Methods Of Fertilizer Application

By The Old House Web

Methods Of Fertilizer Application


The various methods of fertilizer application include injecting liquids into the soil, placing dry fertilizer in holes drilled in the soil, applying fertilizer to the soil surface and spraying it on the foliage. Which method you choose should depend on the site and plant condition.

With most woody plant species, surface application is as effective in provoking a positive plant response as other methods. This method requires the least application time and is the least expensive, but it could cause excessive in high quality turf areas.

Liquid fertilizer injected into the soil is rapidly taken into the plant by the roots, so injection is a good why apply necessary nutrients. Also, the addition of water to dry soil is desirable during periods of drought. Injection sites should be 2 to 3 feet apart, depending on the injection pressure and 15 to 18 inches deep for trees.

A major advantage to the drill hole method is the opening of heavy (clay) or compacted soils, which allows air and fertilizer to penetrate. With this technique and liquid injection you avoid the excess grass growth surface applications cause in turf areas.

The drill holes should be placed in concentric circles in the soil around the plant, beginning 3 feet from the main stem and extending 3 feet beyond the dripline. Space holes 2 feet apart and drill them 15 to 18 inches deep. The recommended rate of fertilizer should be uniformly distributed among the holes. Fill small holes with sand following fertilization but only partially fill large holes.

Liquid fertilizer sprayed on the foliage can not provide all the necessary nutrients required by plants in the amounts needed for satisfactory growth, but it can be very effect for correcting minor nutrient deficiencies, especially for treating iron deficiency using chelated iron.

Micronutrient spray applications are most effective when made just before or during a period of active growth, usually from spring to early summer. Plant response-- greening of chlorotic foliage and normal growth coming from buds on affected shoots--is usually observed from two to eight weeks after treatment, but response time varies, depending on species, age of the plant and its parts, the time of year, the severity of the deficiency and the soil conditions under which plants are growing. One or two applications during the year will prevent or control deficiencies, but under some conditions it may be necessary to make several treatments annually to continue healthy growth. Using annual foliar sprays to correct a chronic nutrient deficiency is usually not a practical management practice for large trees.

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