These aim at giving the crop the best conditions which will favour its growth so that it can out compete weeds. They include;
i) Early planting;
This enables plants to grow vigorously and establish themselves early enough before weeds become competitive.
ii) Proper spacing;
Well spaced crops quickly cover up the ground with their leaves and smoother weeds then weeds that manage to grow remaib fible with yellow leaves.
iii) Crop rotation
This controls parasitic weeds by denying them nutrients and breaking their life cycle
iv) Use of clean planting materials
This prevents introduction of weed seeds into the field
v) Controlled burning
This will kill both weeds and their seeds if the fire is hot enough
Weeds are completely submerged and killed by suffocation e.g. weeds in paddy rice
vii) Mulching; Mulches convert the weeds and seeds making them unable to germinate due to lack of light i.e. smoother
viii) Use of trap crops
These attract numerous weed plants and then are destroyed with weeds.
ix) Controlled grazing;
If the number of animals grazing on a piece of land is greater than that it can support, the animals graze on species to outcompete the palatable ones
x) Use of Intercropping
This reduces space and light available for the weeds to grow