- Using Micronutrients
- Vegetable Response To Micronutrients
- Micronutrients - Soil
- Micronutrients - Foliar Applied
- Soil Tests
- Conversion Tables
Micronutrient deficiencies have not been commonly reported in California. Furthermore, even if a deficiency is found, some vegetable crops yield little, if any, better when you correct the deficiency. To find out which vegetables are most helped when a deficiency is corrected, see Table 9.
From "Illinois Agronomy Handbook, 1979-1980," University of Illinois Cooperative Extension Service, Circ. 1129.
Table 9. Here's our best estimate on how vegetables might react to added micronutrients when a deficiency is corrected.
|1/low -- little or no response
medium -- intermediate response
high -- highly responsive
Table 10. How to apply micronutrients on deficient soils (General guide).
Soil tests (for zinc or boron) will give you a clue on whether your soil is deficient.
ADDING ZINC TO SOIL (General guide)
Amount of element usually applied per acre
- 10-20 pounds broadcast or 5 pounds banded.
- Zinc sulfate or zinc oxide or zinc chelate.
- Zinc sulfate @ 36% actual zinc;
- zinc oxide @ 78% actual zinc;
- zinc chelate @ various formulations.
Amount of usual formulation per acre:
- 28 to 56 pounds zinc sulfate or 13 to 26 pounds zinc oxide.
- 14 pounds zinc sulfate or 6.5 pounds zinc oxide. Chelates are applied according to label instructions.
- Broadcast or banded.
How often to apply
- Every 4 to 7 years if broadcast; every year if banded.
ADDING COPPER TO SOIL
Copper chelate is suggested, since other sources may become unavailable on alkaline soils. Foliar sprays may be used. Follow label instructions.
To prevent soil buildup of boron on sensitive crops that might follow, foliar sprays are often preferred.
Foliar sprays have normally been more practical on row crops, except perhaps on leafy vegetables. On leafy vegetables, you will need to be very careful not to burn leaves, especially with unproven formulations.
Table 11. Foliar sprays for deficient crops; General guidelines for usual amounts applied in various states:
|Material||HOW TO APPLY|
Grams of material per gallon of water for small trial *
|Pounds of material per acre**||Comments|
|* Actual B applied is 0.1 lb for medium responsive crops or 0.3 lb for highly responsive crops.|
|** The range shown in grams per gallon of test spray is the same range shown in pounds per 100 gal per acre.|
|Manganese sulfate||18.1 to 27.2 g||4 to 6||Do not apply without testing for leaf burn first.|
|Zinc sulfate||3.6 to 9.0 g||0.8 to 2||A second spray may be needed in 2 or 3 weeks.Do not apply zinc sulfate without testing for leaf burn first.|
|Fixed copper or chelated copper or Bordeaux mixture||Follow label directions; 1 lb per 100 gal = 4.5 g per 1 gal.||Follow label directions.||One spray should be enough for deficient crops. Do not apply without testing for leaf burn first.|
|Solubor ®||2.3 g to 6.8 g 20% material*||0.5 to 1.5 lb of 20% material*||Do not apply without testing for leaf burn first.|
|Iron chelate||Follow label directions; 1 lb per 100 gal = 4.5 g per 1 gal.||Follow label directions||One to 2 sprays. Do not apply without testing for leaf burn first.|
|Sodium molybdate||0.6 g||2 oz||Rarely applied except when deficient on cauliflower, broccoli, onion. Do not apply without testing for leaf burn first.|
|Calcium nitrate||22.7 g to 68.0 g||5 to 15||Use the 15 pound rate for prevention of blackheart on celery. May be tested on tomatoes where tissue is low in calcium. Do not apply without testing for leaf burn first.|
|Magnesium sulfate||45.4 g||10||Where used on celery it should be tested with 5 lb calcium nitrate to prevent blackheart. Do not use on crops without testing for leaf burn first.|
WARNING: Do not spray crops, especially leafy vegetables, with micronutrients shown in Table 11 unless you first test the spray on several feet of row.
USING TABLE 11 FOR DEFICIENT CROPS
Certain conditions could cause the spray to "burn" the crop. For this reason, grams per gallon of "test spray" are listed.
You should use a simple, inexpensive gram scale for such tests. After you've sprayed several feet of row, check plants in 48 to 72 hours. If you see no injury and the weather holds, you can consider going ahead with larger scale treatments. Such "test sprays" are especially important on leafy vegetables. Here, you don't even want a slight "cosmetic" burn.
Here are the pages to show the lab. You don't need to understand the technical terms. Just be sure your lab can run these specific tests (not just any testing method).
- Saturation percentage (SP)--grams of water required to saturate 100 grams of soil.
- Phosphorus--extraction by 0.5 M, pH 8.5 NaHCO3 solution. Also called Olsen bicarbonate extraction. Water soluble P is used to estimate available P in peat and muck soils. Phosphate may be determined in extracts as the molybdenum blue, using ascorbic acid or SnCl2 as the reducing agent.
- Potassium--exchangeable K is measured in ammonium acetate or other suitable extract. Except on celery or potatoes, the boiling nitric acid test is also used if the ammonium or sodium acetate test is below 100-120 ppm K.
- Zinc--DTPA extraction.
- Boron--expressed as water soluble ppm in the saturation extract.
- pH--determined as a soil paste wet to the saturation percentage.
- ECe--electrical conductivity of the saturation extract expressed as millimhos per centimeter at 250C.
- SAR--Sodium Adsorption Ratio; a calculated value used to estimate exchangeable sodium percentage (ESP) after long-term use of the water.
- Calcium--exchangeable Ca. For SAR determination, water soluble Na, CA and Mg are used.
- Magnesium--exchangeable Mg. (See also calcium, test 9, above.)
- Sulfur--available S is extracted by shaking 10 g of soil with 50 ml 0.1 M LiCl. Sulfate is determined in the filtrate using methods of Johnson and Nishita. This has not been a highly reliable test.
CONVERSION TABLE - POUNDS PER ACRE TO KILOGRAMS PER HECTARE
|Pounds per acre|
|Kilograms per hectare|
|Pounds per acre|
|Kilograms per hectare|
|Kilograms per hectare pounds per acre x 1.12|
|Pounds per acre = kilograms per hectare x 0.89|
CONVERSION TABLE - APPLYING NITROGEN
|Pounds N per acre||Kilograms N per hectare||Pounds N per acre||Kilograms N per hectare|
|Or kilograms N per acre = pounds N per acre x 1.12|
CONVERSION TABLE - APPLYING PHOSPHORUS
|Pounds P205 per acre|
|Kilograms P205 per hectare|
|Pounds P per acre|
|Kilograms P per hectare|
|* Example:, 100 pounds P205 per acre 112 kilograms P205 per hectare
44 pounds P per acre = 49 kilograms P per hectare
Pounds P205 x .44 = pounds P
|* 100||* 112||* 44||* 49|
CONVERSION TABLE APPLYING POTASSIUM
|Pounds K20 per acre|
|Kilograms K20 per hectare|
|Pounds K per acre|
|Kilograms K per hectare|
|* Example: 100 pounds K20 per acre 112 kilograms K 20 per hectare
83 pounds K per acre = 93 kilograms K per hectare
Pounds K2 x .83 = pounds K
|* 100||* 112||* 83||* 93|
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