Environmental Management: Agriculture and the Environment

Flashcards on Agriculture and the Environment topics. Focus on soil composition, plant growth, agriculture types, increasing yields, impacts, erosion, and sustainable strategies.

Mineral particles, organic content, air, and water.

What are the four main components of soil?

Due to physical, chemical, and biological weathering of the parent rock.

How do mineral particles form in soil?

Sand, silt, and clay.

What are the three main soil types classified by size?

They are essential elements that construct proteins and carry out life processes.

What is the function of nitrogen, phosphorus, and potassium (NPK) in plant growth?

Increase water-holding capacity, increase air spaces, increase number of decomposers, prevent loss of mineral nutrients, and reduce soil erosion.

What are some advantages of high levels of organic matter in soil?

It affects the uptake of nutrients by plant roots and the availability of nutrients.

How does soil pH affect plant growth?

Sand has larger air spaces, low water content, drains well and is easier to cultivate, while clay has poor air spaces, high water content, poor drainage, and is hard to cultivate.

What are the key differences between sand and clay soil in terms of air content, water content, drainage, and cultivation?

Cultivation of crops to provide enough food for farmers and their families, practiced on small patches using primitive tools with low production.

What is subsistence agriculture?

Cultivation of crops with the main aim of selling them for cash (cash crops) to make a profit, practiced on a large scale using modern technology with high production.

What is commercial agriculture?

Production of plants for consumption by humans, such as rice, wheat, maize, and soybeans.

What is arable farming?

Production of animals or animal-related products, such as grass/grain to feed the animals that produce milk, wool, and eggs.

What is pastoral farming?

Farms that grow crops for food and rear animals.

What is mixed farming?

The principle of growing different types of plants in different plots each year.

What is crop rotation?

Diseases in the soil affecting the plant are left behind, pests need to find a new site, the soil in the new plot likely has essential nutrients, and crops are ready to harvest at different times so there is less potential waste.

What are the advantages of crop rotation?

Advantages: uses natural resources, supplies organic matter, and is cheap. Disadvantages: unpleasant to handle, harder to transport, and variable in composition.

What are the advantages and disadvantages of organic fertilizers?

Advantages: meet a particular need and are easier to store. Disadvantages: expensive, quick acting/easily leached, and little immediate impact/slow acting.

What are the advantages and disadvantages of inorganic fertilizers?

Advantages: easy to setup and can cover a large area. Disadvantages: large droplets may cap the soil, small droplets may be blown away by wind, and water lands on leaves and soil, which evaporates quickly.

What are the advantages and disadvantages of overhead sprinklers as an irrigation method?

Advantages: simple technology and easy to check the amount of water. Disadvantages: only suitable for permanent plants and large labor cost.

What are the advantages and disadvantages of a clay pot irrigation system?

Advantages: automated and well controlled, constant flow of water, avoids waterlogging, less water usage, and water is placed directly at the roots. Disadvantages: expensive to install, complex to maintain, grit can block tubes, and inflexible.

What are the advantages and disadvantages of drip irrigation?

Advantages: inexpensive and can cover large areas quickly. Disadvantages: inefficient water use, damages soil structure, and salinization.

What are the advantages and disadvantages of flood irrigation?

A pest is an animal, insect, or fungi that attacks or feeds upon a crop plant, while a pesticide is used to kill pests.

What is a pest and a pesticide?

Advantages: no chemical residues, no impact of sprays, and no need for reapplication. Disadvantages: not as instant as chemical control, pests may breed faster than the predator, and the predator may feed on an unintended plant.

What are the advantages and disadvantages of biological control for insect control?

Weeds compete with crops for light, water, and nutrients; might be poisonous; make cultivation difficult; can block drainage systems; can be a source of pests and diseases; and can look untidy.

What are some reasons to control weeds?

Easy to manage, cheap, results are predictable, effect is rapid, and alternatives may be less effective.

What are the advantages of using herbicides?

Hand weeding and weed barriers.

What are some examples of cultural controls as alternatives to herbicides?

To choose parents that exhibit the desired characteristics of the species, raise the offspring, select the best offspring, and repeat the process.

What is the purpose of selective breeding?

Pest-resistance, dought-resistance, disease-resistance, size.

What are some examples of desired characteristics in selective breeding?

The DNA of one organism is extracted then inserted into another.

What are Genetically Modified Organisms (GMO)?

Higher yield from lower inputs, less area needed to produce a crop, crops can be made with longer storage lives, crops can be made resistant to drought and salinity, increased disease and insect resistance, more appealing crops.

What are some advantages of GMOs?

Risk of GM characteristics getting into other plants, genes might get into wild plants, unknown impact on human health and environment, reduction in the gene pool.

What are some disadvantages of GMOs?

Greenhouses/glasshouses that provide optimum conditions for plant growth.

What are controlled environments in agriculture?

Temperature: Operate heating system (increase), open roof ventilators (decrease). Light: Artificial lighting (increase), shading material in the roof (decrease). Carbon Dioxide: Sprinkler or irrigation (increase), Drainage material underneath (decrease).

How can temperature, light, and carbon dioxide be increased or decreased in a controlled environment?

Growing plants without soil, with the nutrients the plant needs dissolved in water.

What is hydroponics?

No need for soil, can be used anywhere, easy to harvest, exact nutrients provided, water is recycled, reduce number of pests.

What are the advantages of hydroponics?

Expensive to set up, suitable for small production areas, technical knowledge required, disease may spread rapidly, plants can die quickly if conditions are not maintained.

What are the disadvantages of hydroponics?

Disturbed food web, decreased biodiversity, unintended environmental damage (reduction in insect pollinators, other animals eat poisoned insects), resistance within pest population, water contamination, toxic effect on marine life (bioaccumulation), air pollution, and can remain in the environment for generations.

What are the impacts of overuse of herbicides and insecticides?

Excess water containing dissolved fertilizers leach into nearby lakes and rivers, causing increase of algae growth (algal bloom), so sunlight is blocked, and photosynthesis is reduced, this causes the algae to die, which causes an increase in bacterial count to decompose the dead algae. The bacterial increase uses up oxygen, so aquatic organisms die due to the lack of oxygen.

What is eutrophication and how is it caused by overuse of fertilizers?

Death of plant roots, salts are toxic so land becomes unusable, damage to soil structure, loss of nutrients, run off increases soil erosion, and salinization.

What are the impacts of mismanagement of irrigation causing salinization and waterlogging?

Irrigation water soaks into the soil to a great depth, salts dissolve in the water at a great depth, water evaporates from the field, water and salts are drawn up to the surface, salt remains at the surface and kills plant roots.

What are some causes of salinization?

Waste from unsold proportion of the crop, waste of storage space, waste of transportation, and waste of labor.

What are the impacts of overproduction and waste?

Crop rotation, mixed cropping, and leaving the land fallow.

What are some solutions to exhaustion of mineral ion content in soil?

Wearing away of the top soil by the force of water or wind.

What is soil erosion?

Precipitation that does not reach the soil but is instead intercepted by the leaves and branches of plants.

What is interception?

Precipitation soaks into sub-surface soils and moves into rocks through cracks and pore spaces.

What is infiltration?

Water from rainfall or snowmelt that flows over the ground.

What is surface run-off?

Removal of natural vegetation, overcultivation, overgrazing, urbanization, increased demand for wood, wind erosion, water erosion, and soil compaction.

What are some causes of soil erosion?

Loss of habitat, desertification, silting of rivers, displacement of people, malnutrition, and famine.

What are the impacts of soil erosion?

Land is cut into flat surfaces and then into levels, so it reduces the slope. The speed of the surface run-off is reduced as soil is held back by terraces and water is held back by bunds.

Describe the terracing strategy for managing soil erosion.

Ploughing of land along the contour in a parallel way. Ridges and troughs run along the contour. Each furrow holds water and prevents large torrents of water running down the slope.

Describe the contour ploughing strategy for managing soil erosion.

Artificial banks at the edges of growing spaces built along contour lines by raising up the soil. Used to hold back water, slow down and collect the surface run-off of water to reduce water erosion and increase time for infiltration and reduce wind speed to reduce wind erosion.

What are bunds and how do they help manage soil erosion?

Rows of trees that act as permeable barriers used to reduce loss of soil due to wind on an area.

How do windbreaks help manage soil erosion?

Maintaining vegetation cover, adding organic matter to improve soil structure, planting trees, mixed cropping, and crop rotation.

What are some additional strategies to manage soil erosion?

Meeting the needs of the population for agricultural products, making efficient use of non-renewable resources, supporting the natural ecosystem by following natural processes with farming techniques, and sustaining the economic independence of farmers.

What are the aims of sustainable agriculture?

Organic fertilizers (crop residue, manure), managed grazing (livestock), crop rotation, use of pest and drought resistant varieties of crops, trickle drip irrigation, and rainwater harvesting.

What are some strategies for sustainable agriculture?