AY Honors/Agriculture/Answer Key

1. List the components of soil. Why is soil important to plants?

Soil Components

Soil has three components: solid, liquid, and gas. The solid phase is a mixture of mineral and organic matter. Soil particles pack loosely, forming a soil structure filled with voids. The solid phase occupies about half of the soil volume. The remaining void space contains water (liquid) and air (gas).

Soil texture refers to sand, silt and clay composition. Sand and silt are the product of physical weathering while clay is the product of chemical weathering. Clay content is particularly influential on soil behavior due to a high retention capacity for nutrients and water.

Importance to Plants

Soil provides minerals and water to plants. Soil absorbs rainwater and releases it later thus preventing floods and drought. Soil cleans the water as it percolates. Soil is the habitat for many organisms.

2. Explain the difference between clay, sand, and loam soils. List three crops that grow well in each.

Clay

Clayey soils are made from very fine particles which stick together easily. Water does not easily soak through clayey soils, but once it penetrates, the clay holds it well. It must be broken up before it can be used for agriculture. This can be done by mixing it with sand, sawdust, wood chips, lime, or manure. Crops that grow well in clayey soils include celery, wheat, oats, beans, and clover.

Sand

Sandy soils are made from coarse particles. Water soaks into sand quickly, but will not remain there for very long. This can be addressed by adding clayey soil to it. Crops that grow well in sandy soil include melons, cucumbers, peaches, peanuts, and beans.

Loam

Loam is soil composed of sand, silt, manure, and clay in relatively even concentration (about 40-40-10-10% concentration respectively). Loams are gritty, plastic when moist, and retain water easily. They generally contain more nutrients than sandy soils. In addition to the term loam, different names are given to soils with slightly different proportions of sand, silt, manure and clay: sandy loam, silty loam, clay loam, sandy clay loam, silty clay loam, and manural loam. Loam soil is ideal for growing crops because it retains nutrients well and retains water while still allowing the water to flow freely. This soil is found in a majority of successful farms in regions around the world known for their fertile land. Crops that do well in loamy soil include barley, turnips, and potatoes.

3. Test the germination of three varieties of seeds, 100 seeds in each variety. Record germination percentage after three, four, and five days.

First, wrap each variety seeds in a paper towel. Then dampen the paper towels and place them each inside their own clear plastic bag (such as a sandwich bag or a freezer bag) so that they retain moisture. Do not seal the bags. Place the bags in a warm place. After three days, carefully remove the paper towel from each bag, open it, and count the number of seeds that have sprouted. If you started with 100 seeds as per this requirement, the germination percentage will equal the number of seeds that have sprouted. Write this percentage down for each variety.

Do not remove the sprouted seeds. Rewrap the seeds in the paper towels, place the paper towels back in the bags, and return them to the warm place. Repeat after day four and day five.

4. Explain how plants obtain nutrients and convert them to food. Explain the differences between primary, secondary, and micronutrients.

Fertilizers can be divided into macronutrients or micronutrients based on their concentrations in plant dry matter. There are six macronutrients: nitrogen, phosphorus, and potassium, often termed "primary macronutrients" because their availability is usually managed with NPK fertilizers, and the "secondary macronutrients" — calcium, magnesium, and sulfur — which are required in roughly similar quantities but whose availability is often managed as part of liming and manuring practices rather than fertilizers. The macronutrients are consumed in larger quantities and normally present as a whole number or tenths of percentages in plant tissues (on a dry matter weight basis). There are many micronutrients (such as boron, chlorine, manganese, iron, zinc, copper, and molybdenum), required in concentrations ranging from 5 to 100 parts per million (ppm) by mass.

The uptake of nutrients by plants is accomplished through both the roots and the leaves. These nutrients are then used in the process of photosynthesis, which is a complex chemical reaction that converts light, carbon dioxide, and water into sugars.

5. Name and identify ten common weeds of your community and tell how to best eliminate them, using cultural or chemical methods.

Chenopodium album

Chenopodium album (Fat hen)

Where found: Worldwide Description: Chenopodium album is a fast-growing weedy annual plant in the genus Chenopodium. The standard English name is Fat-hen; other names include white goosefoot, lamb's quarters, pigweed or dungweed, or more ambiguously as just goosefoot. Control: It may be controlled by dark tillage, rotary hoeing, or flaming when the plants are small. Crop rotation of small grains will suppress an infestation. It is, however, difficult to control with chemical means.

Stellaria

Stellaria (Chickweed)

Where found: Europe, North America Description: Stellaria is a genus of about 90-120 species flowering plants in the family Caryophyllaceae, with a cosmopolitan distribution. Common names include stitchwort and chickweed. Control: Control is difficult due to the heavy seed sets, although herbicides are effective when the plants are small. Common Chickweed is very competitive with small grains, and can produce up to 80% yield losses among barley.

Ranunculus ficaria

Ranunculus ficaria (Lesser celandine)

Where found: The plant is found throughout Europe and west Asia and is now introduced in North America. Description: The window of opportunity for controlling lesser celandine is very short, due to its life cycle. In order to have the greatest negative impact to celandine and the least impact to desirable native wildflower species, herbicide should be applied in late winter-early spring (March through May). Apply a 1.5% rate of a 39 to 41% glyphosate isopropylamine salt (e.g., Rodeo® for wetland areas) mixed with water and a non-ionic surfactant to foliage, avoiding application to anything but the celandine. Glyphosate is systemic; that is, the active ingredient is absorbed by the plant and translocated to the roots, eventually killing the entire plant. The full effect on the plant may take 1-2 weeks. Applications can be made during the winter season as long as the temperature is above about 50 degrees Fahrenheit, and no rain is anticipated within 12 hours. Because glyphosate is non-specific, spray should be controlled such that it touches only lesser celandine and does not drift onto desirable plants. To minimize impacts to sensitive-skinned frogs and salamanders, some experts recommend applying herbicide in March and then switching to manual methods.

Oxalis

Oxalis (Wood sorrel)

Where found: The genus occurs throughout most of the world, except for the polar areas; species diversity is particularly rich in tropical Brazil and Mexico and in South Africa. Description: Oxalis is the largest genus in the wood sorrel family Oxalidaceae. Of the approximately 900 known species in the Oxalidaceae, 800 belong to Oxalis. Many of the species are known as Wood Sorrel or Woodsorrel. These plants are annual or perennial. The leaves are divided into three to ten or more round, heart-shaped or lanceolate leaflets, arranged in a whorl with all the leaflets of roughly equal size. The majority of species have three leaflets; in these species, the leaves are superficially similar to those of some clovers, though clovers differ in having the leaflets not in a whorl, and of unequal size with two smaller side leaflets and one larger central leaflet. Control: Diuron has potential for use as an over-the-top application for postemergence oxalis control, and timely irrigation has the potential to reduce injury to sensitive crops.

Elytrigia repens

Elytrigia repens (Couch Grass)

Where found: Elytrigia repens is a very common species of grass native to most of Europe, Asia, and northwest Africa. Description: Other names include twitch, quick grass, quitch grass, dog grass, and quackgrass. It has creeping rhizomes which enable it to grow rapidly across grassland. The stems ('culms') grow to 40–150 cm tall; the leaves are linear, 15–40 cm long and 3–10 mm broad at the base of the plant, with leaves higher on the stems 2–8.5 mm broad. The flower spike is 10–30 cm long, with spikelets 1–2 cm long, 5–7 mm broad and 3 mm thick with three to eight florets. The glumes are 7–12 mm long, usually without an awn or with only a short one. Control: Couch Grass is very difficult to remove from garden environments. One method is to dig deep into the ground in order to remove as much of the grass as possible. The area should then be covered with a thick layer of woodchips. To further prevent re-growth cardboard can be placed underneath the woodchips. The long, white rhizomes will, however, dry out and die if left on the surface.

Ranunculus repens

Ranunculus repens (Creeping Buttercup)

Where found: Native to Europe, Asia and northwestern Africa. Introduced to North America. Description: Creeping Buttercup is a herbaceous, stoloniferous perennial plant growing to 50 cm tall. It has both prostrate running stems, which produce roots and new plants at the nodes, and more or less erect flowering stems. The basal leaves are divided into three broad leaflets 1.5–8 cm long, shallowly to deeply lobed, borne on a 4–20 cm long petiole; leaves higher on the stems are smaller, with narrower leaflets. Both the stems and the leaves are finely hairy. The flowers are bright golden yellow, 2–3 cm diameter, usually with five petals. The fruit is a cluster of achenes 2.5–4 mm long. Creeping buttercup has three-lobed dark green, white-spotted leaves that grow out of the node. It grows in fields and pastures and prefers wet soil. Control: From the USDA Chemical control is probably the best strategy to employ to eliminate the buttercup. Your local Cooperative Extension office can provide information on which pasture herbicides are most effective for controlling buttercup. Additionally, there is probably a large quantity of buttercup seed in the soil seedbank that may emerge after your initial control. Following best management practices can reduce future buttercups from emerging. Also, adding desirable pasture seed to the soil where the buttercup was growing will help fill in the bare areas.

Sinapis arvensis

Sinapis arvensis (Charlock)

Where found: A native of Europe, it has also become naturalized throughout much of North America. Description: Charlock, also known as wild mustard, is an annual or winter annual up to 1 m tall. The stems are erect with coarse spreading hairs near the base. The basal leaves are pinnatifid to dentate. The cauline leaves are much reduced and are short petiolate to sessile but not auriculate-clasping. The inflorescence is a raceme made up of yellow flowers having four petals. The fruit is a silique 3-5 cm long with a beak 1-2 cm long that is flattened-quadrangular. The valves of the silique are glabrous or rarely bristly, three to five nerved. The seeds are smooth 1-1.5 mm in diameter. Control: Can be controlled by tilling the affected areas.

Senecio vulgaris

Senecio vulgaris (Common groundsel)

Where found: Common groundsel is a tenacious deciduous annual whose presence now encompasses the globe in a wide area of easy to somewhat difficult growing conditions. Description: Standing only between 4 and 16 inches (10 to 41 cm) tall, bright florets mostly hidden by the characteristic bract giving it the appearance of never opening flowers and with a life span of 5-6 weeks, the self fertilizing Senecio vulgaris lives humbly among and occasionally under the other weeds and is easy to not notice. Control: The ragwort flea beetle and ragwort seed fly have been approved and released for Senecio control in California, Australia and elsewhere.

Galium aparine

Galium aparine (Cleavers, Bedstraw)

Where found: Native to North America and Eurasia. Description: The long stems of this climbing plant sprawl over the ground and other plants, reaching heights of 1-1.5 m, occasionally 2 m. The leaves are simple and borne in whorls of six to eight. Both leaves and stem have fine hairs tipped with tiny hooks, making them cling to clothes and fur much like velcro. The white to greenish flowers are 2-3 mm across, with four petals. Control: Cleavers, or Bedstraw, tends to grow in uncultivated areas, such as beneath fencelines and at the edges of fields. The main problem it presents to agriculture is that it clogs harvesting machinery. It is best controlled before it is allowed to propagate into cultivated fields by mechanical means, or by livestock.

Cardamine hirsuta

Cardamine hirsuta (Hairy bittercress)

Where found: Native to Europe and Asia, but also present in North America as an invasive weed. Description: The plant is a member of the mustard family (Brassicaceae), and is edible as a bitter herb. It flowers from quite early in the Spring until the Autumn. The small white flowers are borne in a corymb on wiry green stems, soon followed by the seeds and often continuing to flower as the first seeds ripen. The seed will burst explosively, often when touched, sending the seeds flying far from the parent plant. Seeds germinate in the Autumn, and the plants are green throughout the winter months. Control: Cultivation is effective on young plants that have not yet flowered. Mulching in late summer will prevent germination. Pulled plants should be placed directly into a container, as the seeds will continue to ripen even after the plant is pulled up. Flameweeding is effective.

Rumex

Rumex (Dock)

Where found: Members of this family are very common perennial herbs growing in acidic, sour soils mainly in the northern hemisphere, but have been introduced almost everywhere. Description: These are erect plants with long tap roots. The fleshy to leathery leaves form a basal rosette at the root. The basal leaves may be different from those near the inflorescence. They may or may not have stipules. There are minor leaf veins. The leaf blade margins are entire or crenate. Control: Keeping fields well drained will help control dock. Young plants may be controlled by cultivation, but because mature plants send tap roots deep into the soil, it is difficult to eradicate them this way. Chemical controls include applying a combination of glyphosate and dicamba via a wiper when the plants are at least 30cm higher than the crops in which they grow.

Taraxacum

Taraxacum (Dandelion)

Where found: Dandelions are native to Africa, Asia and Europe, and have been widely introduced elsewhere. Away from their native regions, dandelions have become established in the Americas, Australia and New Zealand and are now common throughout all temperate regions. Description: The leaves are 5-25 cm long, simple and basal, entire or lobed, forming a rosette above the central taproot. As the leaves grow outward they push down the surrounding vegetation, such as grass in a lawn, which kills other plants by cutting off their access to sunlight. A bright yellow flower head (which is open in the daytime but closes at night) is borne singly on a hollow stem (scape) which rises 4-30 cm above the leaves and exudes a milky sap (latex) when broken. A rosette may produce several flowering stems at a time. The flower head is 2-5 cm in diameter and consists entirely of ray florets. The flower head matures into a spherical "clock" containing many single-seeded fruits (achenes). Each achene is attached to a pappus of fine hairs, which enable wind-dispersal over long distances. Control: Dandelion seeds are windborn, so it is difficult to prevent an infestation. If possible, dig the plants up at the edge of a field before they produce seeds. Otherwise, chemicl controls may be necessary. Glyphosate, mecoprop, and other herbicides can be applied to young plants. 2, 4-D is effective against established infestations.

Calystegia

Calystegia (Bindweed, Morning Glory)

Where found: The genus has a cosmopolitan distribution in temperate and subtropical regions, but with half of the species endemic to California Description: Bindweed are annual or herbaceous perennial twining vines growing to 1-5 m tall, with spirally arranged leaves. The flowers are trumpet shaped, 3-10 cm diameter, white or pink, with a sometimes inflated basal calyx. Some of the species, notably C. silvatica, are problematic weeds, which can swamp other more valuable plants by climbing over them, but some are also deliberately grown for their attractive flowers. Control: Bindweed is difficult to control once it becomes established. It is a very persistent weed, so control methods must necessarily be more persistent. Bindweed should be tilled under about eight days following emergence. It will re-emerge, so it will need to be retilled several times during the growing season. A systemic herbicide can also be used, such as 2,4-D or glyphosate. These herbicides must move in sufficient amounts through the roots, stems, and leaves in order to be effective.

Urtica

Urtica (Nettle)

Where found: Urtica has a cosmopolitan though mainly temperate distribution. The most prominent member of the genus is the stinging nettle Urtica dioica, native to Europe, north Africa, Asia, and North America. Description: This species have spiny hairs, or stinging trichomes, whose tips come off when touched, transforming the hair into a needle that will inject a cocktail of poisons: acetylcholine, histamine, 5-HT and possibly formic acid. This mix of poisons cause a sting or paresthesia from which the species derives its common name, as well as the colloquial name "7 minute itch". Control: Nettles should be trimmed to the ground and then sprayed with glyphosate. If the re-emerge, they should quickly be hit with glyphosate a second time.

Polygonum cuspidatum

Polygonum cuspidatum (Japanese knotweed)

Where found: Japanese knotweed is native to eastern Asia in Japan, China and Korea. In the U.S.A. and Europe the species is very successful and has been classified as invasive in several countries. Description: A member of the family Polygonaceae, Japanese knotweed has hollow stems with distinct raised nodes that give it the appearance of bamboo, though it is not related. While stems may reach a maximum height of 3–4 m each growing season, it is typical to see much smaller plants in places where they sprout through cracks in the pavement or are repeatedly cut down. The leaves are broad oval with a truncated base, 7–14 cm long and 5–12 cm broad, with an entire margin. The flowers are small, creamy white, produced in erect racemes 6–15 cm long in late summer and early autumn. Control: The success of the species has been partially attributed to its tolerance of a very wide range of soil types, pH and salinity.[2] Its rhizomes can survive temperatures of −35 °C (−30 °F) and can extend 7 meters (23 ft) horizontally and 3 meters (9.8 ft) deep, making removal by excavation difficult. The most effective method of control is by herbicide application close to the flowering stage in late summer or autumn. In some cases it is possible to eradicate Japanese knotweed in one growing season using only herbicides.

Cirsium arvense

Cirsium arvense (Creeping thistle)

Where found: Native throughout Europe and northern Asia, and widely introduced elsewhere. Description: It is a tall herbaceous perennial plant, forming extensive clonal colonies from an underground root system that sends up numerous erect stems each spring, reaching 1–1.2 m tall (occasionally more); the stems often lie partly flat by summer but can stay erect if supported by other vegetation. The leaves are very spiny, lobed, up to 15–20 cm long and 2–3 cm broad (smaller on the upper part of the flower stem). The inflorescence is 10–22 mm diameter, pink-purple, with all the florets of similar form (no division into disc and ray florets). Control: This plant is extremely difficult to control, as it can regrow from fairly small root fragments and is resistant to many herbicides. Pre-emergents can help prevent the plant from becoming established, but it is generally more often encountered as a perennial problem. Contact herbicides are only partially effective. Glyphosate in particular needs to be repeatedly applied. Mowing is effective over time, if done regularly. Goldenrods are allelopathic to this plant. Smothercropping of buckwheat and winter rye will also weaken the plant considerably. Pulling must be done repeatedly over a long period, but will eventually kill the plant. Gloves should be worn. Smothering techniques such as paper mulch barriers are quite effective. Canada thistle should never be added to a cold-composting system. All parts of the plant should be burned, thrown away, or put into high-temperature composting systems.

6. Identify six common insect pests or diseases. Tell what plants they usually affect and how to eliminate or prevent their occurrence.

Slug

Limax maximus (Great Grey Slug)

Where found: Native to Europe, the slugs have been introduced to Northern America and occur along the East and West sides of that continent. The slugs are almost always found near human habitation — usually in lawns, gardens, cellars or in other damp areas. Description: The Great Grey Slug, Limax maximus (literally, "great slug"), also known as the Tiger slug or the Spotted leopard slug, is one of the largest kinds of keeled slug (second only to Limax cinereoniger). The species is noted for its dark-spotted pale-grey body and the short keel on its tail. These nocturnal animals can grow to be as long as 8 inches (20 cm), feeding mostly on rotting plant matter and fungi. They live for up to three years and are inactive during the winter. Affected crops: Lettuce and cabbage are their favorites, but they will eat about anything. Control: Diatomite is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. It is sometimes used as an insecticide, due to its physico-sorptive properties. The fine powder absorbs lipids from the cuticle, the waxy outer layer of insects' exoskeletons, causing them to dehydrate. This also works against gastropods and is commonly employed in gardening to defeat slugs. However, since slugs inhabit humid environments, efficacy is very low. It is sometimes mixed with an attractant or other additives to increase its effectiveness. Among the disadvantages of using diatomaceous earth for pest control include the health risk to humans (see below), and that it is harmful to the many insects that are beneficial to gardens, including predatory beetles and bugs and many detritivores (such as earthworms). One mechanical control is to cut a soda bottle in half and place it around the plants to keep slugs out. This is obviously labor intensive, and is therefore not practical for large crops.

Colorado potato beetle

Leptinotarsa decemlineata (Colorado potato beetle)

Where found: Range of Leptinotarsa decemlineata Native to the Southwestern USA and Mexico, the Colorado potato beetle spread through the rest of the country, and into much of Canada. It then spread to continental Europe and Asia. Description: The Colorado potato beetle (Leptinotarsa decemlineata, also known as the Colorado beetle, ten-striped spearman, the ten-lined potato beetle) is an important pest of potato crops. It is approximately 10 mm (0.4 inches) long, with a bright yellow/orange body and 5 bold brown stripes along the length of each of its elytra, and it can easily be confused with its close cousin and look-alike, the false potato beetle Affected crops: Potato, tomato, eggplant, pepper Control: Insecticides are often unsuccessful when used against Leptinotarsa because of the beetle's resistance to toxins and ability to rapidly develop resistance to them. The Colorado beetle has developed resistance to all major insecticide classes. In areas where the CPB has not developed resistance to pesticides, it is crucially important to not repeated reuse the same type of chemical control, or the CPB will develop resistance to it. The CPB can be hand picked from the plants. Crop rotation is another effective strategy, the key being to put next year's potato crop as far as possible from last year's crop. Plants can also be covered with floating row covers - a thin fabric which allows moisture and air to circulate, but prevents access to the plants by the beetle.

Japanese beetle

Popillia japonica (Japanese beetle)

Where found: Map showing the parts of the United States currently infested by Japanese beetles. As the name suggests, the Japanese beetle is native to Japan. The insect was first found in the United States in 1916 in a nursery near Riverton, New Jersey. It is thought that beetle larvae entered the United States in a shipment of iris bulbs prior to 1912 when inspections of commodities entering the country began. Description: The Japanese beetle (Popillia japonica) is a beetle about 1.5 cm (0.6 inches) long and 1 cm (0.4 inches) wide (smaller in Canada), with shiny copper-colored elytra and a shiny green top of the thorax and head. It is not very destructive in Japan, where it is controlled by natural enemies, but in America it is a serious pest. Affected crops: Rose bushes, grapes, canna, crape myrtles, squash, strawberries, tomatoes, peppers, grapes, plums, pears, peaches, raspberries, blackberries, corn, peas and other plants. Control: During the larval stage, the Japanese beetle lives in lawns and other grasslands, where it eats the roots of grass. During that stage, it is susceptible to a fatal disease called milky spore disease, caused by a bacterium called milky spore, Paenibacillus (formerly Bacillus) popilliae. The USDA developed this biological control and it is commercially available in powder form for application to lawn areas. Standard applications (low density across a broad area) take from one to five years to establish maximal protection against larval survival (depending on climate), expanding through the soil through repeated rounds of infection, in-host multiplication, release from killed host, and infection. Typically proper application can lead to a 15-20 year period of protection. On field crops such as squash, floating row covers can be used to exclude the beetles, however this may necessitate hand pollination of flowers. Kaolin sprays can also be used as barriers. Research performed by many US extension service branches has shown that pheromone traps may attract more beetles than they catch, and so they have fallen out of favor. Natural repellents include catnip, chives, garlic, and tansy, as well as the remains of dead beetles.

European corn borer

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Boll weevil

[[w:|]] (Boll weevil)

Cutworm

[[w:|]] (Cutworm)

Brown marmorated stink bug

[[w:|]] (Brown marmorated stink bug)

7. Locate two sources of agricultural weather information. How is this information helpful to the farmer?

1. USDA's Weekly Weather and Climate Bulletin
2. U.S. National Climate Data Center

Climate is what to expect. Weather is what you get. Climate is basically a long-term average of what the weather has done in the past.

Knowing the climate helps the farmer plan agricultural activities such as planting and harvesting, as well as assisting in crop selection. Crops need to be in the ground early enough that they will be able to produce their yield before the first frost, but late enough to avoid springtime frosts. The climate tells the farmer how many growing days to expect, and that can be compared to the number of growing days required by various crops. Some crops also need to be harvested before the weather gets too hot, and other crops may allow multiple plantings and harvestings per season.

Weather also plays a hand in timing agricultural activities. A field needs to dry out before it is plowed, and then it may need to dry out for a few more days before it is disced. Dry weather is also needed to allow hay time to cure between mowing and bailing, and it is sometimes important when applying fertilizers or pesticides.

8. Assist in planting, cultivating, and harvesting at least four different crops. Maintain a log of work done and problems encountered from seeding to harvest.

Your log need not be any more complicated than a notebook and pen. You could include information such as:

• Plowing/Discing
  • When was it done?
  • What was the condition of the soil?
  • Cost
• Planting
  • Date
  • Amount of seed used
  • Method (how was the planting done?)
  • Cost
• Fertilizer
  • When applied
  • What kind was applied
  • Cost
• Pest Control
  • Dates and types of pesticides and herbicides
  • Cultivation dates
  • Mechanical/cultural controls applied
  • Cost
• Irrigation
  • Dates
  • Rainfall dates
  • Cost
• Harvest
  • Date
  • Yield

9. Know the purpose of the following:
a. Plowing
b. Disking
c. Cultivating
d. Irrigation
e. Harvesting

a. Plowing

The primary purpose of plowing is to turn over the upper layer of the soil, bringing fresh nutrients to the surface, while burying weeds and the remains of previous crops, allowing them to break down. It also aerates the soil, and allows it to hold moisture better. In modern use, a plowed field is typically left to dry out, and is then harrowed before planting.

b. Disking

Disking is often carried out on fields to follow the rough finish left by plowing operations. The purpose of this is generally to break up clods and lumps of soil and to provide a finer finish, a good tilth or soil structure that is suitable for seeding and planting operations.

c. Cultivating

A cultivator is a farm implement for stirring and pulverizing the soil, either before planting or to remove weeds and to aerate and loosen the soil after the crop has begun to grow.

d. Irrigation

Irrigation is the artificial application of water to the soil for assisting in growing crops. In crop production it is mainly used in dry areas and in periods of rainfall shortfalls, but also to protect plants against frost.

e. Harvesting

The purpose of harvesting is to collect the salable product grown in a field when it reaches maturity.

11. What is erosion? How can it be prevented?

Erosion is the displacement of soil by wind, water, or ice by downward or down-slope movement. It can occur quickly on steep ground - especially if there is nothing growing there. It can be slowed by minimizing the amount of time the land has nothing growing on it. When plowing, discing, or planting, it is best to make furrows perpendicular to the slope of the ground. Plowing straight uphill will cause furrows to act as ever-widening ditches that channel the water quickly away, carrying soil with it. Plowing across a hill instead slows the descent of rainwater and allows it to drop the sediments it picks up rather than carrying it off.