Pecans, along with Almonds andWalnuts, are among the salt sensitive tree cropscurrently grown under irrigation. Yet, manygrowers are not convinced that salts areaffecting yields, probably because symptoms ofsalt-affected trees are difficult to differentiatefrom those of water-stressed trees.Salt problems usually appear whensalinity of water used for irrigation exceedsabout 500 mg L-1, and the orchard consists ofclayey soils or has a shallow water table.Pecans are especially sensitive to sodium (Na)and chloride (Cl) ions (Miyamoto, et. al., 1985).In other words, salt damage tends to be greaterwhen irrigated with Na-dominated water thanwith gypsum or Ca-rich water. Salt problemsare not wide-spread, but are common in areasirrigated with salty ground water or saltyirrigation returnflow.Recent drought in the Southwest and northern Mexico has also accentuated saltproblems as the supply of the fresh project waterhas dwindled. The shortfall is usuallysupplemented with ground water which mayhave elevated salinity. Salt problems alsoappear when soil and irrigation managementpractices are out of order.This short article outlines ways todiagnose and manage salt problems. Readerswho are interested in technical details shouldrefer to separate publications listed at the end ofthis article.
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