source ref: ebookwas.html
For salad vegetables, these hydroponic greenhouses are still not a break-even technology. Higher costs for water and transportation may change that. Meanwhile, similar methods used by Archer Daniels Midland look profitable for growing ornamental plants such as African violets.
Besides looking for ways to use less water per unit of production, farmers are looking for ways to use lower-quality water. About one-twelfth of the United States lies over groundwater too saline for traditional crops. So far, farmers don't have much opportunity to use brackish water for irrigation, unless they can dilute it to higher quality. Some research on salt-tolerant plants looks promising.
Treated sewage effluent is another story. Around Tucson, the political issue has been who gets the opportunity to use effluent, not who has to. The Cortaro-Marana Irrigation District figured that the 76 pounds of nitrogen and 37 pounds of phosphate in an acre-foot of effluent are worth $15 as fertilizer. That value is discounted by the amount of nitrogen naturally in the district's groundwater. Other estimates peg the fertilizer value of treated effluent at $30 per acre-foot. Delivery of effluent piped basically by gravity flow from a nearby treatment plant can also save money compared to pumping deep groundwater. In most
- 386 -
applications, effluent needs to be diluted one-to-one or further with fresher water.
Besides major changes in field preparation, irrigation systems, or water source, better management of existing systems offers farmers several chances to cut water costs.
A farmer needs to know exactly how much water he is using to grow a crop. For this, pumps should be metered. One part of Arizona's Groundwater Management Act will work to farmers' advantage: they can no longer put off installing the flow meters that can help save money. Every farmer knows how big his fields are, but with water costs approaching half of total production costs, it may be smarter to think about yields per acre-inch rather than just yields per acre. Flow meters can figure pump efficiency as well as water use. Pump companies in Arizona indicate that farmers are replacing pump bowls much more frequently than in the past. This step toward efficient pumping reduces the cost of water, though not the amount of water used.
To minimize water use, farm managers need to keep abreast of developments in irrigation systems and crop choices, and frequently calculate their options. Scheduling of irrigation will be fitted more precisely to the needs of the crop rather than to labor schedules. Center-pivot or linear-move sprinkler systems require less labor than open-furrow irrigation, but level-basin systems need more. For higher technology systems, labor must be skilled. Water application can be combined with application of fertilizer and pesticides.
The high initial costs of high-technology irrigation weigh in favor of larger farm sizes. Farms using the deepest groundwater may face an insuperable disadvantage no matter what irrigation efficiencies they adopt.
What crops should farmers be growing to cope with high water costs? Some predict a shift away from field crops such as grains and cotton toward higher-value specialty crops such as vegetables, fruits, and nuts. The value of these crops is, however, highly sensitive to supply. Tomatoes and lemons can bring a good price when they hit the market at the right time, but if too many other growers have the same crop, it may not be even worth the cost of harvesting. Farmers considering high-value crops need to spot a market niche they can fit.
- 387 -
Though grapes, lettuce, and melons are all high-value crops that can be grown with efficient drip-irrigation systems, the acreage of each in Arizona has declined from 1965 to 1980 (see Table 16.2). Citrus acreage in the state dropped by one-fifth between 1975 and 1980. Near Yuma, a big wind machine now stands in the middle of an alfalfa field. The lemon trees have been ripped out as unprofitable.
Vegetables have shorter growing seasons than some other crops, hence use less water per season. Making use of slower evaporation rates in winter gives winter crops an advantage in water consumption. However, some higher value crops, especially tree crops, use no less water than field crops (see Table 16.3).
Growers are finding markets for some specialty crops and that gives them an edge in covering high production costs due to expensive water. In the past 12 years, the certified seed industry has grown fourfold in Arizona, to more than 70,000 acres.
Several new crops are on the horizon as potential choices for western farmers. Guayule yields latex for rubber and grows with two to three feet of irrigation a year. Buffalo gourd grows with about half that much; it has seeds rich in oil and protein, plus a large, starchy root. Jojoba bushes need about a foot and a half of annual irrigation after they are established. The liquid wax pressed from jojoba seeds is useful in cosmetics and lubricants. Grain amaranth, once a major crop of the Aztecs, is among several other candidates for desert crops of the future.
- 388 -
Of these plants, only jojoba has been planted on a commercial scale. About 22,000 acres of it are growing in the West. Some farmers are following closely the development of markets and of production know-how for these potential crops.
Halophytes draw interest as potential crops that thrive on salty water. They are in an even earlier stage of development than buffalo gourd or guayule. Researchers are developing salt-tolerant varieties of barley, tomatoes, alfalfa, and other traditional crop plants. They have even produced a barley that can grow in seawater, but yields are not yet sufficient economically. Barley-breeder Dr. R.T. Ramage puts the point concisely. "Right now, you could grow thousands of acres of barley on sand dunes with seawater, and lose money on every acre of it. Still, it's good to know that if we did have to depend on seawater sometime in the future, we could take these domesticated crops and have a usable production from them."
What actions should be taken by western farmers? Not only do we need to reduce water use, we need to do it without going
- 389 -
broke. Besides exploring options on our own and practicing alert management, we can join with other farmers to encourage beneficial developments.
First, we can seek public support for water-saving measures. Arizona's state legislators are granting tax credits for the installation of precise water measuring devices. The U.S. Agricultural Stabilization and Conservation Service offers a cost-sharing program for laser leveling. Accelerated depreciation allowances for private investment in laser leveling also encourage that technology. Similar incentive programs could be started for other ways to conserve water.
Second, we can urge water suppliers to adopt inverse pricing policies. That is, the more gallons used per unit of production, the higher the price per gallon. This would reward efficiency more than flat rates do.
Third, we can encourage conservation by other water users. Inverse pricing for home water bills would help cut urban use. In a more direct action, the Arizona Cotton Growers' Association has been distributing water-saving shower heads at cost as part of a public relations effort to encourage water conservation in cities.
Fourth, we can give financial and political support to research. Development of better irrigation systems and of water-saving crop varieties deserves our backing. Similarly, we should support studies of potential new supplies of water, such as solar desalination, a delivery system from the Northwest, and containment of flood waters.
Fifth, we can help educate young people about the importance of water to agriculture and the importance of agriculture to society. As one example, the American Farm Bureau Federation is working with a group called Water & Man, Incorporated, to develop a curriculum for fifth to twelfth graders about water and agriculture.
Western agriculture can't survive unless individual farmers find ways to make a living while using less water. But individual farmers will have a better chance to do that if we join forces with other farmers and with other water users.
Miller and Cardon present a graphic picture of farming in Arizona today, and we who farm the High Plains of northwestern Texas share many of their problems. As the two regions are quite distinct in character, some differences in procedure will be discussed. While much of Southwest farming is located in the desert and is almost fully dependent on applied water, the High Plains can be dry farmed.
Our soils and terrain generally are excellent, among the best in the world. Rainfall averages 20 inches annually on the east side, perhaps 14 inches on the west, and comes in two peaks of May-June and September-October. The early peak often is violent, thus shortening an already short growing season due to the altitude of 3,000 to 4,000 feet. Even so, cotton is the dominant crop of the southern part around Lubbock. In the northern part around Amarillo the dominant crops are wheat, feed grains, and some sugarbeets and vegetables. Soybeans are fairly common, often replacing cotton crops damaged by storms in late May and early June. Summers are hot and winters almost arctic.
Irrigation began seriously to be a factor on the High Plains after World War II, and was aimed primarily toward
- 391 -
supplementing rainfall during the dry spell of July-August. Later, irrigation began to be aimed toward maximum growth and yield until the 1970s when escalating fuel costs and higher pump lifts caused us to begin to take another look at some of the dry farming techniques we once used.
Most of the more obvious water-saving techniques such as underground pipe and tailwater pits have been put to use, and there has been a rapid increase in the number of sprinkler systems. Next there has been a shift to crops requiring less water-corn to milo to cotton, for example. The most widely used techniques in cotton culture have been the deliberate use of less water to create a smaller plant, and a skip-row system, usually two rows planted and one blank, where the blank area serves as a moisture reservoir. Irrigation, if done at all, usually goes only in the middle between the two rows. Thus only one middle in three is irrigated.
The skip-row method generally has been confined to cotton areas, but it has been used for milo and soybeans. Corn and sugarbeets generally are grown where the soils are not too sandy and the irrigation wells are strong. In the corn growing area are two interesting specialty crops, white corn for the tortilla trade and popcorn for the movie trade.
Vegetable and fruit crops have not been too successful on the High Plains due to unpredictable weather and lack of hand labor. Efforts to move into higher value crops have been taking place as long as most of us can remember. Onions and potatoes are the most widely grown vegetables while about the only tree crop to survive is the pecan. Wine grapes are being grown on a small scale and seem to show some promise. Pecans and grapes work well with drip systems of irrigation, and thus fit well into the trend toward conservation of water and energy. Subirrigation systems would seem to be the approach to an ideal, but so far such systems have had maintenance problems and costs such as to preclude their ready acceptance.
Furrow irrigation is, admittedly, an inefficient system. Dead-level basins are a near-ultimate in efficient use of irrigation water, but economics, soils, and water supply do not encourage use of the system on the High Plains. The trend has been toward sprinkler systems instead.
At first glance, sprinklers don't appear to be very efficient as they spray water into the wind to be evaporated, but most farmers saw the advantages over furrow irrigation very quickly. Even application was the difference. Later, many sprinkler
- 392 -
systems were modified to emit a low, coarse spray, or even to emit water at ground level through a sock with an efficiency about on par with a drip system. Even rice farmers on the Texas Gulf coast are experimenting with sprinklers to replace the flood borders traditional to rice culture since the beginning of history.
Use of effluent water for irrigation has a long history on the High Plains, going back at least to 1930 when Lubbock's effluent irrigated a 320-acre field of alfalfa. Today several thousand acres are irrigated from a much larger Lubbock, and electric utilities and industries compete to use the effluent.
Although the High Plains traditionally has produced bulk crops of relatively low value, soaring costs are forcing us to look toward crops of higher value, or toward crops which can be grown more economically. Our agricultural experiment stations have done a good job of exposing us to new crops and new ideas. We have tried sesame, sunflowers, castor beans, safflower, various millets-the list goes on and on. One of the best crops to come along was hybrid sorghum seed, introduced in the 1930s, and many thousands of acres of land are devoted to this crop.
We are fully aware of how greenhouses can turn out crops with low water use. Tomato greenhouses were very common on the High Plains a few years ago, but most of them either have gone out of business or have switched to growing ornamental plants.
The vast feedyards for cattle on the High Plains help our farmers with a nearby market for our grain, and we appreciate the price advantage thus established. Our grain used to suffer heavy shipping discounts.
Many of us are aware of desert crops such as jojoba, guayule, and some of the others, but we don't know much about their adaptation and practicability. One of our animal husbandry professors at Texas Tech is a strong promoter of the common weed, Kochia scoparia, as being about as good as alfalfa when handled and harvested properly. It grows rapidly and easily without irrigation and with little care. Its progress will be observed.
Our area has little if any work going on in use of low quality water other than effluent. Generally we have either good quality water or none.
In closing, we have been warned by the utility people that natural gas under deregulation may continue to escalate in price even if other petroleum products tend to stabilize in cost, all based on energy equivalents. The implications are obvious for farmers who use natural gas, directly or by way of the power plant, to pump irrigation water.
With the vast array of crops produced in California, no single system of irrigation is suitable for all use, regardless of its efficiency. Even so, minimizing the use of water consistent with the maximizing of yields is going to be necessary for the very survival of many of our California farming operations. Computer analysis of water needs is in the farmer's future. The dairy and livestock industries in their computerized ration analysis are teaching us the techniques we will need to know.
A number of problems are associated with the various alternative means of minimizing water use discussed in the Miller-Cardon paper; my comments follow.
Conservation. Probably the cheapest approach to water conservation a farmer has is to shift to drought-tolerant crops or to set aside land in fallow. Unfortunately, those opportunities are severely limited by economic considerations. Farmers should certainly consider options in this regard; it does raise the question of producing for world markets in view of national or regional needs. Of course, wide swings in world prices and political influences may be an even more important factor in cropping patterns.
Drip and Sprinkler. The use of new irrigation systems, including drip and sprinkler, may be comparatively energy-inefficient, and both are expensive to install. For example, a farmer with riparian rights along a river may pump water once and irrigate his entire farm with a gravity system. Any other system will require additional purchased energy and high capital investment. Moreover, water quality must be such as to avoid salt buildup in soils and clogging of tubing and emitters. Besides, what do we do with abandoned hose systems when we change to another crop? Does anyone know the half-life of polypropylene?
Some of the sprinkler systems in current use require high water pressure and may be costly in terms of energy use and evaporation losses. As the authors point out, we are in a transition phase between high and low pressure sprinkler systems, and conversions will occur favoring the most cost-effective systems.
Plastic Mulch. California producers have used plastic mulches for some crops for a number of years, particularly for such high value crops as strawberries. The cost must be recovered from water conservation, reduction in tillage, enhancement of yields, and also from earlier production which increases the value of the crop. The use of plastic mulch purely to conserve water is not
- 394 -
likely to be cost-effective within the foreseeable future in large-scale applications in California.
Greenhouses. While California has a large acreage of floral and some vegetable production in greenhouses, the greenhouses have not been used principally as a means of water conservation. The scale of operation, the cost of the facilities, and the intense nature of the business, tend to discourage any rush into hydroponics on a commercial scale, unless justified on grounds other than merely water conservation. It may, however, be a way to return specialized crops to urban areas to avoid transportation costs and to reduce urban unemployment.
Reclaimed Wastewater. California has been conducting experiments in the use of reclaimed sewage effluent for a number of years. Virtually all of our dairy operations are designed to collect water used in the dairy barns and apply it to forage and field crops as a combination program of irrigation and fertilization. Water which was formerly a disposal problem has thus become an asset. Treated sewage or other wastewater also can be pumped back underground, especially where existing quality underground is undesirable for drinking anyway. In fact, the quality could actually be improved, aquifers would be maintained, and intrusion from adjoining aquifers could be challenged.
Effluent, particularly industrial effluent, may contain dissolved heavy metals or levels of nitrates, making it unacceptable for general irrigation purposes. For purposes of acceptance and safety, the use of sewage effluent has been largely confined to irrigation of forage crops, golf courses, parks, and similar public and private areas. Someday, however, the public will likely accept the idea-after all, didn't Erma Bombeck observe that the garden is always greenest over the septic tank?
Agricultural Load Management. Experimental work is being done by California's Public Utilities Commission, in cooperation with the two major utilities, Pacific Gas and Electric and Southern California Edison, in the area of Agricultural Load Management (A.L.M.). A.L.M. is a program allowing a lower electric rate for farmers who are willing to confine their use of electricity for irrigation to off-peak hours. Peak hours for electricity use are 1:00 to 6:00 p.m., which coincide with the high heat hours of the summer. A spinoff of this experiment may be a discovery that avoiding irrigation water application during the heat of the day results in reduced evaporation, thus saving water as well as power costs to farmers. This practice is limited, of course, by many elements, such as the source of the water, whether it is
- 395 -
used in open ditches or sprinklers, and whether it requires labor to monitor its use.
Crop Selection. The problem of which crops a farmer can grow is determined not by one factor like saving of water, but by the entire mix of factors which influence his farming operation. Soil limitations may dictate that a farmer grow rice, for example, even though other crops might use less water. Rice, incidentally, is not as big a water user as many other irrigated crops with high evapotranspiration rates, such as walnuts.
The farmer's decision on crop selection must be based on prospective yields, price expectations, and production costs, coupled with available land, equipment, and financing resources, as well as his ability to produce the given crop.
Inverse Pricing. Inverse pricing of water, as suggested by Miller and Cardon, may be entirely appropriate in the urban setting, but the economics of agriculture and the complexity of such a system make the concept difficult to apply to farmers. It would have to take into account such diverse factors as crop rotation, world food supply, and annual rainfall. Besides, one farmer's tailwater may be his neighbor's main supply.
Soil Modification. Soil modification s a means toward increased irrigation efficiency also should be recognized as a developing tool. The emergence of laser-controlled leveling equipment has resulted n substantially improved water efficiency through precise modification of soil grading. Deep ripping of some soils has permitted better water use.
In a relatively free-market economy, such as we like to think we have, economics is the guiding force. In the semiarid West, water availability and water costs may well be the axle upon which the farm's economy rotates or comes to a grinding halt. There is much that farmers can do for themselves, but the variables are so many (as are the farmers), that the best we can do is to record the changes as they happen and avoid being surprised. It is doubtful that we can predict the end results very well, or manipulate the process even if we predict accurately.