User:Ghmd
Field cultivators[edit]
The field cultivator was invented in 1977 by Harold A. Kirchner. Field cultivators are used to complete tillage operations in many different types of crop fields. This implement has many shanks mounted on the underside of a metal frame. The rear of this machine is also equipped with small narrow rods that smooth out the soil surface for easier travel when planting. These machines are pulled by tractors through the field and can vary greatly in size and shape.
Row crop cultivators[edit]
Row cultivators have a slighty different design than field cultivators. Instead of many rows of shanks for the purposes of preparing a seedbed, a row cultivator has one row of shanks or tools. The main function of this implement is to control weeds after the weeds have grown to 4-8" tall. The implement has gauge wheels located near the shanks that ensure proper tillage depth. The use of this machine has declined greatly since the use of herbicides has become a widespread practice among farmers in developed countries. Using row crop cultivators is still widely used in organic farming. This type of farming does not use any pesticides and row cultivating is an important tool that ensures good yields. This practice is also used in developing countries where herbicides are not widely available as they are in developed countries.
Uses and configurations[edit]
There are many different sizes and configurations of field cultivators and row crop cultivators. Choosing which type is best for a particular farm depends on many different factors. Some of these factors include farm size, the size of tractor available to pull the implement, and what types of crops are included in the farming operation. The main functions of the field cultivator is to prepare a proper seedbed for the crop that is going to be planted, burry crop residue in the soil which helps to warm the soil before planting, and mix and incorporate the soil to ensure the growing crop has enough water and nutrients to grow well during the growing season. A proper seedbed is important for the seed to imbibe water and to germinate properly. Weed control is the main function of the row crop cultivator. Many of the implements are equipped with hydraulic wings that fold up that makes road travel much easier and safer.
Sizing[edit]
When determining the size of cultivator needed for a particular farming operation, you need to first determine how much horsepower it takes to pull the implement and then compare that to horsepower capabilities of tractors available on the farm. To do this, you first need to determine how many pounds of force are required to pull the implement through the soil. The following equation is used to determin this:
D=Fi[A+B(S)+C(S)2]WT
where:
D is implement draft (lbf)
F is a dimensionless soil texture adjusment parameter
i = 1 for fine, 2 for medium, and 3 for course textured soils
A, B, and C are machine specific parameters
S is field speed (mile/hr)
W is machine width in ft or number of tools
T is tillage depth (in) for major tilage tools and dimensionless for minor tillage tools and seeding implements
A table with F, A, B, and C parameters can be found in the external link section.
Once the answer is generated it will be in terms pounds and needs to be converted into an answer in terms of horsepower. To do this, complete the following equation:
(D(lbf) x S(ft/min))/33,000(ft-lb/min) Multiply D x S first and then divide by 33,000 to convert the answer to horsepower.
Another concept that needs to be considered to compute an accurate answer is tractive efficiency.
Tractive efficiency=power at the drawbar divided by the power at the axle.
Most tractive efficencies are between 70% and 80%. If the answer found above is multiplied by the tractive efficency as a decimal you will find the HP that is actually available at the drawbar.
The last step is to simply compare the HP requirement of the field cultivator to the HP capabilities of the tractors that are part of the farming operation.
Sizes of field cultivators rangle from 20-60 feet wide. Most row cultivators come in sizes of 4, 8, 12, or 16 rows of shanks.
Producers of cultivators used in row crop agriculture[edit]
Almost every type of a agriculture machinery producer has some variation of the field cultivator in their production line. Not all companies produce row crop cultivators simply because they are not as widely used as they have been in the past. Some of these companies include Case New Holland, John Deere, and Massey Ferguson just to name a few. Each of these companies have different styles of designing and manufacturing these implements.
Safety[edit]
Agriculture in the United States is one of the most hazardous occupations a person can have. When using a cultivator of any size, safety needs to be considered at all times. The most care needs to be taken when traveling from field to field. Many cultivators are so large it can be difficult for the driver to see behind them. Extra care needs to be taken by the farmer to make sure that they ensure safety. Drivers around these types of farm machinery also need to be careful to not crowd the machine or try and pass when it is unclear. Also, almost all cultivators use some sort of hydraulic power. Hydraulic power is usually a safe and useful form of power, but problems can arrise if the proper precautions are not taken. Some hazards that can arise in the field are such things as hooking the implement in a fence line or on a tree. Both of these situations can cause damage to the tractor as well as to the cultivator.
References[edit]
1. http://www3.abe.iastate.edu/ast330/Lectures/ASAE_S414.1.pdf
2. http://www3.abe.iastate.edu/ast330/Lectures/ASAE_D497.4.pdf parameters for draft equation
3. http://www.freepatentsonline.com/4167978.html
4. http://www.equipmentlocator.com/ag-fp/new-used-tillage-equipment.htm
External links[edit]
http://www.caseih.com/products/series.aspx?seriesid=129&RL=ENNA