World Soil Day: It’s time to regenerate our soils
These days, stories about the health of our soils seem to be trending from all spheres, giving a glimpse of how important the issue is to everybody. Recently, the Daily Nation and Business Daily newspapers highlighted how unhealthy our soils have become by mentioning a study that was done covering 11 counties in Kenya. The situation seems worrying as the results showed that the once fertile and healthy soils are now degraded, too acidic for nutrients to be taken up which has been linked to unsustainable farming methods such as overuse of Diammonium Phosphate (DAP) fertilizer. Despite having easy access to subsidized fertilizers, farmers in the country are getting worried about the reduction of yields from their farms. As a matter of fact, they should be concerned.
The UN-FAO estimates that for every 5 seconds, an equivalent of one soccer field of soil gets eroded globally. It is not shocking since agricultural practices that encourage the protection of soils are not very popular, as seen in the rise of industrialized agriculture that encourages tilling, heavy fertilizer, pesticide use, and monoculture. This special day-Earth Day- should remind Kenya to look after the soil, regenerate it and take care of it, to ensure food security for its citizens for the next decades.
Soil health and climate change
United Nations Framework Convention on Climate Change (UNFCCC) was adopted in 1994 as an international environmental treaty whose main objective is to reduce the greenhouse gases in the environment to levels that are not harmful. Since 1995, parties to this convention have met every year in Conferences of the Parties (COP) to review the progress being made toward this main objective. This year’s COP25 will be in Madrid. While many nations have made drastic steps such as reduced reliance on fossil fuels, there is still ground to cover which calls for more ways, amongst which is removing carbon from the atmosphere and storing it back into the soil.
As a matter of fact, soil holds very large quantities of carbon, which gets there primarily due to photosynthesis and also the death of plants and animals. Over the years, levels of soil carbon have been decreasing due to unsustainable farming techniques such as fallowing, cultivation, stubble burning or removal and overgrazing. Therefore, we do have the ability to build our soils by increasing carbon content and in so doing, we improve get to reduce the amounts of carbon in the atmosphere.
But how do we regenerate the soil?
We can’t only sustain our soil anymore, since most of it degraded. So the time of sustainability is over. We need to improve soil structure, texture, soil life and fertility. To facilitate this, we need actively re-introduce life (microbes, earthworms etc.) and organic matter through methods like compost, worm castings and worm juice. Additionally, we should rebuild structure and texture through a balance between clay, silt and sand, and by not tilling or ploughing, and to protect the soil by growing living cover crops, mulching and crop rotation.
What are microbes?
Microbes are the back bone of soil health. Microbes are tiny friends of plants whose role is underrated and despised by conventional farming techniques. Plants and microbes have a symbiotic relationship: Plants excrete some of the sugars and proteins they make through the roots to feed microbes. In return, microbes either directly secrete nutrients to the plant or metabolites that make nutrients available to the plant. In addition, these microbes break down organic matter to provide nutrients to the plant. Microbes also help plants to detect and defend themselves against attacks from pathogens and pests through an underground network.
Heavy fertilizer use, as previously mentioned, makes life difficult for these important microbes. Fertilizers are made for feeding the plants not the soil. As plants absorb these fertilizers, they get lacy and do not produce sugars for the microbes anymore. Furthermore they produce exudates that are harmful to microbes. As a result the microbe community in the soil is heavily impacted by artificial fertilizers. This creates an unsustainable pattern, a vicious circle, of heavier fertilizer use every time, which is costly, and harmful to the soil.
How to restore microbes?
Microbe harvesting from forest
One practical way is to harvest microbes in forest soils or an area with bamboo growing. These regions have very high concentrations of useful microbes that we can harvest for use. A substrate is used, which can be as simple as a cup of uncooked rice, which is put in a sock. Once a site is identified, preferably where there are a lot of dead trees, we dig a small hole and cover the sock and leave it for a month. After one month is over, it is time to harvest our microbes, which will have already moved to feed on the rice, as evident by the change of color. The microbes should not be exposed too long in the sun and should be introduced to diluted molasses. Molasses have a high concentration of sugars, and the mixture should stay for another one month for the microbes to multiply further. After a month, we can then spray the result into a farm to effectively introduce microbes!
Compost making is a simple, practical process that utilizes green plant materials, dry plant matter, accelerants like healthy soil, already made compost, manure and ash to stabilize the pH. Getting these materials is unbelievably easy as there is so much wastes from kitchen, hotels, schools, and so on, a process that can be as easy as getting them for free or very cheaply. One can drop these materials on the farm where they will form mulch and decompose to release nutrients. Other than this, preparation of high-quality compost that builds up the soil involves the use of green, nitrogen rich plant materials and dry, carbon-rich plant materials that are piled in layers. An accelerant such as manure, and previous compost or ash is added to fasten the process. The compost should be turned occasionally to ensure circulation of air to avoid anaerobic conditions. Soils rich in compost mean that microbes stay happy, water retention of the soil is much higher hence less watering, and that yields will be higher.
Worm casting & worm juice
Besides microbes, worms are the other category of organisms that are important friends to plants. By their movements in soils, worms benefit soils by making nutrients more available for uptake by plants, improving soil structure, and improving the drainage system. Worms feed on organic matter such as plant debris such as dead leaves, roots, manure, soil, and even fruit peels. The worm castings are very high in the nutrients (nitrogen and phosphorus) and enriching the soil they live in. When the worms die, they decompose rather fast, and this adds more nutrients to the soil.
A worm farm is the other important farming method that achieves worm tea and worm castings. As previously mentioned, worm castings are full of nutrients that plants need, and the worm farm can be able to generate this more practically. Worm tea is similar to worm castings in terms of nutrients, only that they are in liquid form and have lots of microbes. To make a worm farm, one ought to ensure it is aerobic to prevent the build-up of toxic anaerobic pathogens that can harm plants. A simple bucket that is perforated on top can be used to host the worms. There should be a tap from where the leachate is collected ad is brewed into a tea by the addition of starch or molasses and aerated to introduce oxygen.
Adding these components into our soils will transform our agriculture immensely, as our soils will regain the health it ought to have to produce healthy and adequate food. As we celebrate this day, we need to know that the responsibility is with us to heal our soils. If we do not do this, future generations will have nothing to eat as food will not grow, and they will become extinct! Well, it might not get there but it could… You know?
This article was written by Silke Bollmohr and Crispus Mugo of Hamana