My experiments

140924-03 Sintang

Drying leaf samples in a home-made drying oven, heated by a light bulb

This week, I would like to explain a bit more about the project I’m doing in Indonesia. My project is an applied research project, which hopefully will provide me with sufficient data to write my PhD thesis. I am basically doing field experiments with oil palm farmers, to try and improve productivity as well as the efficiency of management in the plantation.


Plantation in Jambi

Let’s have a look at an average oil palm plantation, and consider the different elements. The photo above shows a mature plantation with trees of about 12 years old. The trees are planted in triangles, each tree being about nine meters away from its six neighbours. Above, the canopy of leaves is quite closed. Rats and squirrels skitter over the leaves from tree to tree, in search of ripening fruits to eat. On the palm trunks, epiphytes compete with each other for the scarce sunlight. On the plantation floor it is cool and shady, and silent apart from the chirping of crickets, the buzzing of insects and the singing of birds. Frogs and lizards hide under the weeds, and snakes slither along in search of a nice fat rat. Under the ground, the oil palm roots go down to about five meters deep, to provide the palm with water and to anchor it to the soil. But most of the roots are actually in the top 40 centimetres of the soil, stretching six metres in each direction in search of nutrients.

Where does the profit come from in this plantation? Obviously, from the bunches that are harvested from the trees and sold to the trader or the factory. In my project, we’re trying to find out what the optimum profitability is that smallholder farmers can achieve. So, together with our partner in the field, SNV, we’ve found two enthusiastic groups of smallholders, one in Jambi in Sumatra, and one in West-Kalimantan. In total, 14 farmers are participating in the project. Each farmer has set aside a two-hectare field, which is divided in two plots. One plot, where we’ve marked the trees in blue, is the part where we use Better Management Practices: better weed management, better canopy management, better nutrient management, and better harvesting. The other plot, where we’ve marked the trees in red, is for the normal practices of the farmer. These red plots are my control plots, which are the benchmark. My challenge to the farmers is to try the better practices that I suggest, for at least two-and-a-half years, and to see if the management has become easier and the yields and profits have increased compared with the red plots.


Marking trees of the red plot in Jambi

Everyone who has worked in the field with farmers knows that it is not an easy thing to set up long-term experiments and to keep people motivated. That is why we are lucky to work together with a company that produces fertilisers of super good quality. The farmers get the fertilisers for the blue field from us, for free. The fertiliser costs per one-hectare plot per year are 300 to 400 euros, so that’s quite a lot! This gift of good fertilisers is highly appreciated by the farmers, and hopefully will keep them enthusiastic and dedicated. It is a nice win-win-win arrangement. We get dedicated farmers and we know that we are using fertilisers of good quality, which benefits the experiments. The farmers get knowledge and fertilisers, and hopefully better yields. And the fertiliser company gets engaged in research that supports development and is relevant to their core activities.


Oil palm fertilisers: urea (46% nitrogen), borax (11% B2O3) and KCl (60% potassium)

For the more technical agronomic side of the project, I have collected soil and leaf samples from all of the plots in the beginning, and will do so every year, to follow the effects of our better fertilisation. I also yearly measure the size of the palm leaves, to see if they grow larger. And we have a local person in each areas who keeps track of the yields at every harvest for the red and the blue plots separately, and who also notes down all the management activities that the farmers carry out in each plot, plus the associated costs. So, in the end, we’ll have both the more ‘technical’ data such as vegetative growth and nutrient content of the palm leaves, as well as economic data. By analysing the costs (for inputs and labour) and the benefits (from selling the bunches) from the blue plots and the red plots, we can hopefully conclude in the end what the potential profitability is of our 14 participating plantations, what the costs are of implementing better management practices, and how these costs and benefits compare with the farmer practices. What we expect is that in the first year, the profits for the blue plots are less than for the red plots, because the farmers need to invest but the yield does not yet go up. But in the second and third year, when we hope to see the yield improve, the blue plot should get more profitable. How much more? No idea, that’s what we hope to find out!

Let me give two examples of better management practices in the blue plots, to get an idea of what we do. For the better weeding, we teach the farmers not to kill all the weeds, but rather to make weeded circles around each palm for harvesting purposes. Outside these circles, we do selective weeding, where we kill the woody weeds manually or with herbicides, and leave the other weeds. That way the soil quality improves and the weeds help to control populations of leaf-eating pests. For the better fertilisation, we want to demonstrate the importance of applying good-quality fertilisers in the right balance. We use the simple ‘4R’ principle: Right type, Right amount, Right place, Right time. In general, farmers have many questions about fertilisers. Often, they apply the most important nutrients (nitrogen, phosphorus, potassium and magnesium) in the wrong balance which means some are wasted and others are lacking. Also, many farmers don’t apply boron, which oil palm really needs. In the blue plots, we apply the five nutrients in the right balance, and we hope to see larger leaves and better yields in the coming year.


Clidemia hirta, a very persistent and fast-growing woody weed common in oil palm plantations

If the project works out well, then we can use the ‘lessons learned’ to train other smallholders in Indonesia. Together with SNV, we’ve developed a better management practices handbook and a training package, which is now being tested. That means that my experiments are not just science, but have a practical use as well. I find that very motivating!

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