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21 April 2023 | Story Leonie Bolleurs | Photo Supplied
Striving to make a difference in the field of biodiversity conservation, Dr Katlego Mashiane decided to pursue a PhD in Geography, focusing on the spatial modelling of grassland diversity and nutrients in subalpine environments. He received his PhD during the recent April graduation ceremonies on the Qwaqwa Campus.

In the small village of Ga-Mabotia about 25 km outside of Polokwane, Dr Katlego Mashiane grew up, surrounded by rocky mountains characterised by boulder outcrops, where he interacted with nature from an early age. 

He recently obtained his PhD, majoring in Geography, from the University of the Free State (UFS), which was conferred on him during the April graduation ceremonies that took place on the UFS Qwaqwa Campus. The title of his dissertation is Grass nutrients estimation as an Indicator of rangeland quality using satellite remote.

Predicting the presence of biodiversity and nutrients in an area

Based on the principle that diverse grasslands tend to perform better, environmental changes threaten the resilience and services these grassland ecosystems provide. The study examined how many different types of plants and animals can be found at a particular place to enhance our understanding of the ecosystem’s value to humans, and that biodiversity loss will reduce these ecosystem services. Focusing on spatial modelling of grassland diversity, Dr Mashiane specifically investigated the influence of topography and remotely sensed satellite data on species richness and diversity in subalpine environments, and how they are affected by the availability of grass species. To determine this, he used a random forest machine-learning algorithm to find the best information in the data that could be used to estimate the levels of species richness, diversity, and nitrogen in a protected national conservation park. 

His study discovered that some data types – such as the near-infrared variable and certain vegetation data (EVI and SAVI) – were especially useful for determining the number and variety of species in a certain area. With this information, scientists can create models that predict the presence of different types of biodiversity and nutrients in an area.

Playing a key role in protecting our natural assets

Equipped with this knowledge, one will be able to understand how to protect and preserve different types of biodiversity and promote the nutritional value of both plants and animals in the environment. “Land managers could use this information for conservation strategies,” states Dr Mashiane, who decided to pursue this study because he was curious about how environmental changes will affect species.

“Grasslands provide important ecosystem services underpinning human well-being, and therefore warrant our protection; I would like to play a role in protecting our natural assets and contribute to understanding our biomes, especially in the context of global change,” he says.

In the next five years, Dr Mashiane plans to pursue further research and mentor other students in his field of study.

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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