ENV334H1 Lecture Notes - Lecture 4: Chemotroph, Holland Marsh, Histosol
Document Summary
Lecture 4: intensive agriculture and its effects on soils: erosion & depletion of organic matter. Intensification of crop production: contributed to most of the increases in yield. Increased food production: allowed us to keep up with population growth, maintained/increased macronutrients in soils, reduced pressure on fragile lands, don"t have to clear new land if just increase pressure on what you"ve already cleared. Improved crop varieties: for wheat, went from 45 kg of wheat for every kg of n you put on field to 70 kg for every kg of n. Improving crop variety helps in producing more food: but has negative effects: Env334 january 16, 2017: soil erosion, depletion of organic matter. If not careful about how to manage field: nutrient imbalance, what leaches out of field and ends up in aquatic systems, reduced biodiversity, salinization, pesticides. Soil formation is slow: takes thousands of years to develop all of these layers and get good a or o soil (organic)
