More kilograms and healthier plants due to better soil life

Small banana growers in, amongst other countries, Peru with an area of only a few hectares, are struggling to keep up the yield of their plantations. The plantations were generously irrigated, or rather, flooded. Besides, there’s still the threat of fusarium, of which TR4 is the variant most feared. Pius Floris of Plant Health Cure (PHC) has his own visions for these challenges. His team travelled to banana growers in Peru to work on soil quality.

“We were approached by Arjan van Ruijven of Agrofair after I gave a lecture for MVO Nederland some years ago,” Pius says. Pius talked about, among other things, tests they conducted, after which Arjan asked them to help set up a major experiment in South America, in Ecuador and Peru, to improve the soil. Agrofair imports a broad range of fruit, and Fair Trade bananas are an important part of this.

Most growers in, for instance, Peru, some of whom work organically, have an area of two to six hectares, Pius describes the situation. “The harvest is supplied to a cooperative every week, and they collect and number the bananas, so they can be traced back to their grower.” All of these growers had problems. The organic growers don’t use pesticides, which is challenging. The banana production is a monoculture, and the availability of water varies.

In Peru, sluices are opened once a month in certain regions, so that ditches become filled with water and growers can irrigate their land, Pius explains. This type of irrigation involves the flooding of the entire plantation. “The land is flooded for some days,” Pius says. He had a similar experience in Ecuador, where he sank into the mud among the plants, while irrigation was in full swing. “The soil was completely saturated,” he says.

Against that backdrop, Plant Health Cure was asked to do an experiment to improve the production. Last year, with the aid of an MVO subsidy, soil analysis was started. To that end, they looked into, for example, fungus colonisation in the soil. The mycorrhiza fungus in particular is important and says something about the health of the soil. Additionally, this fungus helps plants to absorb nutrients. “This fungus lives in symbiosis with the roots of plants,” Pius explains. “We’ve concluded that the soils were in bad shape.” There were practically no mycorrhiza around the roots of banana plants, and other useful bacteria were also lacking. The soil did have many pathogens. “We also found many dead roots.”

Soil life is essential for the status of the crops that are grown, but soil biology is “fairly complex” and “often not understood.” One example is the film made by PHC. It took three years before the 12-minute film was finally completed. “Globally, growers are becoming more aware of soil quality,” Pius mentions. According to him, that’s also because the options of chemicals and ploughing are becoming exhausted, and customers are becoming more demanding. “Soil quality has direct consequences for food quality.”

Two to four plots of nine banana plants each were reserved on eight plantations in Peru. Half of them had their soil dealt with, the other plots functioned as the control group. “We’re still monitoring, because not all plots were harvested, and we repeated the test on the same plots this year,” Pius says. Although the project isn’t finished yet, he sees a “difference of night and day” between the plots. “We’ve interviewed the growers to find out their experiences, and every single one of them is enthusiastic. The plants are healthier, they grow faster and better, leaves are standing up more, there are no fusarium problems and the yield per bunch is one kilogram higher, and these are the results after just one year.”

The plants have now been treated for the second time in order to improve soil quality. In this new test, the bananas are followed from the plantation to the supermarket shelves. “A good soil has an effect on the quality in storage,” Pius explains. That isn’t just the case for bananas, but also for potatoes and onions, for instance. “The quality for storage has to do with the plan’s internal substances.” Simply put, the more internal substances, the better the storage. The amount of internal substances is determined by, among other things, the soil and fertilisers. The general thought is that a plant absorbs no more than 16 elements from fertilisers. This theory is 160 years old, but scientifically out of date, according to Pius. According to current scientific knowledge, a plant absorbs at least 32 elements. Considering fertilising occurs according to the outmoded thought, the plants receive a diet that’s too one-sided. That sounds complicated, but Pius simplifies it with an example: A potato contains 20 nutrients, but a diet consisting of just potatoes won’t make a person healthier. The same is true for plants, a one-sided diet doesn’t make a plant healthier.

It can take up to a year before the soil is completely used to the new situation. “Once the soil has a good fungus colony, you just have to maintain it,” Pius says. The fact that the banana production is mostly a monoculture is only of limited influence. “Looking at how many hundreds of thousands of hectares are monocultures globally, and completely naturally, and considering trees can grow in the same place for hundreds of years, it all plays a limited part. We focus on it being a monoculture too much, and we pay too little attention to the soil itself.”

The part importers play in all this shouldn’t be underestimated. Pius refers to a covenant of MVO Nederland that was signed by 30 major fruit importers. The covenant states that importers have to take care that imported fruit is sustainably produced by 2030. “That means natural fertilisers have to be used, among other things, because the energy needed to make artificial fertiliser isn’t sustainable.”

More information:
Plant Health Cure
Pius Floris