The present invention relates to a Water soluble balanced nutrient Food Product for plants and a process for the preparation thereof. The invented product is a complete plant food hereinafter referred to as 'PLANT-FD' in which the essential macro-micro elements come together in forms and quantities beneficial to a variety of food crops, ornamentals and flowering annuals in many conditions. Solubility in water tends to serve: the pressing needs of injecting it direct to drip system every time we irrigate or even on ppm basis. Foliar applications for instance in the wheat crop, when differentiation of spikelets takes place, would help expression of potential head size. Application when the grain filling commences will improve the flag leaf life important to pre-and post-anthesis photosynthesis. The assimilates so available will relocate to grains and prevent the number of grains per ear and individual grain weight to compensate for each other. This is significant in improving the total grain number per unit area —a potential means to reach the anticipated 10tons per hectare from a wheat genotype bioengineered in the 21st century, and to tap the untapped production reservoir available between potential and actual yields. Readily absorbable both by the leaves and the roots, instant continuing responses reflected in better root strength, large leaf area, high chlorophyll content, prolific flowering and grain/fruit, number and sizes culminate into unbelievable pjjsh in the yield curve up from 28 to 130 (464%), 50 to 111 (222%), 11 to 24 (218%), 4 to 11 (275%), and 1.3 to 7.7 (592%) metric tons per hectare of watermelon, tomatoes, lady's finger, winter maize and pomegranate respectively. Recuperative to soils not now in good health on account of heavy cropping and widespread use singly or in combination of N P K ever since the inception of green revolution, the product closest to the science and technology is available at a time when 'Grain care' and 'Land care' movements are to be launched throughout India. BACKGROUND OF THE INVENTION One billion people of the world's six billion live in India alone. If our population explosion is not halted, our number may soon exceed that of China. Food for such a population growth requires an increase in the production from 200 million tons in 2000 to about 300 million tons by the year 2020 - a factor of 150%. India has 2.4% of global land and 1% of global water resources. There is increasing evidence of decline in the growth rate of agricultural productivity and production in the 1990s. Green revolution fatigue, soil depletions, heavy cropping, and chronic use of N P K, either singly or in combination, together have largely contributed to this decrease in agricultural productivity. The stipulated rise in the food grain production needs vertical increase in yield that we cannot achieve from the use of plant varieties and agrochemicals of the green revolutioa Plant breeders therefore are to develop a genotype for instance of the wheat crop, a mainstay for food, to produce the top profitable yield at least of 10 tons per hectare. See Figure 1 that shows support of hi-tech nutrient management at the physiological optimum of relevance in "Green Revolution" areas, where a vast untapped production reservoir is available for use. It would therefore fulfill the pressing human needs as to more food (grain care), besides recovering the heavily depleted soils hungry in micronutrients (land care). INSURE AGAINST HIDDEN HUNGER (DiagramRemoved) - A blueprint to reach 10 tons per hectare required an 18000 grains per m2 and Harvest Index (HI) of 0.55 under Douch growing conditions. Since the number of grains per spike and grain size compensate for each other, 0.55 HI in the wheat crop is unachievable -a value higher than 0.43 reported in the 1920s has never been obtained. What is left to improve is the grain number per unit area. Differentiation of spikelets establishes potential head size. Pre-and post-anthesis photosynthesis keeps assimilates available for relocation to grains. Applications of PLANT-FD to wheat crop 20 to 25 days after planting when differentiation of spikelets takes place will help the expression of potential head size. Foliar applications at the grain filling stage to improve flag leaf life important to pre-and post-anthesis photosynthesis would keep assimilates available for relocation to grains. Potential head size and post-anthesis relocation of assimilates to grain resulting in normal grains nearly in all spikelets on a spike will together help increase the number of grain A balanced nutrient ration for plants is one in which all essential elements are in forms readily available to plants and in concentrations optimum for growth. Of 13 nutrient elements listed essential that plants obtain from the soil, calcium and magnesium are applied as lime in acid soils, rarely found in India. Sulphur is present in some commercial fertilizers. Very few chlorine deficiency symptoms have actually been observed/ conventionally. This leaves three fertilizer elements, N P K, and six micronutrients namely boron, copper, iron, manganese, molybdenum and zinc that need to be managed. Their use tends to support and supplement one another, bringing about the economy and effectiveness of fertilizers, and producing a large normal crop growth. Invented product is a unique multi-nutrient plant food containing chemicals and their compositions. It is concentrated to have the advantage of holding afore-mentioned plant food ingredients in small amount with a view to minimize labour, transportation, and storage costs. The approach to integrate small amounts of micronutrients to N P K intended for general use is practical in view of evidences on record. Micronutrient needs on each field are impossible to determine. Absence of deficiency symptoms does not preclude hidden hunger. The soil applications of some micronutrient salts are economically impractical. Inorganic ionic forms of metal elements (Cu, Fe, Mn, and Zn) undergo chemical tie-up in the soil or fertilizer tank attached to drip system or sprinkler main, Fe2+ + 2 OH" = Fe(OH)2 (Soluble) . (Insoluble) Mn2 + 2 OH = Mn(OH)2 (Soluble) (Insoluble) Water soluble chelates of metallic elements included in this PLANT-FD will never ionize to any degree. The chelates retain the metallic cations in a water soluble form permitting their absorption by plants yet preventing their chemical tie-up in the soil and fertilizer tank. They are also required in small quantities to correct deficiency symptoms The PLANT-FD made in accordance with the invention is non-hygroscopic i.e. will not absorb much water from the atmosphere. It contains urea phosphate-a feature not present in any of the plant nutrients mixtures currently on the market. A PRESSING NEED On arid and semiarid lands, drip irrigation is by far the best technological advancement for making the most of precious water. Irrigation water is distributed to plants through a network of driplines with emitters. The orifice of the emitters may be very small, e.g. lOO.mu.m Water filters of screen sizes typically 100-150 mu.m is provided in a system. In spite of the small orifice, partially water soluble phosphate and potassium fertilizers, or even fertilizer suspensions of particle sizes 150-1000 mu.m clog the emitters, whereupon the plant will receive neither water nor fertilizer. In a drip system, irrigation water drips directly to the root system of the plant. Injection of invented plant food suitable in smaller, more frequent applications, or even on ppm basis will contain plant nutrients in the potential root zone. Faster uptake of nutrients therefrom will take place in mass flow (ions from dilute external solution entering the roots and carried upward under considerable ion concentration gradient in the transpiration stream) and by root interception. There is acceleration consequent to high root length density and over 90% of the total root mass is present in the plant food confinement zone (Fig.2). The distance nutrients traverse before entering into the root system will also reduce. (DiagramRemoved) Fig-2: Root weight density (g x 10'5 cm ~3) of winter maize, 1996-97 The applied P in all likelihood will remain readily available to plants on account of minimum applied P-soil contact, large total surface of phosphate ion, large P-root hair contact and only 25% wet surface area found, to come into contact with P. Cobs in maize mature on green leaves. The meshy young roots exerting heavy nutrient uptake thrust will help set conditions favourable for uptake of phosphate ion before the soil fixes it. A frequent light application too is advantageous in respect of potassium, considering the luxury consumption of (wasteful removal above the level needed for optimum yields) by crops and the fact that excess potassium is subject to fixation. The present invention provides a Water soluble balanced nutrient Food Product for plants wherein the Food Product contains primary nutrients total Nitrogen (N), available Phosphorous (P205) and water-soluble Potassium (K20) in the nutrient ratio of 1-2-1, which process comprises the following steps: (i) Dissolving 282 kg spray grade Urea in pill or crystalline form containing a maximum of 0.3% biuret in 451 kg commercial grade phosphoric acid of acid strength 85% (containing 62% P2O5), heating the mixture up to 80°C while stirring, the resulting clear solution is cooled to 40°C. (ii) Adding to the clear solution 220 kg of potassium chloride salt, stirring the mixture to have thorough mixing with Urea-phosphoric acid solution and to avoid clustering of the salt particles. (iii) Cooling the mixture to about 20°C, adding micronutrients namely Boron, Copper, Iron, Manganese, Molybdate and Zinc containing laboratory grade compounds, as herein described and Diatmite powder, in amount to give 2% of final product weight. (iv) The resulting mixture is set to cool until the viscosity thereof is such that settling out of uh-dissolved solids is minimal and the mixture turn's to a solid mass, completely soluble in water, being the desired Water-soluble balanced nutrient plant Food Product, 0.1% aqueous solution of which has a pH of 6.8 and electrical conductivity of 0.875 dSm"1 All percentages stated in this complete specification are percentages by weight According to an embodiment of the present invention in the step (ii) of the process, in addition to potassium, laboratory grade ammonium sulphate is added to the urea-phosphoric acid solution. The final product obtained is non-hygroscopic. When ammonium sulphate is not used, the final product obtained is hygroscopic and is required to be packed immediately before it absorbs moisture from the air. The micronutrients i.e. non-primary nutrients which are used in the process according to the present invention are Boron(B), Copper (Cu), Iron(Fe), Manganese(Mn), Molybdate(Mo) and Zinc(Zn). Sources of micronutrients are B from boric acid, Mo from ammonium molybdate and bivalent metallic cations in the form of chelates. Such cations and their sources are Cu2+ from copper ethylenediaminetetraacetic acid (EDTA), Fe2+ from iron EDTA, Mn2+ from manganese EDTA and Zn2+ from zinc EDTA. The final Food Product contains in addition Chlorine (Cl) from potassium chloride and Sulphur (S) from ammonium sulphate used to supply primary nutrients potassium and a part of total nitrogen. Preferably the Water soluble balanced nutrient Food Product for plants prepared according to the present invention contains 14 % total Nitrogen, 28 % available phosphorous pentoxide, 14% water soluble potassium oxide, 0.02% Boron, 0.20% Copper, 0.30% Iron, 0.10% Manganese, 0.0005% Molybdenum and 0.50% Zinc. The Food Product prepared according to the present invention is suitable for fertigation through drip irrigation, sprinkler irrigation in open fields and microsprinklers in green houses. Suitable additionally to feed nursery plants, ornamentals, flowering annuals and indoor plants. In addition to 14% by weight of nitrogen, 28% by weight of phosphorus, 14% by weight of potassium, the invented Food Product contains micronutrients within the range from 0.0005% to 0.50% by weight of the total mass of the Food Product. In accordance with the invention the plant-nutrient containing substance in the composition is based on at least one of the cations NH/, K+ or on at least one of the anions H2PO4", C1 andSO42~. According to the invention, one or more plant-nutrient containing raw materials used are spray grade urea, phosphoric acid, ammonium sulphate and potassium chloride. A balanced nutrient Food Product for plants according to the invention additionally contains micronutrients containing substances like boric acid, ammonium molybdate and metallic cations Cu2+, Fe2+, Mn2+, and Zn2+ in the form of chelates-readily available to plants and economical to correct deficiency symptoms. The plant Food Product in accordance with_tbe,,invention contains plant-nutrient, containing substance that do not chemically react with each other ..Urea is not free to dissociate. "Potassium chloride is stable. EDTA-complexes (chelates) with divalent metal" ions are also stable in basic or slightly acidic reaction. Substances in the end product rather interact in such a manner as their coordinated actions produces unexpected and amazing responses in the economically significant food crops, ornamentals and flowering annuals. Plant Food Product prepared is used in foliar applications and/or in water irrigation systems (drip and sprinkler) is typically diluted to a concentration of 0.1% (1000 ppm) to 0.2% (2000 ppm) in sprays on the leaves). A 0.1% solution has a pH of 6.8 and electrical conductivity (EC) of 0.875 dSm"1 ' similar to pH (7.0) and EC (