Questions answered………….

Some questions answered about tropical farming

Examples of two types of plant root

  • Tap Root System
  • Adventitious Root System

 What is tillering?

 When you pull up a grass or cereal plant, you will see several stems or shoots. Originally when the seed germinated, only one stem is produced and the others grew from it. The additional stems are called tillers and one of the objectives of crop husbandry is to encourage tillering.

Three examples of biennial crops.

Biennial crops grow for two years.  Examples are:

  • Potatoes
  • Carrots
  • Cabbages

These are harvested after the first growing season and not allowed to go to seed.

 Three examples of trace elements.

 Trace elements are chemical substances required in very small amounts for a plant to grow. Examples are:

  • Boron
  • Managanese
  • Iron and Zinc
  • Copper

 How do you calculate plant populations?

 When the seeds were planted, they should have been mechanically planted with certain spacing.  So assuming an area planted with a sole crop:


No.of plants per hectare = _______10,000______________________

                                                Meters between plants x meters between rows

 Three advantages of mixed cropping.

  • Makes more efficient use of solar radiation
  • The soil is better and more continuously covered suppressing weeds and helping prevent erosion
  • It gives security to food supplies and income as it lessens the risk of crop failure
  • The harvest is spread which is important when the harvested crops don’t store well.
  • Legumes mixed in with the other crops fix nitrogen into the companion crops
  • An association of crops is less susceptible to an attack from pest of disease which are generally confined to one crop of the association

What are the beneficial insects? Give two examples

  • Ladybird beetles lay their eggs among aphids as the young feed on them
  • Praying mantis, centipedes, scorpions and spiders all attack an eat other insects
  • Ichneumon flies lay their eggs in the larvae of caterpillars which hatch out inside the caterpillar and kill it by feeding on them

  How can traditional methods of storing crops be improved?

  • Ventilate storage houses and net windows against insects
  • Thatched roofs harbour rats so a simple metal roof is better
  • Floors should be cement with corners and edges curved to the walls so no insects can hide in corners
  • Doors should fit flush with the ground and kept shut to keep out rats and insects
  • Store houses should be thoroughly cleaned using chemicals and fumigated before a new crop is bought in
  • Grain should be kept separate from meal and flour
  • Stores should be used in rotation so no stock is disturbed for long. Inspect stores regularly for pests so any problems can be treated promptly
  • Metal containers for grain are better than sacks as they are rat proof
  • Spaces should be left between sacks and between sacks and the walls
  • Ensure crops going into store are dry, clean and free from broken grains and pods
  • The temperature of the grain should be checked now and again. If there is a slight rise in temperature or a sign of pests, this must be dealt with immediately

  How can you control termite damage?

  Use chemicals Diedein and Aldrin – they are very poisonous but mixed with the soil around trees and in the mud when building a house they are effective.

Alternatively, Neem tea using the bark from a neem tree steeped overnight in boiling water can be poured around trees to protect them from termite damage. Neem is poisonous to lots of things including headlice.

 Written by Fiona Johnson

May 2012

For answers to other questions about farming in the tropics click here