Rainfall Patterns and Forecast- 2020/21 Farming Season Preparedness

By Wendy Madzura, Chief Agronomist

A new farming season brings with it new hope to farmers across the country. As the 2020/21 season beacons, the news of a normal to above normal rainfall season in most parts of the country has been received with a sigh of relief amongst the farming community. The prospect for a better season has seen most farmers embarking on preparations more aggressively in a bid to beat the onset of the rainy season. The meteorological services department of Zimbabwe having been tasked with the role of imparting climate related knowledge announced the 2020/21 seasonal forecast to which farmers are now hinged on for making their crop and variety choices.

The Agroecological Regions – Just as failing to plan is like planning to fail, so is the failure to select the best crop or variety that is in line with one’s agroecological region. Zimbabwe is divided into five ecological regions whose maize variation is in the abiotic or climatic conditions experienced across the different agroecological regions. These factors include altitude (height above sea level) and temperature which affects the growing degree days of a crop (GDD) in an agroecological region thereby affecting days to maturity. However, the most important factor used to distinguish between agroecological region is the amount of rainfall received during the rainy season. The seasonal forecast for 2020/21 states that the rainfall is going to be normal to above normal in almost all parts of the country except for some parts of Matabeleland North, marginal parts of Midlands and Matabeleland South which are expected to receive Normal to below normal rainfall in the 1st half (October, November, December 2020) of the season. The country is then expected to turn “blue” in the 2nd half (January, February, March 2021) of the season with a normal to above normal pattern expected to prevail across the whole country. Farmers should however note that the term “NORMAL rainfall” is in relation to the rainfall amounts expected in a given ecological/ natural farming region. The rainfall amounts for the different farming regions are as follows;

  1. Region I, is referred to as a specialized and diversified farming region owing to its abundant rainfall amounts above 1000mm, in a given rainy season depending on the nature of the season.
  2. Region II, which is further subdivided into 2 regions; II A and II B, receiving an annual rainfall range of 750mm to 1000mm and is classified as an intensive farming region, respectively.
  3. Region III, is referred to as the Semi-intensive farming region owing to the decrease in the amount of the rainfall received during the rainy season, which ranges between 650-800mm.
  4. Region IV, is referred to as the Semi-extensive farming region, which as the name suggests is more about scale than intensity, with cattle ranching becoming a common farming pattern practiced. This region receives rainfall amounts of 450mm-650mm.
  5. Region VA, is characterized by full scale Extensive farming receiving varied rainfall amounts of below 650mm.
  6. Region VB, is a new region according to the updated agroecological regions map that receives rainfall of below 600m.

The information about rainfall patterns based ecological regions is important as it enables farmers to make an informed crop and variety choice, thereby reducing the risk of crop failure in farming. In light of the 2020/21 seasonal forecast farmers can establish field crops like maize, soya bean, and sugar beans at their recommended planting times which are Mid October, Mid November and end December to January, respectively. In addition to this, farmers are encouraged to continue on the positive trajectory seen in the 2019/2020 farming season of establishing small grain traditional crops like sorghum, rapoko, and millet to mitigate against unforeseen weathers vagaries.

The Maize Crop – Maize as Zimbabwe’s staple crop is grown extensively during the rainy season. Farmers should select varieties that fit within the expected rainfall growing season in their ecological regions. With farmers in high potential areas of region 1 and 2 being encouraged to establish long and medium season varieties such as the 700 and 600 series, due to the lengthy rainfall season in these regions which can accommodate the growing period of the late and medium maturing maize varieties ranging between 140 – 160 days to maturity. Farmers in region 3 are encouraged to establish medium maturing varieties (600 series) in areas that receive high rainfall and resort to early maturing varieties (500 and 400 series) in areas of reduced rainfall. In agroecological region 4 and 5 based on their rainfall pattern, farmers are encouraged to establish varieties in the early (500 series), very early (400 series) and ultra-early (300 series) maturity groups as these will fit within their growing regions. However resource endowed farmers with irrigation may cut across the recommended maturity groups and establish any variety since supplementary irrigation will be available to support the crop to maturity. Farmers should embrace new improved seed technologies that are aimed at increasing yields, reducing disease incidence and mitigate against the effects of climate change through breeding varieties that have drought escape and drought tolerance mechanisms.

Growing degree days – Although the rainfall pattern is the major determinant of crop or variety selection for different regions. Farmers should note that growing degree days impact on the rate of growth of any crop thereby varying the days to maturity. For growth and development, the plant needs heat. To enter the new stage of the development, every plant requires a specific amount of heat. Growing degree-days is a measure of heat the plant has to accumulate to enter a new stage in development.   A farmer should always factor this in during planning as it may affected the establishment of the next crop for example wheat. In Zimbabwe 40% of the growing degree days are received within the 1st half of the season (October to December) hence it is recommended to plant during that window.

Having highlighted the different “normal” ranges of rainfall by ecological or natural region farmers should be able to make informed decisions on crop choice and variety selection. Just as Edward Young said “Procrastination is the thief of time”, farming is time sensitive, so farmers should not wait until the last minute to prepare. During this time of the season, farmers should engage in soil conditioning, final land preparation, and purchasing of inputs. Remember farming is a business and a means to food self-sufficiency which will in turn usher in food security at household and national level. Because of this, farmer should prepare for the onset of the 2020/21 farming season with promptness.

Successful Productivity starts with the right seed and Good Agronomic Practices.

Photo by Junior Aklei Chaky from Pexels

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