Boawn, Louis

Dow, A.

Boawn, Louis C.

Dow, A. I.

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Zinc needs of field crops in central Washington

Washington State University  institutional repository

ZINC NEEDS OF CENTRAL 1N ASHINGTON CROPS Extension Circular 290 Revised February 1965 Extension Service Institute of Agricultural Sciences Washington State University Pullman, Washington Z inc-deficient bean plants are stunted and have yellowish leaves. Leaf veins and midribs stay green. The stalks of zinc-deficient corn plants are extremely short between leaves and leaves have broad pale stripes or bands. ZINC NEEDS OF CENTRAL WASHINGTON CROPS A. I. Dow and L . C. Boawn1 Zinc deficiency is commonly seen in many central Washington crops. Those most severely affected are beans, corn, hops, onions, and Russet Burbank potatoes. Under extreme conditions, zinc deficiency symptoms have also been observed in sugar beets, alfalfa, peas, wheat, sudangrass, soybeans, and potato varieties other than Russet Burbank. 2 Zinc deficiency is most likely to occur and is most severe where surface soil has been removed during land leveling~ exposing subsoil with a high lime content. This n1eans the deficiency may develop in irregular patches through-out a field. However, it often affects an entire field. Zinc deficiency can be induced or made worse under certain conditions. 1 Extension Specialist in Outlying Testing, Washington State University, and Research Soil Scientist, Agricultural Research Service, U.S. Department of Agriculture. Both authors are stationed at the Irrigation Experiment Station, Prosser, Washington. 2 Zinc deficiency is also commonly observed on tree fruits and under severe conditions may affect grapes. For information on the use of zinc on these crops, see Fertilizer Recom-mendations, FR-28 (tree fruits) and FR-13 (grapes), Agricultural Extension Service, Wash-ington State University. These can be obtained from your County Extension Agent. Zinc-deficient Russet Burbank plant. Note the reduced size and upward curling of leaves. These include heavy applications of manure, a large accumulation of phos-phorus in the soil, and cropping with sugar beets. CROP RECOMMENDATIONS Corn The outstanding symptoms of zinc deficiency in corn are extreme shortness of the stalk between leaves and striping of expanding leaves. On mature leaves, the striping shows up as a broad band of white, yellow, or pale green tissue between the edge of the leaf and the midrib. Corn plants that are severely stunted in late June often make a remarkable recovery in mid-July and produce ears of corn. Maturity will be delayed, however. Zinc deficiency of corn is almost certain to be a problem when corn is planted on ground where sugar beets have been grown for several years. On fields where zinc deficiency is likely to occur, apply 10 pounds of zinc per acre. 3 Th~ zinc may be broadcast or sidedressed. If symptoms develop in a field, apply one or two zinc sprays. 3 Recommendations given in this circular are in terms of elemental zinc. Use the analysis on the fertilizer bag to find the amount of fertilizer needed. Beans Sidearms of zinc-deficient hop plants produce clusters of leaf growth. Leaves are pale and curled upward. Zinc-deficient onions are yellowish, smaller than normal, and have extremely twisted leaves. Typical symptoms of zinc deficiency in beans are stunted plants with yellow or pale green foliage. Veins and midribs of leaves remain green even though the tissue around them becomes yellowed and bronzed. Older leaves tend to wither and drop off. Watch for symptoms two to three weeks after the plants come up. Beans tend to grow out of zinc deficiency, but in addition to reduced yields, maturity will be delayed by as much as six weeks. -To control zinc deficiency in beans, apply 10 pounds of zinc per acre, broadcast or sidedressed. In emergencies, use zinc spray. Russet Burbank Potatoes Zinc-deficient potato plants are severely stunted with malformed and bronzed or yellowed leaves. Leaf distortion is most severe on youngest growth. Leaflets are narrow and cupped upwards to such an extent that terminal growth resembles the unfolding fronds of some ferns. Zinc sprays applied after deficiency symptoms occur will not correct zinc deficiency of the Russet Burbank potato. To insure against the deficiency, broadcast or sidedress 10 pounds of zinc per acre. In emergencies, zinc sprays will be effective if applied before deficiency symptoms develop. Deficiency symptoms tend to develop at about the early bloom stage. Onions Symptoms of zinc deficiency in onwns are stunting, extreme twisting of the leaves, and general yellowing. Apply 10 pounds of zinc per acre, either broadcast or sidedressed. Zinc sprays are not effective. Hops The first symptom of zinc deficiency in hops is paling and upward curling of the leaves. As the deficiency becomes more severe, especially as the growing season advances, the leaves become bronzed and withered. Sidearms do not lengthen normally, but produce a cluster of leaf growth known as a rosette. Rosetting of leaves is a distinguishing characteristic of zinc deficiency in per-ennial crops. Soil applications of zinc have not been completely satisfactory, especially in old yards. Growers who wish to try soil applications should apply 20 to 30 pounds of zinc per acre, either broadcast or sidedressed. PlmiVing down 20 to 30 pounds of zinc per acre ·would appear to be a desirable practice before establishment of new yards. J Zinc sprays will correct zinc deficiency of hops during the growing season. Apply the first spray as early as possible--as soon as there are enough leaves to retain the spray. Adding zinc to the first pest control spray is a common practice. Other Crops Where zinc has not been applied in recent years, growers may wish to jnsure against zinc deficiency in such crops as sugar beets, alfalfa, peas, sudan-grass, wheat, soybeans, and potato varieties other than Russet Burbank. For such crops, 1 0 pounds of zinc per acre should be broadcast and plowed down before seeding. In the case of row crops, the zinc can be sidedressed. HOW TO USE ZINC FERTILIZERS Soil Application Zinc is held by the soil particles and does not move downward with irriga-tion water. This means zinc fertilizer must be placed deep enough in the soil to be contacted by plant roots. Broadcast applications of zinc can be made either in the fall or spring and should be rototilled in or plowed down. Sidedressed applications should be placed to the side and slightly below the seed. Keep the fertilizer at least 3 inches away from the seed. Make the application at planting time or soon after emergence. Annual soil applications of zinc are not necessary. An application of 10 pounds of zinc per acre should provide ample zinc for at least four years. Effectiveness of soil-applied zinc is greatly increased by mixing with nitrogen fertilizer. Caution: When zinc sulfate is mixed with nitrogen exces-sive caking may occur if the mixture is allowed to stand, especially during damp weather. Any zinc compound that will dissolve in dilute mineral acid is suitable for soil application. Zinc sulfate, zinc oxide, zinc carbona~e, zinc ammonium sulfite, zinc chelates, and brand name products containing these compounds can be used. S pray Applic ation Zinc sprays should consist of 1 to 1 ¥2 pounds of zinc in 7 5 to 100 gallons of water. Use zinc sulfate or a zinc chelate for spray application. Add a commercial sticker-spreader to the spray to insure thorough wetting of the foliage. Apply with a low pressure ground sprayer that will drench the plants thoroughly. Aerial application is not recommended because of incomplete coverage, due to the low gallonage used. Except for hops, sprays have not given as good control as soil application and should be considered primarily as an emergency measure. Since sprays have little residual effect, the treatment will be effective for only one growing season. Published and distributed in furtherance of the Acts of May 8 and June 30, 1914, by the Washington State University Extension Service, C. A. Svinth, Director, and the U.S. Department of Agriculture, cooperating. 4M-265 

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Zinc needs of field crops in central Washington

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