Liquid Smoke-Based Biostimulant (Foliar Fertilizer) for Application to Palm Oil Plantations Using Drones

In palm oil plantations, fertilizer is the highest cost component of their operations. Therefore, various efforts are made to optimize fertilization to ensure its maximum efficiency, including the use of slow-release fertilizers. For more details, read here. To maximize fertilization and maximize fresh fruit bunch (FFB) yields, the use of foliar fertilizers is also worth considering. Liquid smoke (pyroligneous acid) is one such foliar fertilizer, although a more accurate term is biostimulant (booster).

This is because liquid smoke does not provide nutrients such as nitrogen (N), phosphorus (P), and potassium (K). However, liquid smoke acts as a biostimulant, plant growth regulator (PGR), and natural protectant, promoting optimal leaf growth. Optimal leaf growth exponentially increases the growth of all plant organs, including stems, roots, flowers, fruit, and so on. Leaves are the primary "kitchen" of a plant, so leaf health determines the health of the entire plant system. Optimal leaf growth also increases the efficiency of fertilizer absorption (a "pump engine" effect) in the soil.

Furthermore, liquid smoke is not only used as "leaf fertilizer", it turns out that liquid smoke also functions as an organic pesticide (fungicide/insecticide). This repels pests (such as ticks and flies), and prevents leaf diseases. The phenol and acetic acid content is toxic to insects (aphids, thrips, caterpillars) and is effective in suppressing fungi that cause plant diseases. And the distinctive smell of smoke makes insects reluctant to approach and lay their eggs on the surface of the leaves. In addition, its binding properties make it difficult for pathogenic fungal spores to attach and develop on the surface of the leaves

Regarding this dual function, the use of liquid smoke for application to leaves (foliar) can be prioritized, whether it is more specifically used as a "foliar fertilizer" or as a biopesticide. This requires a number of adjustments such as dosage, additional formulations and application time. To maximize the function of liquid smoke as a leaf fertilizer, you must mix it with additional nutrients (such as liquid organic fertilizer / LOF) and apply it when the leaf stomata are fully open. Liquid smoke is able to reduce water molecules. When diluted or mixed with Liquid Organic Fertilizer (LOF), the nutritional content of the fertilizer becomes easier to enter and be absorbed through the stomata (leaf mouth). Meanwhile, to maximize its function as a biopesticide, liquid smoke needs to be combined with other vegetable pesticides. The frequency of spraying for prevention is once a week, while pest attacks are high, namely 2-3 times a week until the pest population is under control.

The use of drones for spraying pesticides and liquid fertilizer has been widely used on various agricultural crops such as rice, corn, sugar cane and palm oil. More specifically in palm oil plantations, drone applications are a modern solution for spraying fertilizers and pesticides. And in Indonesia more than 80% of drone applications are for the forestry and agricultural sectors. Efficiency factors (time, energy, operational costs, fertilizers, pesticides) and precision are the main driving forces for this drone application. This means that drone technology is expected to be an effective solution in controlling pests and diseases, fertilizing and cultivating palm oil plants. Drones are effective in increasing plantation efficiency, especially in areas that are difficult to reach. As a technology, various improvements have been made to improve its functions such as carrying capacity, spray speed, safety features and work efficiency. The use of drones supports precision agriculture and global food security with an environmentally friendly technological approach.

Spraying liquid fertilizer on the underside of leaves (underside spraying) using a drone requires special techniques. This is because drone propellers naturally produce strong downwash. This downwash effect is used to gently move and turn the leaves, so that the droplets can hit the bottom of the leaves. This is because on the bottom of the leaf, where the stomata are located the most are gathered around 80%. The spray texture is also made into mist mode (the finest dew) so that the liquid sticks evenly and doesn't drip onto the ground. Next, the drone's height, speed and nozzle angle need to be adjusted in such a way to achieve this goal. Environmental factors in the form of strong winds need to be avoided so it is necessary to adjust the right time and conditions.

As the use of biochar grows as a solution for health and soil fertility as well as a climate solution, this should also be the case with the application of liquid smoke. Liquid smoke as a by-product in the form of a liquid product from biochar production will increase along with increasing biochar production. Liquid smoke as a product produced from biomass raw materials through a pyrolysis process also encourages the use of natural materials based on renewable resources so that it is environmentally friendly and sustainable. 

Why Is It Better For Palm Oil Mills To Use Pyrolysis Rather Than Combustion Furnaces?

The palm oil mill production process or CPO production always requires steam for sterilization, this means a boiler is needed. The heat needed by the boiler usually comes from a furnace with fuel in the form of mesocarp fiber and palm kernel shells. Apart from being used for sterilization, the steam is also used to rotate turbines and produce electricity. With continuous pyrolysis, heat for the boiler can be supplied from syngas and biooil products. Apart from that, pyrolysis also produces biochar as the main product and pyroligneous acid, which is a kind of wood vinegar. The last two ingredients will be very useful in palm oil plantations. Using these two fuels (gas and liquid fuel) will make the furnace produce cleaner smoke compared to burning solid fuel in the form of mesocarp fiber and palm kernel shells which is usually done up to now.

Many palm oil plantations are on acidic soils so the pH needs to be raised and biochar can be used effectively. The biggest operational cost for palm oil plantations is fertilizer and the use of biochar will increase fertilizer efficiency thereby reducing fertilizer input and saving costs. The application of biochar in palm oil plantations apart from improving soil quality thereby increasing the productivity of palm oil fruit or FFB (Fresh Fruit Bunch) is also part of the climate solution, namely carbon sequestration which receives compensation in the form of carbon credits. The carbon credits will also provide additional income for the palm oil company. Apart from that, pyroligneous acid can also be used as fertilizer and biopesticide.

The development of combustion technology is also increasingly developing, starting with the use of moving grates to reciprocating grates used to increase boiler efficiency. But the basic question is how profitable is the use of this technology for palm oil companies in overall? The use of the combustion furnace only increases the efficiency of the boiler, whereas the use of continuous pyrolysis in addition to sufficient boiler heat can also produce other benefits in the form of environmental and financial benefits. Environmental benefits from improving soil fertility conditions and minimizing fertilizer being leached or lost into the environment with the slow release fertilizer technique, for more details read here and also the income from carbon credits which is also big.

The application of biochar is for palm oil plantations, while biochar production is from palm oil mills, while the plantation division and mill division are two separate organizations within the palm oil company. The role of the general manager in particular is needed to handle this so that the company's big goals as a profitable, environmentally sound and sustainable company can be achieved. Factors in the form of maximizing profits, improving land and the environment, as well as being part of the climate solution with carbon sequestration will be a strong driving force for the use of continuous pyrolysis compared to combustion furnaces.