Chapter 11 Questions:
Q1. Pollution and salinity problems, as a result of poor management of our rivers and an increasingly dry climate, threaten hundreds of millions of dollars in an agricultural production.
Q2. To support the irrigation systems, the natural landscape is changed, dams and channels are built and paddocks are leveled to move water from natural waterways to agricultural production areas.
Q3. Salinity occurs if groundwater rises, generally when excess water is added to groundwater supplies, such as through irrigation. As the watertable reaches the surface, waterlogging become apparent and water and salt emerge through the topsoil, forming salt crusts and killing vegetation and crops.
Q4.

Q5. Some of the strategies used to ensure effective water use are; monitoring water quality regularly, using new technologies, such as laser leveling, to flood paddocks quickly. Using only just enough water for maximum growth and good health of the crop pasture; for example, using drip-irrigation systems controlled and monitored by sophisticated computer systems, and maintaining and repairing breaks in channels and banks to avoid water loss.
Q6. The Australian Cooperative Research centre for sustainable rice production has developed a method for selecting low-water-use soils for rice production using electromagnetic induction surveys. This is beneficial to the environment because the soils selected to grow the rice crop, which traditionally uses large quantities of irrigation water, use much less water. It also reduces the risk of salinity in rice-growing areas because the characteristics of the soil selected mean that water is less likely to leak into the groundwater and raise the watertable.
Q7. Chemical or inorganic fertilisers, especially those that are nitrogen-based, are widely used in agriculture to improve crop yields. Most food crops are grown on an intensive farming system where new crops are planted in the same soil each season. This farming practice does not allow the soil to replenish the nutrients they lose naturally.
Q8. Herbicides are sprayed on weeds that compete with food crops such as wheat, oats, rice and barley for nutrients from the soil, whereas Pesticides are chemicals that control a particular pest on specific crops.
Q9. Producing clean food is also very important to Australian primary producers as they currently have a strong reputation around the world for producing clean, healthy and safe food. Chemicals are also very expensive for farmers to purchase, so it is to their economic advantage to use the minimum amount to protect their food crops effectively.
Q10. A range of strategies is used to ensure effective use of chemicals such as aerial spray contractors flying low to the ground to spray the crop accurately and prevent spray drifting onto other paddocks. Ensuring that aerial spraying is done on days when there is little wind to prevent wind-drift. The use of satellite tracking technology (GPS) by aerial spray contractors to determine their flight path and application area so the correct amount of chemicals is applied. Monitoring crops on a weekly basis to evaluate the insects present on the crops to determine those that are beneficial or whether spraying is required.
Q11. Australia is one of the oldest continents and, as a result, has some of the oldest soils on the planet, which are nutrient poor and extremely shallow. Unlike soils in other parts of the world, Australian soils replenish themselves very slowly and in many areas are considered non-renewable.
Q12. Erosion of soil occurs when vegetation covering the land and the surface of the land’s crust is damaged, often creating large gullies. The main causes of soil erosion are extreme weather conditions, such as drought, and poor land management.
Q13. A range of strategies can be implemented to minimize soil erosion that includes. Minimizing the amount of tillage, so the soil is not dug up and exposed to the water and wind,