Biochar and Land Reclamation of Ex-Coal Mines

Reclamation of ex-coal mining land is the obligation of the mining company, but often this is not done properly for various reasons. These are mainly due to weak rule enforcement and light sanctions. With the area of ex-coal mines that has reached millions of hectares and the reclamation efforts are needed, but the realization in the field is still very minimal, making environmental damage even greater. The thing that can encourage efforts to improve the ex-coal mining land is the profit or economic factor that can be obtained. This means that if the reclamation effort also bring economic benefits - in addition to environmental benefits, of course - then the coal companies will also be happy to do so. So what activity is it?

The photo is taken from here

After the coal deposit is taken, the top soil should be returned to the land. The basic thing that needs to be done is to improve the quality of the soil so that it can be used for planting various crops. By improving soil quality, besides soil fertility can be restored and even increased, it also includes isolating (immobilizing) a number of harmful elements from the ex-coal mining land. Creating a profitable and sustainable business activity is the next step. The improved soil can then be planted and legumes are the best choice, this is because legumes are other than pioneer plant types with high survivability, strong and deep roots that prevent erosion, root nodules from azetobacter symbiosis by binding nitrogen from the atmosphere which fertilizes the soil also provides many other benefits. Ruminant husbandry is a profitable and sustainable business activity, because it mainly utilizes the leaves of the legume plant as a source of feed. The livestock manure can also be used to further improve the health and quality of the soil so that soil fertility continues to increase and is maintained. The wood from the legume plantation can also be used for productions namely briquettes, charcoal briquettes and even wood pellets.

As a basic thing and the entry point for the above business is improving the quality of the land or soil of the ex-coal mines. There are a number of ways to do this, but the use of biochar is one of the best options. With biochar not only increases the pH or acidity of the soil so that many nutrients will be absorbed by plants better and soil microbial activity to decompose organic matter is more active, but it is also able to absorb a number of harmful chemical elements in the soil, increasing soil organic carbon that can last hundreds of years and also absorbs the greenhouse gase from atmosphere. The biochar can be made from a number of agricultural, forestry and agro-industrial wastes, such as wood chips from logging or from palm oil mill waste such as empty fruit bunches and fiber. A number of areas in Kalimantan are not only rich in coal deposits and also currently many of these ex-coal mining lands are abandoned, as well as a lot of biomass materials such as forest waste and palm oil mill waste for the production of biochar.

In order to reduce CO2 emissions in the atmosphere, biochar is also able to absorb CO2 from the atmosphere (carbon sequestration) and is a carbon negative scenario. The biochar applied to the soil is a carbon sink, as an option for carbon credit other than carbon offset. In the current era of decarbonization, efforts to reduce CO2 level in the atmosphere are important. In Indonesia, where there is still a lot of forest land, carbon credit can be obtained from the absorption of CO2 by the trees in the forest, so that the forest acts as a carbon sink as well. But in other countries where the use of fossil energy is very large or massive, they must reduce the adverse climate impacts caused by burning fossil energy materials, especially coal. They can buy carbon credits on this biochar application.

 

Coal is the most widely used fossil energy for power generation in the world today and Indonesia is one of the producers of such coal. Although in the near future the use of coal will be reduced and in some countries it will be stopped altogether, but the negative impacts of coal mining are still many, damaging and even endangering the environment. This is an urgency to improve the land or ex-coal mining land which is estimated to reach 8 million hectares in Indonesia. On the one hand, coal power plants can buy carbon credits for biochar applications like the scheme above. Palm oil mills on the other hand also produce a lot of solid waste, especially empty fruit bunches (EFB) that can be used for the production of biochar. These big companies could collaborate to solve climate problems due to the increasing concentration of CO2 in the atmosphere. To this day, it is reported from the Mauna loa observatory, in Hawaii, United States that the concentration of CO2 in the atmosphere has exceeded 400 ppm or there is still an increase of about 2 ppm every year, even though the global target is to decrease the concentration to only 350 ppm.    

Large Plantations and Large Farms

Fertilizer problems or soil fertility have always been the main topic or discussion for a large plantation business. This is very reasonable because maintaining productivity of crops can only be done by maintaining soil fertility or providing adequate fertilizer. For this reason, the budget for the supply of fertilizer is always a large portion of the plantation business. Then the condition leads to the question of how to make efficiency or save the fertilizer budget? Of course many techniques can be used for this purpose, but basically the selection or use of fertilizer that is appropriate and the effectiveness or absorption of fertilizer for plants is a key success factor in maintaining soil fertility. Let's try to answer the main question above.

When chemical fertilizers are increasingly abandoned because of their effects which damage the environment, there is no other choice but to use organic fertilizer. In large plantations such as oil palm plantations, basically there are also many biomass wastes from palm oil mills that can be used as fertilizer, such as fronds and palm oil trunks. But when these ingredients are also processed to become a particular product, and also the composting process of fibrous wood species takes a long time, the best choice is with organic manure. The question is where do you get livestock manure compost for the oil palm plantation? Actually there are more sources of organic fertilizer or compost that can be produced from palm oil mill effluent, namely from liquid waste. If the palm oil mill has an anaerobic digester, the biogas residue from the sludge can be used as organic fertilizer. At present there are not many palm oil mills that process liquid waste with the biogas unit, with the reason that the unit is considered expensive.

The history and experience of our predecessors before the use of chemical fertilizers can be used as a reference for this. At that time they were able to meet the fertilizer needs of their agricultural businesses, namely by sheep, goats, cattle and buffalo farming. The livestock manure is used for agricultural fertilizer and agricultural waste is used for animal feed. The basic pattern can also be developed for large plantations with several adjustment techniques to improve efficiency. Technical applications in the field that can be done, namely large plantations must cooperate with large farms or even ideally have a large farm to meet the needs of fertilizer for its plantations. For example, a palm oil plantation that has 10,000 hectares of plantation area, 100-200 (1-2%) hectares are used for sheep farming. The sheep breeding, not by just being caged, but grazing in the fields of pasture.

Why is sheep farming done in the pasture fields? This is because by grazing the cost of feed can be suppressed very large or the business becomes very economical. The biggest cost component of livestock business is feed. If the availability and supply of feed can be overcome then the other components become easier. The pasture is in the form of grass and shade trees. Making grass always available is the essence of the business, even it can be said that the pasture is grass farming itself. Rotational grazing is the best grazing technique at the moment. When the grass is fertilized with sheep dung during the grazing, the dirt produced when in the cage can be used for fertilizer on large plantations such as the oil palm. The biogas unit can be used to optimize the utilization of dirt from the cage.

Basically, sheep farming can also stand alone and also be profitable. Therefore, sheep farming can be done separately. In the case when an energy plantation is used for the production of wood pellets, it is still constrained by various things such as the presence and supply of electricity, so the farm business can still be run properly. The production of large-scale wood pellets in various regions in Indonesia is currently still constrained due to the electricity supply. This will certainly hamper the growth of the wood pellet industry so there needs to be another way to overcome this, which insha Allah will be discussed later.

With this concept, not only increases plantation and meat production, but also a complete closed cycle business that is environmentally friendly and sustainable. Honey bee farming can also be added for optimization because obviously the bees besides helping the pollination process will also produce honey, a superior product of high economic value. Various food problems, insha Allah, can be overcome with this concept. This is because from the production side it can be made very efficient with the 2 biggest cost components being reduced significantly by fertilizer and animal feed with the integration of large plantations and large farms.

Although it has used compost from livestock manure, there are still more techniques that can be applied to improve fertilizer efficiency by using biochar. With biochar, the fertilizer will be retained in the biochar pores so that slow release makes it effective for fertilization. In addition, biochar will also hold the fertilizer from leaching due to high rainfall, so that the use of fertilizer can also be saved significantly. Biochar will also be the home of microbes to decompose organic matter into nutrients needed for plants. So, in short, with biochar, the productivity of plantations is high, but the use of fertilizer is minimal because it is efficient, especially when fertilizer is produced from the farm itself. This biochar can be produced by processing the plantation biomass wastes by pyrolysis. For more details about pyrolysis can be read here.