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Economic Damages to Irrigated Agriculture 29 N ""-l C ~ water table which has a detrimental effect on soil structure and thus on crop production. The saline groundwater also is drawn upward toward the root zone through capillary action damaging seedlings and even some mature plants. Tiling also serves to keep land in production since salt poisoning is most likely to occur on idle land due to increased capillary action drawing the saline water to the surface. One irrigation district official says that land levelling and sprinkler irrigation are increasingly being used to obtain better use of the water and to avoid problems with soil capillary action bring- ing salt into the root zone. Lengthy conversations with irrigation district officials, project managers, and farmers in Imperial, Riverside, and Yuma Counties gener- ally support this position. It was consistently pointed out that all irrigated agriculture requires draining (at leaSt in the American southwest), whether by installed systems, wells, or nature. In the Lower Colorado River Basin, nature pro- vides very little drainage, so man has intervened with tiles or wells. This same type of logic ap- plies to other types of advanced farming prac- tices such as land levelling (level land being easier to irrigate using flood or furrow irrigation). The costs of drain tiles and the resulting O&M, land-levelling, removal of land from production and the type of crops planted have often been attributed to saline irrigation water without any scientific or empirical study to sup- port the attribution. However, drain tiles also serve to aid water conservation by reducing the amount of water application required to maintain salt balance, and soil conservation by reducing opportunities for capillary action. Other types of farm management costs have been attributed by some to saline irrigation water, e.g., installation or use of sprinkler irriga- tion systems for crop germination and limited use of drip irrigation systems. Farmers have also made some soil modifications to the soil profile through additions of organic matter, the use of chemicals, and mechanical methods. These soil modifications could, in part, be attributed to salinity. Although these remedies are expensive, often labor intensive, and subject to climatologi- cal effects or technological breakdown, these im- provements likewise cannot be directly tied to saline irrigation water. Rather these practices appear to form a part of good farm management for t he area, some undefmed portion of which can be attributed to increasingly saline irrigation waler. ,';1 One Palo Verde Irrigation District farmer says that "salt is a miniscule damage," possibly because PVID has better soil drainage than the other major farming areas in the Lower Basin. But, out of all the farmers and officials inter- viewed over the course of 18 months, only one farmer was willing to directly attribute some costs to salinity, and he could not give any clearly linked or defmed costs. While having some germination problems caused by soil salinity in combination with high temperatures or heavy rain, and using portable sprinklers for germination at a cost of $125 per acre, he still finds the relationship between saline irrigation water and non-crop damages to be "pretty subtle." Drainage is clearly needed for farming in the area, but he and all the other district offi- cials and farmers are unwilling to say what per- centage of the related factors (soil, groundwater, weather, irrigation water, etc.) is responsible for each type of farm practice. J .1 Losses in crop production due to shilts in cropping patterns. Although increased salinity may have caused some changes in cropping patterns, for example, reducing the acreage planted in salt-sensitive crops, not all changes in cropping pattern have occurred solely because of salinity. Many of the truck-garden type crops - beans, fresh tomatoes, other vegetables - have been given over to Mexican producers because they are too labor intensive and therefore too expensive to grow in the current U.S. farm labor market. The annual reports published by the Imperial County Agricultural Commissioner also make repeated references to factors other than salinity affecting cropping patterns. A major fac- tor is changing crop prices. For example, in 1980 the market was "disastrous" for lettuce while the costs of production continued to in- crease at a record pace, so lettuce acreage dropped. In 1984 the cotton market was in decline and sizable areas of lettuce were planted in Arizona instead of in California. In 1982 . 11 i i 1