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25 July 2019 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Plant Sciences Congress
At a public seminar, Understanding human evolution through the study of past environments in the Free State, presented by the UFS Department of Plant Sciences, were, from the left, front: Kristen Wroth, Britt Bousman; back: Prof Louis Scott, mentor in the UFS Department of Plant Sciences, and Michael Toffolo.

Florisbad, a thermal spring situated 45 km northwest of Bloemfontein on the edge of a large dry saltpan, is a well-known fossil site that used to be a large lake where giant buffalo, blue wildebeest, and hippos roamed thousands of years ago. Today, this fossil-bearing spring is not only a tourist attraction and a venue for weddings, but also an established quaternary research station that has attracted several palaeo-scientists since the 1930s, following the discovery of a remarkable human cranium and other fauna. 

Studies of past environments 

Three international researchers studying different aspects of archaeology at this and other sites in the Free State, recently presented lectures at the UFS to a multidisciplinary group of academics in plant sciences, geology, geography, and environmental management.

These lectures are part of the ongoing collaboration regarding fossil plant (pollen), fauna, and archaeological studies between the University of the Free State (UFS), the National Museum, and universities abroad.

Florisbad, a key site for understanding the appearance of modern environments as well as modern humans in Southern Africa, is the focus of the investigations of all three visiting scientists, aiming to provide a better understanding of past Free State environments where human evolution has taken place.

Michael Toffolo, a junior research chair from the University of Bordeaux Montaigne in France, focuses on the reconstruction of site-formation processes, palaeo-environments, and ancient human activities based on the study of the micro-morphology of archaeological deposits. He has been working in Southern Africa since 2013. The title of his lecture was: Reconstructing Pleistocene environments in the Free State by looking at the microscopic sedimentary record. 

Fluoride-preserved bones

Florisbad is widely known for the discovery of an archaic modern human skull of c. 260 000 years old. According to Toffolo, the human probably died, and the remains was left at the spring by the hyenas. The bones consequently absorbed fluoride from the spring water, which counteracted decomposition and helped to preserve it. 

Britt Bousman talked about middle and late Pleistocene terraces and archaeology in the Modder River Valley. He has worked in Southern Africa for the past 43 years and started his collaboration with researchers from the UFS and the National Museum in 1985. They have worked together at several sites, investigating palaeo-environments. Bousman teaches Archaeology in the Department of Anthropology at the Texas State University. 

While most scientists study early human records in rock shelters, especially those near the coast where seafood was harvested by prehistoric people, he is one of only a few researchers who studies the evolution of early human behaviour in central South Africa in the context of their activities in the open environment. 

“Rock shelters are good spaces for human behaviour,” says Bousman. He believes, however, that the Modder River area is a better space to study how humans have survived on the land under changing climatic conditions in the long term; for example, how they hunted and slaughtered animals. This can be seen from the many artefacts they left, such as spearheads, scrapers, etc. Interesting animal remains were also found, such as the bones of an extinct giant zebra at the Erfkroon site along the Modder River, with a head measuring 63 cm compared to that of a current zebra, which measures 54 cm. The only complete horn core of an extinct giant wildebeest was also found at the site. 

The first chemists

According to Bousman, technology changed in the Stone Age and included the production of more grinding stones, indicating that humans collected plants and grinded them. Observations of modern plant-collecting activities suggested that not many plant foods needed grinding. Bousman proposes that different plant components may have been grinded for medicinal mixtures, therefore these ancestors may have assumed the role of chemists. 

Kristen Wroth, a postdoctoral researcher in the Geoarchaeology Working Group at the University of Tübingen, Germany, presented a lecture on early human-environment interactions and ancient pyro technology. She uses a suite of micro-archaeological techniques such as phytolith (microscopic plant silica) analysis, micromorphology, and FTIR to understand both human and Neanderthal behaviour and to reconstruct how local environments have changed in space and through time.


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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