Dushyant Agronomy Final

Seed rate , seed treatment & sowing in the nursery Made by :

SEED RATE: Th e quantity of seed required for

sowing or planting in an unit area.  The seed rate for a particular crop would depend not only on its seed size/test weight,  But also on its desired population , germination percentage & purity percentage of seed .

 It is calculated as

seed rate { kg} = area to be sown in m2 × test weight of the seed in gm × 1 /germination % × purity % × spacing (m) × 1000

 A seed rate of about 100 kg of seed

per hectare (2 bushels per acre) is typical, though rates vary considerably depending on crop species, soil conditions, and farmer's preference.  Excessive rates can cause the crop to lodge, while too thin a rate will result in poor utilisation of the land, competition with weedsand a

SEED TREATMENT  Seed treatment refers to the

application of fungicide, insecticide, or a combination of both, to seeds so as to disinfect and disinfect them from seed-borne or soil-borne pathogenic organisms and storage insects. 

Benefits of Seed Treatment:

 1) Prevents spread of plant diseases  2) Protects seed from seed rot and

seedling blights  3) Improves germination  4) Provides protection from storage insects  5) Controls soil insects.

Methods of seed treatment 1) Dry treatment:-

mixing of seed with powder form of pesticides/ nutrients. 3) Wet treatment :soaking of seed in pesticide/nutrient solutions. 5) Slurry treatment:dipping of seeds/seedling in slurry Ex. Rice seedling are dipped in phosphate slurry.

 4) pelleting :-

it is the coating of solid materials in sufficient quantities to make the seeds larger, heavier & to appear uniform in size for sowing with seed drills. Pelleting with pesticides as a protectant against soil organisms, soil pests & as a replellant against birds & rodents .

Types of Seed Treatment:  1) Seed disinfection:

Seed disinfection refers to the eradication of fungal spores that have become established within the seed coat, or more deep-seated tissues.  For effective control, the fungicidal treatment must actually penetrate the seed in order to kill the fungus that is present.

 2) Seed disinfestation: 

Seed disinfestation refers to the destruction of surface-borne organisms that have contaminated the seed surface but not infected the seed surface.  Chemical dips, soaks, fungicides applied as dust, slurry or liquid have been found successful.

 3) Seed Protection: 

The purpose of seed protection is to protect the seed and young seedling from organisms in the soil which might otherwise cause decay of the seed before germination.

Conditions under which seed must be treated  1) Injured Seeds:

Any break in the seed coat of a seed affords an excellent opportunity for fungi to enter the seed and either kill it, or awaken the seedling that will be produced  from it.  Seeds suffer mechanical injury during combining and threshing operations, or from being dropped from excessive heights.  They may also be injured by weather or improper storage.

 2) Diseased seed:

 Seed may be infected by disease organisms even at the time of harvest, or may become infected during processing, if processed on contaminated machinery or if stored in contaminated containers or warehouses.

 3) Undesirable soil conditions:

Seeds are sometimes planted under unfavourable soil conditions such as cold and damp soils, or extremely dry soils.  Such unfavourable soil conditions may be favourable to the growth and development of certain fungi spores enabling them to attack and damage

 4) Disease-free seed: 

Seeds are invariably infected, by disease organisms ranging from no economic consequence to severe economic consequences.  Seed treatment provides a good insurance against diseases, soilborne organisms and thus affords protection to weak seeds enabling

Equipments used for Seed Treatment:  1) Slurry Treaters

 2) Direct Treaters  3) Home-made drum mixer  4)Grain auger  5) Shovel

Precautions in Seed Treatment:

 Most products used in the treatment of

seeds are harmful to humans, but they can also be harmful to seeds.   Extreme care is required  to ensure that treated seed is never used as human or animal food.  To minimise this possibility, treated seed should be clearly labelled as being dangerous, if consumed.   The temptation to use unsold treated seed for human or animal feed can be avoided if care is taken to treat only the quantity for which sales are assured.

 Care must also be taken to treat

seed at the correct dosage rate; applying too much or too little material can be as damaging as never treating at all.   Seed with a very high moisture content is very susceptible to injury when treated with some of the concentrated liquid products.

If the seeds are to be treated with bacterial cultures also, the order in which seed treatments should be done shall be as follows  i) fungicide  ii) bacterial cultures.

Sowing  Sowing is the process of planting 

seeds. before sowing, good quality seeds (clean and healthy seeds) should be selected to produce a high yield.

Methods of sowing  Seed are sown directly in the field

(seed bed) or in the nursery ( nursery bed ) where seedling are raised & transplanted later.  Direct seeding may be done by a) Broadcasting :it is the scattering or spreading of the seeds on the soil which may or may not be done by hand,mechanicaal spreader or

 Broadcasting the seeds is the

easy,quick & cheap method of seeding .  The difficulties observed in broadcasting are uneven distribution,improper placement of seeds & less soil cover & compaction.  As all the seeds are not placed in uniform density & depth , there is no

 It is mostly suited for closely paced &

small seeded crops. b)Dibbling:it is the placing of seeds in a hole or pit made at a predetermined spacing & depth with a dibbler or planeter or very often by hand. Dibbling is mmore laborious,time consuming & expensive compared to germination with good seedling

 C) drilling :-

it is the practice of dropping seeds in a definite depth, covered with soil & compacted. sowing implements like seed drill or seed cum fertilizer drill are used. manures,fertilizers,soil amendments,pesticides,etc. May be applied along with seeds.

 Seeds are drilled continuosly or at

regular intervals in rows.  it requires more time, energy & cost but maintains uniform population per unit area.  rows are set according to the requirements .  Seeds are placed at uniform depth,covered & compacted.

 D) sowing In the nursery :-

it is an operation in which seeds are placed in the plough furrow either continously or at required spacing by a man working behind a plough. when the plough take the next adjacent furrow. depth of sowing is adjusting the depth of the plough furrow.

 E) Planting :-

placing seeds or seed material firmly in the soil to grow. F) Transplanting :planting seedling in the main field after pulling out from the nursery. it is done to reduce the main field duration of the crops facilitating to grow more number of crops in an

 It is easy to give extra care for

tender seedling.  For small seeded crops whhich require shallow sowing & frequent irrigation for proper germination,raising nursery is the easiest way.

Pre-monsoon sowing: Normally sowing is taken up after

receipt of sufficient amount of rainfall (20 mm) in the case of dryland system of farming .  Since sowing is continued for two or three days after a soaking rain,certain amount of moisture is last during the period between the receipt of rainfall & sowing.  In the case of heavy clay soils (black

 To over come this difficult, sowing is

takenup in dry soil prepared with summer rains,7 to 10 days before the anticipated receipt of sowing rains.  The seeds germinate after the receipt of the rainfall .  This method of sowing is known as drysowing or pre-monsoon sowing.  By this method the entire rainfall

Factors involved in sowing management :-

Tthis can be classified into 2 broad groups: 2)Mechanical factors: such as depth of sowing, emergence habit, seed size & weight seed texture, seed contact, seed bed fertility, soil moisture. 4)Biological factor: like companion crops, competition for light, soil

1) Mechanical factor:  A) seed size & weight:

heavy & bold seeds produce vigorous seedling. application of fertilizer to bold seed tends to encourage the seedlings than the seedling from small seeds. B) Depth of sowing : optimum depth of sowing ranges from 2.5-3 cm.

 Depth of sowing depends on seed

size & availability of soil moisture.  Deeper sowing delays field emergence & thus delays crop duration.  Deeper sowing sometimes ensures crop ssurvival under adverse weather & soil conditions mostly in dry lands.  C) emergence habit:

 D) seed bed :

soil texture should minimize crust formation & maximize aeration which in turn influence the gages, temperature & water content of the soil . very fine soil may not maintain adequate temparature & water holding capacity.

 E) seeds-soil contact:

seeds require close contact with soil particles to ensure that water can be absorbed readily. forming the soil around the seed (broadcast seeds) after sowing improves the soil-edd contact. D)Seed bed fertility: tillering crop like rice, ragi,bajra etc.should be sown thinly on fertile

 Similarly high seed rate are used on

poor soil for non tillering crops.  although jigher the seed rate greater he yeild under conditions of low soil fertility, in some cases such as cotton, a lower seed rate gives better result than a higher seed rate .  G)soil moisture: excess moisture in soil reetards

 Adjustment in depth is made

according to moisture conditons,i.e.,deeper sowing on dry soils & shallow sowing on wet soils.  Sowing on riges is usually recommended on poorly drained soil.

2) Biological factor: a) Companion crop:

is usually sown early to suppress weed growth & control soil erosion. in cassava+maize/yam cropping, cassava is planted later in yam or maize to minimize the effect of competition for light. in mixed cropping all the crops are sown at the same time.

 B) competition of ligh:

in mixed stands, optimum spacing for each crop minimizes the competition of light. C) Soil micro organisms: the micro organisms presenting in the soil should favour seed germination & should not

Sowing in practice  Pretreatment of seed and soil

before sowing: Tropical fruit such asavocado also benefit from special seed treatments (specificly invented for that particular tropical fruit)  Before sowing, certain seeds first require a treatment prior to the sowing process. This treatment may be  seed scarification, stratification,  seed soaking orseed cleaning with cold

 Seed soaking is generally done by

placing seeds in medium hot water for at least 24 to up to 48 hours  Seed cleaning is done especially with fruit (as the flesh of the fruit around the seed can quickly become prone to attack from insects or plagues.  ] To clean the seed, usually  seed rubbings with cloth/paper is

 Seed washing is generally done by

submerging cleansed seeds 20 minutes in 50 degree Celsius water .  This (rather hot than moderately hot) water kills any organisms that may have survived on the skin of the seed.  Especially with easily infected tropical fruit such as lychees and  rambutans, seed washing with high

 In addition to the mentioned seed

pretreatments, seed germination is also assisted when disease-free soil is used.  Especially when trying to germinate difficult seed (e.g. certain tropical fruit), prior treatment of the soil (along with the usage of the most suitable soil; e.g. potting soil, prepared soil or othersubstrates) is vital. 

 Depending on the necessity,

pasteurisation is to be preferred as this does not kill all organisms.  Sterilisation can be done when trying to grow truly difficult crops.  To pasteurise the soil, the soil is heated for 15 minutes in an oven of 120 °C.

Plants which are usually sown  Among the major field crops, oats, 

wheat, and rye are sowed, grasses and legumes are seeded, and maize  and soybeans are planted.  In planting, wider rows (generally 75 cm (30 in) or more) are used, and the intent is to have precise, even spacing between individual seeds in the row; various mechanisms have been devised to count out individual

 Sowing depth:

In seeding, little if any soil is placed over the seeds. More precisely, seeds can be generally sown into the soil by maintaining a planting depth of about 2-3 times the size of the seed.

Sowing types and patterns

 For hand sowing, several sowing    



types exist; these include [7]: Flat sowing Ridge sowing Wide bed sowing Several patterns for sowing may be used together with these types; these include: Regular rows

 Rows that are indented at the even

rows (so that the seeds are placed in a crossed pattern). This method is much better, as more light may fall on the seedlings as they come out.

Types of sowing  Hand sowing:

Hand sowing is the process of casting handfuls of seed over prepared ground: broadcasting. Usually, a drag or harrow is employed to incorporate the seed into the soil. Though labor intensive for any but small areas, this method is still used in some situations. Practice is required to sow evenly and at the desired rate.

 A hand seeder can be used for

sowing, though it is less of a help than it is for the smaller seeds of  grasses and legumes.  Hand sowing may be combined with pre-sowing in seed trays. This allows the plants to come to strength indoors during cold periods (eg spring in temperate countries).

 In agriculture, most seed is now

sown using a seed drill, which offers greater precision; seed is sown evenly and at the desired rate.  The drill also places the seed at a measured distance below the soil, so that less seed is required.  The standard design uses a fluted feed metering system, which is volumetric in nature; individual

 Rows are typically about 10-30 cm

apart, depending on the crop species and growing conditions.  Several row opener types are used depending on soil type and local tradition. Grain drills are most often drawn by tractors, but can also be pulled by horses.  Pickup trucks are sometimes used, since little draft is required.

Open field  Open-field refers to the form of

sowing used historically in the agricultural context whereby fields  are prepared generically and left open, as the name suggests, before being sown directly with seed.  The seed is frequently left uncovered at the surface of the soil before germinating and therefore exposed to the prevailing climate and

 This is in contrast to theseedbed

 method used more commonly in domestic gardening or more specific (modern) agricultural scenarios where the seed is applied beneath the soil surface and monitored and manually tended frequently to ensure more successful growth rates and better yields.   

Plant nursery  nursery is a place where plants are 

propagated and grown to usable size.  There are retail nurseries which sell to the general public, wholesale nurseries which sell only to other nurseries and to commercial  landscape gardeners, and private nurseries which supply the needs of institutions or private estates.

Types of plants  Nurseries grow annuals, perennials,

and woody plants (trees and shrubs).  These have a variety of uses: decorative plants for  flower gardening and landscaping, garden  vegetable  plants, and agricultural  plants.

 Some nurseries specialize in one

phase of the process: propagation, growing out, or retail sale; or in one type of plant:  groundcovers, shade plants, fruit trees, or rock garden plants.

Methods  Nurseries often grow plants in a 

greenhouse, a building of glass or in plastic tunnels, designed to protect young plants from harsh weather (especially frost), while allowing access to light and ventilation.  Modern greenhouses allow automated control of temperature, ventilation and light and semiautomated watering and feeding.

 Some also have fold-back roofs to allow

"hardening-off" of plants without the need for manual transfer to outdoor beds.  Most nurseries remain highly labourintensive. Although some processes have been mechanised and automated, others have not. It remains highly unlikely that all plants treated in the same way at the same time will arrive at the same condition together, so plant care requires observation, judgement and manual dexterity; selection for sale requires comparison and judgement.

 Business is highly seasonal,

concentrated in spring and autumn.  There is no guarantee that there will be demand for the product - this will be affected by temperature, drought, cheaper foreign competition, fashion, etc.  A nursery carries these risks and fluctuations.

 Annuals are sold in trays (undivided

containers with multiple plants), flats (trays with built-in cells), peat pots, or plastic pots.  Perennials and woody plants are sold either in pots, bare-root or balled and burlaped and in a variety of sizes, from liners to mature trees.

 Balled and Burlap trees are dug either

by hand or by a loader that has a tree spade attachment on the front of the machine.  Although container grown woody plants are becoming more and more popular due to the versatility. B & B is still widely used throughout the industry.  Plants may be propagated by seeds, but often desirable cultivars are  propagated asexually by budding,  grafting, layering, or other nursery