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Climatic classification is the method of identifying climatologically homogenous regions. The systematic study of climate and its analysis and processing, which is referred as climatology plays an important role in national weather, planning activities and decision making in human activities. Iso climatic regions are those regions which have same climatic conditions.

Specific objectives of climatic classification

To identify the climates for transfer of production technology developed at particular center.

To provide adequate indices of moisture availability for successful crop production in drylands.

To quantify the risk levels associated with production constrains to agriculture production.

Meteorology is defined as the branch of science concerned with the processes and phenomena of the atmosphere. It is also defined as the climate and weather of a region. The word meteorology is derived from two Greek words: Meteor and logus. Meteor means event occurring above the earth surface and logus means to study. Meteorology is science deals with the physics, chemistry and dynamics of atmosphere and also their direct and indirect effects upon the earth surface, oceans and thereby life in general.

Climatology: Climatology is scientifically defined as weather conditions averaged over a period of time. Different regions of the world have different characteristic climates which determine the crops of any region. Climatology is derived from Greek word ‘klima’ – place/zone or slope of the earth and logs is study. It discovers, describes and interprets the climate on the basis of causes and long term effects on variation in regional and global climate. Climatology is the science which studies average condition of weather or the state behavior of the atmosphere over a place or region for a long period of time.

Agrometeorology: Agrometeorology is the study of weather and use of weather and climate information to enhance crop production. Agrometeorology is defined as the branch of meteorology that deals with relationship between weather and climate on crop, livestock production and soil management.

Soil is the top layer of the earth surface in which plants can grow, consisting of rock and mineral particles mixed with decayed organic matter and having the capability of retaining water. Soil is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Earth’s body of soil, called the pedosphere, has four important functions

With renewed interest in rainfed agriculture during 1970s, both the national (AICRPDA and CRIDA) and international institutions (ICRISAT) have studied several aspects of rainwater management. Recommendations have been made after their through testing both at the research Stations and on farmer’s fields. Initially these technologies were accepted by the farmers because of the pursuation by the Scientists and the incentives, but many of them are forgotten once the support is withdrawn. It is now time for us to examine whether the technologies themselves were weak or certain components were missing malfunctioning of the software may be due to a bug right from the beginning or it entered into the system at a later stage. It is also possible that we neglected certain critical inputs which became major constraints making the system defunct. Whatever the reason it should be identified and set right if the technology has to continue as tool for tackling the challenges of rainfed agriculture.

Main constraints of dry land agriculture to enhance the productivity are classified as follows:

The term Rainfed agriculture is used to describe farming practices that rely on rainfall for water. It provides much of the food consumed by poor communities in developing countries. In India, about 52% of total net sown area comes under rainfed lands. Rainfed crops account for 48 per cent area under food crops and 68 per cent under non-food crops. India ranks first among the rainfed agricultural countries of the world in terms of both extent and value of produce. Due to population pressure on agricultural lands, the poverty is concentrated in rainfed regions. The climate in India’s rainfed regions is characterized by complex climatic deficiencies, manifested as water scarcity for rainfed crop production. The climate is largely semi-arid and dry sub-humid with a short (occasionally intense) wet season followed by long dry season. Rainfall is highly unreliable, both in time and space, with strong risks of dry spells at critical growth stages even during good rainfall years. The fluctuations are due to numerous factors affecting the monsoonal climate including the atmospheric circulation and strong links to El-Nino Southern Oscillation (ENSO) phenomenon in the Pacific Ocean.

Rainfed areas in India are highly diverse, ranging from resource rich areas to resource-constrained areas. Some of the resource rich areas are highly productive and have experienced widespread adoption of technology. However, most of the areas are resource constrained and dry areas. In the resource constrained and dry areas, the farming is a survival mechanism rather than a growth oriented activity. Rainfed agriculture is practiced under a wide variety of soil type, agro-climatic and rainfall conditions ranging from 400 mm to 1600 mm per annum. Rainfed Crops are prone to breaks in the monsoon during the crop growth due to water stress. This water stress may be due to variability of rainfall, delay in sowing, diversity in crop management practice and variability of the soil type. The prolonged breaks can result in partial or complete failure of the crops.

1. Multiple Choice Questions

With the increasing health consciousness of consumers, there has been an increasing concern over the use of thermal processing methods like blanching, pasteurization, sterilization etc. for enhancing the shelf life of foods as these methods fail to preserve the fresh like nutritional, therapeutical and sensory qualities of the food. With the increased consumer demand for fresh and fresh-like foods, interest in minimal processing of foods is increasing. The trend is also shifting from the traditional heat processing to those technologies that employ no or minimum heat application, thereby retaining the quality to a maximum level. One of the ways to accomplish this is via use of non-thermal processes. Over the past few years a number of non-thermal processes or cold preservation methods have been invented and developed. These methods are being evaluated in pasteurization and sterilization of various foods or in the extension of shelf life of various packaged foods. Some of such novel technologies and the products prepared, have been discussed here under.

1. Extrusion

Extrusion is a size enlargement process wherein small granular food or powdered particles are re-formed into larger pieces with different shapes, textures, colours and flavours from the basic ingredients. In extrusion food is compressed and forced to pass through a fine opening (die). As soon as it comes out of the opening, the outside pressure is very less as compared to the pressure inside the screw of extruder and the food expands instantaneously. If the food is heated the process is called as extrusion cooking. It is a process which combines several unit operations including cooking, mixing, kneading, shearing, compressing, shaping and forming. Extrusion adds a variety to the products by changing shape, size, texture and even some of the minor ingredients of the food and at a reduced cost than most of the other processing methods. Extrusion cooking (not extrusion) is a high temperature short time (HTST) process that reduces microbial contamination and inactivates enzymes.

Before beginning the actual work on the establishment of a Fruit and Vegetable Processing Industry the following points should be considered:

Availability and possibilities of obtaining Funds: Investment of own money or obtaining loans from banks etc.

The scale of industry (Large, Small, Cottage or Home): Has to be decided based on availability of raw material, funds availability, land, labour and other resources.

The location: The processing unit should be located near to the actual production site of raw material so that the transportation costs of high bulk raw materials is reduced. There is no fun or justification of establishing apple processing industry in Lucknow or Bangalore and mango processing industry in Shimla as the related raw materials would have to be transported through long distances.

Site: Site selected in the location should be sunny area free from dampness and sufficient space for waste disposal should be ensured.

In a commercial horticultural enterprise, if the product is not marketed properly, safely and beneficially, all the investment, inputs, hard work goes in vain. Basically every commodity that is produced should reach the consumer and marketing is all about how the commodity reaches the consumer. There is no fun of producing any commodity if it does not reach the consumer.

The word market has been derived form Latin word “marcatus” meaning merchandise, where people conduct business. Market therefore refers to place where goods/ commodity and services are bought and sold.

Marketing is a sum total of business activities through which the goods and services are either bought or sold. Cundiff and Still defined marketing as “the business process by which products are matched with markets and through which transfer of ownership are affected.

Why Marketing of Fruits and Vegetables is Complex and Risky as Compared to Other Goods

Spoilage may be defined as the deteriorative process which renders the food inedible or results into reduction of quality.

Spoilage is Mainly of Two Types

Abiotic Spoilage: Less potential for causing health hazards to consumers. Occurs due to

Enzymes are biocatalysts that change the rate of reaction without being changed themselves. All (Most) enzymes are proteins but all proteins are not enzymes. Ribonuclease is the enzyme which is non- protein in nature.

Properties of Enzymes

Alcoholic Beverages

These are the beverages which are prepared after alcoholic fermentation of sugars by yeast, contain varying amounts of ethyl alcohol (5-42%), and are consumed directly or after dilution in water.

Wine : Product made by alcoholic fermentation of grapes or grape juice unless otherwise specified, by yeast (Saccharomyces cerevisiae and a subsequent ageing process. Alcohol content is 11-14 %, but may be as low as 7%.

Beverage: It includes all drinks whether they are fermented or unfermented, prepared from fruits or non-fruit, sweetened or unsweetened eg. tea, coffee, coca cola, cider, maaza are all beverages.

Fruit Beverages : Beverage which is prepared partly or fully from fruit juice or pulps with or without additives eg. pure fruit juice, squash, cordial, RTS beverage etc.

Non-fruit Beverage : Beverage which does not contain any fruit part eg. Coca cola, pepsi, sherbet etc.

Unfermented Juice or Pure Fruit Juice: This is the natural juice pressed out of the fruit and practically its composition remains unaltered during preparation and preservation. No additives like sugar, acid, water etc. are added. eg apple juice, orange juice.

Fruit Juice Beverage: This is the fruit juice that has been considerably altered in composition by adding water, sugar, acid, flavour, colours, preservatives etc. before consumption. It may or may not be diluted before it is served as a drink eg. squashes, nectars, appetizers etc.

Freezing : Freezing is a process where temperature of food (fruits, vegetable etc.) is lowered down considerably below freezing point so that the water present inside the food undergoes change in state from liquid to solid (ice) and gets frozen immediately eg Frozen Pea. Water is immobilized and solutes are concentrated to reduce the water activity.

Principles of preservation : Combination of low temperature, low water activity, and pre-treatments like blanching, dipping in sugar syrup etc. stop (reduce) the growth and activity of microorganisms.

Theory of freezing : Freezing takes place in two main steps

Drying/ Dehydration means the process of removal of water.

Drying : Removal of water (moisture) by using non conventional energy sources like Sun or wind.

Dehydration : Process of removal of moisture by the application of artificial heat under controlled conditions of temperature and / or humidity and air flow.

Canning : Process of preservation of various food stuffs including fruits and vegetables whole or in pieces, in sugar syrup or brine by heat processing them in hermetically sealed containers.

Jam : It is a product prepared by boiling to a suitable consistency, fruit pulp with sufficient quantity of sugar, acid and pectin so as to set and become firm enough to hold the tissues in position. About 45 parts of pulp are used with every 55 parts of sugar. The finished product should not contain less than 68 per cent total soluble solids.

Jelly : Jelly is prepared by boiling the fruit pectin extract with sugar in the presence of appropriate amounts of acid so as to set into a clear gel. A perfect jelly is transparent, devoid of haziness or any suspended material well set, but not too stiff and should have original flavour of the fruit. When cut it should retain its shape and show a smooth cut surface.

Marmalade : It is a fruit jelly like product in which slices of fruit or peel are suspended in the set gel. Mostly they are prepared from citrus fruits like oranges, lemons etc.

Pickles known to be good appetizers, aid digestion and pallate are edible products preserved and flavoured in a solution of common salt and vinegar. Spices and oil may also be added. There are a number of pickles very popular in India i.e. mango pickle, cauliflower pickle, lime and lemon pickles, ginger chilli pickle etc. But, some pickles like Sauerkraut are not very common in India but are very popular in European countries.

Essentials for Quality Product Preparation

Plant ripened red tomatoes should be selected. Yellow and green fruits on processing yield dull colour and turn brown due to oxidation.

Never use iron equipment for processing. Lycopene oxidizes and turns brown when comes in contact with iron. It also forms black compounds with the tannins present in tomatoes or the spices which are used for product preparation.

Avoid prolonged heating and cool immediately to avoid over-cooking.

Nature has made such a beautiful system that a fruit does not spoil unless its outer covering is removed and till it is there on the plant. For example banana will not spoil for long time if we do not remove its peel. Similar is the case with apple, guava, mango and many other fruits and vegetables. But as soon as the outer covering is removed the damage begins and the commodity is spoilt very soon.

Preservation is extending shelf life of fresh or processed food by using various methods and prevention or reduction of spoilage. Better the preservation, lesser the spoilage, more the spoilage poorer and inefficient is the preservation.

Therefore, in order to prevent or reduce the spoilage, we have to first identify and understand the causes of spoilage. There are chiefly 3 agencies that cause spoilage in fruits and vegetables i.e. (i) microorganisms, (ii) enzymes & chemical changes and (iii) man, animals, rodents, insects, etc. For effective preservation we have to check the growth and activity of these spoilage causing agencies. So, in order to prevent spoilage and preserve a perishable commodity for long time the following principles and methods are to be followed.

Packaging : Packaging of fruits, vegetables, flowers or any other commodity is chiefly done to assemble the produce in convenient units of different sizes, shapes & types for storage, transportation, marketing and distribution. The size of units may vary depending on the requirement e.g for retail marketing smaller units are preferred and for bulk transportation and storage, large units would be more convenient.

Why do we Require Packaging?

Imagine there is no packaging material and technology available. How we are going to transport apple, mango etc. to distant markets? Definitely as loose. Then how can we weigh or count the fruits being transported or marketed? This would be very difficult. Had there been no packaging the commodity would have suffered great physical, chemical and microbiological losses. It would have been very difficult to handle, manage, transport and market the produce as loose and unpacked. Therefore, the packaging of fresh as well as processed commodities was needed to contain, unitize and protect the produce.

Storage : It can be defined as keeping the commodity fresh or processed in safe condition with minimum of deteriorative changes for later use.

Reasons of Deterioration During Storage

Maturity Standards and Harvesting Indices

Harvesting : Harvesting is detaching a commodity from the point of its origin. This point of origin may be an above ground plant part i.e. shoot eg. apple, tomato etc. or an underground plant part eg potato, carrot, etc. or in water i.e. harvesting of fish from a pond (not to be covered in this book).

Physiological Development

Fruits and vegetables can be divided into 3 stages based n their physiological development i.e. growth, maturation and senescence.

Growth: This generally refers to cell division, enlargement and differentiation ultimately giving a particular size, weight and volume to the commodity.

Maturation: It is initiated before the ceasation of growth and lasts till the onset of senescence.

Senescence: The stage when anabolic (synthetic) processes almost terminate and catabolic (degradative) processes are initiated and speeded up causing ageing and finally death of tissues.

Ripening: Stage that begins with the last stages of maturation and lasts till the beginning (first stage) of senescence. Ripening is a very important event in the life of a plant as it transforms a physiologically mature but inedible (or not preferred to be eaten) plant part into an edible, visually and olfactorily attractive and tasty commodity. Ripening marks the completion of developmental phase and is an irrevessible event.

India, one of the largest food producer countries (I in milk production, II in fruit and vegetable production and III in food grain production at world level), possesses the potential of being the biggest with the food and agricultural sector contributing around 26 percent of the Gross Domestic Product (GDP). It is a paradox that people of the country producing such huge quantities of food including fruits, vegetables, milk, cereals grains etc. are still suffering from many nutritional deficiencies in their diet, and even in some places, the stomachs of people remain unfilled for the want of food. The credit of this would predominantly go to the poor postharvest infrastructure as well as knowhow and accessibility to the facilities. All this makes us one among those countries having largest postharvest losses. The reduction of losses occuring during food handling, processing, storage, distribution and use would be an indirect way of increasing the food production and making the country self-sufficient in nutritional requirements.

Weeds are the plants growing where and when they are not desired. They compete with crops for soil moisture, nutrients, solar radiation and space, and thus reduce crop yields. Weeds also act as alternate hosts that harbour insect pests and diseases and other microorganisms. Some weeds release poisonous substances into the soil which may be harmful to crop plants, human and livestock. Weeds reduce the quality of marketable produce and render harvesting difficult, leading to increased expenditure on labours, equipment and chemicals for their removal.

Classification of weeds

A. Based on life cycle

Annuals-Complete their life cycle in a year or in a single growing season. Based on the season they may be summer annuals and winter annuals.
Summer annual e.g, Echinochloa crusgalli

Removal of entire plants or the economic parts after maturity from the field is called harvesting. Portion that is left behind on the field is known as stubble. The economic product may be grain, seed, leaf, root or entire plant.

Time of Harvesting

If the crop is harvested early, the produce contains high moisture and more immature grains. The yields will be low due to unfilled grains. It is very difficult to store the produce as shriveled grains with high moisture are highly prone to infestation by pest. The quality of the grain as well as germination percentage is also reduced. Late harvest results in shattering of grains, germination even before harvesting in rainy season and breakage during processing. Hence harvesting during correct time is very important.

Plants may be harvested at physiological maturity or harvest maturity. Plants are said to be in physiological maturity when the translocation of the photosynthates ceases to the economic part.

The problematic areas for crop production may be soils affected with acidity, high concentration of salts, water logged soils or soils in steep sloppy areas. These soils have limitations or ill effects for crop growth and productivity.

Cropping system is the cropping patterns used on a farm and their interaction with farm resources, other farm enterprises, available technology and environment (Physical, biological and socioeconomic) which determine their makeup (Krantz et al., 1975). Cropping system is subsystem of the farming system.

The cropping system aims at increasing the benefits derived by crop production from available physical resources (land, climate, water resources etc.) that are not readily changed through optimization of input levels for a given crop or cropping pattern. The objective of any cropping system is to increase the efficiency of utilization of resources. The efficiency in measured by the quantity of product obtained per unit resource in a unit time in cropping system.

Adaptation is any feature of an organism which has survival value under the existing condition of its habitat. The basic of successful crop production is the selection of an adapted plant species and varieties. Plants may have morphological adaptation or physiological adaptation or both for the existing environment.

Adaptation to soil moisture

Hydrophytes: More number of stomata on the upper surface of the leaf, aerenchyma tissue in the roots of rice plants, stem is hollow/straw, internodes are longer in floating and submerged rice,

Mesophytes: Stomata are normal. Present both on upper and lower leaf surface, medium root growth.

An ideotype is a crop plant having desirable morphological and physiological characteristics or both for cultivation in a specific agroclimate situation. An ideotype is constructed by the breeder on the basis of indepth study of morphological and physiological characters including their interrelationships, and intuition of the breeder based on his experience.

Plant growth is defined as the progressive development which is irreversible. It is expressed in terms of dry weight plants, height of plants, girth or diameter of the stem or tree trunks, spread of the tree canopy, number of branches or tillers. Plant growth is a function or various factors which may be expressed as G = f (x, x₂, x₃ x_n ).Some factors may be controlled while some cannot be controlled. The following are the factors which influence the plant growth.

Knowledge of fertilizer dose, selection of fertilizer sources, time and method of application is essential for achieving efficient use of fertilizers and profitable yield.

A. Fertilizer Dose

Fertilizer dose for crops is determined based on the field experimentation. It varies with the crops and varieties, initial fertility of the soil, soil properties, cropping system, climate, season, rainfed or irrigated crop, expected yield etc. Fertilizer dose for rainfedcrops (Kg/ha)

Manures are the plant and animal wastes that are used as source of plant nutrients. They release nutrients upon their decomposition.

Bulky organic manures contain small percentage of nutrients and they are applied in large quantities. e.g,. farmyard manure, compost, green manures.

Criterion for essentiality of plant nutrients

Arnon’s (1954) criteria for essentiality of elements for plant growth:

1. The plant must be unable to grow normally or complete its life cycle in the absence of the element,

2. The element is specific and cannot be replaced by another and,

3. The element plays a direct role in metabolism.

A seed consists of a plant embryo, stored food material surrounded by a seed coat. Seeds of cereals and grasses consist of embryo or germ, endosperm and the pericarp.

Seeds of legumes contain no endosperm, the bulk of the seed being made up of the two cotyledons. The cotyledons constitute the food storage portion.

The embryo of the grass seed is made of epicotyl, hypocotyl and scutellum- the single cotyledon of monocots, the epicotyl gives rise to the shoot and the hypocotyl produces the roots.

Tillage is the physical manipulation of the soil with tools and implements which, results in good tilth for better germination and subsequent growth of crops.

Tilth is the physical condition of the soil resulting from tillage. Soil is said to be in good tilth when it is mellow, friable and adequately aerated. Tilth is dynamic. Mechanical forces may change the roughness of the soil surface, the total porosity and bulk density of the tilled layer and the aggregate or clod size. Heavy rainfall and high velocity wind or water destroys the tilth. The action of wetting and drying, freezing and thawing regenerates desirable tilth. The roughness of the soil surface is an index of the amount of water that can be stored in soil depressions and may also be related to the resistance of the soil surface to sealing. Roughness may be related to rate of evaporation, transfer of heat and air between the soil and atmosphere.

Soil fertility is the ability of the soil to supply all the essential nutrients in optimum amount in balanced proportion in a form readily available to plants under conditions favourable for plant growth and should be free from toxic substances.

Soil productivity: Soil productivity is defined as the capability of soil for producing a specified crop or sequence of crops under defined set of management practices. It is measured in terms of outputs or harvests in relation to the inputs of production factors for specific kinds of soils under a physically defined system of management according to USDA (1957).

The word soil is derived from the Latin word ‘Solum’ means soil. In general the top 15-20 cm cultivated layer is referred as soil. It is a loose and unconsolidated outer layer of the earth crust that is crumbly and powdery in nature. Soil below the plough layer is called subsoil.

Soil is formed by weathering of rocks. Weathering may be physical or chemical or both. Factors of soil formation are parent material, climate, living things-plants, animals and microorganisms, topography and time. Soil formation is a function of parent material (P), climate (C), topography (T_o), life (L) and time (T) which is represented by f(P C To L T).

Field Crops: Refers to the crops grown on a vast scale. They are classified in the following ways

1. According to the place of origin

2. Botanical classification

3. Commercial classification

4. Economic classification

5. Seasonal classification

6. Classification according to ontogeny

7. Agronomic classification

8. Classification based on leaf morphology

9. Classification based on serving special purpose

Crop growth is influenced by internal factors and external factors. Internal factors are controlled by the genes and hereditary. External factors are climate, edaphic, biotic, physiographic and anthropic.

Genetic Factors

Genetic factors are controlled by the genes. Plant height, yield, size and color of the grains or fruit etc. The productivity and quality of the crop can be improved by breeding through conventional methods or by biotechnological approaches.

Environmental factors Climate

Precipitation occurs in the form of rainfall, snow, hail and fog.

Fog: Consists of water droplets so small that their fall velocity is negligible. Fog particles contact vegetation and may adhere, coalesce with other droplets and eventually form a drop which is large enough to fall to ground.

The term agriculture is derived from the Latin words ager or agri meaning soils and cultura means cultivation. Agriculture is the art, science and business of crop production. It encompasses all aspects of crop production, livestock farming, fishery and forestry. Agriculture is the conversion of solar energy into the chemical energy. Crop production is the conversion of environmental inputs like solar energy, carbon dioxide, water and nutrients in soil to economic products in the form of human or animal food or industrial raw materials.

Agriculture is a science, an art and business of crop production

Agriculture is a science of farming. Scientific principles are employed to find ways of making it as efficient as possible. Through scientific principles plants and animals are transformed genetically and most favorable environment is provided to harvest higher yields of good quality with least expense of energy. The scientific principles of various branches viz. soil science, genetics and plant breeding, entomology, plant pathology, microbiology, agricultural engineering etc. were employed in agriculture. Agriculture like any other science is a body of truths synthesized and systematized and arranged in such a way as to show the operation of general laws and principles.

Agriculture is an art which embraces knowledge of the way to perform the operation of a farm in a skillful manner. The physical and mental skills are involved in agriculture. The skills may be acquired through years of experience viz. ploughing, stacking hay bundles, handling animals, sowing seeds, transplanting, driving a tractor etc. Mental skills are those involved in decision making for example when to plough the land, selection of appropriate crops, seed selection etc.

Agriculture is a business which is no longer a way of living or subsistence agriculture, where production is intended to meet the home requirements. Agriculture is intended to earn more income. Land, labour, capital are judiciously used. Like in any industry the farming industry should forecast the demand, tailor the production with demand to earn more profits. It involves processing, value addition, transportation, packing and storage in scientific way. Knowledge of employee and employer relationship or human resource management, export and imports, taxation, customs, tariffs and trade are required. All these aspects demand business knowledge in addition to the production and managerial skills. Traditional agriculture is no longer relevant for success in agriculture. Commercial agriculture or corporate farming, agribusiness development corporations demand entrepreneurs in agriculture rather than technologists alone.

Fig 8.1: A scheme for fertigation program working with automation

In modern farming with fertigation machines (NutriCare) and automated drip irrigation systems, fertigation set up schemes like the above are put into practice. This scheme will stream line the installation, operation and monitoring of the entire process. An informed grower would be able to control crop performance more precisely and achieve his objectives.

The crop growing environment, both soil/media and aerial are controlled in green house. Therefore, the movement of water (liquid and vapour) and minerals (nutrient ions) follow a different pattern altogether. This factor should be considered while preparing the fertigation program. This becomes all the more different if soil-less rooting media is used.

Table 7.1: Differences in Nutrient uptake in open field and Protected (GH) conditions.

There is a lot of confusion and lack of understanding when it comes to scheduling of fertigation. Even crop specialists prepare a fertigation dosage by dividing the total fertilizer quantity by the number of days of crop growth. This is highly erroneous. A scientifically prepared fertigation plan allows coordination of nutrient supply with changing demands of the growing crops which changes with the physiological shifts in the crop. Fertigation planner requires following information to prepare this schedule- which, when and how much plan:

Organic Fertilizers and Manures

Farmers have been using organic waste as fertilizers for a very long time. As previously mentioned, the application of O.M. to a soil can have number of beneficial effects on soil structure, C.E.C. and microbial activity. However, organic manures mainly originate from the waste products of animal and plant production and although rich in carbon compounds, they are usually relatively poor in available plant nutrients.

The nutrient content of organic manures varies widely depending on their source and moisture content. Farm yard manure (F.Y.M.) is one of the most common organic fertilizers used. Others are concentrated animal manures, and crop residues such as straw.

Although the application of fertilizer to even fairly fertile soils can give a great increase in crop yield, soil fertility is not simply a matter of nutrient content. It is dependent on a number of complex of issues:

Soil depth

The volume of soil from which the crop draws its nutrition varies according to the rooting depth of the crop. However hard or rocky layers can restrict natural root development; this is particularly the case with micro irrigation systems.

Soil structure

Particle size and soil aggregate size and distribution, effect the size and distribution of pores and therefore the availability of air and water to the roots.

Only a very brief mention of various basic aspects of plant nutrition is given here. Associates wanting to know more details should refer to any one of the standard Plant Nutrition publication (PRINCIPLES OF PLANT NUTRITION by K. Mengel and E.A. Kirkby).

Increased production of food and cash crops is the need of our times; as land and irrigation water are limited and beyond any means of expansion. Crop yields per unit input should increase. Crop yield under natural production systems is limited by the availability of nutrients in the soil. Unless the supply of nutrients can be enhanced yields cannot be high.

What is that the grower wants to achieve while he nourishes the crop with costly fertilizer inputs? He would like to get maximum output (yield and quality) of the produce; and for the maximization of out-put the fertilizer input should be utilized by the crop to its maximum potential. Thus it is not higher fertilizer dose that decides the highest yield; but the highest efficiency in crop’s use of those fertilizers. The efficiency, yield/unit fertilizer can be enhanced by the following factors;

a) Plant roots absorbing (in-take) total quanta of applied fertilizer and minimizing the loss of applied nutrients by not having spare quantities lying around the soil profile. This is possible only if the quantum of application matches with the quantum of need.

b) Plants utilizing the absorbed nutrients for metabolic activities concurrent to absorption. This is possible only if the fertilizers are applied in times of need of the plants and not before or after. This compels the grower to know the physiological need of the nutrient during each developmental stages; which nutrient required when.

Here the grower must have a powerful tool or method to provide nutrients to the plants strictly following the above two factors. Fertigation offers an opportunity to practice nutrient inputs based on the above two factors: the grower is able to correctly decide the dose, type and time of providing the correct nutrient at precise quantity and at the required stage of plant/ crop development.

Thus the purpose of Agriculture, to maximize yield and quality of crops and minimize the costs of production while maintaining sustainability can be put into practice by fertigation. Two most important prerequisites to achieve all of these are the optimal and balanced supply of water and nutrients. Tuning of plant nutrient supply with the uptake and utilization rates by crops is essentially an art and is made doable by fertigation technology.