Drainage And Irrigation
Overview
Plant roots need water, but they also need air. A waterlogged soil drowns the roots by filling the spaces that should hold oxygen, while a soil that drains too fast may dry out before the crop can drink. Good farming is about getting this balance right, and the two tools for the job are drainage, which removes excess water, and irrigation, which adds water when the rain falls short.
In this lesson you will learn how gravitational water moves down through the soil, why waterlogging starves roots of oxygen and harms the organisms that keep soil healthy, and how ditches and drains rescue wet land. You will then study why and when crops need irrigation and compare the main methods, surface, sprinkler and drip, weighing each for its effect on water use, yield and crop quality.
Objectives
- (a) describe drainage as movement of gravitational water down through the soil and understand the drainage of waterlogged land by means of ditches and the loss of plant nutrients due to leaching.
- (b) understand the effects of poor drainage on soil organisms and root respiration.
- (c) explain the need for irrigation and describe methods of irrigation with the effects on crop yield and quality (details of irrigation programmes for individual crops and of equipment specification are not required).
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Drainage And Irrigation. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Drainage of a soil is best described as the movement of: A. Nutrients up to the leaves B. Gravitational water down through the soil C. Air out of the leaves D. Salts up to the surface Answer: B
- The loss of dissolved plant nutrients as water drains down through the soil is called: A. Leaching B. Erosion C. Transpiration D. Evaporation Answer: A
- Why do roots in a waterlogged soil grow poorly? A. There is too much oxygen B. There is little oxygen for root respiration C. The soil is too acidic D. There are too many nutrients Answer: B
- Which irrigation method generally uses water most efficiently? A. Surface (flood) irrigation B. Furrow irrigation C. Drip (trickle) irrigation D. Basin flooding Answer: C
- Which soil is most likely to become waterlogged after heavy rain? A. A sandy soil with large pores B. A heavy clay soil with tiny pores C. A well-structured loam D. A gravelly soil Answer: B
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
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