Resiliency as a Product of Relationships: Plants and Plants Part 2: Services That Plants Provide Under Ground

I should have titled this post “Mysteries unlocked”. I am so excited about the discoveries I am about to share with you. I am as excited about them as others are about discovering new planets!

Plants provide important and fascinating essential services under ground which in recent years are being examined more in detail by scientists and are changing horticultural practices. Contrary to what many people think, most plants do not deplete soil nutrients, they add fertility to the soil and create better conditions for plant growth for the entire plant community. How does this work? Let’s explore the various services plants provide underground.

Underground plants have many roots. In fact, the root mass can often be many times larger than the canopy above ground. Root systems develop prior to above ground growth and make the growth possible. Roots of different plants inhabit different niches in the soil, allowing bacteria and fungi to thrive at various depths of soil. This improves soil porosity and structure, as well as mineral uptake.

Roots exude and release organic acids and other compounds to the soil close around them. Through the process of photosynthesis plants produce complex sugars. It has been estimated that 12-40% of the total amount of carbohydrates produced by photosynthesis is released into the soil surrounding roots. Roots also secrete hormones and vitamins. Thus, the soil surrounding roots is richer than all other soil in the garden and is called “rhizosphere”. It deserves a special name like that because it is an environment that is home to populations of beneficial soil organisms and especially to very important bacteria whose presence is vital to soil fertility. These bacteria feed on the sugary exudates.

Roots create a dynamic environment where microbes can develop and interact. Knowing about the processes happening in the rhizosphere is important to understanding the power of your garden.

Microorganisms in the rhizosphere do so much work! They decompose organic matter such as compost, fallen leaves and plant debris to release its minerals into the soil. They increase the supply of nutrients in the soil and make them available for plant uptake.

Many plants of the legume family have an association with bacteria called Rhizobia bacteria. The rhizobia bacteria feed on the sugars exuded by the legume roots. They convert atmospheric nitrogen and store it in small nodules along the roots. When those roots are shed in the ground, or in other words die, the nitrogen becomes fixed in the soil in the way that plants using that soil can uptake it.  Many gardeners that practice permaculture love planting herbaceous, woody and vining plants of the legume family, both perennial and annual, among their crop plants. So far, in my small-scale forest garden I have seen a great effect of these legume plants and I also enjoy seeing the many bees that are attracted to their long season blooms.

The nitrogen fixers I have grown so far are: White clover, lupine, showy tick trefoil, beans, peas, wisteria (which I chop and drop but is still popping up), and the non legume but still nitrogen fixing sea-buckthorn. The sea-buckthorn does not provide the charming and showy flowers of the legume family and is only wind pollinated, but its roots are extremely far reaching and are known to efficiently remediate soil and add fertility to neighbouring trees. They also provide humans with superior medicinal berries. In fact, all parts of this plant can be used to promote human and animal health. They are acclimatized to cold growing zones and should be explored for their healing and disease preventative properties. Due to its thorns it can be used as wild animal barriers around gardens, as wind breakers and as slope stabilisers.

If you have experience with other nitrogen fixers and can recommend them to me, I would love to get your suggestions in the comments section below this post. For the large tree members of the legume family there is unfortunately no space in my garden (believe me, I tried to figure a way to fit them in, but I’d need to purchase my neighbour’s property) nevertheless, the pea shrub (Caragana arborescens “Pendula”) is on my wish list as well as the shrubs New Jersey Tea and Sweet Gayle which are native to North America.

Other than increasing availability of nutrients to plants, microbes also produce hormones that stimulate plant growth. Some bacteria even produce antibiotic and anti fungal metabolites that prevent the growth and activity of pathogens. Their secretions control disease and prevent it from affecting roots.

Some bacteria produce enzymes that induce plant defence systems to respond in ways that shield the roots from being infected by disease. Some bacteria produce growth regulators that cause crops to grow greater amounts of fine roots. With the increase of fine roots, the absorptive surface of plant roots is increased which increases their ability to take up water and nutrients.

One other job that bacteria are good at, and I am happy to list here, is that their sticky secretions group fine soil particles into larger aggregates. This is very important to creating a healthy soil structure that supports plant growth. The larger aggregates allow for better drainage and increased oxygen in the soil. This is most important to disease prevention and to making a soil environment favourable to our microbial friends.

Yes, I am happy and excited about healthy soil because it is a key factor and the basis for Eden living, for freedom, peace and abundance. Continue following my blog as I gently explore Eden living, unity and the brotherhood of living things.

Back to our list of services, some plants have long tap roots that penetrate hard-pan levels of soil. They break up soil compaction and mine minerals from depths of soil that other plant roots do not reach. They bring those minerals up into their leaves which either shed in due season or can be chopped and dropped on the soil surface. These are called “nutrient accumulators”. In my garden they include dandelion, comfrey, queen Ann’s lace, parsley, parsnip, and mullein.  Others that you can try are horseradish, dill, and baptisia. If you can think of any other long tap rooted perennials or annuals, I’d love for you to suggest them in the comments of this post.

So, what jobs do roots do? They create – rhizosphere for microbiology. They tunnel through the soil adding live and dead roots that allow water to move through the soil below ground. They promote water infiltration which prevents water and soil runoff. The most precious asset – water precipitation that falls on the garden should be captured, stored and used in the garden. Roots can do it! Just like plants shed leaves above ground they also shed roots below ground level. All this litter increases organic matter which improves water and nutrient storage.

The list I provided here touches briefly on many aspects which deserve to be looked into in more depth. For those of you who are interested, here are some leads for farther research. One book that was recommended to me lately and I pass on the recommendation to you is called “The Hidden Life of Trees” by Peter Wohlleben. It is on the way to my mailbox as we speak. The book “Carrots Love Tomatoes” by Louise Riotte was also highly recommended to me. Don’t forget to write your recommendations in the comments section.

Wishing a creative gardening year to my readers and many cool and neat observations,

Sharona