Back Seedbed preparation for maize

Date: 20 September 2016

Many New Zealand soils require some form of cultivation to create a uniform seed bed. Cultivation methods vary widely but there are some basic factors that need to be considered when looking at the options. These include soil moisture levels, soil types and previous crop residues. 

Regardless of what type of tillage you are looking at using, each individual maize seed you sow requires the following;

  • Good seed to soil contact for germination
  • Uniform depth of seed bed
  • Unrestricted root development
  • Good air/soil/nutrient movement and appropriate levels
  • Unimpeded seedling emergence
  • Soil temperatures that are at a minimum of 10° C at 9am and rising

As well as providing a good growing environment for each maize seedling, tillage is also responsible for incorporating residues and weeds, mixing in lime and fertilisers and warming and aerating the soil.

The soil structure also has an impact on the emergence of seed. An ideal soil structure consists of the following;

  • 40%        Mineral
  • 10%        Organic Matter
  • 25%        Air
  • 25%        Water

Coming into spring most NZ soils have a much higher percentage of water to air. Tillage, or the practice of opening up the soil to the sun and wind, dries and aerates the soil. This helps to increase soil temperature.

Cultivation methods vary widely but there are some basic questions that need to be considered when looking at the options. These are;

  1. Is the field dry enough? Driving heavy machinery over wet soils can cause soil compaction issues. If you have to cultivate when the field is too wet other soil cultivation methods, such as subsoiling, may be able to help reduce compaction.
  2. What residues of previous crops are still in the field? If this is an old pasture paddock and the fallow period is minimal or non-existent, residues need to be completely buried. Residue such as old pasture, greater than two year’s old, will harbour high numbers of Argentine Stem Weevil while residue from a previous maize crop can be a host for leaf diseases. Burying residue also means seedlings can emerge easily and pre-emergent herbicides are more effective.
  3. Will the cultivation method create an even seed bed depth to ensure even seedling emergence and not compound or create a compaction layer?
  4. Will my cultivation be fit for my contour and not dilute my top soil nutrient status by bringing up less fertile subsoil layers? 

For more information on preparing your paddock for maize planting, contact your local Pioneer representative.