In simplest terms soil sterilization consist in getting rid of the organisms harmful to plant growth or atleast, in reducing their numbers to a point where they are no longer of consequence without permanently eliminating or disturbing the balance of those organisms essenstial for fertility. Soil sterilization is indispensable to modern practice, not only because it ensures clean soil but because it provides better nutrition; indeed, it is the basis of the best nutrition. Basically it is treatment of soil of glasshouses , greenhouse and other horticultural soils in order to kill weed, seeds, plant disease organisms, and pests. Sterilisation is distinct from disinfection, sanitization and pasteurization in that sterilization kills, deactivates, or eliminates all forms of life and other biological agents. Example: Molya disease of wheat caused by Heterodera avenae White tip disease of rice caused by Aphelenchoides besseyi . Soil borne pathogens like Fusarium, Rhizoctonia, Sclerotia can be controlled by this.

1. COLLEGE OF AGRICULTURE,RAIPUR.
Presented To; Presented By;
Dr.(Mrs.) SONALI DEOLE SHEKH ALISHA
Dept. of Entomology M.Sc. Prev.(Ag.) Entomology
ENT-518
Techniques In Plant Protection
TOPIC:SOIL STERILIZATION
(SOIL SOLARIZATION)
SESSION 2018-19

2. SOIL STERILIZATION
 In simplest terms soil sterilization consist in getting
rid of the organisms harmful to plant growth or
atleast, in reducing their numbers to a point where
they are no longer of consequence without
permanently eliminating or disturbing the balance of those organisms
essenstial for fertility.
 Soil sterilization is indispensable to modern practice, not only
because it ensures clean soil but because it provides better
nutrition; indeed, it is the basis of the best nutrition.
 Basically it is treatment of soil of glasshouses , greenhouse and other horticultural
soils in order to kill weed, seeds, plant disease organisms, and pests.
 Sterilisation is distinct from disinfection, sanitization and pasteurization in that
sterilization kills, deactivates, or eliminates all forms of life and other biological
agents.
 Example: Molya disease of wheat caused by Heterodera avenae White tip disease
of rice caused by Aphelenchoides besseyi . Soil borne pathogens like Fusarium,
Rhizoctonia, Sclerotia can be controlled by this.

3. It creates ideal condition necessary for plant growth and
development in the soil.
The death of these micro organisms due to sterilization
helps to release certain nutrient to the plant such as
nitrate which increases plant growth.
Soil sterilization leads to high quality in marketing
produce.
Soil sterilization reduces the
population of micro organism that is
harmful to crop plant.
It helps to control disease outbreak
in the soil.

4. SOIL STERILIZATION
 Under this soil is sterilized in greenhouses or
polyhouses and also in nurseries by steam or hot water/air.
 Soil treated with hot water or steam at about 50°C – To inactivate
or kill majority of nematodes, some oomycetes fungi 60-70°C –
most of plant pathogenic fungi and bacteria 82°C – Most of weeds
and plant pathogenic bacteria and insects .
 Some heat tolerant weed seeds and virus like tobacco mosaic
virus are killed at near boiling point depend upon pressure.
 It causes their cell structure to physically degenerate .
 Sterilization can be achieved with one or more of the following:
heat, chemicals, irradiation, high pressure, and filtration.

5. SOIL SOLARIZATION
Soil solarization is an environmentally friendly method of using the sun’s
power to control pests such as bacteria, insects, and weeds in the soil. The
process involves covering the ground with a tarp, usually a transparent
polyethylene cover, to trap solar energy.
The sun heats the soil to temperatures that kill bacteria, fungi, insects,
nematodes, mites, weeds, and weed seeds.
To solarize your soil:
1. Clear the area of plants and debris.
2. Water the soil deeply until it is wet.
3. Cover the area with clear plastic (such as 1 to 4 mil painter’s plastic). Don’t
use white or black plastic; they don’t allow enough heat to get to the soil.
4. Bury the plastic edges in the soil to trap the heat.
5. Leave the plastic in place for at least 4 weeks in the hottest part of the
summer. 6. Remove the plastic

6. Soil solarization works best on heavy soils—those
containing clay, loam, or mixtures of them.
They can hold more water than can light soils, long
enough to produce steam every day.
Steam is needed to kill nematodes, weed seeds, and
insect eggs in the soil.
Solarization may be less effective on sandy soil, which
drains faster and produces less steam.
To maximize the benefit of
solarization in sandy soils, lay drip
irrigation lines under the clear plastic
cover and add water regularly.

7. Solarization
• The solarization period should be from four to six weeks during
the hottest part of the year.
• The longer the soil is exposed to the heat generated by the
solarization process, the greater the kill of undesirable
organisms will be.
• Be sure to restrict the movement of pets across the
polyethylene film.
• Dogs especially will leave holes in the film and allow heat to
dissipate from beneath the film.
• Periodically inspect the film and repair any tears with tape.
• Add water, if needed, during the treatment period without
disturbing the film.

8. Principles of soil solarization
The principles of soil solarization are summarized as follows:
1.Solarization heats the soil through repeated daily cycles. At increasing soil
depths, maximal temperatures decrease, are reached later in the day, and
are maintained for longer periods
Figure 1. The daily course of soil heating by polyethylene at three soil
depths, as compared to nonsolarized (no mulch) soil at a depth of 10 cm.
Typical results obtained during July–August in Rehovot, Israel.

9. 2.The best time for soil mulching, i.e., when climatic conditions are most
favorable, can be determined experimentally by tarping the soil and
measuring the temperatures. Meteorological data from previous years
and predictive models further aid in this task;
3.Adequate soil moisture during solarization is crucial to increase the
thermal sensitivity of the target organisms, improve heat conduction in
the soil, and enable biological activity during solarization. The soil can
be moistened by a single irrigation shortly before tarping. Additional
irrigation during solarization via drip system or furrow irrigation is
usually not necessary, except for very light soils; in addition to which it
may reduce soil temperatures unless carried out during the night;

10. 4.Proper preparation of a soil ready for
planting is essential. This is the case
because, after plastic removal, the soil
should be disturbed as little as possible
to
avoid recontamination;
5.The soil is mulched with thin, transparent polyethylene sheets or other
plastic material. Another method of solarization involves a closed glasshouse
(or plastic house), provided climatic conditions are suitable and the soil is
kept wet. Novel technologies such as the use of sprayable plastics can
replace plastic mulching of the soil;
6.Successful pathogen control in various regions of the world is usually
obtained within 20–60 days of solarization. Extending the solarization period
enables control in deeper soil layers, as well as of pathogens that are less
sensitive to heat;
7.Solarization causes chemical, physical, and biological changes in the soil
that affect pest control, plant growth, and yield.

11. Procedure
Site selection and preparation
• Solarization can be applied to entire areas (gardens) or to linear rows
(beds) that will be cropped using plasticulture techniques.
• Shady areas should be avoided because temperatures likely will not
reach lethal levels. The area to be treated should be well tilled and free
of clods and crop debris.
• Tillage is best applied with a rototiller, but hand spading and raking are
also effective. Because wet soil conducts heat better than dry soil, the
soil should be thoroughly watered to a depth of 12 inches. This can be
done before or after the film is applied.
• Soaker hose or drip irrigation, installed under the film, can be used to
irrigate the soil after application of the film is complete.
• Water then can be added if needed during the solarization period.

12. Film selection and application
• Clear polyethylene film of various thicknesses (0.5 to 4 ml) should be used.
These can be obtained from home improvement stores, hardware stores,
garden centers, or in bulk rolls from agricultural suppliers.
• Agricultural films for commercial application are often treated with
ultraviolet (uv) inhibitors to delay film breakdown.
• Colored films should not be used for solarization because they do not
transmit solar radiation, but rather reflect or absorb it, thus diminishing soil
heating. Thinner (0.5 to 1 mil) films conduct more heat, but are more
susceptible to tearing and have a shorter life than thicker films.
• The film should be applied as tightly as possible to the soils surface to
minimize air gaps and potential damage from wind.
• The film should be firmly anchored by burying the edges in trenches dug by
hand when treating gardens and small plots ,or during bed shaping and
film application when using plasticulture.
• In the treatment of linear rows (beds) using
plasticulture, beds are formed and the film
and drip tape are applied simultaneously

13. a.Preparation of site b.Level the soil
c.Irrigate d.Cover with film and lay the urp

14. ADVANCEMENTIN SOIL SOLARIZATION
India is a country of 29 states and consist of humid and arid
climatic condition in most of the states.
As this strilization technique can easily be used in those areas
where there is hot and arid climates,and have direct contact of
sunlight.
For advancement of this technique research is going on. An article
THE ROLE OF SOIL SOLARIZATION IN INDIA:HOW AN
UNNOTICED PRACTICE COULD SUPPORT PEST CONTROL
was published on sep 2017,in which it is mentioned that trials were
conducted in 15 states of india to launch this soil sterilization as an
approach to overcome conventional treatment that is chemical
usage in plants.
As these chemicals have made a huge agricultural pollution and
ruined the originality of soil properties.
Apart from that the plastic we use for tarping soil is made of
polyethylene which is also harmful for environment,so to overcome
this biodegradable plastics were suggested.

15. BENEFITS AND LIMITATIONS
soil solarization has advantages and limitations.
It is a nonchemical method with less drastic effects on the biotic
and abiotic components of the soil; it is simple (and is therefore
suitable for both developing and developed countries); and it is
frequently less expensive than chemical soil disinfestation.
The limitations of this method stem from its dependence on
climate and it can therefore be used only in certain climatic
regions and during limited periods of the year. In addition, during
solarization, the soil remains without a crop for several weeks.
Nevertheless, this method has attracted many researchers in
more than 60 countries and it is used by farmers, especially in
combination with other methods.
SOURCE: SOIL STERILIZATION by W. J. C. LAWRENCE O.B.E., V.M.I:l.
Head of Department of Physiology and Plant Culture, John Innes HortlculturalIlistitutioll. Hertford.
WEED SCIENCES BASICS AND APPLICATIONS BY T.K.DAS

16. THANK YOU