Question

1. what are some of the living organisms found in soil?
2. what is pedology and pedogenesis?
3. what is the rate of pedogenesis for topsoil?
4. why is topsoil pedogenesis so slow?
5. in commercial modern agriculture, why do soils eventually suffer from nutrient exhaustion?
6. describe two reasons why the use of synthetic fertilizers is not the answer to decreasing soil quality.
7. how does cutting down trees lead to soil erosion?
8. how do you think food security is linked to \food resource wars\?

Explanation:

1. Soil contains a diverse range of living organisms. Microorganisms like bacteria and fungi play crucial roles in decomposition and nutrient cycling. Earthworms are important as they aerate the soil and improve its structure. Insects such as ants and beetles also inhabit the soil.
2. Pedology is the study of soils in their natural environment. Pedogenesis is the process of soil formation, which involves the interaction of climate, organisms, parent material, topography, and time.
3. The rate of pedogenesis for topsoil can vary greatly depending on factors such as climate, parent material, and biological activity. In some cases, it can take hundreds to thousands of years to form a few centimeters of topsoil.
4. Topsoil pedogenesis is slow because it requires the weathering of parent material, the accumulation of organic matter, and the development of soil structure. These processes are influenced by factors such as climate, which can limit the rate of weathering and organic matter decomposition.
5. In commercial modern agriculture, soils eventually suffer from nutrient exhaustion because of continuous cropping without proper nutrient replacement. Crops remove nutrients from the soil, and if these nutrients are not replenished through organic matter addition or fertilization, the soil becomes depleted.
6. Two reasons why the use of synthetic fertilizers is not the answer to decreasing soil quality are: (1) Synthetic fertilizers do not improve soil structure or increase organic matter content, which are important for long - term soil health. (2) Over - reliance on synthetic fertilizers can lead to environmental problems such as water pollution from nutrient runoff.
7. Cutting down trees leads to soil erosion because trees provide a protective canopy that reduces the impact of raindrops on the soil surface. Their roots also bind the soil, preventing it from being washed or blown away. Without trees, the soil is more vulnerable to erosion by wind and water.
8. Food security is linked to "food resource wars" because when there is a scarcity of food resources, competition for these resources can increase. This competition can lead to conflicts, especially in regions where food production is limited or where there are disparities in access to food.

Answer:

1. Bacteria, fungi, earthworms, ants, beetles.
2. Pedology: study of soils in natural environment; Pedogenesis: soil formation process.
3. Varies (hundreds - thousands of years for a few cm).
4. Requires weathering, organic matter accumulation, and structure development (climate - limited).
5. Continuous cropping without nutrient replacement.
6. (1) No improvement of soil structure/organic matter. (2) Environmental problems (nutrient runoff).
7. Trees protect soil (canopy and roots); without them, erosion increases.
8. Scarcity leads to competition (conflicts in resource - limited regions).