Written with Paul Van Mele
In the opening scenes of the film, “Living Soil,” we see the Dust Bowl: the devastated farmland of the 1930s in the southern plains of the USA. Thirty to fifty years of plowing had destroyed the soil, and in times of drought, it drifted like snow.
As the rest of this one-hour film shows, there is now some room for optimism. Nebraska farmer Keith Berns starts by telling us that most people don’t understand the soil, not even farmers. But this is changing as more and more farmers, large and small, organic and conventional, begin to pay attention to soil health, and to the beneficial microbes that add fertility to the soil. Plants produce carbon, and exchange it with fungi and bacteria for nutrients.
A few scientists also appear in the film. Kristin Veum, USDA soil scientist, says that soil organisms are important because they build the soil back up. Most people know that legumes fix nitrogen, but few know that it’s the microbes in association with the plants’ roots that actually fix the nitrogen from the air.
Indiana farmer Dan DeSutter explains that mulch is important not just to retain moisture, but also to keep the soil cool in the summer. This helps the living organisms in the soil to stay more active. Just like people, good microbes prefer a temperature of 20 to 25 degrees Celsius. When it gets either too hot or too cold, the micro-organisms become less active. Cover crops are also important, explains DeSutter, “Nature abhors a mono-crop.” DeSutter plants cover crops with a mix of three to 13 different plants and this not only improves the soil, but keeps his cash crops healthier.
Nebraska’s Keith Berns plants a commercial sunflower crop in a mulch of triticale straw, with a cover crop of Austrian winter pea, cowpeas, buckwheat, flax, squash and other plants growing beneath the sunflowers. This diversity then adds 15 or 20 bushels per acre of yield (1 to 1.35 tons per hectare) to the following maize crop. Three rotations per year (triticale, sunflower and maize), with cover crops, build the soil up, while a simple maize – soy bean rotation depletes it.
Adding carbon to the soil is crucial, says DeSutter, because carbon is the basis of life in the soil. In Indiana, half of this soil carbon has been lost in just 150 to 200 years of farming, and only 50 years of intensive agriculture. No-till farming reduces fertilizer and herbicide costs, increases yield and the soil improves: a win-win-win. This also reduces pollution from agrochemical runoff.
As Keith Berns explains, the Holy Grail of soil health has been no-till without herbicides. It’s difficult to do, because you have to kill the cover crop to plant your next crop. One option is to flatten the cover crop with rollers, and another solution is to graze livestock on the cover crop, although he admits that it’s “really hard” to get this combination just right.
USDA soil health expert Barry Fisher, says “Never have I seen among farmers such a broad quest for knowledge as I’m seeing now.” The farmers are willing to share their best-kept secrets with each other, which you wouldn’t see in many other businesses.
Many of these farmers are experimenting largely on their own, but a little State support can make a huge difference. In the 1990s in Maryland, the Chesapeake Bay had an outbreak of Pfiesteria, a disease that was killing the shellfish. Scientists traced the problem to phosphorous, from chemical fertilizer runoff. Maryland’s State Government began to subsidize and promote cover crops, which farmers widely adopted. After 20 years, as Chesapeake Bay waterman James “Ooker” Eskridge explains, the bay is doing better. The sea grass is coming back. The blue crab population is doing well, the oysters are back and the bay looks healthier than it has in years.
Innovative farmers, who network and encourage each other, are revolutionizing American farming. As of 2017, US farmers had adopted cover crops and other soil health measures on at least 17 million acres (6.9 million hectares), a dramatic increase over ten years earlier, but still less than 10% of the country’s farmland. Fortunately, triggered by increased consumer awareness, these beneficial practices are catching on, which is important, because healthier soil removes carbon from the atmosphere, reduces agrochemical use, retains moisture to produce a crop in dry years, and grows more food. The way forward is clear. Measures like targeted subsidies to help farmers buy seed of cover crops have been instrumental to help spread agroecological practices. Experimenting farmers must be supported with more public research and with policies that promote healthy practices like mulching, compost, crop rotation and cover crops.
Watch the film
Living Soil directed by Chelsea Wright, Soil Health Institute
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Videos on soil health practices
Organic biofertilizer in liquid and solid form
Vermiwash: an organic tonic for crops
Living windbreaks to protect the soil
Good microbes for plants and soil
Mulch for a better soil and crop
Grass strips against soil erosion
Globally an estimated 20 to 60 million hectares of land in developing countries are acquired by foreign companies and investors. This so-called “land grabbing” has taken place for various reasons. The most obvious one is the hunger for maximising profit. The devastating effects on deforestation for the expansion of biofuels, sugar cane, palm oil and soya bean for animal feed are well known. A less visible reason is to secure food by those who have seen large areas of land in their home country become unsuitable for farming. This is particularly the case for India and China, where the Green Revolution model of industrial farming has been promoted for decades. Today, due to this industrial model of farming about a third of China’s total cultivated area is seriously eroded by wind and water. According to Dave Montgomery in his book Growing a Revolution, half of the soil carbon in the midwestern USA has been lost. At EU level, soil erosion affects over 12 million hectares of land – about 7.2% of the total agricultural land – and leads to €1.25 billion loss in crop productivity.
As people have seen the soil as a warehouse full of chemical elements that could be replenished at will to feed crops, they ignored the microorganisms that help plants to take up the nutrients in organic matter, and soil minerals. Microorganisms do not have chlorophyll to do photosynthesis, like plants do, and require organic matter to feed on.
While acquiring land in other countries as a strategy to secure domestic food supplies has created its own problems, it is hopeful to see that more sustainable initiatives triggered by civil society are gaining momentum, and receiving support from their governments. President Xi Jinping recently announced on television that China wants to stop destroying natural resources and instead become a global leader for green technologies. Through his speech he formalised the rising aspirations of Chinese civil society for healthy food.
For several years, the central government in India has strongly advocated “zero budget natural farming,” a form of regenerative agriculture that restores the health of soils without external inputs. By ending the reliance on purchased inputs and loans for farming, natural farming also aims to solve extreme indebtedness and suicides among Indian farmers. Many Indian states have adopted policies that support various forms of agroecology.
When one of our Indian partners produced a farmer training video on how soils can be revived with good microbes, a traditional practice that is now being widely promoted, I thought this would be helpful for our garden as well. When we moved into our house in north-eastern Belgium, some of the land had been under intensive cultivation for decades. The soil was hard and dead. Even though I had mixed some cow manure into the planting pits before planting my fruit trees 4 years ago, they have struggled during summers that seem to have become dryer and hotter year after year.
I watched the good microbes video from the Access Agriculture video platform and downloaded the factsheet. All I needed was fresh cow dung, cow urine, molasses and chickpea flour. But we don’t have cows, only a few sheep, and to have cow dung loaded with good microbes one would have to approach an organic farmer. So, I decided to collect fresh dung from our sheep and give it a try.
Jeff wrote in an earlier blog that farmers and farmer trainers in Bolivia mix dung with their hands without any reservations. Likewise, I have often witnessed during my interactions with farmers in South Asia how respectful they treat dung, as if it were gold. Hence, I started to mix the ingredients. The days before setting up my experiment I had collected my own urine, and because I didn’t have molasses to feed the good microbes I settleed for what we had in the house, brown sugar.
Farmers in India also mix leaves of the neem tree into the solution to help control insect pests and diseases. I replaced neem with a strong-smelling medicinal plant that we have in our garden, called “boerenwormkruid”. After having added all in 10 litres of water, I placed the drum in the shade, as good microbes don’t like direct sunlight.
For 10 days, I let the mixture ferment to increase the number of good microbes, stirring it twice a day to release the gases that could inhibit fermentation. The sweet-sour smell was a good indication that fermentation was successful. The result was a home-made variation of commercially available effective microorganisms, and an Indian recipe adapted to Belgian conditions. I kept the filtered solution in recycled plastic milk bottles. Every 2-3 weeks I mixed one of the bottles into 100 litres of water to then pour the solution around my 30 something fruit trees with a watering can, each tree receiving just enough to moisten the mulch around their base.
Seeing is believing. And doing it yourself adds conviction. In just 6 months the soil around our fruit trees has become black, soft and crumbly, keeping rainwater much better. I am confident that the humus and rich soil life will help the trees cope much better with the changing climate.
While we have destroyed much of our farm land for decades, the solutions to revive our soils are available. Green technologies spread faster when there is political goodwill and when farmers have the opportunity to learn from their peers, across borders. That is what Access Agriculture tries to achieve through its rich video library.
Scientific name
Boerenwormkruid is Tanacetum vulgare. The English common name is tansy.
Credit
The top photo from soil erosion in Ethiopia is by Pascal Boeckx.
Related videos
Organic biofertilizer in liquid and solid form
Good microbes for plants and soil
Some 200 farmer training videos on ecological farming in 85 languages can be found on the Access Agriculture video-sharing platform: www.accessagriculture.org
Related blogs
Encouraging microorganisms that improve the soil
Further reading
GRAIN — GRAIN releases data set with over 400 global land grabs”. www.grain.org.
Montgomery, David R. 2017 Growing a Revolution: Bringing Our Soils Back to Life. New York: Norton. 316 pp.
Panos Panagos et al. 2018. Cost of agricultural productivity loss due to soil erosion in the European Union: From direct cost evaluation approaches to the use of macroeconomic models. Land Degradation & Development, 29(3), https://onlinelibrary.wiley.com/doi/full/10.1002/ldr.2879.
Vea la versión en español a continuación
At a recent event in Cochabamba, just before Bolivia went into lockdown over coronavirus, I had a rare opportunity to see how to make products or inputs used in agroecological farming.
The organizers (the NGO Agroecología y Fe) were well prepared. They had written recipes for the organic fertilizers and natural pesticides, an expert to explain what each product did and to show the practical steps. The materials for making the inputs were neatly laid out in a grassy meadow. We had plenty of space to build fires, mix materials such as cow dung with earth and water, and to stand and chat. Agronomist Freddy Vargas started by making bokashi, which extensionists have frequently demonstrated in Latin America for decades, especially among environmentally sensitive organizations.
Bokashi is sometimes described as fertilizer, but it is more than that; it is also a source of minerals and a culture of microorganisms. Freddy explained that for the past 25 years, ever since university, he has been making bokashi. He uses it on his own farm, and teaches it to farmers who want to bring their soil back to life.
Freddy mixes leaf litter and top soil from around the base of trees (known as sach’a wanu (“tree dung”) in Quechua. The tree dung contains naturally occurring bacteria and fungi that break down organic matter, add life to the soil and help control plant diseases. Freddy adds a few packets of bread yeast for good measure. As a growth medium for the microbes, he adds rice bran and rice husks, but any organic stuff would work. Next, raw sugar is dissolved in water, as food for the microorganisms. He also adds minerals: rock flour (ground stone) and “fosfito” (rock flour and bone flour, burned on a slow fire). The pile of ingredients is mixed with a shovel, made into a heap and covered with a plastic tarpaulin, to let it ferment. Every day or so it gets hot from fermentation, and has to be turned again. The bokashi will be ready in about two weeks, depending on the weather.
This elaborate procedure is why it has taken me some time to accept bokashi. It seemed like so much work. Freddy explained that he adds bokashi to the surface of the soil on his farm, and over the years this has helped to improve the soil, to allow it to retain water. “We used to have to water our apple trees every two days, but now we only have to irrigate once a week,” he explained. His enthusiasm and clear evidence of benefits made me re-assess my previous skeptical view of bokashi.
Next, agronomist Basilio Caspa showed how to make biol, a liquid culture of friendly microbes. He mixed fresh cow dung, raw sugar and water with his hands, in a bucket, a demonstration that perplexes farmers. “How can an educated man like you mix cow dung with your hands?” But Basilio enjoys making things, and he is soon up to his elbows in the mixture before pouring it into a 200-liter barrel, and then filling it the rest of the way with water.
Basilio puts on a tight lid, to keep out the air, and installs a valve he bought for 2 pesos at the hardware store, to let out the methane that is released during the fermentation. The biol will be ready in about four weeks, to spray on crops as a fertilizer and to discourage disease (as the beneficial microorganisms control the pathogens). Basilio has studied biol closely and wrote his thesis on it. He found that he could mix anything from half to two liters of biol into a 20 liter back pack sprayer. Higher concentrations worked best, but he always saw benefits whatever the dilution.
We also learned to brew a sulfur lime mix, an ancient pesticide. This is easy to make: sulfur and lime are simply boiled in water.
But do farmers actually use these products?
Then María Omonte, an agronomist with profound field experience, shared a doubt. With help from Agroecología y Fe, she had taught farmers in Sik’imira, Cochabamba to make these inputs, and then helped the communities to try the inputs on their farms. “In Sik’imira, only one farmer had made bokashi, but many had made biol.” This seasoned group agreed. The farmers tended to accept biol more than bokashi, but they were even more interested in the brews that more closely resembled chemicals, such as sulfur lime, Bordeaux mix (a copper-based fungicide) and ash boiled with soap.
The group excitedly discussed the generally low adoption by farmers of these products. They suggested several reasons: first, the products with microbes are often made incorrectly, with poor results and so the farmers don’t want to make them again. Second, the farmers want immediate results, and when they don’t get them, they lose heart and abandon the idea. Besides, making biol and bokashi takes more time to prepare than agrochemicals, which is discouraging.
Bokashi and biol do improve the soil, otherwise, agronomists like Freddy would not keep using them on their own farms. But perhaps farmers demand inputs that are easier to use. The next step is to study which products farmers accept and which ones they reject. Why do they adopt some homemade inputs while resisting others? An agroecological technology, no matter how environmentally sound, still has to respond to users’ demands, for example, it must be low cost and easy to use. Formal studies will also help to show the benefits of minerals, microbes and organic matter on the soil’s structure and fertility.
Related videos
Good microbes for plants and soil
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Acknowledgements
The event I attended was the Congress of the Regional Soils Platform in Cochabamba, organized by the NGO Agroecología y Fe. Thanks to María Omonte, Germán Vargas, Eric Boa, and Paul Van Mele for reading a previous version of this story.
MICROBIOS AMIGABLES
Por Jeff Bentley, 5 de abril del 2020
En un reciente congreso en Cochabamba, justo antes de que Bolivia entrara en cuarentena por el corona virus, tuve la rara oportunidad, como parte de un grupo pequeño, de ver cómo hacer insumos o productos para la agricultura agroecológica.
Los organizadores (la ONG Agroecología y Fe) estaban bien preparados con recetas escritas para los abonos y plaguicidas naturales, con un experto para cada insumo para explicar qué hacía cada producto y para mostrar los pasos prácticos. También tenían sus materiales debidamente preparados de antemano.
En un campo de pasto, teníamos mucho espacio para hacer hogueras, mezclar materiales como estiércol de vaca con tierra y agua, y para observar y charlar. El Ing. Freddy Vargas comenzó haciendo bocashi, que los extensionistas han demostrado muchas veces en América Latina durante varias décadas, especialmente entre las organizaciones sensibles al medio ambiente.
El bocashi se describe a veces como fertilizante, pero en realidad es más que abono orgánico; es también una fuente de minerales, y microorganismos para el suelo. Freddy explicó que desde que él estuvo en la universidad, durante los últimos 25 años, ha estado fabricando bocashi. Lo usa en su propia finca, y lo enseña a los agricultores que quieren devolver la vida a su suelo.
Freddy mezcla la hojarasca y con tierra que recoge debajo de los árboles (conocido como sach’a wanu, en quechua, “estiércol de árbol”). El estiércol de árbol contiene bacterias y hongos naturales que descomponen la materia orgánica, dan vida al suelo, y controlan las enfermedades de las plantas. Freddy agrega unos cuantos paquetes de levadura de pan por si acaso. Pone salvado de arroz y cascarilla de arroz como un medio de cultivos, pero podría usar cualquier cosa orgánica. También pone minerales: harina de roca (piedra molida) y fosfito (harina de roca y harina de hueso, quemado a fuego lento). Él añade chancaca disuelta en agua, como alimento para los microbios, luego da vuelta a todos los ingredientes con una pala, y se cubre con una lona, para dejarla fermentar. Más o menos cada día el bocashi se calienta por la fermentación, y de nuevo hay que darle vuelta a la mezcla. El bocashi estaría listo en unas dos semanas, según la temperatura ambiental.
Es un procedimiento exigente, que parece mucho trabajo, pero Freddy explicó que él agrega bocashi a la superficie del suelo en su finca para liberar los microorganismos en la tierra. A lo largo de los años esto ha ayudado a mejorar el suelo, para que retenga más humedad. “Antes teníamos que regar nuestros manzanos cada dos días, pero ahora sólo tenemos que regar una vez a la semana”, explicó. Su entusiasmo y la clara evidencia de los beneficios me ayudó a reevaluar mi opinión escéptica del bocashi.
A continuación, el Ing. Basilio Caspa mostró cómo hacer biol, un cultivo líquido de microbios amistosos. En un balde, mezcló estiércol fresco de vaca, chancaca y agua, explicando que cuando muestra a los agricultores cómo mezclar el biol, se oponen. “¿Cómo es que un hombre educado como tú puede mezclar estiércol de vaca con sus manos?” Pero a Basilio le gusta hacer cosas con las manos, y pronto está hasta los codos en la mezcla, antes de echarla en un barril de 200 litros, y luego llenarlo el resto con agua.
Basilio pone una tapa hermética al turril, para que no entre el aire, e instala una válvula que compró por 2 pesos en la ferretería para dejar salir el metano que el biol liberará al fermentar. En un mes, el biol estará listo para fumigar los cultivos como fertilizante foliar y para evitar las enfermedades (por que los microorganismos benéficos controlan a los patógenos). En realidad, Basilio escribió su tesis sobre el biol. Encontró que podía mezclar desde medio litro de biol hasta 2 litros en una bomba de mochila de 20 litros, y que entre más biol que pone, más fuertes son las plantas. En base a eso, él recomiendo poner dos litros de biol para arriba en una bomba de 20 litros.
También aprendimos a preparar una mezcla de azufre y cal (caldo sulfocálcico), un antiguo plaguicida. Es fácil hacerlo; se hierve cal y azufre en agua.
¿Pero los agricultores realmente usan estos productos?
Entonces María Omonte, una ingeniera agrónoma con profunda experiencia de campo, compartió una duda. Con la ayuda de Agroecología y Fe, ella había enseñado a los agricultores de Sik’imira, Cochabamba, a fabricar estos insumos y luego ayudó a las comunidades a probar los insumos en sus fincas. “En Sik’imira, solo un agricultor ha hecho bocashi, pero muchos han hecho biol”. Este experimentado grupo estuvo de acuerdo; así era. Los agricultores tendían a aceptar el biol, más que el bocashi, pero más que eso, están interesados en los caldos que parecen más a los químicos, como el caldo sulfocálcico, el caldo bordelés (un fungicida cúprico) y el caldo ceniza (ceniza hervida con jabón).
El grupo discutió animadamente la poca adopción que en general hacen los productores de estos preparados. Decían que hay varias razones: una es que no siempre se hace correctamente los mezclados con microbios, y los resultados no son buenos y los productores no quieren hacerlos nuevamente. Otra razón es que los campesinos quieren resultados inmediatos, y al no ver esto desconfían y lo dejan. Además, hacer biol y bocashi requiere mayor tiempo y esfuerzo en su preparación que los agroquímicos y eso los desmotiva.
El bocashi y el biol sí mejoran el suelo, si no fuera así, ingenieros como Freddy no los seguirían usando en su propia finca. Pero tal vez los agricultores demandan insumos más fáciles de hacer. El siguiente paso es hacer un estudio más al fondo para averiguar qué insumos aceptan los agricultores y cuáles no. ¿Por qué adoptan algunos insumos caseros y se resisten a usar otros? Una tecnología agroecológica, por más sana que sea, todavía tiene que responder a las demandas de los usuarios, por ejemplo, de tener bajo costo y ser fácil de hacer. Este tema también merece estudios formales sobre los efectos de los minerales, materia orgánica y microbios a la fertilidad y estructura del suelo.
Blogs relacionados
Una revolución para nuestro suelo
Videos relacionados
Buenos microbios para plantas y suelo
Vermiwash: an organic tonic for crops
Agradecimientos
El Congreso de la Plataforma Regional de Suelos en Cochabamba fue organizado por la ONG Agroecología y Fe. Gracias a María Omonte, Germán Vargas, Eric Boa, y Paul Van Mele por leer una versión previa.
la versión en español a continuación
Degraded soil can be repaired, and replenished with nutrients, until it produces abundant harvests at lower costs, while removing carbon from the atmosphere, and putting it back into the ground. This is the optimistic message of David Montgomery’s book, Growing a Revolution.
In many parts of the world, soils have been degraded by frequent plowing. The benefits of releasing a burst of nutrients for the crops and killing weeds are overcome by exposure of the soil to erosion by wind and water (see Out of space on Montgomery’s earlier book Dirt: The Erosion of Civilizations). In the Midwestern USA perhaps half of the original prairie soil, and most of its organic matter, have been lost in little more than a century of conventional tillage. Chemical fertilizers provide the major nutrients of phosphorous, potassium and nitrogen in the short run, but they undermine the soil’s long-term health by suppressing mycorrhizal fungi.
These mycorrhizal fungi feed plants while making glomalin, a protein that binds soil particles together. Plowing destroys the soil structure created by beneficial fungi and their glomalin.
Montgomery, a professional geologist, explains that most soils don’t need chemical fertilizer. They have enough phosphorous, potassium and all the minor nutrients like iron and zinc that plants need, but these minerals are locked up in stone particles and other forms not accessible to the plants. The key to using these nutrients are beneficial microbes, like the mycorrhizal fungi that extract mineral nutrients from rock fragments and help to break down organic matter so plants can use it. Microbes trade phosphorous to plants for sugars. Predatory arthropods, nematodes and protozoa then feast on the microbes and release the nutrients back to the soil. A diverse soil life makes soil more fertile. Synthetic fertilizers interrupt these interactions, and the mycorrhizal fungi die, so the crop becomes chemical-dependent. Soil that is rich in organic matter (that is, in carbon) is healthier and supports a thriving community of beneficial microorganisms.
But with proper care, soil can be brought back to good health in just a few years. The right techniques can boost soil carbon from 1% (typical of degraded soils) to 4% (as in undisturbed forest) or even up to 6%. There are many such techniques and they go by various names, including “conservation agriculture,” “agroecology” or “regenerative agriculture,” and they are based on simple principles: 1) Use cover crops (or mulch) to keep the soil covered all the time; 2) Complex crop rotations of grasses, legumes and other crops; and 3) no-till, planting seeds directly into the unplowed earth.
Montgomery takes his readers to meet farmers from Kansas to Pennsylvania, from Ghana to Costa Rica, who are practicing and profiting from these three principles. Some are organic farmers; others apply small amounts of nitrogen fertilizer directly into the soil, near the seed, where the plant can efficiently take it up. We learn that some use earthworms, while others like Felicia Echeverría in Costa Rica make their own brews of beneficial microorganisms, to add life to dead soil. Gabe Brown in North Dakota rotates cattle in small paddocks, on large fields. As the cows graze, they fertilize the soil with manure.
Montgomery and soil scientist Rattan Lal estimate that conservation agriculture could offset a third to two thirds of current carbon emissions, by putting organic matter back into the soil, while tilling less and so lowering fuel expenses. Stumbling blocks to adoption of conservation agriculture include subsidies and crop insurance that keep farmers plowing and dependent on chemical fertilizer. Another is formal research, which continues to favor studies of products that companies can sell: chemical solutions to biological problems, as Montgomery puts it. Only 2% of US agricultural research goes to regenerative agriculture (and only 1% globally). Much of the innovation to revive the soil is driven not by funded research, but by the farmers themselves, who have shown that conservation agriculture, agroecology and permaculture can be more productive, with fewer pest problems. Conservation agriculture saves on expenses for inputs, so it is more profitable than conventional tillage agriculture. Properly conserved soil has little erosion; it soaks up the rain in wet years and holds the moisture for drought years.
Montgomery is concerned that when large-scale, industrialized farmers convert from tillage to conservation agriculture there must be a transition period when profits sag, before the soil improves enough to bring yield back up. He fears that this can discourage farmers from switching to conservation agriculture. Yet I am sure that the farmers themselves will work this out. As the natural experimenters that they are, farmers can try ecological farming practices with reduced tillage, first on one field, or on part of one, gradually creating the practices they need, one plot at a time. The good news is that conservation agriculture can be adopted on large farms or small ones, conventional or organic, mechanized or not. Farming can rebuild the soil, and does not need to destroy it.
Further reading
Montgomery, David R. 2017 Growing a Revolution: Bringing Our Soils Back to Life. New York: Norton. 316 pp.
Related blog stories
Encouraging microorganisms that improve the soil
Related videos
Good microbes for plants and soil
Mulch for a better soil and crop
Reviving soils with mucuna (how to use a popular cover crop, mucuna, or velvet bean)
Intercropping maize with pigeon peas
The wonder of earthworms (rearing earthworms to fertilize fields and gardens)
Animals & trees for a better crop
SLM00 Introduction (an introduction to a series of 12 videos on conservation agriculture)
Grow more, earn more (small machinery to reduce tillage)
Till less to harvest more (no-till and minimum tillage)
And many other videos on www.accessagriculture.org
UNA REVOLUCIÓN PARA NUESTRO SUELO
Por Jeff Bentley, 22 de marzo del 2020
El suelo degradado puede ser reparado, devolviendo sus nutrientes, hasta que produzca cosechas abundantes a costos más bajos, mientras que se saca carbono de la atmósfera, para ponerlo en el suelo. Este es el mensaje optimista del libro de David Montgomery, Growing a Revolution.
En muchas partes del mundo, el arar frecuentemente ha degradado los suelos. El arado trae los beneficios de liberar nutrientes repentinamente para los cultivos y matar las malezas, pero el daño es mayor debido al exponer el suelo a la erosión del viento y del agua (ver Out of space sobre el libro anterior de Montgomery, Dirt: The Erosion of Civilizations). En el Medio Oeste de los Estados Unidos, quizás la mitad del suelo original de la pradera, y la mayor parte de su materia orgánica, se han perdido en poco más de un siglo de labranza convencional. Los fertilizantes químicos proporcionan los principales nutrientes de fósforo, potasio y nitrógeno a corto plazo, pero socavan la salud del suelo a largo plazo al suprimir los hongos micorriza.
Estos hongos micorriza alimentan a las plantas mientras fabrican glomalina, una proteína que une las partículas del suelo. El arado destruye la estructura del suelo creada por los hongos benéficos y su glomalina.
Montgomery, un geólogo profesional, explica que la mayoría de los suelos no necesitan fertilizantes químicos. Tienen suficiente fósforo, potasio y todos los nutrientes menores como el hierro y el zinc que las plantas necesitan, pero estos minerales están encerrados en partículas de piedra y están en otras formas no accesibles para las plantas. La clave para el uso de estos nutrientes son los microbios buenos, como las micorrizas que extraen nutrientes minerales de los fragmentos de roca y ayudan a descomponer la materia orgánica para que las plantas puedan usarla. Los microbios intercambian fósforo a las plantas por azúcares. Los artrópodos, nematodos y protozoos depredadores comen los microbios y liberan los nutrientes de vuelta al suelo. Una vida diversa en el suelo lo hace más fértil. Los fertilizantes sintéticos interrumpen estas interacciones y las micorrizas mueren, por lo que el cultivo se vuelve químicamente dependiente. El suelo rico en materia orgánica (es decir, en carbono) es más saludable y sostiene una próspera comunidad de microorganismos buenos.
Pero con el cuidado adecuado, el suelo puede volver a tener buena salud en pocos años. Las técnicas correctas pueden aumentar el carbono del suelo del 1% (típico de los suelos degradados) al 4% (como en los bosques vírgenes) o incluso hasta el 6%. Existen muchas de esas técnicas y tiene diversos nombres, como “agricultura de conservación”, “agroecología” o “agricultura regenerativa”, y se basan en principios sencillos: 1) Sembrar cultivos de cobertura (o mulch) para mantener el suelo cubierto todo el tiempo; 2) rotaciones complejas de cultivos de pastos y cereales, leguminosas y otros cultivos; y 3) la labranza cero, sembrando las semillas directamente en la tierra sin arar.
Montgomery lleva a sus lectores a conocer a agricultores de Kansas a Pensilvania, de Ghana a Costa Rica, que practican rentablemente estos tres principios. Algunos son agricultores orgánicos; otros aplican pequeñas cantidades de fertilizante de nitrógeno directamente en el suelo, cerca de la semilla, donde la planta puede absorberlo eficazmente. Aprendemos que algunos usan lombrices de tierra, mientras que otros, como Felicia Echeverría en Costa Rica, elaboran sus propias soluciones de microorganismos benéficos, para dar vida al suelo muerto. Gabe Brown, en Dakota del Norte, rota el ganado en pequeños potreros, en grandes campos. Cuando las vacas pastan, fertilizan el suelo con estiércol.
Montgomery y el científico del suelo Rattan Lal estiman que la agricultura de conservación podría compensar entre un tercio y dos tercios de las actuales emisiones de carbono, devolviendo la materia orgánica al suelo, a la vez que se labra menos y se reducen así los gastos de combustible. Entre los obstáculos para la adopción de la agricultura de conservación hay los subsidios y los seguros de los cultivos que mantienen a los agricultores arando y dependiendo de los fertilizantes químicos. Otro es la investigación formal, que sigue favoreciendo los estudios de productos que las empresas venden: soluciones químicas a problemas biológicos, como dice Montgomery. Sólo el 2% de la investigación agrícola estadounidense se destina a la agricultura regenerativa (y sólo el 1% a nivel mundial). Gran parte de la innovación para revivir el suelo no está impulsada por la investigación académica, sino por los propios agricultores, que han demostrado que la agricultura de conservación, la agroecología y la permacultura pueden ser más productivas, con menos problemas de plagas. La agricultura de conservación ahorra gastos en insumos, por lo que es más rentable que la agricultura de labranza convencional. El suelo conservado adecuadamente tiene poca erosión; absorbe la lluvia en los años húmedos y retiene la humedad en los años secos.
A Montgomery le preocupa que cuando los grandes agricultores industrializados pasen de la agricultura de labranza a la de conservación, debe haber un período de transición no rentable, antes de que el suelo mejore lo suficiente como para que vuelva a rendir bien. El teme que esto pueda desalentar a los agricultores a cambiar a la agricultura de conservación. Sin embargo, estoy seguro de que los propios agricultores lo solucionarán. Como experimentadores naturales que son, los agricultores pueden probar prácticas de agricultura ecológica con labranza reducida, primero en una parcela, o en un rincón, creando gradualmente las prácticas que necesitan, una parcela a la vez. La buena noticia es que la agricultura de conservación puede adoptarse en fincas grandes o pequeñas, convencionales u orgánicas, mecanizadas o no. La agricultura puede reconstruir el suelo, en vez de destruirlo.
Leer más
Montgomery, David R. 2017 Growing a Revolution: Bringing Our Soils Back to Life. New York: Norton. 316 pp.
Blogs previos sobre temas parecidos
Fomentando microorganismos que mejoran el suelo
Videos sobre el tema
Buenosmicrobios para plantas y suelo
El mulch mejora el suelo y la cosecha
Revivir el suelo con la mucuna (cómo usar un popular cultivo de cobertura, la mucuna, o el frijol terciopelo)
Intercropping maize with pigeon peas
La maravillosa lombriz de tierra (criar lombrices de tierra para fertilizar huertos y cultivo)
SLM00 Introducción (una introducción a una serie de 12 videos sobre la agricultura de conservación)
Producir más, ganar más (maquinaria pequeña para la labranza mínima)
Arar menos para cosechar más (cero labranza y labranza mínima)
Además de muchos otros videos en https://www.accessagriculture.org/es
Vea la versión en español a continuación
Like many Bolivians, Diego Ramírez never thought about remaining in the village where he was born, and starting a business on his family’s small farm. As a kid, he loved picking fruit on his grandparents’ small strawberry patch in the village of Ucuchi, and swimming with his friends in a pond fed with spring water, but he had to leave home at a young age to attend high school in the small city of Sacaba, and then he went on to study computer science at the university (UMSS) in the big city of Cochabamba, where he found work after graduation.
Years later, Diego’s dad called his seven children together to tell them that he was selling their grandparents’ farm. It made sense. The grandparents had died, and the land had been idle for about 15 years. Yet, it struck Diego as a tragedy, so he said “I’ll farm it.” Some people thought he was joking. In Ucuchi, people were leaving agriculture, not getting into it. Many had migrated to Bolivia’s eastern lowlands or to foreign countries, so many of the fields in Ucuchi were abandoned. It was not the sort of place that people like Diego normally return to.
When Diego decided to revive his family farm two years ago, he turned to the Internet for inspiration. Although strawberries have been grown for many years in Ucuchi, and they are a profitable crop around Cochabamba, Diego learned of a commercial strawberry farm in Santo Domingo, Santiago, in neighboring Chile, that gave advice and sold plants. Santo Domingo is 2450 km from Cochabamba, but Diego was so serious about strawberries that he went there over a weekend and brought back 500 strawberry plants. Crucially, he also learned about new technologies like drip irrigation, and planting in raised beds covered with plastic sheeting. Encouraged by his new knowledge, he found dealers in Cochabamba who sold drip irrigation equipment and he installed it, along with plastic mulch, a common method in modern strawberry production.
Diego was inclined towards producing strawberries agroecologically, so he contacted the Agrecol Andes Foundation which was then organizing an association of ecological farmers in Sacaba, the small city where Diego lives (half way between the farm and the big city of Cochabamba). In that way Diego became a certified ecological farmer under the SPG PAS (Participatory Guaranty System, Agroecological Farmers of Sacaba). Diego learned to make his own biol (a fermented solution of cow dung that fertilizes the soil and adds beneficial microbes to it). Now he mixes biol into the drip irrigation tank, fertilizing the strawberries one drop at a time.
Diego also makes his own organic sprays, like sulfur-lime brew and Bordeaux mix. He applies these solutions every two weeks to control powdery mildew, a common fungal disease, thrips (a small insect pest), red mites, and damping off. I was impressed. A lot of people talk about organic sprays, but few make their own. “It’s not that hard,” Diego shrugged, when I asked him where he found the time.
Diego finds the time to do a lot of admirable things. He has a natural flair for marketing and has designed his own packing boxes of thin cardboard, which he had printed in La Paz. His customers receive their fruit in a handsome box, rather than in a plastic bag, where fruit is easily damaged. He sells direct to customers who come to his farm, and at agroecological fairs and in stores that sell ecological products.
Diego still does his day job in the city, while also being active in community politics in Ucuchi. He also tends a small field of potatoes and he is planting fruit trees and prickly pear on the rocky slopes above his strawberry field. Diego has also started a farmers’ association with his neighbors, ten men and ten women, including mature adults and young people who are still in university.
The association members grow various crops, not just strawberries. Diego is teaching them to grow strawberries organically and to use drip irrigation. To encourage people to use these methods he has created his own demonstration plots. He has divided his grandparents’ strawberry field into three areas: one with his modern system, one with local varieties grown the old way on bare soil, with flood irrigation, and a third part with modern varieties grown the old way. The modern varieties do poorly when grown the way that Diego’s grandparents used. And Diego says the old way is too much work, mainly because of the weeding, irrigation, pests and diseases.
Ucuchi is an attractive village in the hills, with electricity, running water, a primary school and a small hospital. It is just off the main highway between Cochabamba and Santa Cruz, an hour from the city of Cochabamba where you can buy or sell almost anything. Partly because of these advantages, some young people are returning to Ucuchi. Organic strawberries are hard to grow, and rare in Bolivia. But a unique product, like organic strawberries, and inspired leadership can help to stem the flow of migration, while showing that there are ways for young people to start a viable business in the countryside. Diego clearly loves being back in his home village, stopping his pickup truck to chat with people passing by on the village lanes. He also brings his own family to the farm on weekends, where he has put a new tile roof on his grandparents’ old adobe farm house.
Agriculture is more than making a profit. It is also about family history, community, and finding work that is satisfying and creative.
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EN EL FRUTILLAR DE NUEVO
Por Jeff Bentley, 15 de marzo del 2019
Como muchos bolivianos, Diego Ramírez nunca pensó en quedarse en la comunidad donde nació, y empezar un emprendimiento agrícola en las pequeñas chacras de su familia. Diego cuenta que de niño le encantaba recoger fruta en la pequeña parcela de frutillas de sus abuelos en la comunidad de Ucuchi, y nadar con sus amigos en una poza de riego, llena de agua de manantial, pero de joven tuvo que vivir en la ciudad pequeña de Sacaba para estudiar en colegio. Luego se fue a estudiar a la Universidad UMSS, la carrera de ingeniería de sistemas. Culminado los estudios, empezó a trabajar en la ciudad de Cochabamba.
Años más tarde, el padre de Diego llamó a sus siete hijos para decirles que estaba vendiendo el terreno de sus abuelos. Tenía sentido. Los abuelos habían fallecido, y nadie había trabajado la tierra durante unos 15 años. Sin embargo, a Diego le pareció una tragedia, así que dijo: “Yo la voy a trabajar”. Algunos pensaron que era un chiste. En Ucuchi, la gente estaba en plan de dejar la agricultura, no meterse en ella. Preferían emigrar al Oriente de Bolivia y muchos se habían ido del país. Por esta razón muchas de las parcelas están abandonadas. No es el tipo de lugar al que la gente como Diego normalmente regresa.
Cuando Diego decidió revivir su finca familiar ya hace dos años, buscó inspiración en el Internet. Aunque la frutilla es un cultivo ancestral de la comunidad de Ucuchi y muy rentable en Cochabamba, Diego se enteró de una empresa productora de frutillas en Santo Domingo, Santiago, en el vecino país de Chile, que daba consejos y vendía plantas. Santo Domingo está a 2450 km de Cochabamba, pero Diego se tomó tan en serio las frutillas que fue allí un fin de semana y trajo 500 plantas de frutillas. Crucialmente, también aprendió sobre el cultivo tecnificado de frutillas, aplicando el riego por goteo y plantado en camas tapadas con plástico. Movido por sus nuevos conocimientos, buscó distribuidores en Cochabamba que vendían equipos de riego por goteo y los instaló, junto con el mulch plástico, un método común en la producción moderna de fresas.
Diego se inclinó más en la producción agroecológica para producir frutillas, así que se contactó con la Fundación Agrecol Andes que estaba organizando una asociación de productores ecológicos en Sacaba, la pequeña ciudad donde Diego vive, a medio camino entre su terreno y la ciudad grande de Cochabamba. Diego ya tiene certificación de productor ecológico con SPG PAS (Sistema Participativo de Garantía Productores Agroecológicos Sacaba), Diego aprendió a hacer su propio biol (una solución fermentada de estiércol de vaca que fertiliza el suelo mientras añade microbios buenos). Ahora mezcla el biol en el tanque de riego por goteo, fertilizando las frutillas una gota a la vez.
Diego también hace sus propias soluciones orgánicas, como el sulfocálcico y el caldo bordelés. Fumiga estas preparaciones cada dos semanas para controlar el oídium, los thrips (un pequeño insecto), la arañuela roja, y la pudrición de cuello. Me impresionó. Mucha gente habla de aplicaciones orgánicos, pero pocos hacen las suyas. “No es tan difícil”, Diego dijo cuando le pregunté de dónde hallaba el tiempo.
Diego encuentra tiempo para hacer muchas cosas admirables. Tiene un talento natural para el marketing y ha diseñado sus propias cajas de cartón delgado, que ha hecho imprimir en La Paz. Sus clientes reciben la fruta en una bonita caja, en lugar de en una bolsa de plástico, donde la fruta se daña fácilmente. Vende directamente a los clientes que vienen a la misma parcela, en las ferias agroecológicas y en tiendas que comercializan productos ecológicos.
Diego todavía hace su trabajo normal en la ciudad, mientras que también tiene una cartera en la comunidad de Ucuchi. También cultiva una pequeña chacra de papas y está plantando árboles frutales y tunas en las laderas pedregosas arriba de su frutillar. Diego también ha iniciado una asociación de agricultores con sus vecinos, diez hombres y diez mujeres, incluidos adultos mayores y jóvenes que todavía están en la universidad.
Los miembros de la asociación cultivan diversos cultivos, no sólo frutillas. Diego les enseña a cultivar frutillas orgánicamente y a usar el riego por goteo. Para animar a la gente a usar estos métodos, ha creado sus propias parcelas de demostración. Ha dividido el frutillar de sus abuelos en tres áreas: una con su sistema moderno, tecnificado, otra con variedades locales cultivadas al estilo antiguo en suelo desnudo, con riego por inundación, y una tercera parte con variedades modernas cultivadas a la manera antigua. Las variedades modernas no rinden bien cuando se cultivan al estilo de los abuelos. Y Diego dice que la forma antigua es mucho trabajo, principalmente por el desmalezado, el riego y las enfermedades además de las plagas.
Ucuchi es una atractiva comunidad en las faldas del cerro, con electricidad, agua potable, una escuela primaria y un pequeño hospital. Está justo al lado de la carretera principal a Santa Cruz, a una hora de la ciudad de Cochabamba donde se puede comprar o vender casi cualquier cosa. En parte por estas ventajas, algunos jóvenes se están volviendo a la comunidad de Ucuchi. Las frutillas orgánicas son difíciles de cultivar, y son raras en Bolivia. Pero un producto único, como las frutillas orgánicas, y un liderazgo inspirado pueden ayudar a frenar el flujo de la migración, al mismo tiempo de mostrar que hay maneras viables para que los jóvenes empiecen con un emprendimiento personal en el campo. A Diego le encanta estar de vuelta en su comunidad: para su camioneta para charlar con la gente que pasa por los caminos del pueblo. También trae a su propia familia a la finca los fines de semana, donde ha puesto un nuevo techo de tejas en la vieja casa de adobe de sus abuelos.
La agricultura es más que la búsqueda de lucro. También se trata de la tradición familiar, la comunidad y de sentirse realizado con un trabajo satisfactorio y creativo.
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