Climate, production outlook for the upcoming seasons
08:23 (GMT+2), Fri , 02 September 2016

Johan van den Berg

A modern farmer faces many challenges, the most significant of which are climate conditions.
Johan van den Berg, specialised crop insurance manager at Santam Agriculture, takes a scientific look at what farmers can expect in the 2016/17 spring and summer seasons and offers expert advice about protecting crops in these conditions.
The El Nino phenomenon of the past season gradually declined and disappeared in June. All of the Nino areas are currently within the +0,5ºC to -0,5ºC range, indicating neutral conditions. 
A vertical cross-cut of the Nino areas shows a large area of water with a below average temperature up to a depth of about 250 m that is gradually rising to the surface. Although winter months are traditionally the time of year when rapid changes in sea surfaces can occur in the Nino areas, the current setting is such that changes are unlikely in the next months. Most forecasts indicate a 50-80% probability of a La Nina phenomenon for the 2016/17 spring and summer seasons.
Another element that has a huge impact on climate conditions in South Africa is sea surface temperatures in the Indian Ocean.
Cooler than normal sea surface temperatures favour improved rainfall conditions in summer.
Current values indicate that the Indian Ocean Dipole (IOD) is negative, meaning that cooler water is present in the western Indian Ocean, increasing the probability of rainfall in summer over most of South Africa.
The combined effect of the expected La Nina phenomenon and the negative IOD for the next months, implies the following:
• A probability of average to below average winter and spring rain over most of the country, including the Western Cape, from July to October.
• A high probability of average to above average rainfall in the greatest part of the summer rainfall area from about the second half of October, but especially in December and February/March. The probability of above average rainfall is higher towards the central to western and south-eastern interior, as well as in Namibia and the southern to central parts of Botswana.
• A possibility of drier conditions over the eastern to north-eastern parts of the country in February/March.
Possible implications for agriculture:
• Most of the time, La Nina leads to sufficient rainfall to increase the levels of storage dams in the summer rainfall area. However, the likelihood of runoff water replenishing dam levels before December is low.
Farmers should take this into account when doing crop planning.
• Good rain in summer can stimulate the production area for summer crops, especially maize. This can have a negative impact on commodity prices which farmers should bear in mind when doing financial planning for the season.
• Above average rainfall increases the probability of an outbreak of pests and diseases. Immunity against animal diseases and parasites is low due to the recent droughts and consequent low levels of vaccination.
It is therefore recommended that farmers start vaccinating early in the season against diseases that are traditionally a problem in their area.
• An important factor in summer crop production, that was evident the past season, is the availability of soil moisture. Farmers must change their strategy from “farming with crops” to “farming with water”. Rainfall utilisation must be increased by restricting evaporation, increasing infiltration and keeping areas free of weeds.
• It is also paramount that farmers plan according to two different time scales. Long term or strategic planning concentrates on the type of farming that is best suited to or sustainable in a specific area. 
Short term or tactical planning is based on reigning or expected production conditions. Therefore, given the current conditions, if strategic planning indicates that maize production is viable in an area, then tactical planning should entail to increase the plant population or fertiliser application due to high levels of already stored soil moisture and a favourable rainfall outlook.
The opposite would be vital when an El Nino phenomenon is expected.

Voting Poll