Soil testing in Mexico
In the Pacific region of Mexico (state of Sinaloa), many vegetables are grown mainly for export to the United States and Canada. The soils in these crops have been greatly affected by the intensity of their management, which has unfortunately caused a considerable loss in their fertility and microbial biodiversity. In lieu of this, the use of biotechnologies based on microbial complexes is currently being highly promoted in order to inoculate the soils and recover part of the natural fertility. This is being performed alongside the use of other organic tools such as algae extracts, humic/fulvic acids, and liquid composts.
Mydagro LLC is using microBIOMETER® on vegetable plots where their biotechnology E-Microzyme (mix of beneficial bacteria) is inoculated into the soil. Their results have shown an increase in microorganisms and yield compared with the check plots. With the use of the microBIOMETER® soil test to measure the microbial increase quickly, it is now possible to better understand the behavior of microbiology and the positive effects of this type of horticultural crop.
“microBIOMETER® has proven that the use of biological and organic technologies can substantially help with the renewal of worn-out soils and gradually revitalize them to boost the productivity and health of the crops.” Fernando Cantu Galindo- Technical advisor Mydagro LLC Mexico
Both microbial biomass and respiration are parameters used to assess soil health. Soil respiration is the measure of the carbon dioxide produced by the microbes in a given weight of soil while microbial biomass is the measure of the mass of microbes- both active and dormant.
Microbial biomass (MB) is an excellent predictor of soil health because the size of the microbial population correlates with the available nutrients in the soil. Interestingly, MB is low in soil treated with high levels of mineral fertilizers. Research has shown that the stimulus for the plant to grow a microbial population is its need for nitrogen and phosphorus. If these nutrients are artificially supplied, the plant is not being stimulated to feed the microbes that usually provide these nutrients to the plant. This can alter plant-microbe interactions and cause an increased need for pesticides in order to protect the plant, as microbes play a fundamental role in the function of the plant’s immune system.
Microbial respiration measures the amount of carbon dioxide (CO2) produced by the microbes in a given weight of soil. The soil is dried and then rewetted and put in an airtight jar that allows measurement of the amount of CO2 produced over 24 hours. The CO2 is produced by the activity of the microbes in the rewetted soil. Between 20% and 70% of the microbes die during drying, but their dead bodies often provide nutrition for the survivors to use and regrow the population to its original level. Respiration reflects the regrowing work that is being done. The respiration level is often mistakenly believed to predict microbial biomass, though it doesn’t.
People often assume a high respiration rate is good because it means there is a lot of microbial activity occurring. However, it doesn’t necessarily mean the soil is healthy. Microbes in a low pH or toxic soil have to work harder, and therefore their respiration rate is higher, just as your respiration rate in the gym is higher than when you are watching TV. High respiration rates can indicate an unstable microbial population, which, for example, can be seen after excessive tillage occurs. Tillage aerates the soil, so right after there is often a boost of microbial respiration. That increased activity however does not always last, as the other damage done by tillage – disruption of microbial life and destruction of existing plants- can lead to a decreased soil microbial population over time.
The use of soil primers stimulates an increase in soil organic matter (SOM) decomposition, which temporarily increases microbial respiration. Excessive decomposition of SOM can cause a loss of stored soil carbon and other mineral nutrients, allowing for the increased production of CO2. Basically, when you stimulate the soil using a fertilizer or biostimulant, it’s an all-you-can-eat buffet for the microbes. It wakes them up and they start growing and reproducing. But whether they can continue to grow depends on the continual supply of existing nutrients and plant life in the soil. It’s very important that there be sufficient food for the microbes after stimulation. For most soils, this requires that the fertilizer have the correct C:N ratio for the soil and crop. A fertilizer with too high a C:N ratio will cause the microbes to harvest some of the stored carbon, nitrogen and other nutrients in the soil, boosting respiration. This means the stored carbon is being depleted and released into the atmosphere as CO2, the microbes won’t be able to nourish the plant and build soil structure as needed. Adoption of less invasive management practices, such as select-till and reduced chemical fertilizers can reduce CO2 emissions from agricultural soils by retaining soil organic matter.
Priming can be a good way to understand the difference between and uses of respiration data and microbial biomass data. Testing for both initial respiration and long term microbial biomass population can tell you if the priming worked and if the increase in microbial activity led to increased soil microbial biomass and therefore increased soil health and fertility.
Fig Tree Organic Farm produce at the farmer’s market
Adam Jone’s Fig Tree Organic Farm in Queensland, Australia has moved to organic farming. This farm is one of the key producers of foods for the Organic Weekend Sunshine Coast markets, a famous destination for food consumers and tourists. Adam had spent a lot of his time trying a variety of different solutions to grow his crops for market.
Then, Adam met Bronwyn Holm, founder of Earthfood. Arriving on Figtree Organic Farm, Bronwyn and Adam tested the soil with microBIOMETER®; a soil test Bronwyn has been using for some time. The results showed Adam that Australian soil is damaged. This damage is caused by years of hot bush fires, extended lack of rain, overuse of chemicals, topsoil drying out and blowing away, nutrients locked up making soil water-resistant and land surface flooding. This is Australia. It is an ancient land of beauty with extremely damaged farms.
The microBIOMETER® test results also determined the soil was very low on microbes and fungi, and other tests showed it high in acid forming chemicals, probably from the previous owner. Adam was working hard making composting baths and worm juices, yet there was no deep repair due to many years of damage. The microBIOMETER® soil test was evidence that things needed to be done differently.
Bronwyn then explained to Adam the benefits of using Earthfood products which are made by using live microbes, and how they could change his farm’s health, crop yields, and increase his farm’s income. The two filmed a documentary on the farm just after planting. The original crops in the film were up to their knees and the trees to their waist.
Then after using Earthfood for three months, another microBIOMETER® soil test was performed, and they began to see some improvement. The crops seemed settled, and the pumpkin vine which usually has one crop per season had several wheelbarrows of produce. Adam was pleased with the results so far.
Bronwyn and Adam soil testing
At month nine, they ran more soil tests and took another collection of images and were excited about the changes. The soil under the cover crops was cool, and consistently damp when outside the farm boundary the environment was hot and dry. The trees were now two meters above their heads and all bush crops were up to their waist full of produce. The same pumpkin vine produced three crops in the same season and 2.5 tons of produce. The nine-month-old banana trees that were to their waist previously and not doing well were already fruiting and grown way above their heads. It would normally take eighteen months for these trees to grow and fruit. This outcome proved to be very profitable for Adam and he was happy with the results.
Since then, Adam has dove further into the regenerative farming and microbial world. He holds talks and field days, educating the public on the importance of microbes and syntropic farming. He’s found the crowds are getting bigger and bigger each time, which he believes is a result of consumers becoming more aware of their food and the environment in which it is grown.
Earthfood is excited to share their next documentary with us as well which they are currently finishing up. This documentary is on a farm which grows Heritage tomatoes, beans, squash, kale, dragon fruit, papayas, citrus trees, avocados trees, bell peppers, Japanese greens, bananas, and herbs of all kinds.
“Unless you can measure your soil foundations and biology, it is a guessing game on what can be grown to its potential,” Bronwyn said.
ABOUT EARTHFOOD:
Earthfood is rainforest in a bottle powered by live microbes. Historically handed down in my family since the mid-1880s and used in the Internationally awarded Hermitage Estate Wineries (Dalwood Estate now as one of them) when Eggert Holm, my great-great-grandfather, was their master winemaker using live microbes. With a soil scientist the IP for suspending the microbes to sleep so that the microbial concentrated solution can now be sent globally, and the microbes survive and thrive whether used in a pot-plant or on acres of farming food.
Earthfood has been supplying their liquid microbial concentrate to farms for the past 25 years, in the U.S., Central America, and Australia as well as in trials of vineyard owners in Bordeaux, France, and sugarcane farmers in Fiji, to name a few.
The Biospheres, working through the CDA*, accompanies and trains farmers/agricultural companies in the agroecological transition based on a soil conservation approach. The group is also working on applied research projects and therefore on trials under real farming conditions in which they evaluate the impact of certain changes in practices on different indicators (biological, chemical, physical, economic).
“One of our primary objectives is that farmers succeed in putting biology back into their soils to ensure their natural fertility. We are therefore very interested in everything that lives in the soil, from earthworms and microarthropods to microorganisms (bacteria, fungi, nematodes). For us, microbial biomass is one of the most important indicators that help us understand soil biology. Fungal to bacterial ratio, which is a less documented indicator for the moment, remains interesting to observe in certain situations and is the object of real research by our R&D team to understand how best to interpret it.
We have been using microBIOMETER® for 8 months now to test the soil in different projects in our panel of biological indicators. microBIOMETER® provides us with quick and easy results on microbial biomass and F:B ratio which is a real plus for us. We can perform tests directly in the field and present the results to the farmers. Moreover, the affordable price of the analysis allows us to perform soil biology tests in projects where we had no affordable way to do so before.”
*CDA, Centre de Développement de l’Agroécologie, are affiliates dedicated to R&D and advisory.
Jeff Lowenfels
Jeff Lowenfels, a valued advisor and member of our Board, was recently featured in the New York Times Sunday Magazine article, He Wrote a gardening column: He ended up documenting climate change.
For 45 years Jeff has written a gardening column for the Anchorage Daily News and over this time has helped adapt Alaskan growers to their much longer growing season. And in doing so has become a documenter of climate change.
Jeff joined Prolific Earth Sciences because he knew the only way to wean agriculture off synthetic fertilizers was to trust the microbes to deliver nutrients to plants. Jeff is the well-known author of the all-time best selling gardening book, Teaming with Microbes, as well as Teaming with Fungi, Teaming with Nutrients and DIY Cannabis all very readable, informative and available on Amazon.
Soil testing
Modern agriculture practices have led to the systematic degradation of the world’s soil and release of carbon into the environment. The effects are increased need for expensive and environmentally dangerous inputs (fertilizers, pesticides, and herbicides), the loss of fertile top soil, decrease in water holding capacity of soil and dangerously high levels of atmospheric carbon.
Farmers, industry, and environmentalists are looking for cost-effective and reliable ways to measure soil health, to assess impacts of progressive changes on soil and harvest management, and to measure carbon in soil. Before microBIOMETER®, growers have traditionally relied on expensive lab testing of soil. Many current methods are technique and individual lab dependent. Therefore, run-to-run and lab-to-lab variation can greatly affect consistency leading to increased variability. Current methods are performed in labs and the soil is aged and changed from the time of collection. Furthermore, lab tests are difficult to use in developing countries as they can cost upwards of $500 per sample. This makes the test prohibitive to some markets and limits the number of times a grower can test their soil.
Our mission at Prolific Earth Sciences is to enable soil stewards all over the world to use mobile technology and our low-cost soil test to assess regenerative soil practices, to improve soil health, and work towards increased soil carbon sequestration. microBIOMETER® equips growers with the data necessary to make decisions on which practices are the most cost-effective. Inputs such as fertilizers are expensive and changes to practice are risky. Monitoring soil microbial biomass inexpensively, in real time, can help a soil steward quickly assess if an input and practice is improving soil health and worth the investment. In other words, assess before you invest! We also envision microBIOMETER® one day being a powerful tool in the measurement and audit of carbon sequestration programs.
microBIOMETER® has been on the market for over 3 years with direct and distributor sales and currently has customers in over 20 countries.
Soil carbon is important to soil health because it enables microbial life. Microbes are able to obtain carbon directly from plant exudates, however, much of their carbon source is from the dead plant and plant derived materials that they digest. We harvest much of the above ground matter from crops, but plant roots, cover crops and various manures can provide additional sources of carbon and other nutrients for microbes. Pure carbon, for instance coal, is not something we add to soil to increase fertility. It is the soil organic carbon, the carbon originally derived from the living plant, animal and microbial sources, that predicts soil health. This is because it is food for microbes. Without fungi and bacteria making the glues that allow microbes to stick to soil and create soil texture, the soil becomes a powder that is easily eroded and does not hold water. Moreover, without microbes that are so tightly bound to the soil to store nutrients, the soil becomes barren.
Soil carbon begins as plant exudates and dead plant material and ends as humus, the molecular remnants of the bodies and refuse of dead animals and microbes that digested the plant material. Newly broken-down plant material is close to the surface and available to microbes as soluble organic carbon. Using this easily accessible carbon, microbes can multiply. Furthermore, carbon that is in microbes and other inhabitants of the soil food web can be viewed as a savings account. Turnover in the food web is rapid and these materials are being recycled. As organic carbon molecules become in excess, i.e., they are not rapidly recycling, they attach themselves tightly to minerals and clay. In this state they are more difficult for microbes to access. They begin to descend deeper into the soil becoming even more closely associated with soil particulate matter and can now be described as sequestered carbon. The amount of carbon your soil can potentially sequester depends heavily on the particulate matter of your soil. Some soils can accumulate as much as 20% others probably less than 3%.
Earth has surrendered 50% of its sequestered carbon to the atmosphere. How did this happen? As a plant starts to grow, it sends out exudates that stimulate the dormant microbes to start multiplying and working to bring nutrients to the plant. If there is insufficient soluble organic carbon available, the plant stimulated microbes will need to mine carbon from stored carbon sources. Over many years of non-regenerative farming, the microbes have depleted this stored carbon. Mineral fertilizers have replaced the microbes bringing minerals to the plants, but they do not provide carbon for microbial growth. Moreover, plants do not put out exudates for microbes when supplied with mineral nutrients – the stimulus for exudates is the need for minerals. The tragic outcome of low microbes is the loss of soil texture which leads to soil erosion and the inability of the soil to retain moisture.
You need to have all forms of carbon for soil health; plant exudates to stimulate microbial growth, newly digested matter, soluble organic carbon for the population explosion, and stored carbon for the poor times when the microbes need to delve into their reserves. You also need to store carbon by feeding the microbes carbon and replacing minerals in a manner that does not inhibit microbial growth. Sequestered carbon is 60-80% the remains of dead microbes.
The microbial population or microbial biomass (MB) reflects soil fertility. For over 2 million years, plants and soil microbes have worked together to create what we call fertile “soil”.
How do they work together? The plant supplies the microbes with carbon rich food. The microbes then mine the soil for the required minerals. Microbes can actually manufacture nitrogen and antibiotics that protect the plant from pathogens in return creating carbon stores that build soil structure and sequester carbon.
Like all good partners, what is good for one is good for the other, i.e., a healthy MB predicts a healthy plant. Therefore, supplying NPK directly to plants disrupts the plant microbe relationship – plants no longer feed the microbes and the MB decreases accordingly. Soils with low MB suffer from erosion, compaction, and poor structure. Sadly, this is how we have lost 50% of the earth’s soil.
Soil microbes, like all living things, need food. They need to be fed carbon and nitrogen from plants or organic matter so they can mine the minerals, P, K, Mg, Cu S etc. from the soil. If there is not enough of any nutrient, including the minerals that should be in the soil, it negatively affects the number of microbes; just as humans do not thrive when we are deficient in a critical nutrient.
Oxygen, water, and an agreeable pH and temperature are also important for soil microbes. Compacted soil is low in oxygen and microbial biomass. As soil dries, microbes die or become dormant. MB is much lower in low and high pH soils than in those that are in the neutral range. This is because most enzymes work best at neutral pH and all metabolism is enzyme dependent. MB also contracts during intense cold and heat. Plant roots require these same conditions
Microbes also need shelter to survive. Soil aggregates provide small cubbyholes that accommodate oxygen and water. It is in these areas where microbes attach themselves to be protected from predators. These predators are larger than they are; think of how little fish hide in coral. Not only are soil aggregates homes for microbes, they are homes built by microbes. The capsular material that microbes secrete to attach themselves to soil particles is long lasting. It binds the soil particles, therefore, creating aggregates that build soil structure and prevent erosion. These aggregates provide the water, oxygen and wiggle room needed by plant roots.
Furthermore, soil microbes build up carbon in the soil by producing humic matter. When microbes die, their bodies become stored carbon. This is good for microbes in the way that a savings account is good us. It is important for the soil as well because the humic matter increases soil structure. This allows more oxygen and water storage. It is also a resource that microbes can take a loan from before harvest when plant material is not being released to microbes. For too long we have relied on microbes borrowing from this humic carbon source and have released ½ of the soils stored carbon to the air as carbon dioxide. This has contributed to climate change and loss of 50% of earth’s soil. Microbes have always worked well with plants to create soil and they can help us restore exhausted soils back to fertility.
Increasing your soil microbes increases carbon sequestration. Carbon is stored in the soil as “humic materials” i.e. C,N,P,K etc.; rich organic matter which is the soil organic carbon or sequestered carbon in the soil.
The formation of humus, the final stable carbon, is a stepwise process. All organic carbon in soil comes from plants, either directly or via digested plant material. It starts with plant material being digested by soil microbes, or in the case of brown manure, being predigested by animals and further digested by microbes. The breakdown process begins with soil fungi and bacteria. As these microbes are fed carbon, they multiply. If fresh carbon stores are not utilized, they become attached to soil particles and become stored, therefore, less available as food sources. As microbes die, if they are not immediately cannibalized, their remains also become part of the more recalcitrant humic material.
Slowly, this humic material, which is as much as 80% the bodies of dead microbes, builds up. We measure it as soil organic carbon (SOC) and it reflects the carbon sequestered in the soil, but it also contains all the minerals and other plant nutrients. To increase SOC, the fresh organic matter required to feed the microbes and in turn the plant via the microbes, there needs to be an excess of the minimum required for a low microbial population. If there is an excess, the microbial population increases, and their dead bodies will increase the humic matter, in return increasing carbon sequestration. If it is not adequate, the soil microbes will be stimulated by the plant to mine the stored organic matter, which will decrease the stored carbon. It is not surprising that scientists have compared the plant/microbe/soil fertility index to economic models. A rich soil, like a rich man, has money in his pocket and money in the bank, for soil the currency is carbon.
This system is very much like our agricultural complex. There is fresh food, which we utilize within days, food we freeze or can, which requires freezers and can openers to access, and food stores (our sequestered carbon) that we maintain in silos as protection against disaster.
The Sítio Escola Portão Grande is a Brazilian NGO, nonprofit organization which was founded in October 2012.
Sítio Escola Portão Grande hosted students from the Mentoring and Language Acquisition Program (MLAB) for a full day immersion at the farm in Brazil which featured soil testing with microBIOMETER®. MLAB is a mentoring and language acquisition program for Harvard students and Brazilian high school students, with low income and high performance. In addition to mentoring, the program brings foreign students to an immersion in Brazil, exploring themes that motivate them.
The students were delighted to observe the use of microBIOMETER® to assess fertility based on the measurement of soil microbial biomass. It was explained to the students that microBIOMETER® is used monthly to assess the evolution of fertility due to the different inputs applied to the soil, the crops and harvests carried out, as well as throughout the seasons. Therefore, providing a database of great importance to make future decisions. In addition, due to its ease of use, microBIOMETER® also proved to be an good tool to assess the quality of the inputs we produce on the farm, such as bokashi and compost tea, allowing the tuning of the culture media we use for them.
A big thank you to Antonio Feres Neto for sharing this story with us! We love hearing how our customers are using microBIOMETER®.
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