Questions & Answers

• Compaction - this can be due to irrigation or machinery used.
• Erosion - this comes from wind or water.
• Nutrient depletion.
• Weed growth.

• Enhances soil structure.
• Improves water retention (in sandy soils).
• Boosts drainage (in clay soils).
• Adds nutrients and encourages microbial activity.

• Very wet soil can lead to compaction.
• Dry soil may resist breaking into finer particles many times.
• Optimal moisture makes soil easier to work.

1. Soil texture - involves the roughness or smoothness of the soil. Certain crops need smooth texture while others need Rough texture.
2. Soil structure - Well-structured soil has a balance of large and small pores. Large pores allow air exchange and water drainage, while small pores retain moisture for plant use. Poor soil structure leads to compaction, reducing pore spaces and making it difficult for roots to grow and access nutrients.
3. Organic matter content - Organic matter improves soil structure by promoting aggregation and increasing the soil's ability to hold water and nutrients.
4. Moisture levels - Tells the ease of tillage and seed germination, as overwatering or drought can hinder proper tilth.
5. Drainage and aeration - Support optimal root growth by preventing waterlogging and compaction.
6. Crop-specific requirements - Adapt tilth preparation to individual crop needs (e.g., fine tilth for small seeds, stable soil for transplants).

• Weakening of the metal structure
• Damage of mechanical parts
• Poor appearance
• Development of friction
• Lower costs of resalable parts
• Poor conduction of electricity
• Weakened magnetic attraction

Click here to get Grade 9 whole year Lesson Notes for Integrated Science.

1. Galvanizing - iron metal is coated with zinc.

2. Enameling - the iron surface is baked with a mixture of silicates at a high temperature.

3. Coating with red lead oxide paint or tar on the iron surface.

4. Oils and grease coating on iron surface cuts off moist air and prevents rusting.

5.Electroplating- Iron sheets can be electroplated with a metal which is more reactive than Iron, so that instead of the Iron getting oxidized, the other metal gets oxidized (because it is more reactive)

6. Painting the Iron surface will create a barrier between the Iron and the atmosphere, which will protect the Iron from rusting.

1. An alloy has more tensile strength than its constituent elements. We can increase the hardness of a metal by mixing it with another metal or nonmetal.
2. Metals melt at very high temperatures. When a pure metal is alloyed with another metal or nonmetal, its melting point reduces. 
3. Metals are extremely susceptible to chemical and weather attacks. Alloys, on the other hand, are more resistant to corrosion. When a metal is alloyed, it becomes inert, thereby enhancing its corrosion resistance.
4. Alloying can be used to change the colour of the base metal. By mixing another metal or nonmetal, the alloy so formed will have a different colour.
5. When pure metals are solidified after melting, they tend to contract a little. However, when they are alloyed, they tend to expand on solidification. This helps to obtain good castings.

• Enhancing productivity per unit area
• Proper waste management
• Generation of continuous income round the year
• Reducing use of chemicals
• Maximization of yield of all component enterprises
• Soil health management

1. Fodder can be preserved for long periods of time. This prevents wastage in the farm due to overgrowing and plant deterioration.
2. There is availability of nutritious feed to the animals even during the periods of scarcity.
3. Good quality hay may be used to replace the amount of concentrates given to the animals. This reduces the cost of feeding.
4. Fodder can be harvested at the stage of maximum nutrients to give way for more herbage to sprout. This increases land productivity.
5. It helps to reduce bulkiness of the fodder such that transportation and storage are made easy.

1. Hay should retain the original aroma and colour if properly prepared.
2. It should be free from foreign materials such as dusts.
3. It should maintain leafiness of the original materials. The loss of leaves means hay was scorched and not cured.
4. It should be palatable and acceptable to the animals.