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25 May 2020 | Story Dr Ralph Clark | Photo Charl Devenish
Afromontane research area in the Eastern Free State.

Africa could be called ‘the continent of mountain archipelagos’ for the unusual fact that most of Africa's mountains are isolated ‘islands’ rather than linear, continuous mountain systems such as those in Asia (e.g. the Himalayas), Europe (e.g. the Alps), and the Americas (e.g. Rockies and Andes). Even in Southern Africa, where we have the linear Great Escarpment (5 000 km long), this system is so old that it has been breached in innumerable places by erosion into a series of independent mountain blocks.

The result of this mountain disconnection is that Africa's mountains display biodiversity patterns more akin to islands than to mountains: rich, exciting, and unique, and full of very localised and interesting species. Likewise, mountain communities have established and evolved unique cultural ways of life and traditions in their particular mountains – isolated from other groups on other mountains. But in some mountains, internecine warfare and tribal conflict caused mountains to become boundaries rather than welcoming places. This was certainly the case during the Mfecane in Southern Africa, ultimately leading to the birth of Lesotho as the ‘Mountain Kingdom’. Colonialism took this to a new level, and – for most of Africa – mountains became international borders between empires, splitting ethnic groups into several nationalities and marginalising large segments of the population in these new countries. This same geopolitical situation continues today, with major implications for the sustainable management of mountain ecosystem services, natural capital, and socio-cultural sustainability in multinational contexts.

The Afromontane Research Unit (ARU) – a continental leader in African mountain research – seeks to explore these socio-ecological complexities in terms of sustainable development, providing research that can help to secure a positive future for the people, biodiversity, and goods and services provided by Africa's mountains. As part of its mission, the ARU is leading the way in encouraging a multidisciplinary community of practice that will drive a science-policy-action interface for Southern African mountains in decades to come. As virtually all of Africa's water comes from its mountains, this is a critical service to a region increasingly at risk from drought and the socio-political implications of rivers and taps running dry. 

Although the Qwaqwa Campus is the home of the ARU, the ARU is welcoming affiliations from across the UFS and beyond. Should you wish to become affiliated to the ARU, please contact the Director, Dr Ralph Clark at ClarkVR@ufs.ac.za. Visit the new ARU's website 

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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