eChapters

Drying is an important unit operation in seed processing in order to maintain seed ability and vigor . it is advocated that seeds should be harvested soon after they attain physiological maturity to obtain better quality seeds and to minimize field losses. The traditional method of sun drying is inadequate, uncontrolled and time bound, which may not meet the high demand of quality seeds in time. Hence artificial drying, the effect of certain drying parameters like seed moisture content, drying air temperature, airflow rate, depth of seed loading and time of exposure on drying characteristics and viability of seeds are to be determined for safe and economical drying of seeds.

Objective: To study the seed treatment methods and equipments A key factor in achieving the few potential of good quality seed is the blanket treatment of the seeds with agrochemical in order to control or prevent diseases in the  crops.

Seed is the primary and essential starting point of a wide range of crops, including the majority of vegetables except those vegetative propagated (e.g- potato and sweet potato). Seedling emergence and field stand establishment is one of the problems facing the growers, especially in early planting where adverse conditions are prevailed (low temperature and high soil moisture). Seed germination and seedling emergence are affected by many factors such as: seed genotype, seed quality (seed viability and seed vigor) and the environmental conditions (moisture and temperature) prevailing during seed germination and subsequent seedling emergence, assuming that the seed is not dormant.

Seed Priming is the process of controlled hydration of seeds to a level that permits pre-germinative metabolic actively to proceed, but prevents actual emergence of the radical. It is done to increase the speed and uniformity of germination particularly under adverse conditions of temperature, moisture and salinity conditions. In this condition, seeds go through all the essential preparatory processes of germination but prevent cell elongation and radical emergence. During the waiting period at the osmotic barrier the ‘slower’ seeds tend to catch up with the ‘faster ones’ so that the subsequent germination is more uniform, than that of untreated seeds. The duration of priming varies with the crop as well as method of priming such that priming is allowed for I and II stage of seed imbibitions without allowing radical protrusion.

Objective

    1.    Design drum priming (2-3 kg and drying unit with house hold or commonly available materials.
    2.    Standardization of time for seed priming for different crops.

Probable drum priming unit components

A] A vertical drum which need to be rotating
B] A motor which will rotate
C] A desktop assembly
D] A simple two way seed drier (Fig not given here)

The objective of seed pelleting is to provide an opportunity to package effective quantities of materials such that they can influence the micro-environment of each seed.
 
Process of Pelleting

Seeds are introduced into a coating drum or pan that resembles a cement mixer. An amalgam of pelleting materials (clays, limestone, calcium carbonate, talc, vermiculite) and cementing adhesives (gum Arabic, gelatine, methyl cellulose polyvinyl alchol) are used to form the pellet and other compounds such as inoculants, fungicides, etc. May be added to enhance seed performance.

These materials include barrier coated paper bags, barrier laminated film bags, jute bags, PP woven box bag and cotton bags.
 
A: Paper Bags
    1.    Coated paper:  bags provide a barrier for leaking or staining of the product. This can be done by a greaseproof or claycoated kraftpaper.
    2.    Open-Mouth sacks:  can be manufactured using different types of paper. Simple kraftliner, glossy claycoated and lacquered outerliner are possible. These sacks can be supplied with liners and printed up to 8 colours.

Fumigation is a method of pest control that completely fills an area with gaseous pesticides to suffocate or poison the pests within. It is utilized for control of pests in buildings, soil, seed, and grain produce. It is also used during processing of goods to be imported or exported in order to prevent transfer of exotic organisms. Fumigants are chemical compounds in gaseous form that enter the body of insect through the spiracles spread all over via trachea and tracheoles. The important fumigants are Methyl bromide, Ethylene dibromide, Aluminium phosphide, Ethyl formate, Hydrogen cyanide, Chloropicrin etc.

The moisture content is the amount of water in the seed and is usually expressed as a percentage. It can he expressed on either a wet weight basis (where it is expressed as a percentage of the fresh weight of the seed) or on a dry weight basis (where it is expressed as a percentage of the dry weight of the seed). The seed moisture content is the most vital parameter, which influence the seed quality and storage life of the seed. Seed moisture content is closely associated with several aspects of physiological seed quality. For example, it is related to seed maturity, optimum harvest time, mechanical damage, economics of artificial seed drying, seed longevity and insect & pathogen infestation.

Mechanical damage in oil seeds like soya bean can be induced at any time during harvesting, handling, conditioning and sowing operations. There is relationship between moisture and mechanical damage. In general the low moisture containing seeds are more prone for mechanical damage than the high moisture containing seeds. In this experiment we look for this relationship by measuring seed quality parameters like germination and leakage (electrical conductivity).

According to Harrington’s rule (1960) of thumb, for storage, every one percent increase in moisture content, the seed life is halved far seeds of moisture content of 5-14%. For temperature, every 5^ºC rise in temperature, between 0-50 ^ºC, the seed life is halved.

Seed processing efficiency (SPE) is one of the important aspects in seed processing. It will help in measuring the potential of the shop floor. It will also help in standardizing activities like screens and improving physical purity. SPE will help to improve the quality of the seed material and help in utilizing the machines at their optimum capacity. SPE may vary among the different crops and even among the varieties.
 
To quantify SPE we need to pass the test sample (bulk-pre processed) through the target machine and enter the details in a processing register. To quantify the SPE we need to follow these mathematical formulae:

NAME OF THE UNIT: 

    1.    Location of Seed Storage 
    2.    Date of Inspections/visit

PPEs are the personal protection equipments which protect the personnel against some hazards in the shop floor. PPEs form important aspects of Environment (safe disposal of treated chemicals, dusts coming out of processing), Safety (to seed storages) and Health (personnel) (ESH) strategy of any shop floor.

The “falling number” is a measurement used by plant breeders and grain quality specialists to determine the soundness of wheat, which is primarily influenced by the degree of sprouting in a grain sample. Hagberg Falling Number is the full name of this international standard of sprout measurement.  The term “falling numbers” refers to the amount of time it takes for the Hagberg steel ball in this sprout analysis tool to fall through a flour/water slurry that has been heated to release the starch from water. 

There are stages in seed supply chain where seed losses happen at harvesting and post harvest stage. These losses may occur due to higher moisture at harvest, due to harvesting methods, processing methods, at seed storage, during transport etc. Estimation of these losses is an important function of seed inventory management. Estimating seed losses help to improve processing and seed distribution efficiency. These simple statistical tools will help to measure quantitative post harvest seed losses. Seed testing can be used for measuring qualitative post harvest seed losses.

To assess the quality of the seed is necessary before it is shipped for packaging and made available to the farming community. To assess certain routine seed quality parameters which are statutory for labelling seed sampling and testing are very critical. Seed testing is not only a mandatory trade requirement but also decides the market potential of a particular product in the market and safeguard the brand image of the company. Seed sampling for labelling and other trade requirements is done at processing plant. The reliability of seed testing is depends on the accuracy with which the sample represents the lot and precision of the laboratory test. In many cases variations in the test results are due to variation in the sampling. Hence, seed sampling is one of the important activities of the shop floor or processing unit.

The management of storage in open and closed storage is critical before start of any seed processing activities. When seed lots reach the shop floor, they need to be stored properly. Unlike commercial produce seed lots cannot be stored in bulk. These need to be stacked lot wise and there is problem of “stackburn”-resulting from successive layers in building a bag stack. In crops like soyabean-”stackburn” can have detrimental effect on seed quality. The quality parameters like germination and viability can get lost instantly if not properly stacked on the pallets.

Storage of paddy seed lots after harvesting is one of the crucial aspects of processing shopfloor. Paddy due to increased mechanised harvesting may loose vital seed quality parameters. Since seed growers cannot buy a combined harvester themselves-they resort to hiring of this machine. Sometimes in the hurry of completing harvesting they harvest the crop at un-safe moisture content. This un-safe moisture content may go up to 50-60% also. Harvesting of seed crop with high moisture has adverse effect on storability. Ensuring safe seed moisture is very critical especially during rabi-summer seed production cycle. Most of the growers depend on sun drying for reducing the seed moisture. But paddy should not be dried >3% in one cycle. Follow tempering and convection cooling after every cycle and repeat the cycle till seed attains safe moisture content (14%).

Soil fertility -importance

From edaphological point of view soil is a medium for plant growth. It holds and nourishes the plants. Soil fertility refers to the ability of soil to supply plant nutrients. Soil fertility and fertilizers are very much closely related terms; and cannot be neglected one from the other in their function. Soil fertility acts as a ‘SINK’ where in plants can draw nutrients for maximum productivity, where as fertilizer, acts as a ‘SOURCE’ wherein we can apply continuously different nutrients. The importance of soil fertility and nutrient management is being increasingly recognized in all countries recently to meet the demand for food and other agricultural raw materials. Intensive use of fertilizer, intensive cropping and high yielding seeds have no doubt increased the food production and reduced the food shortage but it has also ushered in innumerable problems of soil fertility, soil and water pollution. On the other hand, fast depletion of nutrients due to over exploitation, a wide spread deficiency of N, P, K and S coupled with micronutrients deficiencies specially Zn, B and Mo is taking place. Further deforestation, shifting cultivation, burning of crop residues, trees, bushes, grasses and cow dung, soil erosion, nutrient losses and imbalanced nutrient application, leaching losses etc., have aggravated the depletion of soil fertility status. The productivity of Indian agriculture solely depends on scientific management of soil fertility along with judicious and efficient use of fertilizers integrated with organic sources.

Terminology

    ·    Nutrient: Nutrients are substances required by an organism for their normal     growth and reproduction. 
    ·    Plant Nutrient: The plant nutrient is a “food” which is composed of certain chemical elements often referred to as ‘plant nutrient’ or plant food elements considered very essential for growth and development of plants. 
    ·    Nutrition: The supply and absorption of chemical compounds needed for growth and metabolism of an organism.

The following graph is a visual representation of how plant growth and/or yield is affected by nutrient concentrations

N-Transformation and availability in soils     
    a.    N-Cycle 
    b.    N transformation in  soils 
Phosphorus transformation & availability in soils: 
    a.    P-Cycle 
    b.    P transformation in soils 
K-transformations& availability in soils: 
    a.    K-Cycle 
    b.    K-Transformations

Organic matter and its composition 
Decomposition  
Types microorganisms involved 
Enzymes involved in decomposition process?

    1.    Acid soil
    2.    Causes of soil acidity   
    3.    Problem of soil acidity 
    4.    Management or Amelioration of soil acidity 
        a.    Lime requirement (LR): 
        b.    Liming reaction in soils      
        c.    Benefits of liming on acidic soils 
    5.    Calcareous soil  
    6.    Formation, characteristics & management of calcareous soil 

    1.    Salt affected soils;
    2.    Classification of salt affected soils; 
    3.    Formation of salt affected soils; 

Alkali soil
 
Alkali soils are those that contain measurable amounts of soluble salts mostly as carbonates and bicarbonates of sodium. 

Definitions of IPNM 
Concept of IPNM 
Main objectives of INM 
Components of IPNM

The objective of nutrient use is to increase the overall performance of cropping systems by providing economically optimum nourishment to the crop while minimizing nutrient losses from the field and supporting agricultural system sustainability through contributions to soil fertility or other soil quality components. NUE addresses some but not all aspects of that performance. The most valuable NUE improvements are those contributing most to overall cropping system performance. Therefore, management practices that improve NUE without reducing productivity or the potential for future productivity increases are likely to be most valuable. An excellent review of NUE measurements and calculations was written by Dobermann (2007). Table  is a summary of common NUE terms, as defined by Dobermann, along with their applications and limitations. The primary question addressed by each term and the most typical use of the term are also listed below.

Fertilizers are applied to supplement nutrient requirement of the crop. It should not be looked as a substitute to organic sources. After determination of nutrient requirement of a crop fora given yield and contribution of nutrients from different sources, articularly, from the soil source, it is necessary to supplement the balance from the inorganic sources. These are determined by field experimentation supplemented by pot-culture, laboratory and green housestudies, if necessary. When a fertilizer is applied all of its nutrient (s) are not absorbed by the crop. The interactions between soil-crop-season and other factors are quite significant. Only a fraction of the nutrient(s) is utilized by the crop.

Methods of soil fertility evaluation          
    I.    Nutrient deficiency symptoms on plants  
    II.    Plant analysis
    III.    Biological tests   
    IV.    Soil testing
    V.    Spectral sensing for site specific evaluation

Soil fertility evaluation is conducted for providing an adequate supply of essential plant nutriens to ensure optimum plant productivity, while maximising economic benefits and minimising environmental degradation.
 
Mathematical modelling of nutrient application

The significance of an essential plant nutrient was contained in the Liebig’s law of minimum.

Fertilizer

Fertilizers are defined as materials having definite chemical composition with a high analytical value that supply essential plant nutrients in available form. They are usually manufactured by industries and sold with a trade name. They are commonly synthetic in nature and also called as chemical fertilizers/inorganic fertilizers/commercial fertilizers other than lime and gypsum. Most of the chemical fertilizers are inorganic in nature.

Methods of fertilizer application

Two major methods are used to apply fertilizers  
I) Application of fertilizers in solid form 
II) Application of fertilizers in liquid forms

Fertilizer (Control) Order, 1985 which is administered by Deptt.of Agriculture Cooperation, Govt. of India has been issued under the Essential Commodities Act, 1955. The FCO lays, down as to what substances qualify for use as fertilizers in the soil, product-wise specifications, methods for sampling and analysis of fertilizers, procedure for obtaining license/registration as manufacture/dealer in fertilizers and conditions to be fulfilled for trading thereof, etc.

Use of biofertilizers in agriculture and their advantage
 
Bio-fertilizers or bio-inoculants

These are productions containing living organisms such as nitrogen fixers or phosphorus solubilises which are useful for agricultural production. Biofertilizers play a significant role in improving soil fertility and plant growth. By fixing atmospheric nitrogen both in association with plants and without plants solubilize insoluble soil phosphates into soluble phosphates there by increasing the availability of phosphorus secrete growth promoting substances and supplies to the inoculated plants.

Plant nutrients are naturally components of the soil orchestrated by weathering processes and that the abundance of these metals in our soil environment now-a-days is due to numerous anthropogenic activities. In the environment, heavy metals are partitioned among the various environmental compartments such as water, soil, suspended solids and biota. Processes such as dilution, dispersion, sedimentation, adsorption and desorption govern their distribution. They also exist in colloidal ionic particulate and dissolved phases,  have a high affinity for humic acids, organic colloids and oxides coated with organic matter. The soluble forms are generally ions or unionised organo metallic chelates or complexes. The solubility of metals in soil and groundwater is predominantly controlled by pH, amount of metal, cation exchange capacity, organic carbon content, the oxidation state of the mineral components and the redox potential of the system.

The requirement of micronutrients is always in low amounts while their moderate decrease causes the deficiency symptoms and a moderate increase causes toxicity. In other words, there is a narrow range of concentration at which the elements are optimum. Any mineral ion concentration in tissues that reduces the dry weight of tissues by about 10 per cent is considered toxic. Such critical concentrations vary widely among different micronutrients. The toxicity symptoms are difficult to identify. Toxicity levels for any element also vary for different plants. Many a times, excess of an element may inhibit the uptake of another element.

Toxic elements like Cadmium (Cd), Fluoride (F), heavy metals, radioactive metals are associated with mainly rock phosphates, other organic wastes like sewage sludge and pollutants. Their chemistry is similar to plant nutrients and replace them in their physiology leading to reduced uptake of nutrients, productivity and contaminated food chain.

India is famous as the ‘Land of Spices’ world over. Spices are nature’s gift to humankind for flavoring our food. They are also used as preservative and in pharmaceuticals. India is the largest producer, consumer and exporter of seed spices and their value added products. About 63 different spice crops are cultivated in the country. Among them, seed spices are annual herbs, whose dried seeds or fruits are used as spices. These crops share 21.87% in terms of quantity and 7.42 % in terms of value to total spices export in the country. The country grows a wide variety of seed spices like coriander, cumin, fenugreek and fennel as major crop, while, dill, nigella, ajwain, anise, celery, caraway, parsley, black cumin and few other are categories as the minor seed spices.

Notified Varieties of Different Seed Spices

Seed
The seed, in botany is a mature ovule, consisting of an embryo together with a store of food all surrounded by a protective coat and bear ability to develop a new plant on optimum conditions of soil, moisture and light. It usually develops after the fertilization on an egg cell by male generative cell from a pollen grain. Seeds of some species develop without the intervention of the male cell, formed entirely of ‘mother’ tissue. Such seeds are called apogamic seeds. In seed technology, the seed is seed or any vegetatively propagated material produced from seed crop in accordance to Indian seed standards and has potential to develop new crop in presence of soil, moisture and light.

Seed Sampling

The size and quantity of seed sample required for seed quality testing remains small as compared to the seed lot hence, representative samples are randomly drawn for this purpose. The process of obtaining a uniform and representative sample from a seed lot for seed quality testing is called seed sampling. The samples are prepared in accordance to ISTA rules to ensure that small size sample should represent truly and in the same proportion all constituents of seed lot.

1. Isolation distance

Physical purity test determines the proportion of pure seed, other crop seed, weed seed, inert matter, moisture and germination components in the seed lot by weight in percentage in accordance to prescribed Seed Standards. It thus, helps in improving the plant stand, raising a pure crop by eliminating other crop seeds, weed seeds and disease free-seeds. Seed must not be sold until the percentage of pure seed, other crop seed, weed seed, and inert matter are in accordance to seed physical purity standards. Physical purity test is required for seed certification or seed law enforcement and it is a pre-requisite for ger- mination test.

Seed Germination Test

Germination is the process of emergence and development of seed embryo into a plant under favourable environmental conditions of water, soil, sunlight and temperature. The best example of germination is the sprouting of a seedling from a seed of an angiosperm plant. It reflects the ability of seed to produce a normal plant under favourable environmental conditions. The germination rate of a particular seed lot is a key indicator of its performance in the field.

Seed Viability Test

Germination test for a seed lot is a pre-requisite to know its potential of emergence under field condition. However, this test requires few days to weeks and a month in some cases. Tetrazolium test gives quick information on seed viability or germinability. It makes possible to distinguish red coloured living parts of seeds from the colourless dead ones. Staining of seeds determines  viability.  Completely  stained  seeds  are  viable  while,  partially and comparatively unstained seeds are non-viable. This test is not valid as compared to seed germination test.

The seed moisture content is the amount of water present in the seed. It is generally expressed in percentage of dry and wet seed weight. It is the loss in weight of the original sample when it is dried. High moisture content in seed sample favors the mechanical damage, seed longevity, incidence of disease and insect pests.

Objective

i. To know the moisture content of seeds by suitable methods
ii. To suggest the seed drying.

Seed storage is the preservation of viable seeds from the time of collection to the required for sowing. It is important to get adequate plant stands in addition to healthy and vigourous plants.

Objectives

i. To maintain initial seed quality during storage period by providing suitable conditions.

ii. To maintain the seed germination and emergence rates.

iii. To prevent the seed deterioration during storage period.

iv. To maintain the physical and physiological seed qualities.

Mini seed testing lab analytical register