Invasive plants and the reduction of agricultural land

• Alien invasive plants are a huge problem in South Africa, where large tracts of farmland and available pasture are threatened by these plants
• Valuable agricultural land is reduced or lost due to the damage caused by alien invasive plants
• Alien invasive plants use much more water than indigenous plants and have well-developed root systems that can absorb deeper groundwater and thereby deplete the water table
• Invasive plants increase the severity of fires, because they increase the fuel load
• The stem, bark and leaves of some plants do no decompose completely as they would in their natural habitat, this causes a leaching effect of valuable soil nutrients as some nutrients are not returned to the soil during decomposition.
• Some alien invasive plants change the pH of the soil (often making it acidic) which makes it unsuitable for agricultural crops
• After removing alien invasive plants, the soil is often to degraded that rehabilitating it for agricultural purposes is difficult, costly or even impossible
• Weeds in cultivated fields can harm crop productivity as it is costly in terms of time and labor to remove them
• Alien invasive plants invade grasslands that serve as pasture for livestock, thereby reducing the available food source
• Some of the invasive plants are inedible or poisonous
• The viability of grass species is adversely affected
• Some alien plants invade areas affected by soil disturbance, such as overgrazed land that has recently been cleared, as well as ploughed fields
• It is very difficult to remove alien invasive plants once they are established and this results in large tracts of land becoming unusable and inaccessible.
• The loss of agriculture productivity due to alien plant invasion costs billions of rand annually and places great pressure on food security.