Strip-till is a conservation system that utilizes a minimum
tillage. It combines the soil drying and warming benefits of conventional tillage with the soil-protecting advantages of no-till by disturbing only the portion of the soil that is to contain the seed row. This type of tillage is performed with special equipment and requires the farmer to make multiple trips. Each row that has been strip-tilled is usually about eight to ten inches wide. Another benefit of strip-tilling is that the farmer can apply chemicals and fertilizer at the same time as tillage.
Comparison of Strip-till and No-tillage
What is no-till?
No-till, as the name implies, means no tillage of the soil to establish the seed bed, the only tillage of the soil is done at the time of planting. The farmer plants the crop directly into the previous year’s crop residue. This means that fifty percent to one hundred percent of the previous crop remains on the soil surface throughout the growing season. This practice is becoming more widely accepted by farmers across the country, and it is projected that by the year 2010 sixty percent of the United States cropland will be no-till (Brady and Weil, 2002). There are some areas, like Kentucky, where this practice has caught on more quickly. Specifically, eighty percent of the cropland in Kentucky is in no-till production.
Challenges with both systems
One disadvantage of no-till is the amount of herbicide needed for weed control. With no-till, a farmer is not able to uproot weeds prior to planting and is forced to spray at least twice during the growing season to minimize the competition to the crop from weeds. Also the soil does not dry out as rapidly after a rain as it would if the field was tilled.
There are a few disadvantages to strip-till systems that are risky for the farmer. For example, some farmers may not be able to strip-till if there is an early freeze. Those who strip-till in the spring may have logistical problems because the application windows for tillage and planting is narrow and the number days with suitable weather for field work are less than in the southern growing areas. There is also a small margin for error because the farmer has rows only eight to ten inches wide. Lastly, a large amount of horsepower is required to pull the strip-till implement across the field. In a flat region a smaller tractor can pull a larger applicator with little trouble; however, in regions with gentle to steep slopes, the tractor may not have enough horsepower. This can be problematic because most farmers do not own a tractor large enough to pull the strip-till implements nor can some justify purchasing a new tractor with sufficient horse power.
Differences in the equipment used
No-till planters have a disk opener (commonly referred to as a no-till coulter) that is located in front of the planting unit. This coulter is designed to cut through crop residue and into the hard crust of the soil. After the coulter has broken through the residue and crust, the disk opener of the planting unit slices the soil and the seed is dropped into the furrow that has been created and then a press wheel closes the furrow. The pictures are of no-till drills and they use the same principles as discussed above to plant the season’s crops.
With strip-tillage systems more precision is needed. The farmer will work the ground with a specialized implement to till up an eight to ten inch row and at the same time incorporate the fertilizer or chemical that the farmer so chooses. If the applicator’s chemical or fertilizer meter is off slightly, the farmer will not be applying an accurate rate of the chemical. This could result in increased expenses or reduction of the efficacy of the fertilizer program.
Effects on the soils properties
When oxygen is introduced into the soil via tillage, the decomposition of organic matter is accelerated. In a no-till system, one would think that the absence of tillage would create an anaerobic situation that would cause the decomposition of organic matter to slow. For an example, C, N, and P were all higher in the no-till system than on reduced till, and conventional till systems in an Australian study (Thomas et al., 2007).
Strip tillage has some similarities with no-till systems because the surface is protected with residue. However, strip-till also has a similar effect on soil properties as conventional tillage systems because the farmer still breaks the soil’s crust which allows aerobic conditions to speed the decay of organic matter. For example, one two-year study found that strip-till did not effect the amount of soil organic C or its extractable P (Kingrey et al., 1996). Another study about strip-till looked at the effects of strip-till and the availability to utilize P. This was proven in Minn. where there is usually a corn - soybean rotation.
Impacts on productivity
In one study, yields were higher in the strip-tilled area than in the area where no-till was practiced. In a low P site yield was 43.5 bu/a in strip-till compared to 41.5 bu/a in a no-till system (Randall et al., 2001).
The areas that are best suited for each tillage system
Each system is adapted to different regions where crops are grown on a large scale agriculture system. What will work for a farmer in Texas may not apply to a farmer in Iowa or Illinois. The systems have been adapted to function differently in their own way as related to that region. The region’s climate has a major factor in the decision with which type of tillage system that the farmer will choose. If the climate is a cool and wet, the farmer is more likely to strip-till than no-till. On the other hand, if the climate is mild and has some moisture, the farmer is more likely to no-till. This is because the farmer will not have to wait for the soil to warm up for grain production.
The Purchase Area of Kentucky and the lower one forth of the Corn Belt are prime environments for no-till crop production. They have mild winters and the soil is warm enough to plant by early April without tillage. Also, the rain usually hits later in the month so farmers can get most of the crop planted without the risk of having the fields too wet to plant.
The northern three fourths of the Corn Belt is the area where strip-till systems is most utilized. In the Corn Belt, farmers will usually strip-till in the fall before the freeze or in the spring to warm up the soil. Some tillage is necessary in this region because the ground will not warm up early enough to have an adequate length for a proper growing season. The farmers in this area have flatter ground and can optimize the use of strip-till applicators across their ground. They also have the right size tractor to pull the implements on the ground that barely has a slope.
The system that should be used from the soil’s standpoint
From the soil’s stand point, strip-till should be the system utilized because it warms the soil, it allows an aerobic condition, and it allows for a better seedbed than no-till. Strip-till allows the soil’s nutrients to be better adapted to the plant’s needs, while still giving ground coverage to the soil between the rows. The system will still allow for some soil water contact that could cause erosion, however, the amount of erosion on a strip-tilled field would be light compared to the amount of erosion on a conventionally tilled field.
Both systems are considered conservational tillage and are meant to minimize soil erosion. In western Kentucky, no-till is by far the best practice to use because of the climate. The regions in which strip-till and no-till should be used are apparent because of the region’s climates. Therefore, it is the farmer’s decision which tillage system to use.
*Brady, N.C., and Ra.R. Weil. [http://books.google.com/books?id=oe-pAAAACAAJ&dq=nature+and+properties+of+soils+brady+weil&ei=6PtWR_KTAo7wpwLt0L3MDw The Nature and Properties of Soils] . 13th ed. Upper Saddle River, NJ: Prentice Hall, 2002.
*Kingrey, W. L., C. W. Wood, and J. C. Williams. [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TC6-3W2YDB4-3&_user=16764&_coverDate=07%2F31%2F1996&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000001898&_version=1&_urlVersion=0&_userid=16764&md5=9c8a4ff4d484bd6296b090d4550173a1 "Tillage and amendment effects on soil carbon and nitrogen mineralization and phosphorus release."] Soil and Tillage Research 37(1996): 239-250.
*Randall, G.W.; Vetsch, J.A.; Murrel, T.S.. [http://www.ipni.net/ppiweb/bcrops.nsf/$webindex/1DFBA56226CD997C85256AEA005C43DD/$file/01-4p12.pdf “Soybean Response to Residual Phosphorus for Various Placements and Tillage Practices.”] Better Crops 85, (2001, 2).
*Thomas, G.A, R.C. Dalal, and J. Standley. "No-till effects on organic matter, pH, cation exchange capacity and nutrient distribution in a Luvisol in the semi-arid subtropics ." Soil and Tillage Research 94, Issue 2(June 2007): 295-304.
* [http://www.deere.com/servlet/com.deere.u90785.productcatalog.view.servlets.ProdCatProduct?tM=FR&pNbr=2510SN "2510S Strip-Till Residue Master Applicator ."] Deere.com. 24 Aug 2007. John Deere. 13 Sep 2007.
* [http://www.oznet.ksu.edu/library/crpsl2/mf2661.pdf Considering Strip-tillage]
Conservation tillage systems
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