drought; seed; herbicide

Crop production: Preparing your soil with drought in mind

Question: With reference to your opinion about the cover crop tillage… I want to know what would be the best method to prepare my soil for crops if you know there are drought conditions predicted for the region?

There are several principles I can discuss. There is no single soil preparation practice or action that you can apply to prepare for drought conditions. When you plan your soil preparation, you should have the following in mind.

  • Your first aim should be to obtain as much moisture in the soil as possible and to keep it there.
  • For this, the soil surface should be coarse and uneven to catch as much water as possible when it rains, and to prevent water run-off.
  • If there is sufficient stubble present or crop residue (mulch) present, it aids to and contributes to the storage ability of the soil surface.
  • More rainwater will eventually sink into the ground and the run-off and erosion will decrease.
  • The soil moisture in the soil profile should be conserved as long as possible.
  • Inland, about 70% of the annual rainfall is lost due to evaporation.
  • To decrease this evaporation, you should try to leave as much stubble on the soil surface as possible.
  • Your fields should also be free of any weeds.
  • You should weed as soon as they emerge or treat them as soon as possible with appropriate chemicals.
  • Weeds can use up to 8 mm of water per day and this would be lost for crop production. Weeds can also be removed through in-crop tillage or inter-crop tillage.
  • Aim to keep soil disturbance as low as possible, as wet soil that is exposed to the atmosphere will lose its moisture completely.
  • Try to refrain from using shallow disc harrowing since it will mix the stubble or mulch into the soil and then the surface will be left exposed.
  • If you want to calculate the amount of water stored in the previous rainy season for crop production, ignore any rain showers that offered less than 12 mm that wasn’t followed up within 1 week with more rain.
  • If there was follow-up rain, then only take half of that shower into account. The depth of the soil and the texture thereof will determine the amount of water you are able to store in the soil during the fallow season.

Also read: Livestock production during drought – guidelines

  • This article was written by Dr. Eduard Hoffman, Head of the Department of Soil Science at Stellenbosch University, and first appeared on Landbou.com.

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