by Haley Ruffner
8 February 2023 | [email protected] | 307.205.6628
An aerial view of farm country displays thousands of round fields, different hues of green and amber that dot the landscape. Some smaller fields, rectangular or irregularly shaped, crop up occasionally, but circular pivot-irrigated farmland dominate the West. Our ability to direct water to our crops has dictated farms’ locations, shapes, and growing schedules for centuries. The origins of irrigation date back 8,000 years, with the first signs of it seen in 6000 BC in Egypt and Mesopotamia. Famers in these river valleys carved canals and dams into the land to channel the water to their crops when the rivers flooded.
Before the high-tech irrigation pivots we see today, there were devices such as the shaduf in ancient Egypt, a pole balanced on a crossbeam with a bucket on one end and a counterweight on the other. The farmer would dip the bucket into the river, then swing it around to dump it in the field. The qanat, invented in Persia but used across North Africa, Asia, and China, tapped into groundwater to channel it into a system of graded tunnels that would direct it into fields. This system cropped up around 800 BC, and iterations of it are still used today.
As much of the western United States deals with drought conditions, farmers are placing more focus on maximizing yields with as little water as possible. While geography and general soil composition remain fairly consistent in any given field, variation in climate and weather patterns can alter the growing season significantly from year to year. Even in the middle of winter, farmers keep an eye on conditions like mountain snowpack to gauge where aquifer levels might be as growing season starts.
According to Vermeer, “Common water-use requirements for alfalfa range from 20 to 46 inches of water per season, depending on climate, elevation, growing season, number of cuttings and the fall dormancy rating of the alfalfa variety.” This wide range and the variety of factors that impact alfalfa’s water needs make growing hay in dry regions an increasingly advanced, technical operation. Frequency of water application also impacts the level of water stress, which in turn affects quality and yield—higher-frequency irrigation systems like sprinkler or drip irrigation produce better results than lower-frequency systems like flood irrigation.
The two most popular modern-day systems for hay farms are sprinkler irrigation and drip irrigation. Sprinkler irrigation is mostly done via large pivots that move around a field to spray water onto crops. Pivots can be used on fields that are not completely level, but they need to be monitored closely to ensure there is little runoff for maximum efficiency. Many farmers using sprinkler irrigation will run their pivots at night to minimize evaporation from the sun, especially in arid climates. Pivots are also labor efficient—one person can manage several pivots remotely.
Subsurface drip irrigation is the most efficient form of irrigation, and while it is currently less common due to the expense of installing and maintaining it, we may see its use increase if water restrictions continue to tighten on farmers. These kinds of systems are typically less visible, with drip tape being buried in the field at various different depths and intervals. This mitigates evaporation and runoff, but these systems can also complicate harvesting and cultivation depending on the depth at which the drip tape is installed. Diagnosing and addressing issues can be more difficult since most of the system is out of sight underground. The increased maintenance and cost often cancel out the added efficiency compared to pivot systems—both types offer over 90% water efficiency according to Valley Irrigation. However, in fields that are too small for a pivot, drip irrigation can be a viable option. We can expect to see continued innovation to make drip irrigation systems sturdier and more user friendly.
Another common type of irrigation is flood irrigation. This system requires less infrastructure and setup cost than sprinklers or drip irrigation, but in turn it is more difficult to manage and less consistent. This system floods sections of a field and ponds water on top of the soil, which ideally will be sloped to allow water to run down across the field to cover its entire surface. Most flood irrigated fields have small levies placed at intervals to keep water in one section of a field at a time. If fields’ grades are not maintained or there are issues with soil composition, flood irrigation may disproportionately irrigate one end of the field while leaving the other dry and much of its water may be lost to runoff. Due to the difficulty of making flood irrigation truly water efficient, many farms (especially in the drought-stricken West) have phased out flood irrigation systems and replaced them with pivots—the increased cost and scarcity of water has outweighed the cost of buying, installing, and maintaining a pivot.
Alongside irrigation, cutting management can help to maintain growth and persistence in drought conditions. Vermeer recommends irrigating 10 to 15 days after cutting and leaving six- to eight-inch top growth to sustain the plant through late-season months, which encourages root growth through moisture-deficient weather patterns.
Western alfalfa is a highly desirable product for both dairy farms and horse owners due to its excellent color, leaf retention, and high protein, but the years-long drought and tightening water restrictions through much of the American West has forced farmers to innovate and make their irrigation systems more and more efficient. Irrigation has been a staple for farmers from as early as 6000 BC when systems were as simple as a bucket on a pole, and a few hundred years down the road our current modern systems may seem as rudimentary as those first systems seem to us now.
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Haley Ruffner is a sales broker for Aden Brook, a lifelong equestrian, and an accomplished writer.