Taken as a percentage of all harvested cropland in the U.S. (approximately 3.65 million acres) for 2007, 16.6 percent was irrigated. Yet water is increasingly a valuable resource and has even been referred to as the, "new oil." For the farmer, a field without adequate water is next to useless to grow crops. Where rainfall is inadequate or too infrequent during the growing season to meet the demands of a crop, the solution is irrigation. Irrigation, efficiently applied, will put the right amount of water in the right place, at the right time. This takes away uncertainty, even where rainfall has been historically plentiful, for your crop's success and ultimately, your bottom line.

Advantages of irrigation cited by the United States Department of Agriculture (USDA) include:

• Certainty of water enables a farmer to control income fluctuation.
• Crop quality, especially vegetables will improve.
• Crop yields, especially from low moisture holding soils, will improve.
• The opportunity for double cropping, such as soybeans after wheat, is greater.
• The irrigation system can be a delivery method for liquid fertilizers.

While crop irrigation could be good for you it is worth bearing in mind that what you do could be detrimental to the environment. You need to consider if your irrigation practices could:

Deplete the water source, causing the water table level to lower or lead to a reduction in the water levels of creeks or reservoirs.

• Cause soil erosion because of over irrigation leading to runoff and the possibility of fertilizers and chemicals traveling to where they are not intended to go.
• Cause soil salinization (salt accumulation) and a build up of minerals and nutrients from the irrigation return flow, which drains away from the irrigated land.

The type of irrigation that you will use will depend on the crops that you are growing and how much you are going to spend. Irrigation systems are either a permanent stationary system or a mobile system; permanent systems are usually more expensive but require less labor. Irrigation systems can be:

• Surface irrigation systems, which cause water to flow over the surface of the soil allowing the entire surface area to be flooded. Such systems are particularly effective for sown, drilled, and seeded crops; irrigation can also be channeled between rows of plants.
• Sprinkler irrigation systems where the water is sprayed through pressurized nozzles. The sprinklers can be fixed in place or be portable systems such as cable tow, center pivot, and linear move; installing variable flow sprinkler heads will improve the precision of water, fertilizer, and any chemical applications.
• Sub irrigation systems that artificially raise the level of the water table by blocking ditches or delivering water though buried perforated pipelines.

An irrigation system will only work at its best if it is managed effectively. You will need to consider:

• Using only the water that your crop needs. Checking your soil's moisture on a regular basis or consider installing a daily water soil accounting system.
• Ensure your irrigation system is efficient, for example, a drip delivery system will reduce water loss through evaporation.
• Test your soil to establish how much water it can absorb. Applying too much water will cause wasteful runoff, which can lead to soil erosion.
• Apply irrigation evenly over the whole area required. Too much water in one place will cause runoff and water leaching.
• Make sure you have good drainage. This is especially important where rainfall is low. Effective drainage will minimize the build up of potentially damaging salts and minerals and allow them to leach through the soil.

Useful Links
USDA (www.ams.usda.gov)
Maryland (www.mda.state.md.us)
West Virginia (www.wvagriculture.org)
Kentucky (www.kyagr.com)
Virginia (www.vdacs.virginia.gov)
North Carolina (www.ncagr.gov)
South Carolina (www.state.sc.us/scda)
Alabama (www.agi.state.al.us)
Georgia (http://agr.georgia.gov)
Florida (www.doacs.state.fl.us)