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13 November 2020 | Story Leonie Bolleurs | Photo Dr Beanelri Janecke
Five of the multidisciplinary team of researchers and some postgraduate students are determining the depth of soil on the underlying rock layer of the sodic site in the Kruger National Park.

When the Vice-Rector: Research, Prof Corli Witthuhn, invited researchers to apply for funding towards multidisciplinary and interdepartmental projects in 2015, Prof Piet le Roux from the Institute for Groundwater Studies, and the late Dr Fred Kruger from the Centre for Environmental Management took the opportunity and proposed a project to study a catenal ecosystem in the Kruger National Park

According to Dr Beanélri Janecke from the Department of Animal, Wildlife and Grassland Sciences, who led the research team on this project, the team of researchers worked for four years, finding links between the catenal ecosystem (which can be described as a hillslope with different zones forming an environmental gradient from crest to foothill) and processes behind some of its abiotic (non-living) and biotic (living) components. 

Large-scale multidisciplinary research project

All their research on this multidisciplinary project was published in one Special Issue of the Koedoe journal at the end of October 2020. Dr Janecke and Prof Johan van Tol from the Department of Soil, Crop and Climate Sciences were guest editors of this special issue. Dr Llewellyn Foxcroft from SANParks is the Editor-in-Chief of the journal. Other UFS departments involved in this project include the Departments of Genetics; Microbial, Biochemical and Food Biotechnology; Plant Sciences; and Zoology and Entomology.

Dr Janecke says there are 12 articles in this issue and, together with the principal researchers (but excluding postgraduate students), there were 12 authors from the UFS (eight departments and divisions in the Faculty of Natural and Agricultural Sciences) and two from SANParks in associated research collaboration with authors from 14 other institutions. 

This special issue of the Koedoe journal covered research on hydrology, flowpaths, and ground water, including the soil types and properties of different zones on the catena. As stated by Dr Janecke, there are also articles on micro-organisms, fungi, and Fusarium in the soil of the root zone of plants (rhizobiome). 

The environment is degrading fast due to human activities, and there is a dire need for research to look at the bigger picture to find solutions on how to conserve ecosystems and not only smaller parts thereof. – Dr Beanélri Janecke

The journal also comprised articles on the vegetation communities and vegetation structure in the different zones. “Research on how the vegetation recovered post-drought of 2016-2017 and on large and small mammals present on the catena and at the closest waterholes was also published. All of these topics were linked in a discussion article on the catenal ecosystem,” says Dr Janecke.

Multidisciplinary research is not conducted very often on this scale. Many researchers will rather focus on one or a few specific aspects of the ecosystem in a specialist research field. 

SANParks introduced supersite concept

Dr Janecke says scientists from SANParks initiated this supersite concept, where research can be focused on specific areas with similar geology and landscapes in the Kruger National Park to generate multidisciplinary data from separate specialist research fields. 

“Our project went one step further and combined different research fields into one project done on a supersite over the same period. This multidisciplinary project created the opportunity for specialist research fields to be published separately in one special issue, but also to combine the expertise in one project that was summarised in a discussion article.”

She believes that the environment is degrading fast due to human activities, and that there is a dire need for research to look at the bigger picture to find solutions on how to conserve ecosystems and not only smaller parts thereof. “There is a need for a more holistic approach to research, and this special issue provides a framework and basis for similar multidisciplinary studies in future,” states Dr Janecke.

This issue is currently widely marketed on all social platforms of the Koedoe journal and AOSIS Publishers, while a podcast interview is also available at:  https://soundcloud.com/aosis-za/koedoe-interview-podcast-2020 (with permission from Louw Lombaard from AOSIS).

News Archive

Sunflowers are satellite dishes for sunshine, or are they?
2016-07-20

Eighty-six percent of South Africa’s
sunflowers are produced in the
Free State and North West provinces.

Helen Mirren, the English actress, said “the sunflower is like a satellite dish for sunshine”. However, researchers at the University of the Free State (UFS) have found that too much of this sunshine could have a negative effect on the growth of sunflowers, which are a major source of oil in South Africa.

According to Dr Gert Ceronio from the Department of Soil, Crop, and Climate Sciences at the UFS, extremely high soil temperatures play a definite role in the sprouting of sunflower seedlings. Together with Lize Henning, professional officer in the department, and Dr André Nel from the Agricultural Research Council, he is doing research on biotic and abiotic factors that could have an impact on sunflowers.

Description: Sonneblom 2 Tags: Sonneblom 2

Various degrees of deformity (bad-left
to none-right) in seedlings of the same
cultivar at very high soil temperatures.
Photo: Dr Gert Ceronio

Impact of high temperatures on sunflower production

The Free State and North West provinces, which produce 86% of South Africa’s sunflowers, are afflicted especially by high summer temperatures that lead to extremely high soil temperatures.

Dr Ceronio says: “Although sunflower seeds are able to germinate at temperatures from as low as 4°C to as high as 41°C, soil temperatures of 35°C and higher could have a negative effect on the vegetative faculty of sunflower seedlings, and could have an adverse effect on the percentage of sunflowers that germinate. From the end of November until mid-January, this is a common phenomenon in the sandy soil of the Free State and North West provinces. Soil temperatures can easily exceed the critical temperature of 43°C, which can lead to poor germination and even the replanting of sunflowers.”

Since temperature have a huge impact not only on the germination of sunflower seeds, but also on the vegetative faculty and sprouting of sunflower seedlings, Dr Ceronio suggests that sunflowers should be planted in soil with soil temperatures of 22 to 30°C. Planting is usually done in October and early November. Unfortunately, this is not always possible, as soil moisture is not optimal for growth. Farmers are then compelled to plant sunflowers later.

Impact of herbicides on sunflower growth

“High soil temperatures, combined with the herbicide sensitivity of some cultivars, could lead to the poor development of seedlings," says Dr Ceronio.

The use of herbicides, such as ALACHLOR, for the control of weeds in sunflowers is common practice in sunflower production. It has already been determined that ALACHLOR could still have a damaging effect on the seedlings of some cultivars during germination and sprouting, even at recommended application dosages.

“The purpose of the continued research is to establish the sensitivity of sunflower cultivars to ALACHLOR when exposed to high soil temperatures,” says Dr Ceronio.

 

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