The Mangaung Metro Municipality experience
Whether or not climate change is a reality is a dilemma faced by many within the farming community and poses different questions. For example, why have the onset date and duration of seasonal rainfall changed? Why are we noticing the intensification of prolonged dry spells that can last up to 28 days? Why do different types of weeds thrive during prolonged dry spells in comparison to planted crops?
Farmers in Mangaung Metro Municipality (MMM) in the Free State Province experienced exceptionally long dry spells during the summer of 2018/19. The average daily rainfall received in December 2018 was 0.7 mm with a maximum of 13.7 mm and a total of only 21.6 mm for the month. With maximum temperatures ranging from 30 to 40ºC, this indicates that the evapotranspiration rate was very high. The following month the first good rains were experienced on 1 January 2019 with an amount of 25.4 mm, followed by 5.3 mm the next day. Thereafter, 8.9 mm was recorded on 29 January. However, a total amount of 97.8 mm was received during February 2019 with rains occurring every 3 to 5 days.
Given the above information, farmers within the MMM are asking questions such as “Has the planting season shifted?” and “What are the best planting dates for this area?” It is customary for them to start planting maize, sunflower, sorghum and other catch crops in late November, mid-December or the first week of January. According to long-term rainfall and temperature data for the Glen weather station, near Bloemfontein, the summer planting season runs from November to March with average monthly rainfall totals of 72.7 and 62.5 mm respectively.
During the 2018/19 planting season, farmers thought that the rainy season was at hand and executed their planting activities as normal. However, prolonged dry spells or drought events resulted in crop failure being experienced by those farmers who opted for early planting under rain-fed conditions (Figure 2), except where they were able to supply supplementary irrigation to increase the soil water content. Studies have shown that climate change and variability is affecting farming and food production systems due to a shift in season, which necessitates careful planting date selection to minimize wastage of agricultural inputs.
Daily rainfall in the MMM area varies from year to year. Figure 3 shows that at Glen in the month of January between 2010 and 2020, wetter months were experienced in 2010, 2011 and 2020 with totals >100 mm, whereas in January 2014 only 16.8 mm was recorded. Understanding monthly and seasonal rainfall variation and occurrences is critical towards implementing any tactical and operational decisions within the agricultural sector. Amounts of 10 mm or more are considered significant rainfall events, those above 15 mm are heavy rainfall events and those exceeding 25 mm are very heavy rainfall events. A very heavy rainfall event is important to crop producers to determine the exact planting date. It is evident that although January has the highest monthly average rainfall in this area, some years experienced prolonged dry spells of up to 28 days (Figure 3). Significantly high seasonal rainfall is associated with above-normal rainfall which may guide farmers to make informed decisions such as planting early or late, increasing, or reducing planting density, or choosing a short or long season cultivar.
Abnormal climate scenarios require a transparent and informative platform to equip the farmers. Regrettably, in most instances such abnormal scenarios occur when farmers are least expecting them, as happened in 2018/19 when the absence of advisories to avoid the traditional early planting resulted in widespread crop failure. Risks experienced by farmers are mainly due to their inexperience, lack of access to weather and climate knowledge, unwillingness to adapt and denial of future climate conditions. This inexperience has persisted given the lack of localized early warning systems and climate services provided to farmers as well as the absence of agrometeorological training for extension agents.The full article is for subscribed members only. To view the full article please subscribe. It’s FREE!Log In Register
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