Fertilizers, fluid micronutrients

Micronutrients in Fluid Fertilizers. In terms of homogeneity and even distribution, fluid fertilizers are probably the best micronuttient carriers. Fluid carriers of micronutrients usually are nitrogen solutions, clear Hquid mixtures, or suspensions. Some micronutrients, however, are appHed as simple water solutions or suspensions. FoHar micronuttient sprays often contain only the micronuttient material in water solution. 

Both hydrated and anhydrous metal borates have numerous industrial uses. Some of the major uses of hydrated metal borates are the manufacture of glasses, ceramics, and industrial fluids, and as micronutrient fertilizers, fire retardants, and biostats. Anhydrous borates find use as heterogeneous catalysts, scintillation hosts, and in the fabrication of optoelectronic devices. Anhydrous aluminum borates are used as additives in oxide ceramics to promote the formation of desirable phases. Also, aluminum borate whiskers are used as reinforcing additives in composite materials. Specific nses of sodium, calcium, zinc, and barium borates are discussed in sections below. 

Since micronutrient fertilizers must be applied at very low rates to avoid plant toxicity, the prevailing practice is to incorporate them with macronutrient fertilizers. This can be accomplished by incorporation with solid fertilizers during the manufacturing process, by bulk blending with granular fertilizers, or by mixing with fluid fertilizers just prior to application. Care must be taken to select micronutrient sources and macronutrient fertilizers that are compatible to avoid the formation of reaction products that reduce availability of nutrients to plants (Mortvedt and Cunningham, 1971). 

Achorn, F. P. 1969. Use of Micronutrients in Ruid Fertilizers, Presented at the Conference of the National Fertilizer Solutions Association, Kansas City, Missouri, July 22-23, Published in NFSA Additives and Fluid Fertilizers 69 Round-Up. 

Methods of micronutrient application include application directly to soil, in foliar sprays, and as seed treatment. The most common application method for crops is soil application [12]. Because recommended application rates usually are less than 10 kg/ha (on an elemental basis), it is difficult to achieve uniformity when individual micronutrient sources are applied separately in the field. Therefore, both granular and fluid fertilizers are commonly used as carriers of micronutrients. Including micronutrients with mixed fertilizers is a convenient method of application, and it allows a more uniform distribution with conventional application equipment. 

Micronutrients can be combined with NPK fertilizers by dry mixing, bulk blending with granular fertilizers, coating onto granular fertilizers, incorporation durir the manufacturir process, and mixing with fluid fertilizers 112],... 

Fluid fertilizers may be used for foliar application or for application to the soil. Micronutrient sprays are often used for correcting deficiendes particularly for tree crops. A soluble salt or chelate of the micronutrient material may be dissolved in water to form a solution of SQitableT t)ncCfitrati5i r Firidypbwdered insoluble materials also may be used for foliar application. Because some metal sdts form acidic solutions, the sBghtly soluble basic salts may be preferable for foliar application [291. An example is CuS04 3Cu(0H)2 H20, a basic copper sulfate. 

The most popular nonpressurized nitrogen solutions are prepared from urea and ammonium nitrate and contain between 28 and 32% of nitrogen. No special equipment is needed for their storage and application they are easier to mix and to handle than solids, have low distribution losses, can be accurately placed, are suitable for foliar and aircraft application, and are excellent carriers of micronutrients as well as of pesticides and herbicides. As a result, about 60% of U.S. fertilizer nitrogen is now applied in fluids, and the use of solutions is becoming also more widespread in Europe. ... 

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