Agriculture Revision Questions Question Paper
Agriculture Revision Questions
Course:Secondary Level
Institution: Kcse question papers
Exam Year:2010
3.0 FACTORS INFLUENCING AGRICULTURE.
1. List four characteristics of clay soil. (2mks)
? Clay is sticky we/it is difficult to work with.
? Clay has a higher water retention capacity.
? It cracks when dry.
? It is poorly drained/easily water logged/poor aeration.
? Has higher ion exchange capacity/higher fertility.
? Swells when wet.
? Has high capillarity.
? It becomes hard when dry.
? It has fine particles.
2. State any four faming practices which help improve soil structure. (2mks)
? Inclusion of a ley in rotation/crop rotation/leaving the land fallow.
? Minimum tillage
? Cover cropping.
? Mulching.
? Liming/addition of soil amendments.
? Intercropping/mixed cropping.
? Working the soil at the right moisture content.
3. State three properties of soil that are influenced by its texture. (3mks)
? Aeration/ porosity.
? Drainage.
? Water holding capacity/capillarity.
? Stickness/consistencey.
? Cation exchange capacity/soil pH/availability of nutrients.
4. State two roles of good soil aeration in crop growth. (1mks)
? To facilitate growth of crop roots/root respiration.
? To facilitate absorption of nutrients and water by plants.
? To prevent formation of certain inorganic compounds a toxic to plant growth/reduce toxic forms of such elements like Fe, Mn.
? Enhance microbial activity hence release of plant nutrients.
5. State two roles of micro –organisms in the soil that are beneficial to crops. (2mks)
? Help to decomposes organic matter/helps to release minerals for plant use.
? Some micro-organisms produce toxic substances which may kill some soil borne diseases causing organisms.
? Some micro – organisms fix nitrogen in the soil.
6. Outline three effects of soil organism which benefit plant growth. (11/2mks)
? Decompose organic matter.
? Help to aerate soil.
? Some fix/make available plant nutrient e.g. nitrogen and phosphorous.
? Source of nutrients upon death and decay.
7. Give six farming practices that could be used to improve soil structure. (3mks)
? Use of organic manure.
? Growing of cover crops.
? Crop rotation/fallowing.
? Use of organic mulch/mulching.
? Use of agricultural lime/C.A.N
? Minimum tillage.
? Cultivating when soil moisture content is optimum.
8. Give three ways by which a farmer would add organic matter to the soil. (1/2mks)
? Addition of manure.
? Using organic mulch.
? Incorporation of crop residues/organic residues.
? Including grass/ley/bush/fallow in a rotation.
? Practicing some form of agroforestry.
9. Give two processes of soil weathering (1mk)
? Physical/mechanical weathering.
? Biological
? Chemical.
10. Differentiate soil texture and soil structure. (2mks)
? Soil texture is the relative proportion and distribution of various sizes of soil particles while soil structure is the arrangement of soil particles
11. State three benefits of a good soil structure to crop production. (3mks)
? Holds more moisture for crop production.
? Hass better aeration/prevents excessive accumulation of Carbon IV Oxide.
? Is well drained/has better infiltration/percolation
? Allows better root penetration for nutrients and moisture uptake/plant anchorage.
? Allows better root development and tuber expansion.
12. Give three reasons why soil is important to crops. (11/2mks)
? Provides anchorage to crops.
? Provides minerals/nutrients to crops.
? Provides water to crops.
? Contain oxygen/air necessary for crop growth.
13. Give four reasons why a well drained soil is suitable for crop production. (4mks)
? Good aeration which is beneficial for plant respiration.
? Suitable for microbial activity.
? Easy to cultivate/worn on.
? Raises soil temperature.
? Removal of toxic substances such as sodium.
14. State two benefits of optimum soil temperature in crop production. (2mks)
? Enhances seed germination.
? Enhances plant growth.
? Enhances soil microbial activities.
? Improves quality of crops e.g. pineapple tea etc.
15. State three soil factors that influence soil productivity. (4mks)
? Soil depth.
? Drainage/permeability.
? Aeration/porosity
16. State three advantages of adding organic matter to sandy soil. (11/2mks)
? Improve soil structure.
? Reduces leaching.
? Improves water holding capacity.
? Increases microbial activity.
? Increases cation exchange capacity.
? Improves nutrient status of the soil after decomposition.
? Moderates soil temperature.
? Buffers the soil pH
17. State two effects of good soil aeration in crop growth. (2mks)
? Facilitates proper root respiration/root growth development.
? Facilitates absorption of nutrients and water.
? Prevents formation of certain compounds.
? Toxic to plants/reduce toxic forms of elements like iron and manganese.
? Enhances microbial activities.
18. State three ways by which biological agents can enhance the process of soil formation. (11/2mks)
? Movement of animas in large numbers.
? Decomposition of plant and animal remains by soil micro – organisms.
? Physical breaking of rocks by roots of higher plants.
? Man’s activities e.g. cultivation, mining and road construction.
? Mixing up of soil by burrowing animals e.g. earthworms and termites.
19. List three physical weathering agents in the soil formation process. (11/2mks)
? Wind.
? Glaciations/ice.
? Temperature.
? Running water(RT water alone)
20. State two mechanical methods of separating soil particles according to size during soil analysis. (1mk)
? By mixing soil with water, shaking stirring and allowing the particles to settle/sedimentation.
? By the use of a series of sieved with different mesh sizes/sieve method.
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