Fertilizer is often a critical input

ZIMSEC O Level Geography Notes:Agriculture:Human Farm Inputs: Seeds and Fertilizer


  • These determine the germination rate, growth status and productivity level of crops.
  • Traditional farmers use seeds from the previous year’s harvest.
  • These seed mostly would have been damaged by fungi, insects and rodents such that their germination rate is very poor.
  • A modern farmer at the other hand, uses hybrid seeds treated with chemicals.
  • Such seeds have nearly 100% germination rate, the plants grow healthy and yields are very high.


  • These come in different forms.
  • Traditional varieties include cowdung, anthill soil, night soil, humus, boma manure and potash (ash).
  • Chemical fertilisers are manufactured from factories through chemical processes.
  • These include all the nitrates, sulphates, ammonias and urea.

Problems currently being faced in the acquisition and use of both groups of fertilisers in Zimbabwe

  • For traditional sources, cattle are too few now from dying from droughts and diseases resulting in very small amounts of cow dung being produced.
  • Antihills have virtually disappeared through exploitation and overuse especially in communal areas.
  • Trees are the major source of humus and ash. These too have reduced due to deforestation and desertification.
  • Chemical fertilisers are very expensive for both communal and commercial farmers.
  • Their continued use has negative effects on ecosystems.
  • For example they pollute water, leading to eutrophication.
  • Eutrophication is excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.
  • Following this, overcrowding occurs and plants compete for sunlight, space and oxygen.
  • Continued use of chemical fertlisers does not guarantee a proportional product from the soil as the law of diminishing returns starts operating.
  • Shortage of real foreign currency to import necessary chemicals used in the manufacture of fertilizer and components used by the industry

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