Trash farming – simple but effective!

It’s rich, it’s dark, it’s the most important thing in farming: healthy soil. Countless scientific studies and articles discuss the negative effects of soil depletion through carbon-intensive farming practices. At CaneCo we employ a modern, light-touch approach to farming and soil management. This next series of articles takes a look at a number of strategies we use to maintain and improve soil health on our farms.

History

The concept of trash farming – or simply put mulching – has been around for a long time in the sugar cane industry and scientifically studied since around the 1950s. It’s only in recent decades though that sugarcane producers have really started paying attention to preserving soil fertility this way. Prior to the 1970s soils were still relatively healthy, fertilizers were cheap and cheerful, and few people had heard of climate change. The spikes of oil prices in the 1970s changed that equation economically and ecologically. Concerns about the impact of conventional, chemical fertiliser heavy farming on soil fertility and resulting nutrient depletion over time are now commonplace.

Our method

In Grenada we are blessed with fertile loamy and volcanic clay soils. We reclaimed a lot of formerly neglected agricultural land, which has proven to be exceptionally productive since the recultivation with our sugarcane. Amongst other methods, we use mulching or trash farming as one of our foremost strategies to preserve the soil quality on our farms. This way we also enhance our soils for many ratoons and years to come.

A simple and highly effective method, we use both the leaves from detrashing the sugarcane and the bagasse left from the milling as an organic mulch. Milled at the Renegade Rum Distillery, the sugarcane stalks are shredded and crushed to a fine, fibery ‘waste’ substrate. Seeing how valuable the bagasse truly is though, it’s a waste calling it waste! In reality, it is the perfect mulch for adding to the soil and provides (quite literally) tons of benefits.

Soil protection

Mulching improves the soil’s capacity for moisture retention and prevents up to 70% of water loss from surface evaporation. During the dry season mulched soils are more drought-resistant. During the rainy season, the extra layer of substrate slows down water flow across the fields, which increases absorption and keeps the fields from eroding, especially when battered by heavy tropical downpours.

Soil enhancement

By fertilising the soil with nutrients and organic matter, the sugarcane mulch nurtures itself so to speak. A field study in Vietnam has shown that consistently mulched sugar cane fields accumulate higher levels of carbon, phosphorus, potassium, nitrogen, and less harmful bacteria and fungi than unmulched fields. This reduces the need for high volumes of nitrogen and phosphorus fertilization. Rather than depleting soil fertility with heavy fertilizer usage over time, we build up critical topsoil – the earthy gold of farming.

Encourage beneficial critters

A healthy soil also means happy critters! Mulching encourages earthworms and soil microbes, which thrive in an ambient microbiome. These unpaid, highly productive, little farm workers break down the mulch into humus and efficiently turn over the soil. This improves soil tilth, reduces the need for tillage and prevents soil compaction. The effect – improved soil aeration and frailability – the perfect conditions for better sugarcane growth.

Support root development

After harvesting we cover the ground with detrashed leaves. This way we protect the field from the scorching sun and cool down soil temperature. This shields the roots of the next sugarcane ratoon against heat stress. The roots also get to proliferate closer to the surface, where nutrient levels of phosphorus are higher – again a win for root and cane development.

Weed control

Another useful benefit – mulching suppresses the growth of existing weeds and the ability of weed seeds to reach the soil and germinate. Protecting the young cane from being smothered or overgrown by weed is particularly important, as they compete with the fresh shoots for moisture, nutrients, space and light. This economical way of weed control also reduces the need for herbicide use. Another victory for the land and our budget!

An economic no-brainer

Compared to conventional farming methods, trash farming increases yield in the ratoon crop and decreases cost of production per tonne of cane. It requires less energy input overall – making it a more energy efficient and less carbon intensive approach. Best of all, our sugarcane mulch is a renewable, in-house resource which, besides the transport and labour required to put it on the field, is almost cost free. What’s not to like?