Modern Irrigation

The New World of Irrigation- More Bushel Per Unit of Water

By Loren Seaman

Many people are affected by irrigated agriculture across the world; good farmers, crop consultants, equipment dealers, suppliers, the transportation industry, grain handlers, marketers, processors, manufacturers feed mills and of course the end users- feedlots and private consumers. We all are involved and must regard water conservation of paramount importance.

A lot of advances have been made since since the early 1960s, when we started to replace the furrow or flood irrigation approaches of yesteryear. Now, more than four decades later we have also learned the value of drip tape irrigation. Every day we are realizing more and more, the value of the water supply to agriculture, especially since drought conditions are upon us again. Water simply cannot be wasted. It is uneconomical to waste water for everyone, from the farmer on down.

Some of the most important advances, have been made by the enterprising businesses that we have throughout agriculture, including educators and researchers, product development teams and, retailers offering products, to the educators; all have an interest in water conservation and have done a lot of effective work.

Sprinkler pivots were developed to even out the water application through the fields. The old practice of furrow irrigating by running water down a slight slope was very inefficient. The upper end of the field was soaked 6 ft deep and the lower end of the field just didn't soak much at all. It took a lot of extra labor to even out the water applications, and still up to 50% of the water was wasted by runoff. Pivots are essentially mainline pipe that is supported up in the air on wheels. It rotates around a center point. They became "center pivots". The first ones had nozzles on top that were spaced approx 30' apart and a water pressure of 65-70 psi was required to effectively distribute the water.

The pivot companies have progressively improved their systems (from 70% efficiency to now 90%)

A. Due to better nozzling, pressure regulation, uniformity of pivot application has increased.

B. Due to lowering of operating pressures, energy costs of pumping have come down

C. Due to better structures and mobility, there are fewer pivots getting stuck, wasting water.

D. Due to better control panels, downtime is a lot less, so not pumping water at a standstill

E. Due to use of drip tapes at or below ground level reduces evaporation even further.

Computers, satellites, and phones now can bring data together easily. Defined, knowledgeable management (instead of just letting water flow) can save 3 inches of water per acre per season. An inch of water on 1 acre equals 27,225 gallons. So 3 inches/ac equals 81,675 gallons/ac. If the field is 122 ac, then the gallons saved is 81,675 x 122 equals 9,964,350 gallons saved per field. Sounds like a lot of water doesn't it. Just consider, though, --whether we are talking of crops, grassland, or forests, or lawns in the cities, they all use about the same amount of water; any vegetation in our latitude will use about the same amount moisture per season regardless of whether it comes from rainfall or irrigation.

A. Due to new technology, farmers and crop consultants can better determine scheduling

1. Using moisture sensing probes, they can check moisture readings every 30 minutes

2. Using websites, the farmer can check on pivot operation

3. Using his phone, and website, the farmer can change pivot speeds

B. Due to new Variable Rate Irrigation (VRI) computer programs, correlating soil type, to water holding capacity, we can save additional 2 in/ac water, use less nitrogen and still increase crop yields.

1. The farmer can vary the amount of water applied to differing areas within the field by crop, soil type, slope, and time of season.

Agriculture research has expanded further into irrigation. This research also has brought us genetically selected and produced, drought traits in crops. I can remember back when sugar beets were grown in Southwest Kansas and Eastern Colorado. The common thinking of the day was that you had to pump 36 inches of water per season to grow a good crop. Research in the 1970s finally showed that good sugar beets could be grown with a management program that allowed 22 inches of water per season. It is the same with other crops. As seed companies have become better at identifying strains that increase yield, and are more efficient in their water utilization, we are growing 30-40% more grain on the same water. It is not true that more water automatically means more yield, and it never has been true. If it ever was true, it was only because we were so inefficient and didn’t know any better! Time and again, we have proved a little less water provides the same or higher yields.

Costs for these investments in efficiency are best figured on a five-year basis or return on investment. The farmer has always had to figure repair, depreciation, and maintenance costs for his irrig pivot and it is the same for the investment in technology. The tech fees of Water Probes, EM mapping and VRI tend to run a five-year average annual costs of around $15-20 per acre. These tech efficiency costs have shown to be covered easily by reduced pumping expense and higher yields. And if we can slow the decline on groundwater, it means reduced pumping costs far into the future. We expect use of these technologies to increase greatly over the next three years.

I have watched the advances in irrigation now for 37 years in the Great Plains area of Nebraska, Kansas, Oklahoma and Texas. I applaud all the efforts farmers are making now in water conservation. With fresh regard for new ideas, we can go even further.

Mr. Seaman, founder of Seaman Crop Consulting has been an agriculture consultant for 37 years and is based in Hugoton, Kansas. He can be reached at www.seamancrop.com

Article published in Okla. for Responsible Water Policy  (Spring 2014)