(1)Advantages of Micronutrient chelates compared to other fertilizers.
Compared to traditional fertilizers like MAP,DAP,UP ,chelated micronutrients contain not only major plant nutrients such as nitrogen, phosphorus and potassium but also micronutrient trace elements such as iron , manganese,zinc,copper and the like which is the crucial part to plant growing .If a plant lacks any of the micronutrients it requires, its development, growth or reproduction will be affected, resulting in lower yields. This may not always be immediately apparent. A plant may suffer from micronutrient malnutrition long before any symptoms become evident. Such a plant may appear healthy, but the quality and quantity of the crop will be adversely affected.

(2)Effects of EDTA-Fe and EDDHA-Fe
At different pH lever, the effects of EDTA-Fe and EDDHA-Fe are different . EDTA-Fe is very effective in the acid-neutral pH range 5 - 7.0 while EDDHA is particularly good at chelating Iron over a very wide pH range, going as high as 8.5 .

(3)What fields can micronutrient be applied to ?
Micronutrients hit a wide range of application and are used as fertilizers for agriculture and horticulture. Which chelate type you need, depends on the micronutrient involved, the pH and the application method.

(4)Do micronutrient fertilizers do any harm to the corn?

This is a matter of micronutrient toxicidy. It is possible to apply excessive amounts of the micronutrients and this can result in a subsequent reduction in yield.Special attention should be given to the application of boron. Excessive rates can produce barren stalks in corn. Since the expected response to applying boron is very rare, it's best not to include this nutrient in the fertilizer. Irrigation water contains some boron, so it's especially important to be concerned about excessive boron under irrigationd conditions.If micronutrients are applied at excessive rates, the amount in the soil can reach toxic levels and reduce yields. Excessive rates of copper, a heavy metal known to accumulate in the soil, are of major concern.

(5)Micronutrient fertilizers in China

(6)What is micronutrient fertilizer ?
Micronutrient Fertilizer ¨C A produced or imported commercial fertilizer that contains commercially valuable concentrations of micronutrients (boron, chlorine, cobalt, copper, iron, manganese, molybdenum, sodium, and zinc), but does not contain commercially valuable concentrations of nitrogen, phosphoric acid, available phosphorus, potash, calcium, magnesium, or sulfur.

(7)Why include micronutrients to your crop program?
Plants need more than just the Macro nutrients. (Nitrogen, Phosphorus, Potash,) to survive in a healthy state. Micro nutrients will add more quality and mineral content to the plants. Just the same as humans need more than just food to survive in a healthy state they also need an array of minerals and vitamins such as Magnesium, Manganese, Iron, Zinc, and vitamin A to E.

Research has shown the plant can assimilate Micro nutrients better via foliar application than if the Micro nutrients where applied to the soil. The response is quicker and seems to be more effective.

Micronutrient elements which is important to plant health :
Of the 16 elements known to be essential for plant growth, 7 are used in very small amounts and are classified as micronutrients. These are zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), boron (B), molybdenum (Mo) and chlorine (Cl).
Iron (Fe) Gives green color to plants. Iron is part of the make up of enzymes. Aids in protein synthesis, photosynthesis and the metabolic functions of the plant. Iron is needed for chlorophyll synthesis.
Zinc (Zn) Speeds up the metabolic rate of the plant. Zinc deficient plants will have impaired cell functions. Zinc is also part of the make up of enzymes.
Manganese (Mn) Manganese is part of the make up of enzymes. Aids in photosynthesis and the metabolic functions of the plant.
Copper(Cu)Because it undergoes oxidation-reduction reactions relatively easily, Cu is involved in electron transfer and enzyme systems much like Fe, most notably the oxidase enzymes.
Boron (B) Aids in the metabolic function of the plant and aids in cell division.
Molybdenum (Mo) Molybdenum is part of the make up of enzymes. Aids in the metabolic functions of the plant. Molybdenum is also needed for nitrogen fixing bacteria.
Chlorine (Cl) Cl functions in plants mainly as a mobile anion in processes related to osmotic pressure regulation (stomatal openings) and charge compensation (as a counter ion in cation transport).

Magnesium (Mg) Available plant nutrient for plants. Important to have soil pH over 4.5 or can be toxic to plant. Can be considered as a secondary nutrient, rather than a trace nutrient.

(8)Symptom of micronutrient elements deficiency:
Copper The critical deficiency concentration is about 1 to 3 ppm.
Typical deficiency symptoms are chlorosis (white tip), necrosis, and die-back in the youngest leaves.
Manganese (Mn)The critical deficiency concentration is about 10 - 15 ppm.
Deficiency symptoms include ¡°gray speck¡± in cereals, a condition that results when there is interveinal discoloration on the middle-aged leaves.
Iron (Fe)The deficiency concentration of Fe in mature plant tissue is about 50 ppm. The main symptom of iron deficiency is chlorosis or yellowing between the veins of new leaves.
Boron (B) Critical deficiency concentration ranges from 5-10 ppm in monocotyledons to 50-70 ppm in dicotyledons, to as high as 100 ppm in latex producing plants such as dandelion. the symptoms of boron deficiency vary from one species to another. Black gram deficient in boron does not show any visible symptoms in the seed, but the yield may fall by as much as 50%. In peanut or soybean, boron deficiency often results in an empty space within the seed, known as "hollow heart". A common result of boron deficiency in all crops is an interruption in flowering and fruiting . Yields are poor, and the fruit or grain is deformed or discolored.
Zinc (Zn) The critical deficiency concentration is from 15 to 30 ppm, higher if leaf P is above normal . Deficiencies are manifested by a shortening of internodes to the extent it appears leaves are all emanating from the same point on stems (condition is called ¡°rosetting¡±). In corn, chlorotic bands appear along the leaf midrib. Zn deficiency symptoms on older leaves is mainly a result of P toxicity (retranslocation of P is inhibited by Zn deficiency.) Deficiencies are common in pecans and corn, but have not been reported for wheat even in very deficient soil.
Chlorine (Cl) Average concentration in plants ranges from 1 to 20 g kg-1 (0.1 to 2%), while the concentration required for optimum growth ranges from 150-300 mg kg-1 (0.015-0.03%).
Deficiency symptoms include reduced root growth, wilting and curling of leaves and leaflets, bronzing and chlorosis similar to that for Mn deficiency.
Molybdenum (Mo) The critical deficiency level ranges from 0.1 to 1 ppm in leaves, whereas critical toxicity concentrations range from 100 to 1,000 ppm. deficiency symptoms are normally found in the oldest leaves. For legumes the symptoms are like that for N deficiency. In non-legumes the condition of ¡°whip tail¡±, where leaf blades are reduced and irregularly formed is common together with interveinal mottling, marginal chlorosis, and accumulation of NO3.

(9)How to solve micronutrient deficiency .
Applying corresponding elements is the answer. But you should know which type to choose. Chelates are the best solution and last the longest. There are several formulations of chelated compound. Different types of chelating agents are used and are designated as EDTA ,EDDHA and DTPA. The type of chelating agent recommended depends mainly on the pH value of the soil. In soil application EDDHA are preferable chelating agents for ensuring elements availability in alkaline soils. Chelates of DTPA and EDTA are effective in less alkaline or slightly acidic soils. The most common chelating agent is EDTA. Chelated compound are more expensive but last much longer. They can be found in liquid, powder or granular forms. The powder form is the most common. For more information ,click here

(10)EDTA,DTPA and EDDHA
They are all chelating agent for carrying micronutrient elements . EDTA was the first synthetic chelate used in nutrient solutions for hydroponics, although it was earlier noted that its effectiveness was limited to pH 6 or lower. That means that EDTA is not stable under strong light and/or with pH more than 6.5 . A closely related synthetic chelate is DTPA, commonly known as diethylenetriamine pentaacetic acid. DTPA is widely used as an iron chelate in hydroponic solutions. It is occasionally soil-applied as an iron or zinc source. And it's more stable then EDTA, at least till pH 7.5.
An aromatic chemical relative of EDTA is EDDHA, commonly known as ethylenediaminedi(o-hydroxyphenylacetic) acid, or EHPG (N,N'-ethylenebis-2-(o-hydroxyphenyl) glycine).Due to special structrue of EDDHA, chelates of this type are much stronger than purely carboxylic chelates. EDDHA is stronger than both EDTA and DTPA.

(11)Methods of Fertilizer Application
Many methods exist for applying fertilizer to soil or to plants. Among these methods include:
1) Broadcast - fertilizer is uniformly spread or sprayed over the entire soil surface often followed by incorporation using a tillage implement.
2) Localized placement - this method consists of placing the fertilizer in a band or localized point close to the plant. Localized placement includes starter, deep, surface, top-dressing and side-dressing fertilizer placements. This method is used for several reasons including providing fertilizer nutrients to seedlings with immature root systems, overcoming soil processes which reduce nutrient availability such as precipitation of phosphorus, convenience due to the difficulty of applying fertilizer to rows of fully-grown plants, and cost-saving since less fertilizer may be required when a limited soil volume is involved.
3) Foliar sprays - fertilizer is sprayed directly on the leaves of the affected plant. This method is usually used to overcome micronutrient deficiencies caused by soil conditions. Uptake of the nutrient is by absorption through the opening on leaves called stomates.
4) Fertigation - fertilizer is applied through the irrigation system. If trickle irrigation is used then fertilizer is released from the emittors at a point source and results in an effect similar to localized placement.
5) Injection - Fertilizer or manure is placed into the soil using a tanker and an implement which cuts through the soil and injects the fertilizer behind the cutting edge of the implement. The most common fertilizer applied in this manner is anhydrous ammonia, which is not currently available on Guam. Manure is also not commonly applied on Guam using this method.
6) Site-specific application - the most modern method of fertilizer application uses advances in mapping technology to apply fertilizer in varying amounts to a field based on previous soil sampling. This method requires sophisticated computer software to allow the fertilizer spreader to recognize its geographic position in relation to the soil test results and then adjust the amount of fertilizer applied.

(12)Soil Acidity or pH
Soil acidity is an important soil chemical characteristic primarily because it affects the availability of plant nutrients and plant growth. Other effects of soil acidity include effects on soil microbial activity, on exchange capacity, and the physical structure of the soil.
Soil pH has many effects on the soil environment including affecting:
1. the availability and toxicity of plant nutrient elements (see attached figure).
2. the activity and diversity of soil organisms involved in important soil reactions such as nitrification and decomposition
Soils with high pH can reduce plant growth because:
1. The availability of essential plant micronutrients, such as iron, manganese, copper and zinc is reduced.
2. Phosphorus is precipitated and also reduced in plant availability.

(13)Factors to Consider in Choosing a Fertilizer
There are several factors that should be considered when choosing your fertilizer material or other soil amendments,
1) Availability
2) Nutrient content
3) Nutrient availability and chemical reactivity
a. Solubility of the product
b. Particle size and form
4) Acid, neutral or base forming
5) Salt index