Agriculture and Nutrient Cycles. Chapter 2.7. Agriculture and Nutrient Cycles. The seeds, leaves, flowers and fruits of plants all contain valuable nutrients. As crops are harvested, the valuable nutrients are removed from the soil.
Read the first paragraph of “Fertilizer and ecosystems” on page 70 (10 minutes)
What can happen to organisms when too much fertilizer is used?
CHAPTER 2.2 ( Case Study )
Scan figure 4
1st Generation – natural chemicals
(Metallic based, ex. Lead, mercury and arsenic)
Not only did they kill insects, they were highly poisonous for people.
2nd Generation – made in Laboratory
DDT is a potent insecticide made in 1874.
3rd Generation Modern Day Pesticides – Water Soluble
A number of pests won’t be affected by pesticides (ex 10% of a population). They reproduce and their offspring are resistant as well.