Agriculture Flashcards
exam questions
Describe the formation of productive soils and the horizons that result.
Soil is formed from parent material
Involves interactions between
1. Earth’s solid crust
2. biosphere
3. topography.
Horizons (starting at the surface)
O - organic matter
A - topsoil, high organic matter
B - subsoil, clay and cations leached from A-horizons
C - weathered parent material
R - bedrock (parent material)
What are the goals in soil structure and fertility?
Allowance for air and water in the soil
*vital for long term, healthy plant growth
What are some features as well as as challenges and advantages of industrial agricultural strategies?
Features of industrial strategies - Industrial agriculture is the large-scale, intensive production of crops and animals, often involving chemical fertilizers on crops.
Challenges - contamination of water and soil(fertilizer)
-use of broad spectrum pesticides can lead to genetic resistance and the need for further development of pesticides.
Benefits - Allows for food to be produced quickly at a large scale
-cheaper cost of produce for consumer.
What are some features as well as as challenges and advantages of subsistent agricultural strategies?
Features of subsistent strategies - small capital/finance requirements, mixed cropping, limited use of agrochemicals.
Challenges - low yields and high rate of crop failure.
Benefits - environmentally friendly (uses relatively few inputs) and it gives people food security because it allows people to be self-sufficient.
What are five different sustainability strategies in agriculture?
- Alley Cropping - growing rows of trees with space in between each row (alley) to grow crops.
- Shelterbelt - A row of trees planted beside fields to act as a windbreak.
- Cover Crops - planting any crop that will cover soil
- Strip Cropping - cultivating a field partitioned into long, narrow strips which are alternated in a crop rotation system
- Conservation/Minimal Tillage - soil conservation system with the goal of minimum soil manipulation.
How do the five different sustainable agriculture strategies contribute to overall soil fertility and other environmental challenges?
- Alley Cropping - reduces soil erosion, increases water infiltration, adds organic carbon to the soil as well as recycles and adds nutrients
- Shelterbelt - acts as a windbreak to reduce soil erosion of agricultural land
- Cover Crops - slows erosion, improves soil health, enhances water availability, smothers weeds, helps control pests and diseases and increases biodiversity
- Strip Cropping - a regular practice on sloped lands to control soil erosion
- Conservation/Minimal Tillage - reduces soil erosion, increases the organic material in the soil and decomposing organic matter releases nutrient minerals more gradually
What role can agriculture have in climate change mitigation/prevention?
Agriculture can assist in
1. reducing greenhouse gas (GHG) emissions
2. increase soil carbon stores in land
3. replace fossil fuels by using biomass and animal waste
Why are acidic soils a problem?
Acidic soil is a problem because:
1. choice of crops is restricted to acid tolerant species and varieties
2. increase of leaching resulting in the decrease of essential nutrients available in the soil
How does precipitation and temperature influence the status of soils?
High rates of precipitation can result in a lot of surface runoff that will transport organic material on the surface, away from its current location. Along with the movement of organic material, precipitation will percolate through the soil; this can cause increased leaching. This can be a problem as the removal of nutrients through leaching leads to deficiencies in crops as well as soil acidification.
Warmer temperatures result in greater bacterial activities; increase in decomposition. The organic material on the surface will not be beneficial for fertilizing soil but will go through a faster decomposition cycle resulting in more CO2 emissions.
What is the importance of soil biology in relation to the health and productivity of soils?
Soil biology is crucial in the
1. functioning of the phosphorus cycle (supplying nitrogen & phosphorus)
2. can reduce soil erosion
3. a huge increase in the water holding capacity of the soil.
What is the importance of the soil community in relation to the health and productivity of soils?
Soil microbial communities play several important ecological and physiological functions
- soil organic matter decomposition and control of the decomposition cycle
- regulation of mineral nutrient availability
- atmospheric nitrogen fixation
What are some comparisons to be made regarding soil features from the boreal regions of the Northern Hemisphere and soil features from southern Manitoba?
Boreal Regions - The soils tend to be acidic from conifer needles and there is significant leaching.
Southern MB - The presence of grasslands; an ideal climate for soils to be rich, little precipitation with a moderate temperature as well as the length of the winter season allows organic matter to build in soils.
What are some comparisons to be made regarding the soil features from deciduous forests and soil features from the boreal forest?
Deciduous - Soil is highly productive because of the amount of plant litter available to sustain high organic content in soils; this results in less nutrient runoff from precipitation as the soil can absorb it instead.
Boreal - There is significant leaching resulting in soil acidity.
What are some comparisons to be made regarding the soil features from the grasslands in Canada and the soil features from the Savanna in Africa?
Grasslands - High levels of organic matter which accumulate in the upper layers of soil allowing them to be productive. There is also minimal leaching due to the climate as well as minerals are accessible in the top layers.
Savanna - A desert climate; there is minimal organic matter development and minimal clay content resulting in poorly developed soils.
What are the concerns with industrial approaches in agriculture? What are some strategies that offer approaches to minimize these concerns?
Concerns - Synthetic fertilizers deplete soil health and require intensive use of fossil fuels to produce
- Emissions and pollution resulting from all stages of agriculture affect air quality and contribute to climate change.
Strategies - Implementation of alternative methods such as crop rotation, reduced tillage, mulching, cover cropping and cross-slope farming help to increase soil organic matter content, soil structure and rooting depth.
