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Crop Science Exam 2

Based on annual precipitation, Alabama is in the crop region best described as Humid
The water-use efficiency ratio for crop plants can best be described as the ratio between amount of water used and Total dry matter yield
Insect, disease and weed pests are best managed using a system of biological, cultural, chemical, and other tools otherwise known as Integrated Pest Management
The primary function of sulfur in plant metabolism is component of proteins
the three major tools of the plant breeder are introduction, selection, and hybridization
of the following fertilizer materials, the only one that is currently NOT a commercial source of phosphate is dinitogen phosphate
Ammonium nitrate (33-0-0) sells for $12.80 for a 50 pound bag at the local co-op. The cost per pound of N would be approximately $0.78
An example of the disease management principle of therapy is removal of diseased plant parts by surgery
In the backcross method of crop improvement the major objective is improvement of one specific trait for an otherwise acceptable cultivar
In integrated pest management (IPM), the first step is to determine the species and numbers of any pests present as well as the number and type of beneficial insects
The tillage implement that leave the least crop debris on the soil surface is the Cultivator
One of the main reasons why weed control in crops is so difficult is because weeds have very efficient mechanisms for reproduction and survival
The non-selective herbicide most often used in conjunction with GMO crops is roundup
an example of a preventative method of weed management is planting weed free seed
The two most critical factors in determining the effectiveness of a selective herbicide are application rate and stage of weed and crop growth
Two major issues regarding water availability in Alabama are Distribution of rainfall and poor water-holding capacity of coils
Since 1900, crop yields for cotton, corn, and soybean in the US have increased slowly or not at all in the beginning, then increasing at an increasing rate
Two nutrient elements that are both an important part of nucleic acids (DNA, the genetic material) are Nitrogen and phosphorus
A nonselective herbicide is capable of killing almost any green plant species
Weeds are classified according to life cycle (annual vs. perennial) and broadleaf vs. grasses
Plant breeding is primarily concerned with two major areas of work: germplasm development and development of new cultivars
The oldest and most familiar form of weed control is mechanical (the hoe)
Nitrogen fertilizer recommendations for specific crops are based on type of crop to be grown
The "GMO" in GMO crops is an acronym for Genetically Modified Organism
Example of conservation tillage programs include ridge till, strip-till, and no-tillage
Give two ways that planting in a timely fashion (early planting dates) can improve water-use efficiency 1. the crops will get any rainfall that is to come 2. they can begin to use what moisture is already in the soil before the receive any rainfall 3. less competition
Describe the single most important way that conservation tillage systems differ from conventional tillage systems no residue burial
What method of weed management is most relied upon in conservation tillage systems selective herbicieds
Briefly explain the difference between a systemic and contact herbicide, and give one example of each. systemic: takes time to kill the weed, better. example: Roundup contact: kills weeds very quickly, almost instantly, not as good
How to weeds compete with man for food? Give 3 ways weeds can be detrimental in a crop production system 1. Host insects and diseases 2. nutrient absorption 3. poorer quality weeds can survive better than crops and take away energy, water, and nutrients that the plants need
explain how conservation tillage improves soil water holding capacity less disruption of soil, more organic matter so it holds water better
how does conservation tillage improve water quality less rainfall run-off, not as much toxic water runoff is able to escape
Give two reasons why genetic resistance is one of the best strategies for the management of disease or insect pests more economical, better for environment and the crop, easier to manage
How can the over-use or extensive use of a non-selective herbicide, such as Roundup, eventually lead to a loss of its effectiveness against certain weed species? weeds just like any other species can develop an immunity to these herbicides
of the following, the only fertilizer material that is a commercial source of both N and P is monoammonium phosphate
in spite of receiving a fairly high amount of annual precipitation, water is often a limiting factor in crop production in Alabama and the Southeast because of poor water-holding capacity of soils, high evapotranspiration rates, and uneven seasonal rainfall distribution
A fallow cropping system is one in which a crop is grown only every two or three years to conserve soil moisture
One disadvantage of ridge-tillage systems is all crops must be grown on the same row-spacing
The major function of the subsoiler or chisel plow is to break up deep hardpans or compacted layers
An example of the disease management principle of protection is seed treatment with a fungicide to protect against seedling diseases
The botanical type of corn that is the most widely-grown and is the principle feed-grain type in the US is flour
Cultivated corn has its origins in Central America
In order to qualify as conservation tillage, a field must have at least 30% of the field area covered by debris from the previous crop
A very popular method of crop improvement, used most often to improve an established cultivar for a single, specific, simply-inherited trait is backcross method
The type of organism responsible for the majority of plant diseases are fungi
Among others, one of the major difference between domesticated plants (crops) and undomesticated plants (weeds and wild plant species) is weeds have very efficient methods of seed dispersal; crops do not
the two most critical factors in determining effectiveness of a herbicide treatment are the rate at which it is applied and the stage of crop of weed growth
The major fertilizer material used to supply potassium in commercial fertilizers is Muritate of potash, Potassium chloride (KCl)
The first basic strategy of any integrated pest management (IPM) program is identification of pest and any beneficial species that may be present
One major disadvantage of over-use of insecticides for insect management is selection pressure creates insecticide resistant insect genotypes, beneficial insects as well as pest insects are killed, and it is harmful to the environment (birds, rabbits, humans)
Many crop plants now have weed and insect management strategies "built in" in the form of genetically-engineered tolerance to herbicides and production of insecticides
One of the unique things about corn production in the US is all cultivated types are marked F1 hybrids
Advantages of reduced tillage programs include better moisture retention by the soil
Herbicides can be grouped largely as either systemic or Contact
One of the major problems faced in plant breeding (genetic improvement of plants) is lack of trained plant breeders
A 100lb bag of fertilizer of grade 5-10-15 actually contains the equivalent of 5lbs N, 10lbs P20, and 15lbs K20
Two possible consequences of excessive cultivation in crops are loss of soil moisture and root pruning
Give 2 reasons why we till the soil 1. prepare for seedbeds 2. bury crop debris
Give an example of a primary tillage implement moldboard plow
Give and example of a secondary tillage implement disk harrows
Give and example of a mechanical method of weed management mowing
Give and example of a selective herbicide 2-4-D
Give and example of a commercial source of Nitrogen Ammonium Nitrate
Explain the difference between preplant and post emerge herbicide preplant: you spray before the plant is planted at 2 inches deep post emerge: you spray after the plant has been emerged from the soil
how does conservation tillage reduce soil compaction low traffic
how does conservation tillage reduce fuel requirements less tillage so it reduces fuel requirements
how does conservation tillage increase soul water-holding capacity increase organic matter so that soil will hold more water
how does conservation tillage reduce erosion and water runoff, and improve water quality leaving organic matter, using less pesticides
how does conservation tillage help remove CO2 from the atmosphere more carbon left in the soil, less in the atmosphere
Julius Sachs discovered in the 1860s he could grow plants successfully in a mixture of 3 salts: Calcium Nitrate, Potassium Phosphate, and Magnesium Sulfate
Functions of C, H, and O metabolism (respiration and photosynthesis)
Function of N constituent of chlorphyll, in all amino acids and also in DNA
Function of P involved in energy transfer (ATP) and a component of DNA
Function of K+ exists in the plant primarily in ionic form, functions in electrolyte balance, manages the opening and closing of stomates
Function of Ca constituent of cell walls, structural element
Function of Mg part of chlorophyll
Function of S component of some amino acids and also in proteins
Anhydrous Ammonia source of nitrogen. Gas. 82% N you can inject this into the soil. relatively cheap and easy to handle, generally only for crop fields, mainly for corn
Urea soild source of nitrogen, 46% N, injected into the soil
Ammonium Nitrate solid source of nitrogen, is 33 to 34% nitrogen
Sources of Phosphorus Super Phosphate, Triple Super Phosphate, Diammonium Phosphate, Monoammonium Phosphate, Ammonium phosphate sulfate
Fertilizer Analysis % N, % P2O5, %K2O
Sources of Potassium muriate of potash, potassium sulfate (used for plants sensitive to chlorine)
Why do we till the soil to prepare the seedbed, manage weeds, diseases and insect pests, incorporate residues, and level land
Moldboard Plow essentially a triple wedge, forced through the soil to invert the upper 6-8 inches completely, burying all plant debris. Soil conditions must be right, too moist or too dry does not get plowed efficiently. usually results in 100% residue burial
Disk Plow same as moldboard plow but have a disc instead of a triple wedge
Chisel Plow deep tillage, but does so in a way to disturb the soil surface in the least possible way. had a large energy requirement
Disking Harrows general purpose tillage instrument that can smooth soil . used to incorporate pesticides
Cultivation and Cultivators used to kill weeds. over cultivation can lead to loss of soil moisture, root pruning, and soil compaction. is being replaced by non-selective herbicides and GMO's
Soil compaction caused by large equipment and too many trips over the soil. causes poor root penetration, poor water infiltration, excess water runoff, water logged top soil, and lower yields
Correcting soil compaction deep tillage, particularly deeper than normal, using a subsoiler or chisel plow
Reduced tillage programs leaving crop debris on the surface, instead of incorporating as in a conventional tillage program
No till complete lack of tillage. planting a crop directly into existing plant debris
strip till growing crops in a narrow, residue-free strip no more than 1/3 the row width
ridge till growing crops in pre-formed ridges alternated with debris
Benefits of conservation tillage reduces labor and saves time. Saves fuel, reduces machinery wear, improves soil tilth, traps soil moisture, reduces soil erosion, provides cover for wildlife, improves air quality
Estimating percentage residue cover stretch 100ft measuring tape diagonally across field and count the number of times the foot markers are touching residue. add that up and the sum equals the percent residue
Disadvantages of reduced tillage pest management may be more difficult at first, may require a higher level of management skills
Weeds planting crops in rows reduces weeds. weeds are very efficient at reproduction and growth compared to crops. the cost of weed management is enormous
How weeds cause losses 1. Competition for water, sunlight, and nutrients 2. Lower crop quality 3. Serve as hosts for diseases and insects 4. Decrease land values 5. Can cause livestock injury
Weed Classification 1. Perennial vs. Annuals 2. Broadleaf vs. Grasses
Preventative Weed Management don't let your field get infested in the first place. Use clean seed, sanitize equipment, maintain areas around field (mow around field)
Crop Competition Weed Management plant population, row spacing close for early canopy, early planting
Biological Control Weed Management introduce pest of the weed into the field. diseases, insect pests, etc.
Mechanical Control of Weeds oldest and most familiar method. hand weeding, using a hoe. mechanical cultivation
Chemical Control of Weeds saves a lot of labor. classified by selectivity
Selective Chemical Control only kills certain plants. Examples: 2, 4D, Simazine, and Treflan
Non-selective Chemical Control chemicals designed to kill any plant. examples: Roundup and Gramoxone
Systemic Chemical Control kills by getting on leaf tissue and being translocated throughout the plant. Good for perennials. Example: Roundup
Contact Chemical Control like walking around with a flame thrower, the plant dies within a couple of minutes. Good for annuals. Example: Gramoxone
Exclusion keeping diseases out. Agricultural customs at state and country borders. Quarantines for plants and animals
Eradication practice sanitization around crop area. Eliminate alternate hosts.
Therapy plant is already infected, how to save plant. Chemicals, surgery (cutting off diseased part), heat.
Resistance (genetic) plant is selectively bred to have resistance to pathogens. Economical, easy to use, and environmentally safe. Method of choice for agronomic crops
Protection doing something to specifically protect a plant from a known disease in a localized area. example: seed treatment
Avoidance if you have a disease in a certain field, don't plant crops that are susceptible to that disease. Also pay attention to planting date to avoid the plant being infected
Insects reduce yield, may kill plants, reduce quality and can transmit disease.
Biological Control of Insects using 1 insect to manage or control another. Ladybugs can be used to control aphids
Bacillus thuriengensis infect lepidoptera and worms, you can genetically engineer this into the plant and kill the lepidoptera and worm that tries to eat it
BT technology common in corn and cotton. Tobacco was the first plant genetically engineered this way
Genetic Resistance antibiosis: feeding on the plant causes physical harm to the insect. example, Hessian fly resistance in wheat
Pesticides chief way of fighting insect infestations in some crops
DDT caused serious ecological problems because insects and animals share certain physiological characteristics
Integrated Pest Management (IPM) integrating many different strategies to manage a pest. focuses on long term management/prevention of pests. 1. Identify the pest, and beneficial insects/organisms that may be present 2. Determination of economic threshold
Contributions of Plant Breeding higher crop yields, improve crop quality, better pest resistance, improved agronomic traits, and new crops for new areas of production
Three tools of the Plant Breeder Introduction, Selection, Hybridization
Introduction basically, exhausted as a tool except in unusual circumstances for most crops, less so for forages, cover crops and turf
Selection the selection of superior plant types from larger populations, usually used in conjunction with hybridization
Hybridization the sexual crossing of plants to generate new genetic combinations
Pedigree Selection idea is to cross two adapted parents, hoping to select superior progeny in the following segregating generations
Backcross Method used to improve a single trait for an established widely used cultivar. Involves repeated backcrosses to the adapted cultivar
2 Major Objectives of Plant Breeding Programs 1. Cultivar Development 2. Germplasm Enhancement
Cultivar Development new varieties of crop and ornamental plants suited for producers, industry, and the consumer
Created by: asculpepper



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