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Be a WINNER in the war against weeds

October 2016

A ‘weed’ is generally considered to be any unwanted plant, even though in itself, it could be a crop.

Weeds aggressively compete for the limited resources available in the soil – natural nutrients, applied fertiliser and water. Weeds can also restrict the essential amount of sunlight that is required by the planted crop – especially in early growth stages. In addition, some weeds act as hosts to other pests or produce toxic seeds dangerous to animals and humans.

When we plant our crops we go to great lengths to establish and apply the correct amount and type of fertiliser required to obtain an optimum yield. We carefully calibrate our planters to space the seeds for optimum growth – allowing the root system of each plant to develop optimally, without competing with each other. Obviously, any other unwanted plants growing and thriving in the midst of this carefully planned crop, will consume much of the nutrients and water intended for the crop, and in turn have a negative effect on the expected results (yield).

Crop farming in South Africa presents enormous, uncontrollable challenges – given the unpredictable climate, volatile markets and the difficulty accessing affordable comprehensive insurance. The only things we can control are our farming practices and discipline. Weeds are problematic but they can be controlled. All contracts for comprehensive insurance, production loans and grants have clauses that specifically require absolute adherence to effective weed control.

Don’t be fooled by the ‘height or size of the weed, compared to the height or size of the crop planted. A young maize plant might seem healthy and stand tall in comparison to the surrounding weeds, but if it has had to compete for food, the growth has certainly been compromised.

A simple analogy: A chicken broiler operation – a specific amount of food and water is supplied to the chicks daily, in order for them to attain a desired weight after six weeks. But, each night, an infestation of rats consume much of the rations. The chicks obviously do not get to eat all the food and will not reach their required weight (yield).

Ways that weeds affect your yield and profitability

There are other ways weeds can affect your yield and profitability. A few examples are:

  • A maize plant can also be considered a weed in a cultivated maize land, when there is ‘opslag’ – the random germination of maize seeds spilled during the previous harvest. The biggest nuisance is that the plant usually becomes the host for the first flight of moths (stalk borer) to lay their eggs. If not removed, it creates an exponential problem later in the season, when second generation moths hatch and infest the new crop planted. Worm infestation damages the plant as well as the cob. This not only translates to a lower yield, but also exposes the maize cob to viruses like ‘diplodia’ which results in a damaged, contaminated, lower grade pip.
  • The uintjie seems a relatively harmless, thin plant. It is extremely competitive and destructive. Its roots excrete toxins that severely inhibit the growth of crop plants. Olieboom is a severe competitor for water and nutrients. The seeds are most poisonous to animals and humans and end up in the harvested crop, resulting in severe penalties at the silo. Jongosgras is the most common of grass weeds found in cultivated fields. The extensive and dense root system has a choking effect on the roots of crops. It will destroy any surrounding crop plant.

Most conflicts are caused by greed of man, and the lack of sustainable resources the earth provides for survival. It’s the same with crops, weeds and the available resources in the soil. This is one war you must get involved in. Assist your crops with good discipline, implements… and chemicals. In this war, there could always be a winner – YOU.

Article submitted by Raymond Boardman, Farmer and Mentor at Buckingham, Ventersdorp, North West Province.
For more information, send an email to rhboardman@gmail.com.


Publication: October 2016

Section: Pula/Imvula