produced in regions with different climates. Climate change is expected to result in higher temperatures, thus increasing the incidence of heat stress, but lowering the risk of frosts in mid-altitude areas. Increasing ambient carbon dioxide levels can enhance photosynthetic rates and reduce water use of potato. This s...
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Satellite-based weather estimates are spatially and temporally continuous data that seamlessly capture weather variability across the globe. A need was identified to assess the usefulness and reliability of satellite-based weather estimates in the lower Vaal River Catchment due to the scarcity of weather data. We explored the utility of Climate For...
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Climbing bean is the key staple legume crop in the highlands of East and Central Africa. We assessed the impact of interactions between soil fertility characteristics, crop management and socio-economic factors, such as household resource endowment and gender of the farmer, on climbing bean productivity and yield responses to basal P fertiliser in...
Article
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The large diversity of farms and farming systems in sub-Saharan Africa calls for agricultural improvement options that are adapted to the context in which smallholder farmers operate. The socio-ecological niche concept incorporates the agro-ecological, socio-cultural, economic and institutional dimensions and the multiple levels of this context in...
Article
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Soil nutrient constraints coupled with erratic rainfall have led to poor crop yields and occasionally to crop failure in sole cropping in the Guinea savanna of West Africa. We explored different maize-grain legume diversification and intensification options that can contribute to mitigating risks of crop failure, increase crop productivity under di...
Chapter
The Quantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model recommended as a decision support tool for deriving optimal site-specific fertilizer rates for cassava has limited ability to estimate water-limited yields. We assessed potential and water-limited yields based on the light interception and utilization (LINTUL) modelling a...
Article
We adapted and used a crop simulation model based on light interception and use efficiency (LINTUL-Cassava) to improve our understanding of water-limited yields of cassava under rain-fed conditions in Southern Togo. Data collected in four different fields in two locations, Sevekpota and Djakakope, during two consecutive growing seasons from 2012 to...
Article
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Orange-fleshed sweet potato (OFSP) can contribute to combating vitamin A deficiency and establishing more resilient cropping systems in sub-Saharan Africa. There is limited understanding of the factors that affect yield and quality of OFSP on smallholder farmers' fields. This study aimed to assess the performance of six OFSP varieties, identify fac...
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Background and aims Enhanced understanding of plant and nutrient interactions is key to improving yields. We adapted the model for QUantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) to assess cassava yield response to soil and fertilizer nutrients in West Africa. Methods Data from on-station and farmer’s field experiments across T...
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Smallholder farmers in the Guinea savanna practise cereal-legume intercropping to mitigate risks of crop failure in mono-cropping. The productivity of cereal-legume intercrops could be influenced by the spatial arrangement of the intercrops and the soil fertility status. Knowledge on the effect of soil fertility status on intercrop productivity is...
Article
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We conducted a systematic review of literature on the residual effects of grain legumes in cereal-based systems of sub-Saharan Africa (SSA) to quantify the magnitude and variability of rotational effects, to explore the importance of environmental and management factors in determining variability and to evaluate the evidence of the different mechan...
Article
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Continuous cereal-based cropping has led to a rapid decline in soil fertility in the Guinea savanna agro-ecological zone of northern Ghana with corresponding low crop yields. We evaluated the effects of cropping system and soil fertility status on grain yields and N2-fixation by grain legumes and net N contribution to soil fertility improvement in...
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Soybean production can contribute to the nitrogen economy of smallholder farming systems, but our understanding of factors explaining variability in nitrogen fixation and rotational benefits across farms and regions is limited. Biological nitrogen fixation (BNF) was quantified with the natural abundance method in 150 farmer-managed soybean plots un...
Article
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This paper presents the results of field studies conducted in Togo (Djakakope and Sevekpota) to assess the effect of potassium (K) on cassava yield, water use efficiency (WUE) and transpiration as affected by nitrogen (N) and phosphorus (P) availability under rainfed conditions. It was shown that an adequate K fertilizer supply was requisite for in...
Article
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SUMMARY The large diversity of farms and farming systems in sub-Saharan Africa calls for agricultural improvement options that are adapted to the context in which smallholder farmers operate. The socio-ecological niche concept incorporates the agro-ecological, socio-cultural, economic and institutional dimensions and the multiple levels of this con...
Article
Full-text available
A potato crop multi-model assessment was conducted to quantify variation among models and evaluate responses to climate change. Nine modeling groups simulated agronomic and climatic responses at low- (Chinoli, Bolivia and Gisozi, Burundi) and high- (Jyndevad, Denmark and Washington, United States) input management sites. Two calibration stages were...
Article
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Soybean yields on smallholder farmers’ fields in Malawi are constrained by poor soil fertility, limited application of external inputs and poor crop husbandry. We tested crop management practices through on-farm experimentation and participatory technology evaluation. Two agronomic soybean trials were established in 2009 and 2010 in three contrasti...
Article
Full-text available
Climbing bean is the key staple legume crop in the highlands of East and Central Africa. We assessed the impact of interactions between soil fertility characteristics, crop management and socio-economic factors, such as household resource endowment and gender of the farmer, on climbing bean productivity and yield responses to basal P fertiliser in...
Article
In 1994, LINTUL-POTATO was published, a comprehensive model of potato development and growth. The mechanistic model simulated early crop processes (emergence and leaf expansion) and light interception until extinction, through leaf layers. Photosynthesis and respiration in a previous crop growth model—SUCROS—were substituted by a temperature-depend...
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A set of daily weather data simulations for 1961 to 2050 were used to calculate past and future trends in pest and disease pressure in potato cropping systems at three agro-ecologically distinct sites in South Africa: the Sandveld, the Eastern Free State and Limpopo. The diseases and pests modelled were late blight, early blight and brown spot, bla...
Article
This study aims to assess the risks and opportunities posed by climate change to potato growers in South Africa and to evaluate adaptation measures in the form of changes in planting time growers could adopt to optimise land and water use efficiencies in potato, using a climate model of past, present-day and future climate over southern Africa and...
Article
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Explorations of the impact of climate change on potential potato yields were obtained by downscaling the projections of six different coupled climate models to high spatial resolution over southern Africa. The simulations of daily maximum and minimum temperatures, precipitation, wind speed, and solar radiation were used as input to run the crop gro...
Article
To develop a modelling framework which can simulate long-term quality of life, societal costs and cost-effectiveness as affected by sequential drug treatment strategies for ankylosing spondylitis (AS). Discrete event simulation paradigm was selected for model development. Drug efficacy was modelled as changes in disease activity (Bath Ankylosing Sp...
Article
The sustainability of agricultural production is linked to the environment from which it draws its resources. Potato production in the Sandveld in the South African Western Cape occurs in the Cape Floral Kingdom: a vulnerable and globally significant biodiversity hotspot. A scientific approach defining and monitoring sustainability criteria and ind...
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Cited By (since 1996):4, Export Date: 12 November 2013, Source: Scopus, CODEN: MCBEB, doi: 10.1007/s00248-011-9845-4, PubMed ID: 21424277, Language of Original Document: English, Correspondence Address: Overbeek, L. S.; Plant Research International BV, Wageningen University and Research Center, Droevendaalsesteeg 1, 6708 PB, Wageningen, Netherlands...
Article
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This report adresses the question whether the cultivation of genetically modified (GM) crops abroad for import in the Netherlands, as compared to the cultivation of their conventional (non-GM) counterparts, is in line with Dutch policy and societal aims striving after more sustainable forms of agriculture worldwide and the utilization of the benefi...
Article
Deze studie richt zich op genetische modificatie bij gewassen. Wereldwijd werden in 2010 op meer dan 140 miljoen hectare GG-gewassen verbouwd. Dit is ongeveer 70 maal het totale Nederlandse landbouwareaal. Het gaat met name om de handelsgewassen soja, maïs, katoen en koolzaad. Twee GG gewassen zijn ondertussern in de EU toegelaten voor teelt, namel...
Article
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Integrated crop-livestock farming in the Guinea savanna of West Africa is often assumed to lead to synergies between crop and livestock production, thereby improving the overall productivity and resilience of agricultural production. Whether these synergies actually occur remains poorly studied. On-farm trials were conducted in northern Nigeria ove...
Technical Report
Full-text available
Drift from the application of crop protection products can cause damage to neighboring crops, ecosystems and human health. In this report, estimations of spray drift with reference to Chinese agricultural systems are provided, based on data from literature and a modeling study. As knapsack sprayers make up the most important tool for pesticide appl...