While solarisation, we expect changes in DOC, which will changes many of the soil physical properties like Soil aggregate stability , aggregate size, AWC rtf, in addition to other soil chemical and biological properties as we discussed previously...

In fact we were looking at , how to arrive at critical time of exposure of soil to different solarisation treatments ...

Dear Sir,

Please have a look at these PDF attachments.

Good luck

Hello friend,

 The effect of soil sterilisation on soil physical and chemical properties depends upon the nature of the sterilisation. So what sort of sterilisation you are planning for?

Have a good day

Soil solarization increases the soil temperature by 50 to 80 C depending upon the average daily temperature and thickness of the polythene sheet. There are significant effects on soil microbial population and function, consequently altering the soil organic matter, as had been reported in  literature, few rightly provided by Arvind Singh. Consequently, the effect would be on chemical properties, but may not be on physical properties as the treatment is given for a shorter period.

Changes in physical soil properties is time requiring aspect while chemical changes take place over a short time treatment. However, certain chemical changes could help decrease or increase the rate of physical changes. Thus the context of treatment of soils must be kept in mind.

Dear Abdul sir,

  As you have clearly said that method of soil solarization is important for affecting the soil properties. Can you comprehend about the different soil solarization techniques available?

Have a good day

To solarize your soil, general method is:

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.

Soil solarization works best on heavy soils—those containing clay, loam, or mixtures of them.

 However, because solarization kills all organisms—even the beneficial ones—farmers and gardeners should replace the beneficial organisms by adding compost to soil after it has been solarized.

 Pl. Consult

(!) Wayne Schmidt's Solarization Page at http://www.waynesthisandthat.com/solarization.htm

(2)  Soil Solarization: A Nonpesticidal Method for Controlling Diseases, Nematodes, and Weeds at vhttp://vric.ucdavis.edu/pdf/soil_solarization.pdf

Soil solarization is a procedure used for controlling a wide spectrum of soilborne pathogens and weeds . It is achieved by mulching tilled and irrigated soil with transparent polyethylene sheeting. The soil is heated by the solar irradiation, and many soilborne pests are killed due to physical and biological processes. Soil mulching can be done with separate plastic film strips , or alternatively with a continuous film covering on the whole plot applied either manually or by laying separate strips which are melded together, depending on the technology available .

Soil solarization is a natural, hydrothermal process of disinfesting soil of plant pests that is accomplished through passive solar heating. Solarization occurs through a combination of physical, chemical, and biological mechanisms, and is compatible with many other disinfestation methods to provide integrated pest management. Commercially, it is used on a relatively small scale worldwide as a substitute for synthetic chemical toxicants, but its use is increasing as methyl bromide, the major chemical fumigant, is phased out due to its ozone-depleting properties. Solarization currently is an important and widespread practice for home gardeners. In production agriculture, the principal use of solarization (on a treated area basis), is probably in conjunction with greenhouse growncrops. Another application for which solarization has come into common use is for disinfestation of seedbeds, containerized planting media, and cold-frames. Around the world, solarization for disinfesting soil in open "elds is being implemented at a relatively slow but increasing rate. It has been mainly used for commercial production in areas where air temperatures are very high during the summer and much of the cropland is rotated out of production due to excessive heat. As global concerns regarding environmental quality grow along with the human population in the 21st century, concepts such as solarization and other uses of solar energy in agriculture will likely become increasingly important.

Effect on physical properties: Properties like  soil moisture and humidity at the soil/tarp interface,  soil  color and tilth, . 

Effect on chemical properties: Thermal decomposition -induced changes in availability of nutrients like P, Ca, Mg, K , but nitrates go down..

Effect on biological properties: Most pronounced effect  is seen on biological properties like counts on Pseudomonas , Bacillus, Trichoderma increase due re-colonization of different soil microbial communities and shifts in their biological equilibrium. But , most of the pathogenic microbes disappear , with inconsistent effect on beneficial microbes , depending upon the solarisation conditions 

I do not agreed with the answer given by Nilay Borah as he mentioned that soil solarization may not altered the physical properties of soil if given for short period. Changing of soil temperature from 5-80 C is not possible through short solarization process rather takes longer duration. This much variation in soil temperature changes physical properties such as infiltration rate, hydraulic conductivity, soil respiration rate, water holding capacity etc. remarkably. As whole soil solarization effects all kind of soil properties in different magnitude depending on duration of soil solarization.

Good points Dr Veer Singh . If solarisation is really effective , it will surely bring distinct changes different soil properties of varied nature comprising soil physics , soil chemistry , and soil ecology/biology /biochemistry...  

More valid question arises, how will you ensure , solarisation is really effective..? What parameters shall we use to define the effective solarisation..?

Respected sir

Soil solarisation bring distinct changes in soil physical, chemical as well as biological properties of soil has been proven by different experiment conducted by various institutions. Sir this is a good topic for research, I will waiting for your findings.

Thank you sir

Dear Mohammed Fayyadh Sir,

Intially you asked the question that " does soil sterilization change physical and chemical properties of soil?" Therefore I and Suresh Ramanan Sunderam have answered taking soil sterilization into account. I don't know when and why you have replaced the word sterilization with solarization? Still the word sterilization exist in the other line of the question. 

I fully agree with detail answer by Dr. Anoop Kumar Srivastava Sir. Please have a look at these useful PDF attachments also dealing with effects of soil solarization on physical, chemical and biological properties of the soil.

Regards

Views and observations by Dr Veer Singh Sir are appreciated. The points mentioned by Dr Abdul Ghafoor Sir may kindly be noted. Since solarization significantly reduces population and also function of beneficial soil microorganisms, it's obvious that decomposition and build up of soil organic matter would be affected. Except few, most soil physical properties (HC, WHC etc) are influenced by close interaction of clay and SOM. Thus, physical properties too would be affected, but the magnitude is not up to that of chemical and biological properties. Answer by Dr Anoop Sir may be seen, properties like soil colour, soil moisture are instantly affected following soil solarization. Secondly, the point regarding soil temperature change in short term treatment was not clear. Even if the soil is covered for one day, that much variation had been observed in day time soil temperature, which falls during night time. Anyway thanks for the interaction.

Very good response Dr Nilay. I feel , the net impact of solarisation on the changes in different soil properties  is more dependent upon the  atmospheric temperature , which guides the temperature to be realised inside the solarisation unit . If this is not the case , why do we recommend solarisation to be done preferably  during summer months ..?

Dear all.

my project for soil solarization,so i apologize for the word sterilization .

great Thank for all 

Our experience in arid soils are,  soil solarisation by using polythene sheets increased the temperature between 8 and 14 degree Celsius. The effect on physical and chemical soil properties due to solanisation are:

1. Increased concentration of NO3 and NH4 nitrogen almost by 2 folds.

2. Increased the concentration of P, Ca and Mg (5 to 28%)

3. Increase soil EC almost by 30%

4. Does not affect the available K, Fe , Mn and Cu

5. Does not change soil pH and organic matter content

6. Change in soil moisture status ( depends on time of solarisation)

Soil solarization: a non-chemical approach for management of plant pathogens and pests

ABSTRACT. Soil solarization is a special mulching process which causes hydrothermal disinfestation and other physical and biological changes in soil which are beneficial to plant health and growth. Plastic film laid over moist soil during periods of high air temperature, usually for l-2 months, can greatly reduce or eradicate a number of pathogens and pests including fungi, bacteria, nematodes,arthropods and weeds. Following soil solarization, growth of microflora beneficial to plant growth or antagonistic to pathogens and pests may slow the reinfestation of soil by these organisms for more than one growing season. Increased plant growth and yield of annual and perennial field, row, and nursery crops usually occur following soil solarization. In addition, the availability of increased mineral nutrients following solarization may reduce crop fertilization requirements. Soil solarization has been effective as a pre-plant and as a post-plant treatment, and has been compatible with chemical soil treatments and also biological soil amendments after solarization. Soil solarization is a significant advance in the non-chemical control of many pathogens and pests. Source ;CROP PROTECTION (1986) 5 (3), 190-198 , PDF enclosed for further reading 

Certainly soil solarisation will impact soil chemical properties rather than physical properties

Infact , soil solarisation is practiced , never to bring any possible improvements  in any of the soil properties , physical , chemical or biological in nature. Its  a kind of mulching , primarily aimed to deactivate the load of the pathogenic microbes, but in the process , many of the beneficial microbes are also reduced. Therefore,  various aspects of soil solarisation as a techniques ,  must be standardized in a given climate and in a given season 

Dear Dr. Anoop

Thank you for your response ,but  i thank some  thermotolerant  or thermophiles fungi can be increased and my be this process  improve biological nature of soil.

Best regard

Dr Fayyadh , its a good point to look at , but  i dont think so, depending upon your objective of solarisation .  . For the simple reason , there could a possibility , only thermophiles will survive as an ultimate microbial load of the solarised soil, since the net effect of solarisation is a combined function of temperature and time of exposure. But , how effectively , those  thermophiles will later on contribute towards sustaining the the required biological properties of the soil vis-a-vis crop metabolism , would be an interesting preposition. ...

Interesting work , i thought , let me upload the PDF..

Soil solarization in various agricultural production systems

Soil solarization is a natural, hydrothermal process of disinfesting soil of plant pests that is accomplished through passive solar heating. Solarization occurs through a combination of physical, chemical, and biological mechanisms, and is compatible with many other disinfestation methods to provide integrated pest management. Commercially, it is used on a relatively small scale worldwide as a substitute for synthetic chemical toxicants, but its use is increasing as methyl bromide, the major chemical fumigant, is phased out due to its ozone-depleting properties. Solarization currently is an important and widespread practice for home gardeners. In production agriculture, the principal use of solarization (on a treated area basis), is probably in conjunction with greenhouse grown crops. Another application for which solarization has come into common use is for disinfestation of seedbeds, containerized planting media, and cold-frames. Around the world, solarization for disinfesting soil in open "elds is being implemented at a relatively slow but

increasing rate. It has been mainly used for commercial production in areas where air temperatures are very high during the summer and much of the cropland is rotated out of production due to excessive heat. As global concerns regarding environmental quality grow along with the human population in the 21st century, concepts such as solarization and other uses of solar energy in agriculture will

likely become increasingly important. Source ; Crop Protection 19 (2000) 837}841, PDF enclosed for further reading...

Thank you so much Dr.Srivastava

I agree to the "As global concerns regarding environmental quality grow along with the human population in the 21st century, concepts such as solarization and other uses of solar energy in agriculture will likely become increasingly important"  of Dr. James J. Stapleton. Of course we may realize late and slowly. Dr. Anoop Kumar Srivastava is fond of to dig out the hidden facts and papers which are backbone of research.

Thanks Dr Ghafoor, i equally admire your critical comments as well. Is it possible to screen out some thermophilic microbes at the end of the solarisation , but this cannot be taken as an index of improvement in biological properties of the solarised soil , Dr Fayyadh.

Dear Dr Srivastava

"In fact , soil solarisation is practiced , never to bring any possible improvements  in any of the soil properties , physical , chemical or biological in nature"

I contradict this statement. Soil solarisation certainly increases soil temperature. There are some research evidences indicating that an enhancement in soil temperature solublises soil phosphorus. 

Dear Ramesh , this issue, we have already debated. Its better to review the earlier discussion before giving such sweeping statement.I was responding to the remarks of Dr Fayyadh ( which could be a  possibility ), that there could be any possibility of improving biological properties of solarised soil in terms of possible survival of thermophillic microbes after solarisation .  I would , therefore , request you to please  go through the whole discussion . We have been practicing soil solarisation for production of disease free planting material of citrus over last 15 years ..

I agree with Dr. Srivastava. In Sindh province of Pakistan, Dr. Suleman Memon conducted field studies for several years to record/establish that native P availability (solubilization) increased during summer compared to that in winter (25-30 0C) from the same fields. Owing to very high temperatures during summer (45-54 0C), this increase was noticed which was of practical significance in calcareous soils where  around  > 90 % insoluble P resides as lime - P complexes.

Very useful feedback  Dr Ghafoor. It is very often questioned , we can do solarisation during any time of year , though best results accrue during summer months only. Can we take up solarisation , regardless of season..?

I am sure that there shall be no change in physical properties esp. soil texture and structure as this takes hundreds of years of metamorphism/sedimentation process to take place.However ,it shall be definitely having effect on chemical aspects by mobilising/immobilising of certain nutrients/elements by affecting microbial interactions and organic carbon esp of top 0-15 cm layer only.Beyond that changes might be of trivial in nature.

While solarisation, we expect changes in DOC, which will changes many of the soil physical properties like Soil aggregate stability , aggregate size, AWC rtf, in addition to other soil chemical and biological properties as we discussed previously...

In fact we were looking at , how to arrive at critical time of exposure of soil to different solarisation treatments ...

Dr. Srivastava, hot summer months are the ideal time. As our basic aim is to control soil borne pests by placing plastic sheets on moist soil, therefore, high ambient temperature is needed so that plastic sheets allow the suns radiant energy to be trapped in the soil, heating the upper levels. Moreover, solarization during the hot summer months can increase soil temperature to levels that kill many disease-causing organisms (pathogens), nematode, weed seed or seedlings. It has been reported, as well as our experience in the arid regions, that soil solarisation improves soil structure and increases the availability of N beside some other essential plant nutrients.

Thanks Dr Tarafdar. Many of the reports suggests that solarisation can be performed during any time of the year , since we need to create humidity -induced high temperature , regardless of what is the temperature outside the solarisation unit...

Dr.Srivastava, humidity you may create by applying irrigation on soil surface before covering with plastic sheets but high temperature and strong sun-shine is must. Therefore, one should prefer the months between April to June depends on the maximum sun-shine on that particular area.