Impact of bioc har on acid soils is far more profound than on alkaline soils. But it will be damn too interesting to know , biochar could play some roles in control of termites in  acid soils. Fantastic ..

Interesting research

Very few papers studied the effect of biochar on termites. The only paper I found that focused on your question  is"Spatial variation of soil macrofauna and nutrients in tropical agricultural systems influenced by historical charcoal production in South Nandi, Kenya", Kamau et al., 2017. Biochar don't seems to control termites.

Biochar is able to increase the pH but another technique can consist to re-use domestic ashes as a fertilizer, that also increase pH without the need to "spent" wood. In many countries, increase pH by biochar use is more expensive that by limestone application. Here in Brazil-where wood is available and cheap -,limestone costs less than 30$/T while biochar costs 100-200 $/T and limestone is much more efficient to increase soil pH that biochar.

In this case, I wouldn't advise to use biochar for the pH problem, but as Waqas think, the effect on termites should be studied: there is not enough information to answer your question.

Dear Raphael Anzalone,

Thanks for your interesting suggestion. In areas where plant biomass is high like western Ethiopia, biochar availability is not a problem. Lime is more scarce. The problem with biochar production may be its impact on forest. Termites were less common on soils containing high organic matter. Traditionally, farmers in Ethiopia adds ash to soil to protect termites. That is the assumption.

If biochar is available, biochar can be used to improve soil pH. In this case, biochar should be produced at temperature >500ºC. At that temperature, CaCO3 produced at low temperature transforms in CaO.

While CaCO3 will neutralize only one H+ :

CaCO3 + H2O --> Ca2+ + HCO3- + OH-   only 1 OH- produced;

CaO will neutralize two H+CaO + H2O --> Ca2+ + 2 OH-     two OH- produced

And what do you think to add bones to the material to be pyrolised to increase soil pH?

Yes. It seems the best choice in the given circumstances.

Dear Anzalone,

It is an interesting idea, but the issue is availability bones whenever and wherever required. Thank you very much, I will try that.

Hi Birhanu,

Please note that Raphael did not compare the proton balance at the same end point.

Biochar can increase nutrients in the cropping area only by supplementing the biomass from the cropping area, i.e. by adding nutrients from another source.  Whether that is bones or plant material, the process transfers nutrients into the cropping area.  This is fine if the supplementary feed stock would otherwise be disposed of as waste, e.g. urban green waste.  Otherwise you need to consider the effects on the source of the supplement. 

Paul.

Impact of bioc har on acid soils is far more profound than on alkaline soils. But it will be damn too interesting to know , biochar could play some roles in control of termites in  acid soils. Fantastic ..

Biochar is a very fundamental issue ! Helps both soils and human guts to attempt reaching neutral ph ! Sometimes it does not work well , but that is the motivation to perform tests and assays !

I wrote in my question that framers traditionally apply ash to control termites from gardens. What ingredients or chemicals, do you suggest, are there in the ash? 

I feel , its predominantly silica plus potassium and magnesium....Please have a look at enclosed PDFs...

The application of biochar will improve soil moiture status which may worsen the situation. 

Dear Pathania,

Do you meanapplication of biochar worsen termites infestation? I am dealing with termites problem during cropping period i.e. during summer season when moisture cintent is already too high. The area exhibits humid climate and contains highly weathered clay soil (remember the acidity vs high rainfall relations) with high water holding capacity. Thus, do you mean high moisture is the cause for termites infestation? If yes, we are going to conclude that there is little termite problem in drylands where I already observed very challenging termites. Please how?

Birhanu, what is that constituent of bio char that checks termites infestation , a common  pest problem of humid regions

I don't think, application of biochar will greater over-moist conditions where termites would be a problem  , especially in arid regions. In this region , it's waterlogging conditions because of impeded drainage plus presence of calcium carbonate indurated hardpan further accentuates the situation. Biochar will no way create any such situation, predisposing to termites infestation where rainfall is so low..

 Dear Dr. Anoop,

Biochar composition is highly heterogeneous, containing both stable and labile components. Carbon, volatile matter, mineral matter (ash) and moisture are its major constituents. Total carbon content in biochar was found to range between 172 to 905 g kg-1. By proportion, it contains 50-90% carbon, 0-40% volatile matter, 1-15% moisture and 0.5-5% ash for a variety of source materials and pyrolysis conditions. increasing temperature above the recommended range to obtain more active charcoal will automatically increases the ash content. Biochar can be of three types based on my research interest.

(a) those with high carbon and low ash content (containing activated carbon)

(b) those having medium carbon and ash content

(c) those having low carbon but high ash content

Choose among those three types depends on the predefined objective. Dr. Anoop, we need to remember again the traditional wisdom of using ash to check termites in the garden by our farmers.

I am waiting for Dr. Anoop's suggestion.

Hi Birhanu: we did a small work in Uganda and also in western Ethiopia-Wolega ( diga). The whole problem is much related to organic matter management.Termite damage to grasses on grazing land and conserved fodder is one of the major challenges in the maize system of Diga. Discussion with farmers shows that the problem is serious during the dry season. Experiences of CPWF research, in the cattle corridor of Uganda, show that termite infestation could be an indication of ecosystem degradation and scarcity of biomass resources. It would also be interesting to understand why these problems are associated with soil moisture dynamics  . Chomo grass is also found to reduce termite infestation  and check the link below.  http://hdl.handle.net/10568/33570.. what ever evidence is available if you want to manage termite in natural way just improve the organic matter contents of these soils... hope this helps...

Dear Dr. Amare 

If so, as biochar contains substantial quantity of carbon, it could be another option. Why I focused on biochar is because of another issue i.e. soil acidity. You know the saying "hitting two birds with one stone". That means checking termites while amending soil acidity.

From my recent observation (a year ago) in Diga area, there is a practice of crop residue burning. I think the farmers are doing this by the advises of extension workers for the purpose of crop protection. As a result the soils in most farms are sealed and had very low  water infiltration. First, this practice should stop. If crop protection is an issue, the farmers can be advised to make compost  from the residues.  Biochar is a better option I think. It  stays longer (I am not sure if it resists termite though), improves the soil structural formation and thereby infiltration. 

On the other hand, as mentioned above, may be termites are destroying crops because they get nothing on the ground other than the crops themselves.  Therefore, partly it is about OM management as indicated by Dr. Amare.  Give it a try and let us learn all. Thanks for bringing the issue here.    

Birhanu and other colleagues , so sorry for  my delayed response. Infact , biochar ,has higher amount of silica and potassium , combined together could offer some resistance to termites dont prefer , with the result , their population might not be assuming an alarming proportion . This is simply my assumption based on the observation that biochar treated soils had lesser infestation of termites...And  its so interesting observation indeed...

Dear colleagues, is there any research finding on plant materials best suited for biochar production?

Dr. Amare reckoned one interesting issue.. about Chamo grass that is used to check termites. Dr. Amare,

The link you put for Chamo grass did not open. Please would you elaborate some points on this important grass please. How it works? What makes it so unique plant to control termites?

In addition to the above discussion points, I need input from some body who comes across application rate of biochar in highly degraded acid soils?

No response for the latest questions my colleagues?

Birhanu, usual rate of application of biochar varies from 2- 50 tons/ha , very high rate thereby affected economics of crop production.

Whole range of crops have been reported to be benefited by biochar application from field crops to perennial fruit crops including vegetables.. 

Dr. Anoop, the range of application rate is too wide. I think this application rate is also another issue unsolved well for biochar.

Apart from biochar, what are the biological measures used to control termites? For instance, Dr. Amare has mentioned one plant (Chamo grass).

Import a lot of anteaters from different parts of the country and release them in the affected area. That is an ultimate solution. Do not waste money on chemicals, that has been tried many times and failed.

Crop residue burning should never be encouraged , regardless of any magnitude of benefit , so claimed . Surely biochar is a better option, since it provides the most recalcitrant form of carbon to stay back in soil and contribute handsomely towards build up of non-labile fraction of soil SOC.

I agree with you Birhanu , recommendation is highly varying and doses are so high , some concrete efforts are needed to cut down these doses to a manageable limits...

Dear Gunte, the problem of this termites is that they eat root of the whole crop biomass in the soil. You do not see the termites. You observe only gradual wilting and drying of crops before maturity. But what are these anteaters?

I am highly motivated to know biological termite control measures especially plants that check termites.

Hi Birhanu,

I am not aware of the presence of plant based control for termites. But there are animals which feed on termites and ants. In my discussions I had with farmers in west Wollega a couple of years back, I was informed that there was an animal which feeds on ants and termites. According to my sources, some decades back termites were not big problems as they are today. I think, the animal is a mammal species suborder Vermilingua. It has its own name in Oromifa, which I forgot now.

However, there is a tradition in the area which says "if a young man kills that animal, he gets some kind of luck" that resulted in mass killings and elimination of the animals. But again, you can find some remnants in some areas. Protecting and reinstating these animals therefore, may help to solve the problem. It is an indigenous solution.

Good point Aweke, using the information let me discuss with farmers. I raised the issue of termite check using plants based on recommendation given by Dr. Amare that Chamo grass as a useful option.

Check for Desho grass (Pennisetum pedicellatum) too. ILRI with other CGIAR centers were popularizing it through the humid tropics project in Diga area. It is a very good feed resource for mid and high altitude regions of Ethiopia.

Thank you Aweke, we have got Desho grass. Currently, we are multiplying it. We are using it as SWC measure. It grows in the area vigorously.

Hi Berhanu, I know the problem and I have been involved in the termite control project. I visited many of the affected areas. I think we need to be open to a combination of control measures. An eaters could be a good natural control measure. You may need the help of NRM people on this.

Do you think, biochar indirectly helps the labile portion of soil organic carbon to be retained for relatively long period of time?

I mean the effect of biochar in improving soil aggregation then protecting the labile organic matter from microbial attack.

As biochar is resistant to microbial decomposition, it helps to protect the labile fraction of SOM by forming aggregates that protect the labile portions. As a result, it is highly recommended for agricultural soils. If compost is added in combination with biochar, it forms the most sustainable and suitable organic manures.

Yes Birhanu, well said

Based on our recent works on acid soils of pH as low as 2, organic matter addition will help increase the soil. What will addition of organic matter do to termite infestation am not sure but termites would probably like a moist to damp soil condition. If that was the case, addition of organic matter creates a micro niche in which moisture begins to develop, in part due to microbial respiration and in part oxidation of the organic matter itself, this will attract the termites to build up. One way would be to expose the area infested with termites to air before adding the organic matter. If infestation happens after the OM addition, would be a bigger problem because ones intention was to counter soil acidity.

Dr. Patrick, you raised important points. The hypothesis set is that the ash in the biochar is used to check termites. If there is termite infestation in your area, please add an ash and see the result. So, use a highly pyrolised biochar and let do together. Obviously, the labile portions of SOM such as residues cannot check termites rather it is a good source of food

Birhanu, there is something , in addition to silica , not used by termites as their preferred diet. And termites feel starved of food to multiply, it's just an assumption...

Biochar is made up of two portions:

· The “mobile” portion that will dissolve (leach) into the soil water and

· The “resident” portion that will remain as a stable part of the non leachable soil matrix.

Each portion contains both organic and inorganic fractions

(A) Mobile Portions

The mobile portion of biochar-the portion that can move in water or be rapidly decomposed by microbes-contains both organic and inorganic parts.

📷 Mobile organic portion of biochar

The function of the mobile organic portion is fairly straightforward: it will be a source of dissolved OC and will also be available organic matter for soil microbes. In this regard, the biochar acts like many other sources of degradable soil carbon, such as compost and naturally deposited detritus. The leachable and biodegradable organic portions of the biochar are metabolized by the microbes in the soil.

📷 Mobile inorganic portions of biochar

The inorganic portion of biochar is transformed into ash after the biochar is burned or heated at high temperature to oxidize and remove the organic portion (which includes the carbon atoms of the char). Measurements have shown that most biochar ash is soluble in water. The mobile inorganic portion of biochar may include fertilizers, such as phosphorus and potassium, and other components that have a liming effect on the soil (raise its pH). Generally, these inorganic constituents have the potential to improve soil fertility and crop yield in places where the specific nutrients are limiting and higher pH levels in the soil are desirable.

(B) Resident portion

The resident portion of biochar that stays within the soil matrix also contains both organic and inorganic parts.

• Resident inorganic portion

Some plants convert dissolved minerals into stable insoluble forms, such as silica (silicon dioxide). This non-leachable component of biochar ash is a minor constituent of the biochar, and is typically inert or slowly dissolved and re-posited into soil aggregates over time. Carbon can be locked up in these silica structures, and they have been proposed as making a significant contribution to long-term carbon sequestration.

• Resident organic Portion

The most fascinating and unique fraction of biochar is the organic portion that becomes a permanent soil component. This portion can also be described as “recalcitrant” and insoluble (non-leachable). It appears to be degraded by both non-biological and biological processes over a very long time scale. The bulk of biochar remains substantially unchanged, yet enables improvements in the overall environment that the soil provides for the plants and microbes that live in it.

Here, I want to show that biochar contains silica and ash. Other constituents of biochar that you think termites may dislike?

Birhanu, this was my first reaction, if you remember my post. Silica is no longer a prefered diet for termites ...

Dear colleagues, I am digging the constituents of ash.

Wood ash contains all macro and micro nutrients except N and S in proportions relatively close the proportions found in the biomass fuel. Along with oxygen, the major components of wood ash are calcium (Ca), potassium (K), magnesium (Mg), silicon (Si) and phosphorus (P). Thus, much wood ash contains calcium carbonate as its major component, representing 25 or even 45%. Less than 10% is potash. Ash is generally very low in nitrogen (N) because it is vaporised during combustion and considerable part of the sulphur (S) may also be lost. Trace elements found in ash include As, Ba, B, Cd, Cu, Cr, Ag, Mo, Hg, Ni, V and Zn, of which B, Cu, Mo and Zn can also be regarded as micronutrients.

Wood ash has a liming effect of between 8 and 90% of the total neutralizing power of lime, and can increase plant growth up to 45% over traditional limestone.

What is the benefit of biochar over lime application to agricultural soils?

That's quite interesting. But I feel, biochar will have distinct edge over like since former provides most recalcitrant form of carbon to degraded acid soils...

Exactly Dr. Anoop, biochar provides recalcitrant form of carbon that maintains soil health for a long period of time. Besides, biochar supplies many nutrients in addition to Ca and Mg that we get from lime.

In acidic soils, crop productivity is mostly constrained by aluminum and Iron toxicity, phosphorus deficiency and other acidity related fertility problems. Incorporation of biochar increased the soil pH from acidic soil and account sharp reduction in the concentration of the exchangeable Al3+ ions. Besides the soil pH, significant increased the base cations with incorporation of biochar. The conversion of organic waste to produce biochar using the pyrolysis process is one viable option that can enhance the carbon sequestration in the soil and reduce the farm waste and improve the soil quality. Thus, the use of biochar would be suitable for management of moderate to highly acidic soils.

• Article Ameliorating Effects of Leucaena Biochar on Soil Acidity and...

Dear friends, what is meant by the statement:

"Biochar application increased the solubility and leaching of anionic trace elements and caused elevated anionic trace element concentrations in plants, but decreased cationic trace element concentrations in plants".

Dear colleagues, when we apply biochar to a soil, it is about adding organic colloids to the soil. Organic colloids are dominated by negatively charged surfaces that repel opposite charged ions. The negatively charged surfaces on organic colloids repel anionic elements making them vulnerable to solublization and leaching. Solublized ions are very suitable for plants to uptake than ions retained on soil colloids. However, cations are attracted towards organic colloids and resist leaching loss and uptake by plants.

Does this mean "biochar is more useful in cleaning (remediation) of the environment from cationic trace elements?"

In case of plant nutrients, however, addition of more biochar means:

(a) Supply wide range of nutrients to the soil

(b) Giving more chance to the soil by retaining cationic nutrients (preventing leaching loss)

Nice feedback Birhanu. Th every procedural steps involved in cation exchange or anion exchange capacity of biochar do not vary much compared to typical clays , however the source of origin of these charges could be different ...

Yes Dr. Anoop, the process is same. Charge on soil colloids may depend on source of charge. Releasing or accepting H+ ions can provide either –ve or +ve charges). The isomorphic substitution in some clay structures is also another source of charge. Under moderate to extreme acid soil conditions, some silicate clays and Fe, Al oxides may exhibit net positive charges (e.g. kaolinite, organic colloids, allophane).

Researchers have pointed out positive effects of biochar on soil remediation due to its adsorption of pesticides or metals. This adsorption is related to charge dominated on the surface of biochar.

Yes Birhanu, very much so...

Bre! Rely, it is an interesting issue specially for areas with termite problem. We have to take in to account our farmers indigenous knowledge. There is something behind the secret why farmers in Western Ethiopia add ash to control termites. We scholars have to prove or disprove our farmers assumption. I have found a little information regarding the effects of bio-char on termites. Let we examine the effect of bio-chars (of different feed stocks, pyrolysis temperature, application time and method....etc ) on termites

Hi Kedir, I am happy to work with you. We have already started something.

Biochar is good source of nutrients but problems of biochar how much used regarding the quantity. I am also congrats to you and your team if prepare biochar through rice/paddy straw with out any pollution.

Dear Dr. Yaduvanshi, you are right. The application rate for biochar is not clearly defined. How to estimate the rate is another point to be dealt. What is benefit of using rice/straw for biochar preparation?

Animal manures have high contents of labile organic and inorganic compounds, resulting in biochars with high ash content.

Future control prospects for termites

Nature has a profusion of plants for use in crop protection, a potential which deserves man's interest. In natural crop protection, nature s own instruments, are applied. Even though they often are regarded as old fashioned they can contribute to an appropriate pest management, especially when considering the possible risks for farmers, consumers and the environment. In view of the above, it is suggested that future termite control programmes should make maximum use of natural products. Some of these natural products include the following:

(1) Wood ash. Ash is suitable material for use by small-scale farmers. It may be just as effective as chemical pesticides, but has the great advantage that it is harmless to health and cheap. Farmers need only to make the necessary provisions to collect the ash from their cooking fires.

(2) Cow dung spray. In Monze district, some farmers use fresh cow dung to spray in their maize fields. Probable the strong smell deters the termites form attacking the maize.

(3) Green manure crops/grass (organic matter). While the plants are green, they are ploughed into the soil. This increases the content of organic matter in the soil, thereby improving the preservation of moisture. Moisture plus organic matter attract the termites and prevent them from attacking the target crop. This method is most effective when the crop is still in the green stage.

(4) Cattle melon. In Southern Province of Zambia (Kalomo district), farmers use water extract of cattle melon to spray on their field. This concoction has a repellent effect on termites.

(5) Tephrosia vogelii. Preliminary research results at the National Council of Scientific Research and Kasisi Mission showed that extracts form this plant produced a significantly increased mortality of termites and stemborers (Kaposhi and Lesseps, pers. comm). T. vogelii is a perennial plant and occurs widely in Central, Northern and Luapula provinces. The plant can easily be grown under nursery conditions.

Very useful information.

Nobody has said what termite is causing the problem. Hodotermitidae (Harvester termites), Rhinotermitidae (Subterranean termites) , Termitidae (Apicotermitinae (Soldierless termites), Macrotermitinae (Mound-building termites), Nasutitermitinae (Nasute termites) , or Termitinae). Pangolins, aardvarks, and aardwolves are termite feeders but are rare if not endangered and their digging for termites may cause intolerable damage to the crops. Various ant species tend to be the most effective termite predators.

Dear colleagues,

Is their a relationship between termite infestation of soils and soil organic matter content?

Please also consider wood vinegar as a means to control the termites, by spraying on ground or so, and also to make the biochar amendment more effective by adding it to the biochar.