Vulnerability and impact of climate change on horticultural crop production in the Western Cape Province, South Africa

Climate change has the potential to alter the spatio-temporal distribution of rainfall, subsequently affecting the supply and demand of water resources. In a water-stressed country such as South Africa, this effect has significant consequences. To this end, we investigated annual and winter rainfall and river flow trends for the Western Cape Province over two periods: 1987–2017 and 1960–2017. Annual rainfall for the most recent 30-year period shows decreasing trends, with the largest magnitude of decrease at the SA Astronomical Observatory rainfall station (-54.38 mm/decade). With the exception of the significant decreasing winter rainfall trend at Langewens (-34.88 mm/decade), the trends vary between stations for the period 1960–2017. For the period 1987–2017, statistically significant decreasing winter trends were found at four of the seven stations, and range from -6.8 mm/decade at Cape Columbine to -34.88 mm/decade at Langewens. Similarly, the magnitudes of decreasing winter river flow at Bree@Ceres and Berg@Franschoek are greater for the more recent 30-year period than for 1960–2017. Correlation coefficients for Vilij@Voeliv rainfall and four river flow stations Berg@Franschoek, Bree@Ceres, Wit River@Drosterkloof and Little Berg@Nieuwkloof) are stronger for shorter periods (i.e. 1987–2017 and 2007–2017) than that for the longer period, 1960–2017. The Intergovernmental Panel on Climate Change emphasises the importance of studies to assist with model prediction uncertainties. To this end, our study expands the understanding of regional hydrological responses to rainfall change in the water stressed region of the Western Cape Province.

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Impact of climate change on primary agriculture, water sources and food security in Western Cape, South Africa

Jàmbá Journal of Disaster Risk Studies ◽

10.4102/jamba.v11i1.562 ◽

2019 ◽

Vol 11 (1) ◽

Cited By ~ 4

Author(s):

Elliot M. Zwane

Keyword(s):

Climate Change ◽

South Africa ◽

Food Security ◽

Water Sources ◽

Western Cape ◽

Impact Of Climate Change ◽

Agriculture Water

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Extent of Soil Acidity in No-Tillage Systems in the Western Cape Province of South Africa

Land ◽

10.3390/land9100361 ◽

2020 ◽

Vol 9 (10) ◽

pp. 361

Author(s):

Adriaan Liebenberg ◽

John Richard (Ruan) van der Nest ◽

Ailsa G. Hardie ◽

Johan Labuschagne ◽

Pieter Andreas Swanepoel

Keyword(s):

South Africa ◽

Crop Production ◽

Acid Soils ◽

Soil Survey ◽

Annual Rainfall ◽

Western Cape ◽

No Tillage ◽

Western Cape Province ◽

Tillage Systems ◽

Depth Increment

Roughly 90% of farmers in the Western Cape Province of South Africa have converted to no-tillage systems to improve the efficiency of crop production. Implementation of no-tillage restricts the mixing of soil amendments, such as limestone, into soil. Stratification of nutrients and pH is expected. A soil survey was conducted to determine the extent and geographical spread of acid soils and pH stratification throughout the Western Cape. Soil samples (n = 653) were taken at three depths (0–5, 5–15, 15–30 cm) from no-tillage fields. Differential responses (p ≤ 0.05) between the two regions (Swartland and southern Cape), as well as soil depth, and annual rainfall influenced (p ≤ 0.05) exchangeable acidity, Ca and Mg, pH(KCl), and acid saturation. A large portion (19.3%) of soils (specifically in the Swartland region) had at least one depth increment with pH(KCl) ≤ 5.0, which is suboptimal for wheat (Triticum aestivum), barley (Hordeum vulgare), and canola (Brassica napus). Acid saturation in the 5–15 cm depth increment in the Swartland was above the 8% threshold for production of most crops. Acid soils are a significant threat to crop production in the region and needs tactical agronomic intervention (e.g. strategic tillage) to ensure sustainability.

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Facing the heat: Barriers to mainstreaming climate change adaptation in local government in the Western Cape Province, South Africa

Habitat International ◽

10.1016/j.habitatint.2013.05.003 ◽

2013 ◽

Vol 40 ◽

pp. 225-232 ◽

Cited By ~ 77

Author(s):

L. Pasquini ◽

R.M. Cowling ◽

G. Ziervogel

Keyword(s):

Climate Change ◽

South Africa ◽

Local Government ◽

Climate Change Adaptation ◽

Western Cape ◽

Western Cape Province

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Characterization of Rhizoctonia spp. Recovered from Crop Plants Used in Rotational Cropping Systems in the Western Cape Province of South Africa

Plant Disease ◽

10.1094/pd-90-1399 ◽

2006 ◽

Vol 90 (11) ◽

pp. 1399-1406 ◽

Cited By ~ 31

Author(s):

Y. T. Tewoldemedhin ◽

S. C. Lamprecht ◽

A. McLeod ◽

M. Mazzola

Keyword(s):

South Africa ◽

Crop Production ◽

Optimal Time ◽

Limiting Factor ◽

Western Cape ◽

Optimum Growth ◽

Western Cape Province ◽

Binucleate Rhizoctonia ◽

Weakly Virulent

Isolates of Rhizoctonia spp. associated with barley, canola, clover, lucerne, lupin, annual Medicago spp. (medic), and wheat were recovered during the conduct of a 4-year (2000 to 2003) crop rotation trial in the Western Cape province of South Africa. These isolates were characterized by determining their anastomosis group (AG), in vitro optimum growth temperature, and pathogenicity toward emerging and 14-day-old seedlings of all the aforementioned crops. During the 4-year rotational trial, 428 Rhizoctonia isolates, in all, were obtained. The most abundant multinucleate AG was AG-4 HG-II (69%), followed by AG-2-1 (19%), AG-3 (8%), AG-2-2 (2%), and AG-11 (2%). The population of binucleate Rhizoctonia spp. comprised AG-K (53%), AG-A (10%), AG-I (5%), and unidentified AGs (32%). The optimal time for isolating Rhizoctonia spp. was found to be at the flowering or seedpod stage (20 to 22 weeks after planting). Temperature studies showed that isolates belonging to AG-2-2, AG-4 HG-II, and AG-K had significantly higher optimum growth temperatures than those from other AGs. In pathogenicity assays conducted on emerging as well as 14-day-old seedlings, isolates of AG-2-2 and AG-4 HG-II were the most virulent on all crops. Rhizoctonia solani AG-2-1 was highly virulent on canola, moderately virulent on medic and lupin, weakly virulent on lucerne and barley, and nonpathogenic on wheat. AG-11 isolates were moderate to weakly virulent on all crops, with the exception of barley and wheat. AG-3 was weakly virulent on canola, lupin, and medic. AG-K was the only binucleate Rhizoctonia sp. capable of inciting disease in our assays. This is the first comprehensive study to elucidate the identity and potential importance of Rhizoctonia spp. as a yield limiting factor in crop production systems in the Western Cape province of South Africa.

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The impact of climate change on food security in South Africa: Current realities and challenges ahead

Jàmbá Journal of Disaster Risk Studies ◽

10.4102/jamba.v9i1.411 ◽

2017 ◽

Vol 9 (1) ◽

Cited By ~ 12

Author(s):

Tshepo S. Masipa

Keyword(s):

Climate Change ◽

South Africa ◽

Global Warming ◽

Food Security ◽

Crop Production ◽

Arable Land ◽

Food Distribution ◽

Impact Of Climate Change ◽

Food Items ◽

The Impact

This article aims to examine the impact of climate change on food security in South Africa. For this purpose, the article adopted a desktop study approach. Previous studies, reports, surveys and policies on climate change and food (in)security. From this paper’s analysis, climate change presents a high risk to food security in sub-Saharan countries from crop production to food distribution and consumption. In light of this, it is found that climate change, particularly global warming, affects food security through food availability, accessibility, utilisation and affordability. To mitigate these risks, there is a need for an integrated policy approach to protect the arable land against global warming. The argument advanced in this article is that South Africa’s ability to adapt and protect its food items depends on the understanding of risks and the vulnerability of various food items to climate change. However, this poses a challenge in developing countries, including South Africa, because such countries have weak institutions and limited access to technology. Another concern is a wide gap between the cost of adapting and the necessary financial support from the government. There is also a need to invest in technologies that will resist risks on food systems.

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Impact of Climate Change on Crop Production and Potential Adaptive Measures in the Olifants Catchment, South Africa

Climate ◽

10.3390/cli9010006 ◽

2020 ◽

Vol 9 (1) ◽

pp. 6

Author(s):

Mary Funke Olabanji ◽

Thando Ndarana ◽

Nerhene Davis

Keyword(s):

Climate Change ◽

South Africa ◽

Crop Production ◽

Rainwater Harvesting ◽

Climate Change Scenarios ◽

Full Irrigation ◽

Dry Beans ◽

Planting Dates ◽

Impact Of Climate Change ◽

The Impact

Climate change is expected to substantially reduce future crop yields in South Africa, thus affecting food security and livelihood. Adaptation strategies need to be implemented to mitigate the effect of climate change-induced yield losses. In this paper, we used the WEAP-MABIA model, driven by six CORDEX climate change data for representative concentration pathways (RCPs) 4.5 and 8.5, to quantify the effect of climate change on several key crops, namely maize, soya beans, dry beans, and sunflower, in the Olifants catchment. The study further investigated climate change adaptation such as the effects of changing planting dates with the application of full irrigation, rainwater harvesting, deficit irrigation method, and the application of efficient irrigation devices on reducing the impact of climate change on crop production. The results show that average monthly temperature is expected to increase by 1 °C to 5 °C while a reduction in precipitation ranging between 2.5% to 58.7% is projected for both RCP 4.5 and RCP 8.5 relative to the baseline climate for 1976–2005, respectively. The results also reveal that increased temperature and decreased precipitation during planting seasons are expected to increase crop water requirements. A steady decline in crop yield ranging between 19–65%, 11–38%, 16–42%, and 5–30% for maize, soya beans, dry beans, and sunflower, respectively, is also projected under both RCPs climate change scenarios. The study concludes that adaptation measures such as the integration of changing planting dates with full irrigation application and the use of rainwater harvest will help improve current and future crop production under the impact of climate change.

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