Final Flashcards
(38 cards)
Explain why crop genetic diversity in important and relevant in changing physical and biological environments.
Genetic diversity can be both good and bad.
Good: resistance to diseases, drought, etc.
Bad: ununiformity of production.
Diversity is especially important in breeding programs. In fields, however, we want less diversity and more uniformity.
Define ecosystem service and disservice.
Functions of natural and managed ecosystems that enhance human well being.
Functions of natural and managed ecosystems that negative affect human well being.
What are direct and indirect energy uses in respect to agricultural production. Examples?
Direct: on farm uses, such as fuels (equipment), natural gas, energy (pumping water, etc.).
Indirect: “embodied;” energy used off-farm in the production/transport of external inputs (fertilizers, pesticides, seeds, machinery, labor, etc.)
What are the biggest energy uses in agricultural production? Which is direct/indirect?
(#1) Fertilizer/agrochemical production (indirect).
(#2) Fossil fuels for machinery (direct).
Food waste is another big indirect.
Which is more energy-efficient, grain or vegetable production? What does the energy-centric perspective ignore about this?
Grain production, as per energy density compared to energy used in production.
It ignores nutrition value, and potential externalities up and downstream.
How can grazing enhance rangeland productivity?
Optimal intensity/duration grazing stimulates roots and increases exudation, can suppress invasive species and free up space for other species, and livestock wastes prime decomposition pathways.
What are ways that energy costs related to equipment use and fertilization can be reduced? What tradeoffs and other areas of management are involved?
Reduced tillage, reduce external inputs.
Electric equipment/tractors, optimize equipment efficiency, reduced passes through technology. Tradeoffs include costs of new equipment/maintenance etc.
Decrease equipment use. Tradeoff includes increases labor requirements for weeding etc.
Cover crops/compost to substitute for fertilizer inputs. Tradeoffs include seed/compost costs (cover crops more expensive than fertilizers, when including management), management considerations of cover crops, nutrient synchrony, etc.
What is a portfolio effect in the context of biodiversity and ecosystem services? How does it relate
to resilience as discussed in the lecture on regenerative agriculture?
The stabilizing influence of biodiversity on ecosystem processes and services.
Greater biodiversity -> greater stability/resistance -> greater resilience
How can we use traditional crop breeding to get genes into existing high quality rice strains while avoiding negative genetic impacts? What is the name of this process?
Artificial selection.
Two main categories of methane reduction strategies.
Absolute reduction (feed additives, optimized feed, methane inhibitors, etc.) and product-based reduction (breeding for greater efficiency).
What is upstream cost? What does including it to the energy ratio do? Why?
Refers to the raw materials required for production, including transportation, fertilizers, water, labor, etc.
Including it in the energy ratio lowers the efficiency (more input compared to less output).
Explain how domestication, dispersal, and modern breeding have affected crop genetic diversity.
Reduced genetic diversity compared to wild progenitors.
Why are crop wild relatives used in breeding programs? What are possible benefits and tradeoffs?
Important in breeding specific resistances (drought, disease, etc.). Adapted to different environments/stressors. Source of useful alleles for crop improvement.
Tradeoffs: difficult to cross different species, linked traits may be undesirable.
What stages of the food system use the most energy?
Processing, transport, retail, packaging.
Regenerative agriculture in its full definition moves through 5 levels. What are these?
Increase efficiency, substitute inputs, redesign the agroecosystem, re-establish food system connections, new global food systems.
For a given crop, what quantities go into calculating its energy output?
Calories per unit yield. (per bushel, hectare, etc.)
MJ/ha/yr
Define domestication in the context of agricultural crops. Identify traits that were commonly selected for during domestication (at least 6). Examples?
Selection to facilitate cultivation by humans and improve edibility/palatability.
- Seed dispersal (indehiscence in beans/peas, loss of shattering in wheat)
- No toxicity, bitterness, off flavors (cucumber, brassicas)
- Growth habit/branching (tomatoes, corn)
- Gigantism (grain size in rice, wheat, maize, barley; fruit size in tomato; flower size in sunflower)
- Shape/color (brassicas)
- Seedling vigor (???)
What stages of the food system create the most GHG emissions?
Land use change, on-farm, and animal feed production.
Negative impacts of overgrazing.
Loss of biodiversity, reduced water infiltration, topsoil erosion, compaction, waterway pollution, flooding.
Tools to manage proper grazing.
Match number of animals to available forage, residual dry matter management, availability of water for animals (manages where animals go).
Also types of animals.
Dietary gaps in world food/nutrition. How do they fit into importance of animals and animal products in different regions of the world?
Some regions have lower access to certain types of food that provide important nutrients and/or adequate caloric intake. Animal products can fill in important nutrient/calorie gaps in these regions, especially the global south.
Define response diversity and provide an example of it. Explain how redundancy is an important
part of response diversity.
Refers to the variety of responses that different species or functional groups exhibit to environmental changes or disturbances. This diversity allows ecosystems to maintain their functions and services even when some species are lost or impaired.
What is a landrace? Where in the historical timeline of domestication up through modern crop varieties do landraces fit in?
Landraces come after domestication. Initial dispersion from center of origin, recombination and adaptation to local environments.
The main cause of high GHG emissions from ruminants in low income countries. How can it be mitigated?
Poor diet of animals. Increasing diet quality can reduce GHG emissions.
