The Tribune

By Dr Selima Hauber, One Eleuthera Foundation

Summer is officially here with its hot, blindingly sunny days and warmer nights. Thankfully, the breeze is not as humid as it would be in the upcoming months, so that as the sun sets, it’s still comfortable to sit outside and enjoy the countdown to another day, minus the mosquitoes and sandflies. It’s hard to believe that a couple of months ago, vegetable gardens were still churning out produce that we proudly enjoyed on our tables. Now, the enthusiasm to tend to the garden has waned, and the weeds are taking over until we begin planting again next Fall.

Traditionally, vegetable production in our isles occurs during the coolest periods of the year, beginning with seed planting in September or October. By the time the first harvest of tomatoes is ready, for example, the oppressive heat and humidity of summer have been replaced by milder days and cool nights typical of November and December. The bounty of fresh vegetables pours out of our farms and gardens until the barrage of heat and insect pests hits again in May and June.

So, what’s one to do during the summer when so few vegetables can thrive? While it may be tempting to abandon the garden and allow the weeds to take over, this practice will only make your next season miserable when the seeds the weeds deposited germinate amongst your precious crops. If you don’t want to fill your garden with a few heat-tolerant crops such as okra, eggplant, or melons, summer is the ideal time to replenish the fertility that the previous crop removed from the soil.

Taking care of the soil is of utmost importance for the success of growing vegetables, particularly when using sustainable or organic production practices. If you’ve been treating your soil like ‘dirt’ and engaging it only when you’re attempting to coax a meal out of it, then grab a pen and paper and take some notes.

Soil is a complex, living system of minerals, air, water, and organic matter. The minerals, in our case, limestone, compose forty-five percent of the soil volume. Air and water each take up twenty-five percent, and the remaining five percent is composed of organic matter. Even though it occupies the smallest fraction of total soil volume, organic matter is critically important and is made up of living and non-living components, and micro and macro-organisms.

Picture walking through a mature, undisturbed forest. Here in Eleuthera, there are vast acreages of forests that haven’t been disturbed in decades, quite possibly a century or more. The bouncy, spongy feeling as you step on the forest floor is the result of layers of leaf litter, which is one component of non-living organic matter.

Over time, the leaf litter breaks down, turning into the other component of non-living organic matter - humus. Humus is the product of soil-borne microorganisms decomposing leaf litter and other plant material. There is a beautiful relationship between the soil microorganisms and the plants and trees growing in the soil.

The soil microorganisms provide plants with nutrients by creating humus; and the plants and trees feed the microorganisms sugars that they make through photosynthesis. This exchange must be encouraged to have successful crops. Soil microorganisms also create sticky substances that cause the soil particles to clump together, holding them in place and lessening the chance of erosion.

Microorganisms are a food source for larger living organisms like earthworms, beetles, and ants. These larger creatures contribute to soil health in a number of ways. By tunneling and burrowing through the soil, they allow air and water to penetrate, which ensures healthy roots. Earthworms are prized for bringing humus from the soil surface deep into the soil nearer to the plants’ roots to close the nutrient cycling loop.

Now that we understand the importance of keeping soil microbes happy, let’s explore ways to ensure they thrive in the soil.

Never leave soil barren. Leaving soil unplanted means there are no plants to feed the microbes, and they eventually die off. If you’re not planting a vegetable crop that can be harvested, plant a cover crop. A cover crop is a crop planted strictly for the purpose of improving and protecting the soil. Cover crops protect the soil from wind and intense rains that would cause erosion.

Over time, unprotected soil would be blown or washed away, leaving very little to plant your crop in. Choosing a cover crop from the bean family, also known as legumes, is ideal as they naturally fertilise the soil. With the help of certain soil bacteria, leguminous plants take nitrogen from the air and convert it to a form that plants can access – a process of the nitrogen cycle called nitrogen fixation. The most efficient legume at fixing nitrogen in our climate is Sunn Hemp (Crotolaria juncea). Sunn hemp fixes 340-480lbs of nitrogen per acre! At the end of its nitrogen-fixing duties, the cover crop can be tilled into the soil, adding organic matter that is essential for enabling the soil to hold water, making it readily available to plants.

Avoid using petroleum-derived, synthetic fertilisers. When applied to soil, synthetic fertilizers make the soil environment inhospitable to microorganisms. Readily soluble fertilizers are easily leached from the root zone during heavy rain. This is not only a loss to the plants but also poses a threat to the water table and our marine environment. Use organic materials like compost, composted animal manure, and seaweed to add fertility to the soil. Organic-based fertilisers, such as manure and compost, also introduce billions of microorganisms while posing no harm to the existing population.

By protecting the microbes in your soil and encouraging their growth, you are not only ensuring a successful harvest but also improving your own gut microbiome and ultimately your health. Just as soil microbes break down organic matter to release nutrients for plants, our own gut microbes break down food we consume to release nutrients contributing to our health. Studies show that we can fortify our gut microbiome by consuming foods grown naturally in soils with a rich and diverse microbial population. So, before you abandon your garden until the fall season, consider your soil and enhance your own health and thriving gut flora by protecting the soil and its microbes.

• Dr Selima Hauber, PhD, is the agricultural education and outreach officer at OEF and CTI. Established in 2012, the One Eleuthera Foundation (OEF) is a non-profit organisation located in Rock Sound, Eleuthera. For more information, visit www.oneeleuthera.org or email info@oneeleuthera. org. The Centre for Training and Innovation (CTI) is the first and only postsecondary, non-profit education and training institution and social enterprise on Eleuthera. CTI operates a student training campus in Rock Sound, Eleuthera, with a 16-room training hotel, restaurant and farm. For more information about CTI’s programmes, email: info@oneeleuthera.org.