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Capturing carbon in our soils December 12th, 2021 by

Nederlandse versie hieronder

Participants at the recent climate summit in Glasgow (COP26) spent considerable energy discussing about ways to further reduce carbon emissions and improve regulation of carbon markets. For the first time in history, fossil fuels have been officially recognised as the main cause of heating our planet. While investments in renewable energy have been long overdue, agriculture continues to be a net polluter and contributor to greenhouse gas (GHG) emissions. Yet, with some relatively modest investment agriculture could even become a net absorber of GHGs.

Few people realise that more carbon can be captured by soils than what is stored in the wood of trees. So, paying attention to what we do with our soils is as important as protecting our forests.

A high level of organic matter is the main indicator of soil health, determining the level of resilience of farms to cope with the effects of disruption in the climate. Carbon-rich soils are essential to secure future food production, because carbon feeds soil microorganisms and helps soils to retain water and nutrients, which are all essential for growing plants.

Adding compost to soils is one common way of enriching the soil with carbon. When plants die and decompose, the living organisms of the soil, such as bacteria, fungi or earthworms, transform the plants into forms of organic matter that the earth can absorb. But also living plants transfer lots of carbon from the air to the soil in a remarkable way. In the daytime, plants absorb carbon dioxide (CO2) from the air through the pores of their leaves. During photosynthesis, plants use water and sunlight to turn the carbon into leaves, stems, seeds and roots. However, as one third of the CO2 captured is released as sugars by plant roots to the soil, one may wonder why the plants are “leaking”.

Plants, like all living creatures, cannot live in isolation; they need others to survive. The liquid sugars released by plant roots are part of a symbiotic relationship between mycorrhizal fungi and 90% of all plants, an arrangement that has developed over the past 420 million years. In fact, plants cannot survive without these soil fungi and vice versa.

Mycorrhizal fungi cannot live without a host plant and, in exchange for the plant’s sugar, the fungi will absorb and transport nutrients and water back to its host.  For every cubic meter of soil, these fungi will send out as much as 20,000 km of fungal threads, also called hyphae, so that they infiltrate every area of soil.  Fungi can access nutrients and water unavailable to the larger plant roots.

Fungi can also use their acids to release nutrients from soils and even rocks — transforming rock minerals into formats that the plant can use. The complexity of interactions between plants and soil organisms goes even further. Certain nutrients can only be extracted from soils by bacteria and fungi will exchange sugar for the nutrients requested by the plant in a complex symbiotic exchange.

Studies have shown that soils under mature, perennial crops contain more available nutrients than soils treated with agricultural chemicals, which kill soil microbes, resulting in the net loss of soil carbon. Policies that promote agroecology, regenerative farming and organic agriculture are therefore directly contributing to soil carbon sequestration and hence help to fight against climate change. But more can be done.

It has long been thought that most of the soil carbon was contained in the top 30 centimetres of the soil in the form of the organic matter in humus. In 1996, Dr. Sara Wright discovered in the USA that soils contain large amounts of carbon up to more than a meter deep. Carbon is stored in the form of glomalin, a highly persistent protein produced by mycorrhizal fungi. As the mycorrhizal fungi go deeper into the soil to mine nutrients and water for the plant, they deposit more and more carbon in the form of glomalin. The more mature this relationship is between plant and microbe the more volume of soil is accessed on behalf of the plant and the better the crop will produce and be able to cope with harsh weather conditions.

Ploughing destroys soil organic matter by oxidation and releases much of the carbon stored in the top soil as CO2, which finds its way to the atmosphere. Ploughing also depletes the micro-organisms in the soil. Reduced tillage and ensuring more permanent soil coverage by plants is therefore crucial to build up a healthy soil life and keep carbon stored in the soil.

Permanent pasture soils with healthy microbial life have been increasing the amount of carbon that they sequester beneath the grasses each year. Practices such as agroforestry and establishing field hedges are other low-cost strategies that can help turn the tide of our warming planet.

In fact, an annual increase of soil organic carbon by 0.4% would neutralise the human-caused emissions of CO2 into the atmosphere. This scientific insight was at the basis of the “4 per 1000” initiative to which many governments, research institutes, civil society and companies already subscribed during the climate summit in Paris in 2015. While the European Green Deal has set a target to be climate-neutral by 2050, the increasing natural calamities we witness year after year shows us that we have no more time to lose.

Illustration credit

Mycorrhiza by Nefronus, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=80931388

Read more

The Liquid Carbon Pathway (LCP): http://www.carbon-drawdown.com/liquid-carbon-pathway.html

The 4 per 1000 Initiative: https://www.4p1000.org/

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Inspiring knowledge platforms

Access Agriculture: https://www.accessagriculture.org is a specialised video platform with freely downloadable farmer training videos on ecological farming with a focus on the Global South.

EcoAgtube: https://www.ecoagtube.org is the alternative to Youtube where anyone from across the globe can upload their own videos related to ecological farming and circular economy.


Koolstof vastleggen in onze bodem

Deelnemers aan de recente klimaattop in Glasgow (COP26) besteedden veel energie aan het bespreken van manieren om de koolstofemissies verder te verminderen en de regulering van koolstofmarkten te verbeteren. Voor het eerst in de geschiedenis zijn fossiele brandstoffen officieel erkend als de belangrijkste oorzaak van de opwarming van onze planeet. Hoewel investeringen in hernieuwbare energie al lang op zich lieten wachten, blijft de landbouw een netto vervuiler en bijdrager aan de uitstoot van broeikasgassen (BKG). Maar met relatief bescheiden investeringen zou de landbouw zelfs een netto absorbeerder van broeikasgassen kunnen worden.

Weinig mensen realiseren zich dat er meer koolstof door de bodem kan worden vastgelegd dan er in het hout van bomen wordt opgeslagen. Aandacht besteden aan wat we met onze bodem doen, is dus net zo belangrijk als het beschermen van onze bossen.

Een hoog gehalte aan organische stof is de belangrijkste indicator voor de gezondheid van de bodem en bepaalt de mate van veerkracht van bedrijven om de effecten van verstoringen in het klimaat het hoofd te bieden. Koolstofrijke bodems zijn essentieel om de toekomstige voedselproductie veilig te stellen, omdat koolstof de bodemmicro-organismen voedt en de bodem helpt om water en voedingsstoffen vast te houden, die allemaal essentieel zijn voor het kweken van planten.

Het toevoegen van compost aan de bodem is een veelgebruikte manier om de bodem met koolstof te verrijken. Wanneer planten afsterven en uiteenvallen, transformeren de levende organismen van de bodem, zoals bacteriën, schimmels en regenwormen, ze in vormen van organisch materiaal dat de aarde kan opnemen. Maar ook levende planten brengen op opmerkelijke wijze veel koolstof uit de lucht naar de bodem. Overdag nemen planten koolstofdioxide (CO2) op uit de lucht via de poriën van hun bladeren. Tijdens de fotosynthese gebruiken planten water en zonlicht om de koolstof om te zetten in bladeren, stengels en wortels. Echter, aangezien een derde van de opgevangen CO2 als suikers door plantenwortels aan de bodem wordt afgegeven, kan men zich afvragen waarom de planten “lekken”.

Planten, zoals alle levende wezens, kunnen niet geïsoleerd leven; ze hebben anderen nodig om te overleven. De vloeibare suikers die door plantenwortels vrijkomen, maken deel uit van een symbiotische relatie tussen mycorrhiza-schimmels en 90% van alle planten, een arrangement dat zich in de afgelopen 420 miljoen jaar heeft ontwikkeld. Sterker nog, planten kunnen niet zonder deze bodemschimmels en vice versa.

Mycorrhiza-schimmels kunnen niet leven zonder een waardplant en in ruil voor de suiker van de plant zullen de schimmels voedingsstoffen en water opnemen en terugvoeren naar de gastheer. Voor elke kubieke meter grond sturen deze schimmels maar liefst 20.000 km schimmeldraden, ook wel hyfen genoemd, uit, zodat ze in elk gebied van de bodem infiltreren. Schimmels hebben toegang tot voedingsstoffen en water die niet beschikbaar zijn voor de grotere plantenwortels.

Schimmels kunnen hun zuren ook gebruiken om voedingsstoffen uit de bodem en zelfs uit rotsen vrij te maken, waardoor gesteentemineralen worden omgezet in nutrienten die de plant kan gebruiken. De complexiteit van interacties tussen planten en bodemorganismen gaat nog verder. Bepaalde voedingsstoffen kunnen alleen door bacteriën uit de bodem worden gehaald en schimmels wisselen suiker uit voor de voedingsstoffen die de plant nodig heeft in een complexe symbiotische uitwisseling.

Studies hebben aangetoond dat bodems onder volgroeide, meerjarige gewassen meer beschikbare voedingsstoffen bevatten dan bodems die zijn behandeld met landbouwchemicaliën, die bodemmicroben doden, wat resulteert in het netto verlies van bodemkoolstof. Beleid dat agro-ecologie, regeneratieve landbouw en biologische landbouw bevordert, draagt ​​daarom rechtstreeks bij aan de vastlegging van koolstof in de bodem en helpt zo de klimaatverandering tegen te gaan. Maar er kan meer gedaan worden.

Lange tijd werd gedacht dat de meeste bodemkoolstof zich in de bovenste 30 centimeter van de bodem bevond in de vorm van de organische stof in humus. In 1996 ontdekte Dr. Sara Wright in de VS dat bodems grote hoeveelheden koolstof bevatten tot meer dan een meter diep. Koolstof wordt opgeslagen in de vorm van glomaline, een zeer persistent eiwit dat wordt geproduceerd door mycorrhiza-schimmels. Naarmate de mycorrhiza-schimmels dieper de grond in gaan om voedingsstoffen en water voor de plant te ontginnen, zetten ze steeds meer koolstof af in de vorm van glomaline. Hoe volwassener deze relatie tussen plant en microbe is, hoe meer grond er voor de plant wordt aangesproken en hoe beter het gewas zal produceren en bestand is tegen barre weersomstandigheden.

Ploegen vernietigt organisch bodemmateriaal door oxidatie en geeft veel van de koolstof die in de bovenste bodem is opgeslagen vrij als CO2, dat zijn weg naar de atmosfeer vindt. Ploegen put ook de micro-organismen in de bodem uit. Minder grondbewerking en zorgen voor een meer permanente bodembedekking door planten is daarom cruciaal om een ​​gezond bodemleven op te bouwen en koolstof in de bodem vast te houden.

Bodems van blijvend grasland met gezond microbieel leven verhogen de hoeveelheid koolstof die ze elk jaar onder de grassen vastleggen. Praktijken zoals agroforestry en het aanleggen van heggen en houtkanten zijn andere goedkope strategieën die kunnen helpen het tij van onze opwarmende planeet te keren.

In feite zou een jaarlijkse toename van de organische koolstof in de bodem met 0,4% de door de mens veroorzaakte uitstoot van CO2 in de atmosfeer kunnen neutraliseren. Dit wetenschappelijke inzicht lag aan de basis van het “4 per 1000”-initiatief waar veel overheden, onderzoeksinstituten, het maatschappelijk middenveld en bedrijven al op intekenden tijdens de klimaattop in Parijs in 2015. Terwijl de Europese Green Deal een doelstelling heeft klimaat-neutraal te zijn tegen 2050, laten de toenemende natuurrampen waar we jaar na jaar getuige van zijn, ons zien dat we geen tijd meer te verliezen hebben.

Experimenting with intercrops November 28th, 2021 by

Nederlandse versie hieronder

For thousands of years, farmers have been mixing crops in their fields to meet the diverse needs of their families and to reduce the risk of crop failure. But to know which crops combine well with each other is not an easy matter, and often requires some experimentation to find out what works best for you, as I found out this year in our home garden.

Three years ago, when we moved into our renovated house in Peer, Belgium, we established a raised garden bed from partially rotted woody material and plant debris topped with compost and soil. As this so-called hügelkultur is a great way to keep the soil fertile and moist, we figured this was a good way for us to grow plants without the need for watering them, especially as we are often away from home for several weeks to produce training videos with farmers.

As with many people, Covid has kept us grounded for the past two years. Without international travels we decided we should spend more time growing our own food.

On our 10 meters long, 2 meters wide and 1.5-meter-high bed, my wife Marcella has been growing a diversity of herbs, spices, vegetables and sweet maize. While we tried to anticipate which plants would prefer to grow where exactly on the bed (on the lower end or on top, on the south or north-facing side, in partial shade of the nearby goat willow or in full sunlight), this was clearly something that needed us to try out and observe as we went along.

Last winter, I decided to establish three new raised beds, each aligned north-south and 1.5 meters apart. On one bed I would grow goose berries, blue honeysuckle and red currant; the middle bed would be for my red and yellow raspberries and on the bed closest to the little forest, I would grow a few varieties of blackberries. Unlike with annual plants which you can put in a different location each season, deciding on where to plant which shrub and which variety took some careful thinking. One needs to take into account the plant’s architecture, how vigorous it grows, how it copes with strong winds and what level of shade it tolerates.

Having planted all my shrubs, I felt we could do a little more. Leaving the soil bare while the shrubs were still young did not seem like a good idea. I still had some strawberry plants that I wanted to give a new location. The fast-growing raspberries would soon crowd out my strawberries. And strawberries do not  thrive well in shade, so I decided to plant them on the first bed.

A few months later, in the spring, Marcella thought that her tomato seedlings that she had raised in the warmth of the house were ready for transplanting. Again, we brainstormed around the kitchen table where best we could plant them. “Tomato plants have deep roots and tomatoes need a lot of sun, so let us plant them in between our strawberry plants,” I suggested. To keep the mature tomato plants from shading out the newly planted berry shrubs, we planted them on the north side of the shrubs.

Friends and family said it would not work: growing tomatoes outdoors is asking for trouble, as the tomatoes would rot before they ripen. This may have been true with our traditional wet summers, but given the changing climate I figured it could work. After all, we didn’t have a choice as we don’t have a greenhouse.

One day, I was discussing with Bram Moeskops who manages the Organic Farm Knowledge platform for IFOAM Organics Europe. While he was giving me a virtual guided tour on their excellent platform, it was a real coincidence that he showed me one particular factsheet:

“On this factsheet,” Bram explained, “we show a new technology that we are trying to promote, namely tomato-strawberry intercropping. As the strawberries provide a living mulch, it avoids splashing rainwater to get on the tomato plants”. This was a great new insight. This added benefit hadn’t occurred to me even though

I knew that spores of various soil fungi are typically spread by splashing rain and cause tomato diseases.

Our tomato plants thrived, and surprised every visitor. After three years of extremely warm and dry summers, this year turned out to be the opposite. And in the end, months of high humidity also affected our plants. It was of some comfort to hear that all gardeners had faced the same problem, even those with greenhouses.

As our climate is changing, we will need to continue to experiment with cropping patterns. And the more we learn the better. Experimenting with permanent crops can take years, so it will be all the more important to share the results widely. Innovative platforms such as the Organic Farm Knowledge platform and the Access Agriculture video platform offers great ideas and needed scientific insights to help us make better decisions.

Related Agro-Insight blogs

Experiments with trees

Repurposing farm machinery

From Uniformity to Diversity

The rules and the players

Inspiring knowledge platforms

The Organic Farm Knowledge platform: https://organic-farmknowledge.org contains a wide range of tools and resources about organic agriculture in Europe.

Access Agriculture: https://www.accessagriculture.org is a specialised video platform with freely downloadable training videos on ecological farming with a focus on the Global South.

EcoAgtube: https://www.ecoagtube.org is the alternative to Youtube where anyone from across the globe can upload their own videos related to ecological farming and circular economy.


Experimenteren met mengteelten

Al duizenden jaren mengen boeren gewassen op hun akkers om te voorzien in de uiteenlopende behoeften van hun gezinnen en om het risico op mislukte oogsten te verkleinen. Maar weten welke gewassen goed met elkaar combineren is geen eenvoudige zaak en vereist vaak wat experimenteren om uit te zoeken wat voor jou het beste werkt, zoals ik dit jaar in onze eigen tuin ontdekte.

Drie jaar geleden, toen we verhuisden naar ons gerenoveerde huis in Peer, België, hebben we een verhoogd tuinbed aangelegd van gedeeltelijk verrot houtmateriaal en plantenresten, aangevuld met compost en aarde. Aangezien deze zogenaamde hügelbedden de grond vruchtbaar en vochtig houden, vonden we dit een goede manier om planten te kweken zonder dat we ze water hoefden te geven, vooral omdat we vaak enkele weken van huis zijn om trainingsvideo’s met boeren te maken.

Zoals bij veel mensen heeft Covid ons de afgelopen twee jaar met beide voeten op de grond gehouden. Zonder internationale reizen besloten we dat we meer tijd moesten besteden aan het verbouwen van ons eigen voedsel.

Op ons 10 meter lange, 2 meter brede en 1,5 meter hoge hügelbed, heeft mijn vrouw Marcella een verscheidenheid aan kruiden, specerijen, groenten en zoete maïs gekweekt. Hoewel we probeerden in te schatten welke planten waar precies op het bed het liefst zouden groeien (onderaan of bovenaan, op het zuiden of op het noorden, in de halfschaduw van de nabijgelegen boswilg of in het volle zonlicht), was dit duidelijk iets dat we moesten uitproberen en gaandeweg observeren.

Afgelopen winter besloot ik drie nieuwe verhoogde bedden aan te leggen, elk noord-zuid gericht en 1,5 meter uit elkaar. Op het ene bed zou ik kruisbessen, honingbes en rode bes telen; het middelste bed zou bestemd zijn voor mijn rode en gele frambozen en op het bed dat het dichtst bij het bosje lag, zou ik een paar bramensoorten telen. Anders dan bij eenjarige planten, die je elk seizoen op een andere plaats kunt zetten, moet je goed nadenken over waar je welke struik en welk ras wilt planten. Je moet rekening houden met de architectuur van de plant, hoe sterk hij groeit, hoe hij tegen sterke wind kan en hoeveel schaduw hij verdraagt.

Nadat ik al mijn struiken had geplant, vond ik dat we nog wel wat meer konden doen. De grond kaal laten terwijl de struiken nog jong waren, leek me geen goed idee. Ik had nog een paar aardbeiplanten die ik een nieuwe plek wilde geven. De snelgroeiende frambozen zouden mijn aardbeien snel verdringen. En aardbeien gedijen niet goed in de schaduw, dus besloot ik ze op het eerste bed te planten.

In de lente, brainstormden we rond de keukentafel waar we het beste onze tomatenzaailingen konden uitplanten. “Tomatenplanten hebben diepe wortels en tomaten hebben veel zon nodig, dus laten we ze tussen onze aardbeienplanten planten,” stelde ik voor. Om te voorkomen dat de volgroeide tomatenplanten de pas geplante bessenstruiken in de schaduw zouden stellen, plantten we ze aan de noordkant van de struiken.

Vrienden en familie zeiden dat dit niet zou werken: tomaten in de openlucht kweken is vragen om problemen, omdat de tomaten zouden rotten voordat ze rijp waren. Dat was misschien waar met onze traditionele natte zomers, maar gezien het veranderende klimaat dacht ik dat het zou kunnen werken. We hadden tenslotte geen keus, want we hebben geen serre.

Op een dag was ik in gesprek met Bram Moeskops, die het platform voor biologische landbouwkennis van IFOAM Organics Europe beheert. Terwijl hij me een virtuele rondleiding gaf op hun uitstekende platform, was het een echt toeval dat hij me één specifieke factsheet liet zien:

“Op deze factsheet,” legde Bram uit, “laten we een nieuwe technologie zien die we proberen te promoten, namelijk de tomaat-aardbei mengteelt. Omdat de aardbeien een levende mulch vormen, wordt vermeden dat opspattend regenwater op de tomatenplanten terechtkomt”. Dit was een geweldig nieuw inzicht. Dit extra voordeel was niet bij me opgekomen, hoewel ik wist dat sporen van verschillende bodemschimmels gewoonlijk worden verspreid door opspattend regenwater en alzo tomatenziektes veroorzaken.

Onze tomatenplanten floreerden, en verrasten iedere bezoeker. Na drie jaren van extreem warme en droge zomers, was dit jaar het tegenovergestelde. En jammer genoeg hebben de maanden van hoge vochtigheid uiteindelijk ook onze planten aangetast. Het was een troost te horen dat alle tuiniers met hetzelfde probleem te kampen hadden gehad, zelfs die met serres.

Aangezien ons klimaat verandert, zullen we moeten blijven experimenteren met teeltpatronen. En hoe meer we leren, hoe beter. Experimenteren met blijvende teelten kan jaren duren, dus is het des te belangrijker om de resultaten op grote schaal te delen. Innovatieve platforms zoals het platform Organic Farm Knowledge en het videoplatform Access Agriculture bieden goede ideeën en de nodige wetenschappelijke inzichten om ons te helpen betere beslissingen te nemen.

Inspirerende kennisplatformen

The Organic Farm Knowledge platform: https://organic-farmknowledge.org met informatie over biolandbouw in Europe.

Access Agriculture: https://www.accessagriculture.org  is een gespecialiseerd videoplatform met gratis te downloaden opleidingsvideo’s over ecologische landbouw met een focus op het Zuiden.

Different ways to learn November 21st, 2021 by

Vea la versión en español a continuación

In June I wrote a story about a virtual meeting with some farmers in Iquicachi, on the shores of Lake Titicaca (Zoom to Titicaca), where they discussed how to manage what was (for them) a new pest: the potato tuber moth. Later, several people wrote to me to say that they hoped these farmers could solve their problem. So I’m writing an update.

I went to Lake Titicaca on 16 November to meet the farmers in person, and they’re doing well.

The agronomists they work with taught them to use ground chalk from a building supply shop to coat the seed potatoes. The chalk discourages the tiny larva of the moth from burrowing into the potato. This and some other techniques are helping to keep the tuber moth down.

At our recent meeting, I was impressed (as I often am) how scientists and farmers have different ways of seeing the world. There’s nothing mystical about his. It’s because they use different methods of observation.

An entomologist sees an insect by killing some specimens and looking at them under the microscope. It is an excellent way to see the details of nature that cannot be readily seen with the naked eye. For example, one of the three species of tuber moths has triangular markings on its wings.

But the farmers of Titicaca were less interested in comparing each species of moth, and more intent on comparing them to another pest, one they have had for ages: the Andean potato weevil.

These Yapuchiris (expert farmers) and their neighbors noticed that the moths’ larvae are much smaller than the worms that hatch from weevil eggs. Second, the weevil only eats a part of the tuber, while the larvae of the moth “have no respect for the potato” and destroy the whole thing. Third, the weevil can’t fly, but the moth “flies in jumps” (it takes short flights).

In all fairness, entomologists have also noticed these behaviors, and the Yapuchiris have recently observed that one species of moth is darker than the other. But the farmers emphasize behavior more, and have their own rhetoric for discussing it (e.g. as jumping). Note that this is not ancestral knowledge, because this pest is new on the Altiplano. These Yapuchiris only noticed the moth 10 years ago, and they have been observing it since then. The farmers learn about insects while farming and processing food. They watch while they work. They don’t set up lab experiments.

The Yapuchiris have strengthened their observations by interacting with agronomists. In this case the extensionists explained that the moths are the adults of the worms, so the farmers then began to pay more attention to the moths.

These improved observations have paid off.

While I was in Iquicachi, one of the Yapuchiris, Martín Condori, suggested that since the tuber moth does not fly very far, it could be kept out of potatoes by planting a row of broad beans or lupin beans between every three rows of potatoes. It’s a new idea, that only occurred to don Martín while we were meeting.

His fellow Yapuchiri, Paulino Pari, immediately warmed to don Martín’s suggestion for an intercropping experiment. Don Paulino said that a row of lupin beans might help to stop the moth from spreading into the potatoes, because the lupin plants are toxic to the moths.

This is the value of farmer-scientist collaboration. The farmers learn that the worms in their potatoes have hatched from the eggs laid by moths. Farmers then pay more attention to the moths, and create new ideas for keeping the moths out of the potato field.

Intercropping may or may not help to manage the moth, but it is an idea that farmers and agronomists can try together.

Years ago in Honduras, Keith Andrews, an entomologist, first told me that farmers identify insects more by their behavior and ecology than by their morphology. I’ve spent many years noticing that he was right.


A special thanks to Ing. Roly Cota, who works at PROSUCO, for taking me to Iquicachi and introducing me to the Yapuchiris, so we could validate three new fact sheets for farmers on the potato tuber moth. Our work was supported by the  Collaborative Crop Research Program (CCRP) of the McKnight Foundation.

Photo credit

Photo courtesy of Roly Cota.

Further reading

There is some excellent research on the potato tuber moth. For example, see this paper and references cited.

Olivier Dangles, Mario Herrera, Charlotte Mazoyer and Jean-François Silvain 2013 Temperature-dependent shifts in herbivore performance and interactions drive nonlinear changes in crop damages. Global Change Biology 19, 1056–1063, doi: 10.1111/gcb.12104.

Scientific names

There are two native tuber moths in Bolivia: Symmetrischema tangolias, and Phthorimaea operculella. There is also a Guatemalan tuber moth, Tecia solanivora, but it has not been reported in Bolivia. All three of these moths belong to the Gelechiidae family. They are about a centimeter long, about as long as your smallest fingernail. Many Gelechiidae attack stored cereal products, and so you may have been alarmed to find them in your cupboard.

Video on the fascinating lupin bean

Growing lupin without disease


Por Jeff Bentley, 21 de noviembre del 2021

En junio escribí un relato sobre una reunión virtual con los agricultores de Iquicachi, a orillas del lago Titicaca (Zoom al Titicaca), en la que se discutía cómo gestionar lo que era (para ellos) una nueva plaga: la polilla de la papa. Más tarde, varias personas me escribieron para decirme que esperaban que estos agricultores pudieran resolver su problema. Así que escribo una actualización.

El 16 de noviembre fui al Lago Titicaca para conocer a los agricultores en persona, y están bien.

Los agrónomos con los que trabajan les enseñaron a usar tiza molida de una tienda de materiales de construcción para recubrir la papa semilla. La tiza no deja que la pequeña larva de la polilla penetre a la papa. Esta y otras técnicas están ayudando a reducir la polilla de la papa.

En esta última reunión, me impresionó (como en muchas veces) cómo los científicos y los agricultores tienen formas diferentes de ver el mundo. No tiene nada de místico. Es porque usan distinto métodos de observación.

Un entomólogo observa un insecto al matar algunos ejemplares y mirándolos al microscopio. Es una forma excelente de ver los detalles que no se pueden ver fácilmente a simple vista. Por ejemplo, una de las tres especies de polillas de la papa tiene marcas triangulares en las alas.

Pero los campesinos del Titicaca estaban menos interesados en comparar cada especie de polilla, y más en compararlas con otra plaga, una que tienen desde hace mucho tiempo: el gorgojo de los Andes.

Estos Yapuchiris (agricultores expertos) y sus vecinos se dieron cuenta de que las larvas de las polillas son mucho más pequeñas que los gusanos que nacen de los huevos del gorgojo. En segundo lugar, el gorgojo sólo se come una parte del tubérculo, mientras que las larvas de la polilla “no respetan la papa” y la destruyen completamente. En tercer lugar, el gorgojo no puede volar, pero la polilla “vuela a saltos” (have vuelos cortos).

En realidad, los entomólogos también se han dado cuenta de estos comportamientos, y los Yapuchiris han observado recientemente que una especie de polilla es más oscura que la otra. Pero los campesinos enfatizan más el comportamiento, y tienen su propia retórica para discutirlo (los saltos, por ejemplo). Fíjese que no se trata de un conocimiento ancestral, porque esta plaga es nueva en el Altiplano. Estos Yapuchiris sólo se dieron cuenta de la polilla hace 10 años, y desde entonces la observan. Los campesinos aprenden sobre los insectos mientras cultivan y procesan los alimentos. Observan mientras trabajan. No hacen experimentos de laboratorio.

Los Yapuchiris han reforzado sus observaciones interactuando con los agrónomos. En este caso, los extensionistas les explicaron que las polillas son los adultos de los gusanos, por lo que los agricultores comenzaron a prestar más atención a las polillas.

Estas observaciones mejoradas han dado sus frutos.

Durante mi visita a Iquicachi, uno de los Yapuchiris, Martín Condori, sugirió que, como la polilla de la papa no vuela muy lejos, se podría sembrar un surco de tarwi (lupino) entre cada tres surcos de papa, para que no entre la polilla. Es una idea nueva, que sólo se le ocurrió a don Martín mientras nos reuníamos.

Otro Yapuchiri, don Paulino Pari, aceptó inmediatamente la sugerencia de don Martín de hacer un experimento de cultivo intercalado. Don Paulino dijo que un surco de tarwi podría ser una barrera para la polilla, porque las plantas de tarwi son tóxicas para las polillas.

Este es el valor de la colaboración entre agricultores y científicos. Los agricultores se enteran de que los gusanos de sus papas han nacido de los huevos puestos por las polillas. Los agricultores prestan entonces más atención a las polillas y crean nuevas ideas para mantener las polillas fuera del campo de papas.

Los cultivos intercalados pueden ayudar o no a controlar la polilla, pero es una idea que los agricultores y los agrónomos pueden probar juntos.

Hace años, en Honduras, Keith Andrews, un entomólogo, me explicó por primera vez que los agricultores identifican a los insectos más por su comportamiento y ecología que por su morfología. Llevo muchos años comprobando que tenía razón.


Muchas gracias al Ing. Roly Cota, quien trabaja en PROSUCO, por llevarme a Iquicachi y convocar una reunión con los Yapuchiris, donde pudimos validad tres nuevas hojas volantes para agricultores sobre la polilla de la papa. Nuestro trabajo ha sido auspiciado por el Programa Colaborativo de Investigación sobre Cultivos (CCRP) de la Fundación McKnight.


Foto cortesía de Roly Cota.

Lectura adicional

Hay varios excelentes trabajos de investigación sobre la polilla de la papa. Por ejemplo, vea este artículo y los otros en las referencias citadas.

Olivier Dangles, Mario Herrera, Charlotte Mazoyer and Jean-François Silvain 2013 Temperature-dependent shifts in herbivore performance and interactions drive nonlinear changes in crop damages. Global Change Biology 19, 1056–1063, doi: 10.1111/gcb.12104.

Nombres científicos

Hay dos polillas de la papa nativas en Bolivia: Symmetrischema tangolias, y Phthorimaea operculella. Además, hay una polilla guatemalteca de la papa, Tecia solanivora, pero no ha sido reportada en Bolivia. Las tres polillas pertenecen a la familia Gelechiidae. Miden más o menos un centímetro, más o menos lo largo de su uña meñique. Muchos Gelechiidae atacan cereales almacenados, y es posible que le hayan sorprendido en su dispensa.

Video sobre el fascinante tarwi

Producir tarwi sin enfermedad

El mismo video, en el idioma aymara

Leave the moss, save the forest November 14th, 2021 by

There’s no more dramatic way to release lots of carbon into the atmosphere than to let a forest burn down. I wrote a story in 2016 (Save the trees) explaining how citizens in Cochabamba, Bolivia, have taken ownership of a large forest planted over 30 years earlier as part of a Swiss project. Back then, the project was criticized for not having enough local “participation.”

But the people came to love the forest and volunteers risk their lives to put out fires there. Recently, on 24 October, a 600-hectare fire torched the mountainside just above the city. My daughter, Vera, and I visited one of the local volunteer fire departments (SAR). We were both moved to see the young women and men in orange jump suits, lined up in formation, before getting into pickup trucks to ride to battle at the fire front.

On the north side of the city the fire was so close that ash fell like snowflakes, and the sky turned grey with smoke. Townspeople drove past the station, delivering drinking water, food, and first aid supplies to the citizen firefighters. Fortunately, it rained hard that night, and put out the fire.

But the left hand doesn’t always know what the right hand is up to. The same city that fights so hard to protect the forest is partly to blame for burning it. Every year, people from Cochabamba use moss from the mountains in Christmas decorations. Like people all over Bolivia, folks in Cochabamba make a nativity scene at home or at the office. Besides the Holy Family, shepherds and wisemen, other figurines are included, ranging from Barbie dolls, to plastic dinosaurs, to the Donkey from Shrek, all arranged on a green bed of moss. It’s a riot of fun.

Poor people can make some extra money in December, harvesting moss in the forest, to sell it in the markets or on the street. But it’s not just poor people. One year I took a group of agronomists to see a high, native forest in Santa Cruz, and was dismayed when several came back to the bus with large slabs of moss to take home.

Last year, Ana Gonzáles wrote an article explaining how moss is a primitive plant, without roots, that absorbs up to 20 times its weight in water. Moss acts as a wet blanket in the forest, covering the trees and sheltering them from fire. She urged people not to buy moss at Christmas time. The idea is starting to get across, but some people still like to include moss in the nativity scenes.

In colonial times the idea of the mossy nativity scene was imported from Spain, and in parts of Europe, plants are still taken from the forest at Christmas time. A hundred years ago, moss Christmas decorations may have been sustainable. But now there are a lot more people, more roads, and more pressure on the forest. It’s time to invent new traditions that don’t celebrate Christmas by stripping the forest.

A forest is so much more than trees. The moss and other small plants living on the ground and in the branches of the trees are also part of the forest. Removing some of them can leave a forest dry and vulnerable to burning, which is the last thing our warming planet needs.

Related videos

Managed regeneration

Parkland agroforestry


Por Jeff Bentley, 14 de noviembre de 2021

No hay forma más dramática de liberar mucho carbono a la atmósfera que dejar que un bosque se queme. Escribí un artículo en 2016 (Save the trees) en el que explicaba cómo los ciudadanos de Cochabamba, Bolivia, se han adueñado de un gran bosque plantado más de 30 años antes como parte de un proyecto suizo. En aquel entonces, el proyecto fue criticado por no tener suficiente “participación” local.

Pero la gente llegó a amar el bosque y los voluntarios arriesgan sus vidas para apagar los incendios allí. Recientemente, el 24 de octubre, un incendio de 600 hectáreas calcinó la falda del cerro justo por encima de la ciudad. Mi hija, Vera, y yo visitamos uno de los cuerpos de bomberos voluntarios locales (SAR). Nos conmovió ver a las mujeres y hombres jóvenes con trajes de salto color naranja, alineados en formación, antes de subir a las camionetas para ir a luchar al frente del incendio.

En el lado norte de la ciudad el fuego estaba tan cerca que la ceniza caía como copos de nieve, y el cielo se volvía gris por el humo. La gente del pueblo pasó por delante de la estación, entregando botellas de agua, comida y artículos de primeros auxilios a los bomberos ciudadanos. Afortunadamente, esa noche una gran lluvia apagó el fuego.

Pero la mano izquierda no siempre sabe lo que hace la derecha. La misma ciudad que lucha con tanto esmero por proteger el bosque tiene parte de culpa en su quema. Todos los años, los cochabambinos usan el musgo de las montañas en los adornos navideños. Como en toda Bolivia, los cochabambinos hacen un nacimiento en casa o en la oficina. Además de la Sagrada Familia, los pastores y los reyes magos, se incluyen otras figuras, desde muñecas Barbie, pasando por dinosaurios de plástico, hasta el burro de Shrek, todo puesto sobre un lecho verde de musgo. Es súper divertido.

Los pobres pueden ganar dinero extra en diciembre, cosechando musgo en el bosque, para venderlo en los mercados o en la calle. Pero no se trata sólo de gente pobre. Un año llevé a un grupo de agrónomos a ver un bosque alto y nativo en Santa Cruz, y me quedé consternado cuando varios volvieron al autobús con grandes bultos de musgo para llevarse a casa.

El año pasado, Ana Gonzáles escribió un artículo explicando que el musgo es una planta primitiva, sin raíces, que absorbe hasta 20 veces su peso en agua. El musgo actúa como una manta húmeda en el bosque, cubriendo los árboles y protegiéndolos del fuego. Ella ha instado a la gente a no comprar musgo en Navidad. La idea empieza a ser aceptada, pero a algunas personas les sigue gustando incluir el musgo en los nacimientos.

En la época colonial, la idea del nacimiento de musgo se importó de España, y en algunas partes de Europa se siguen sacando plantas del bosque en Navidad. Tal vez hace cien años, los adornos navideños de musgo eran sostenibles. Pero ahora hay mucha más gente, más caminos que penetran al bosque y más presión sobre ello. Es hora de inventar nuevas tradiciones que no celebren la Navidad despojando al bosque.

Un bosque es mucho más que árboles. El musgo y otras pequeñas plantas que viven en el suelo y en las ramas de los árboles también forman parte del bosque. Eliminar algunas de ellas puede dejar un bosque seco y vulnerable a los incendios, que es lo último que necesita nuestro planeta, que se está calentando.

Videos sobre el manejo del bosque

Regeneración manejada

Agroforestería del bosque ralo

Principles matter July 18th, 2021 by

In this age of restricted travel, when webinars have taken the place of conferences, at first I missed face-to-face meetings a lot. But virtual events do allow one to get exposed to far more ideas than before. This is also the case when digital learning is introduced to farmers. Farmers are increasingly getting information online, like videos. But the videos have to be properly designed. Unlike following a cooking recipe on a Youtube video, in agriculture, recipes must be accompanied by basic principles, so that farmers can decide how to experiment with the new ideas.

I was reminded of this recently during a webinar on the Community-Based Natural Farming Programme in Andhra Pradesh, India. One of the speakers was Vijay Kumar, one of the driving forces behind the programme, which aims to scale up agroecology to millions of farmers in Andhra Pradesh. Vijay is a humble, highly-respected former civil servant. He is much in demand, so meeting him in person would be a challenge, but introduced by a mutual colleague, I was fortunate to have already met him several times on Zoom. Vijay appreciates that Access Agriculture stands for quality training videos that enable South-South learning. According to him, the collaboration with Access Agriculture offers opportunities to help scale community-based natural farming from India to Africa and beyond. It is fortunate to have strong allies who understand the challenges of scaling and that to be cost-effective, one cannot simply visit all the world’s farmers in person.

Still, many people think that farmers can only learn from fellow farmers who live nearby and speak the same language, and that training videos are only useful when they are made locally. The many experiences from local partners with Access Agriculture training videos show that farmers do learn from their peers across cultures, on different continents. Farmers are motivated when they see how fellow farmers in other parts of the world solve their own problems. Access Agriculture videos are effective across borders in part because they explain the scientific principles behind technologies, and not just show how to do things. Vijay is convinced that scientific knowledge and farmer knowledge need to go hand in hand to promote agroecology.

The second speaker at the natural farming conference was Walter Jehne, a renowned Australian soil microbiologist, who talked about the need to build up soil organic matter and micro-organisms as a way to revive soils and cool the planet. I was pleased that he also stressed the importance of principles. When one of the Indian participants asked Walter if he could provide the recipe, he smilingly and patiently explained: “We should focus on the underlying principles, as principles apply across the globe, irrespective of where you are. You need organic matter, you need to build up good soil micro-organisms and make use of natural growth promotors. If a recipe tells you to use cow dung, but you don’t have cows, what can you do? If for instance you have reindeer, their dung will work just as well. You don’t have to be dogmatic about it.”  In two of my earlier blogs (Trying it yourself and Reviving soils) I did exactly do that back home: use ingredients that were available to me: sheep dung, leaves of oak trees in the garden, wheat straw, and so on, but building on ideas from Indian farmers.

Farmers have creative minds and this creativity is fed by basic principles: while recipes surely help, a better understanding of underlying scientific principles are what matter most when it comes down to adaptation to local contexts. We, at Access Agriculture are thrilled to join Andhra Pradesh’s efforts to spread Community-Based Natural Farming across the globe.

Related webinars

365 Days Green Cover & Pre-Monsoon Dry Sowing (PMDS) – Walter Jehne – Streamed on 6th July 12:30 pm

Restoring the water cycles to cool the climate

Related blogs

Trying it yourself

Reviving soils

Effective micro-organisms

Friendly germs

Earthworms from India to Bolivia

A revolution for our soil

Damaging the soil and our health with chemical reductionism

Related videos

Good microbes for plants and soil

Organic biofertilizer in liquid and solid form

Coir pith

Mulch for a better soil and crop

Vermiwash: an organic tonic for crops

Making a vermicompost bed

Inspiring video platforms

Access Agriculture: hosts over 220 training videos in over 90 languages on a diversity of crops and livestock, sustainable soil and water management, basic food processing, etc. Each video describes underlying principles, as such encouraging people to experiment with new ideas.

EcoAgtube: a social media video platform where anyone from across the globe can upload their own videos related to natural farming and circular economy.

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