Increasing Food Agriculture Productivity: Biochar Application or Forest Clearing for Food Estate?

Indonesia currently ranks 69th out of 113 countries in 2022 in food security and this is lower than Malaysia and Vietnam with indicator points below the global average. This condition is concerning considering that Indonesia was once self-sufficient in food before and even the price of rice in Indonesia is the most expensive in ASEAN. Efforts to maintain food productivity are indeed a challenge, let alone increasing it. Along with increasing population growth, the need for food automatically increases. The condition of declining food production and productivity is related to a number of factors including land conversion to non-agricultural land, and soil / land damage. A number of regulations have been made to stem the rate of decline in food productivity due to these two things.

Regarding land damage, repair efforts need to be made so that agricultural productivity increases. It is estimated that the area of ​​land damage that occurs is very large with a high level of severity. This requires gradual and sustainable repair efforts with various strategies including improving farming patterns and even a number of incentives. Only with these efforts can the agricultural sector as a source of food be repaired or if not, the damage to agricultural land will get worse so that repair efforts will be more difficult.

Biochar application or forest clearing for food estate ?
Biochar application will be able to repair damaged lands. In addition to being a slow-release fertilizer agent so that fertilizer use becomes efficient and does not pollute the environment, increasing soil pH, increasing soil organic carbon and increasing agricultural productivity, biochar will also help overcome the management of agricultural waste that has so far polluted the environment. The increase in agricultural productivity from the use of biochar is on average around 20%. If Indonesia's current rice production is around 31 million tons per year, then the application of biochar will increase total rice production to 37.2 million tons (an increase of 6.2 million tons). With an average rice production per hectare of 6 tons, the increase of 6.2 million tons is equivalent to increasing the area of ​​agricultural land by 1.03 million hectares. Even damaged land from post-mining can be reclaimed and rehabilitated with the application of biochar, with the land area also reaching millions of hectares. This is certainly better than clearing new forest land for food estates because of its environmental impact. 

As the human population grows, the need for food and energy will continue to increase. Indonesia's population in 2045 is estimated to reach 319 million people and the world's population in 2050 is approaching 10 billion people. The need and urgency of biochar to improve soil quality is increasing. Tens of millions of hectares of all Indonesian acidic soils, which are classified as dry land acidic soils, need to be improved with biochar. This means that the business potential reaches billions of dollars or trillions of rupiah. Meanwhile, rice imports in 2024 are targeted to reach 3.6 million tons (as a buffer), a large amount. With an annual rice requirement of around 31 million tons, the contribution of imported rice reaches more than 10%.

Biochar in addition to repairing soil damage so that it increases its fertility which ultimately increases agricultural productivity is also part of the climate solution, namely by means of carbon sequestration. Biochar applied to the soil will last hundreds or even thousands years, and does not decompose. This is another advantageous factor for biochar producers, namely getting carbon credits. The quality of biochar will determine the acquisition or price of the carbon credit, so that the raw materials of biochar and its production process are affected. The price of carbon credits is increasing so that it is increasingly attractive and also the carbon credit market continues to grow.

Damage to land or agricultural land that occurs is mostly caused by excessive use of chemical fertilizers. If the use of chemical fertilizers can be reduced in dosage or with sufficient use, there will be improvements in land quality. Even if chemical fertilizers are gradually reduced in dosage and organic fertilizers / compost are increasingly added so that in the end chemical fertilizers are not used at all, soil fertility will be optimal as well as agricultural productivity.

The photo from here

Of course, this requires time and continuous effort. Livestock must also be encouraged so that compost / organic fertilizer can also be produced sufficiently from the processing of livestock manure. Integrated farming with livestock is the best solution for improving agricultural land with biochar, especially increasing the efficiency of fertilization. If the above can be implemented properly, then forest clearing for food estate land can also be slowed down / held back by considering all aspects comprehensively so that it is not a short-term solution that tends to be forced, and rushed because of the regime's image efforts even at a cost of hundreds of trillions.

Biochar to Increase the Porosity of Damaged and Marginal Soils

Basically, porous materials will have large surface areas. The more pores, the greater the surface area of the material. Efforts to increase pores or expand the surface can be done in many ways depending on the goal. The type of pores also affects the total surface area and also the use or application of the material. For example, materials that have more micropores will have a larger surface area and have different specific uses than materials that are dominant with medium pores (mesopores) or large pores (macropores). Designing a material so that it is micropore, mesopore or macropore dominant can be done, namely by selecting raw materials and process technology, for example biochar produced from pyrolysis will produce a larger surface area compared to the initial unprocessed biomass.

In land related to use for agriculture or plant cultivation, the aspect of soil porosity or pores is an important aspect. This is mainly related to nutrient and water retention as well as soil aeration. Expanding soil pores will be very useful for improving soil quality so as to support the success of agriculture or plant cultivation. Soil that has more pore space will be able to store large amounts of water and nutrients too. Soil that has a high number of small (micropore) and medium (mesopore) pores will tend to hold water and nutrients more strongly than soil that has many large pores (macropore). And if there is evaporation or use of water by plants or a leaching process occurs in nutrients, then the large pores (macropores) left behind by the water and nutrients will follow the medium (mesopore) and  micropore.

Providing organic material in the form of compost to the soil is generally used to form more micropore spaces. The more micropore spaces that are formed, the more moisture the soil will have. Soil organic matter has more pores than soil mineral particles, which means that the surface area for absorption is also greater. Providing organic material in the form of compost, apart from increasing the number of pores or soil porosity, also reduces the volume weight. This organic material or compost is a source of energy for soil microbial activity, reduces soil volume, improves soil structure, aeration and air binding capacity. Soil with high total pores, such as clay, tends to have a low volume weight, while soil with low total pores, such as sandy soil (coarse texture), tends to have a high volume weight.

Apart from increasing total pores, adding compost also increases soil pH, namely in sandy soil and acidic soil, including entisol, ultisol and andisol and is able to reduce soil exchangeable Al. The increase in pH is due to the process of breaking down the compost. The results of this overhaul will produce basic cations which can increase the pH or release basic cations from the compost into the soil so that the soil is saturated with basic cations. The weathering or decomposition process of the compost will release alkaline cations which cause the soil pH to increase.

Soil organic C will also increase with the addition of compost and total N (nitrogen). The more organic matter added to the soil, the greater the increase in organic C in the soil. Compost from animal waste has the lowest C/N ratio compared to compost from plants. Organic materials that have a high lignin content will inhibit the speed of N mineralization and the C/N ratio will be high. In fact, further decomposition of organic matter is characterized by a low C/N ratio. Meanwhile, a high C/N ratio indicates that decomposition has not yet continued or has just started. In this process there is a decrease in carbon / C and an increase in nitrogen / N.

The need for compost on marginal land such as sandy land is also much greater, reaching almost twice as much as on ordinary or standard land. Meanwhile, the need for chemical fertilizer on marginal land is usually less than on normal/standard land. Ideally, using compost at optimal doses will be able to increase plant productivity and preserve the environment.

Unlike compost which will completely decompose, as a soil amendment, biochar can last hundreds of years in the soil. Biochar, which has a large surface area, also has many micropores which increase soil porosity, like compost. Pyrolysis conditions are important in determining the quality of biochar besides the biochar raw material itself. In rough textured soils such as sandy land, biochar will improve water and nutrient retention because its micro pores slow down its release (slow velocity). The quality of biochar is directly proportional to the efficacy of biochar treatment. A number of parameters related to the application of biochar for soil improvement/treatment are also similar to compost, including: soil carbon content and mineralization, soil micro-structural & aggregation, bioavailable nitrogen, and microbial activity & diversity. Almost all biochar is not fertilizer like compost, read more details here, so inoculation (charging) of biochar before application can be done by filling the biochar pores with water containing specific chemical elements or microbes. This will produce rapid positive effects compared to biochar alone. Apart from that, biochar is also used to reduce carbon dioxide (CO2) in the atmosphere as carbon sequestration. This is very much in line with the current problems of climate change and global warming.

Biochar is a heterogeneous substance rich in aromatic carbon and minerals. Biochar is produced from the pyrolysis process (a process where organic material is decomposed at temperatures between 350 to 1000 C with well-controlled conditions of minimal or no oxygen and is widely used for soil amendment). The carbon content for biochar must be above 50%, whereas if pyrolysis products of organic material with a carbon content of less than 50% are not included in the biochar category but are referred to as pyrogenic carbonaceous material (PCM). The organic carbon content of pyrolyzed char fluctuates between the range of 5% and 95%, depending on the raw material and temperature. process used. For example, the carbon content from pyrolysis of chicken manure is around 25%, while from wood it is around 85% and bone is less than 10%. When using mineral-rich raw materials such as sewage sludge or animal waste, the pyrolysis products will contain high ash so that the total pores are smaller.

Apart from that, biochar must also have a molar ratio of H/Corg of less than 0.7 and a molar ratio of O/Corg must be less than 0.4. The molar ratio of H/Corg is an indicator of its degree of carbonization (pyrolysis) and is therefore closely related to the stability of biochar, which is one of the most important characteristics of biochar. This ratio fluctuates depending on the type of biomass used and the conditions of the production process. A ratio value that exceeds 0.7 indicates non-pyrolytic char or inadequate pyrolysis process conditions. Meanwhile, the O/Corg ratio is also used to differentiate it from other carbon products. Specific surface area is also a measure of the quality and characteristics of biochar, and also a control value for the pyrolysis method used. Although a surface area of less than 150 m2/gram can be used in certain cases, it is preferred or preferred if it is more than 150 m2/gram.

With the characteristics above, compost and biochar as well as chemical fertilizers can be used together, even in the composting process biochar can also be added to reduce N organic released into the atmosphere. Apart from increasing the number of micro pores in the soil or increasing the total pores, the nutrients from compost and chemical fertilizers will also be released more slowly (slow release). How slow release the fertilizer can be designed depends on needs, for more details you can read here. When biochar is used properly, it can maximize harvest productivity, improve soil fertility and minimize environmental impacts. Four things need to be considered when applying biochar, namely the right source of biochar, the right location (right place), the right dose (right rate) and the right time. Not all types of soil and plants will produce increased yields from biochar applications, so it is important to know what type of soil produces increased productivity. A soil map can help to identify soil types that have the potential to provide benefits or advantages from the application of biochar. Farmers can consult with agricultural consultants or professionals in the field to help with the selection and application of biochar. 

Biochar and Specific Organic Fertilizer for Post-Mining Reclamation Treatment

Mining activities are not just digging, loading and transporting, but environmental sustainability is also an important thing that must be considered. Even post-reclamation has become an obligation for mining companies with severe sanctions if neglected. Environmental damage due to mining if left unchecked will become a serious environmental problem such as natural disasters, and become a bad legacy for future generations. This means that post-mining reclamation must be carried out properly or adequately so that the negative impact on the environment can be minimized or even eliminated. Reclamation planning and implementation needs to be done well so that the reclamation goals can be achieved.

Low fertility on post-mining land is indeed a separate problem for revegetating the land. When a mining company has good management of overburden (OB) and top soil so that it can be returned (backfill) to the former mining pit (void) as before, the decline in soil fertility can be minimized. But if the management is bad, the fertility of the soil will drop drastically or be severely damaged so that in these conditions certain treatments need to be carried out to restore, improve or increase the fertility of the soil. The condition of land that has low fertility or is like barren land is almost the same as sandy land. In general, coastal sandy land has the following characteristics: sandy soil texture (90%), granular soil structure, loose consistency, low nutrient content, low soil ability to store nutrients, very fast permeability, drainage and infiltration, porous (majority with mesopores and macropores, and less of micropores), low water holding capacity, low soil ability to support plant growth and relatively high salt content or is a marginal land for agriculture or plant cultivation, so the treatment approach on sandy land with post-mining land is an effort effective approach.

Agriculture or cultivation of sandy land can be done for both seasonal and annual crops, the same goes for post-mining land. Factors of effectiveness and efficiency need to be done to get optimal results such as the type of nutrient and its amount, water requirement and so on. Conditioning the land so that it can hold water and nutrients must be done so that the added fertilizer can be utilized properly. Minimum input so that production costs can be reduced or economic factors are other important things. With post-mining land areas that can reach thousands of hectares, the input in the form of quality fertilizer is a must. In addition to inorganic fertilizers as macro elements, organic fertilizers as a provider of micro elements also need to be added. Specific organic fertilizer according to land conditions and plant needs can be made for this purpose. The use of compost with volumes ranging from 20-30 tons/hectare can be significantly reduced by using this specific organic fertilizer.

Sandy soils generally have high P and K content. The function of organic matter, in this case manure, can stimulate the availability of P nutrients that have accumulated in the sandy soil in the form of total P, so that available P becomes greater. With the availability of P, the available K is also greater, because P interacts with K. Amelioration technology to increase soil fertility is needed. Amelioration itself is an effort to improve soil fertility through the addition of certain materials. Amelioran is a substance that can increase soil fertility by improving physical and chemical conditions. Biochar as a soil amendment will be effective for this purpose, even when compared to other soil amendments, biochar has many advantages, one of which is being able to last or not decompose in the soil for hundreds of years. While increasing the efficiency of using biochar is by designing slow release fertilizer (SRF) so that the release of fertilizer is according to plant needs or can be used by plants optimally.

Plants are composed of 92 elements, but only 16 are essential for their growth and development. Of the 16 elements, elements C, H, and O are obtained from air and water (in the form of CO2 and H2O), while 13 other essential mineral elements are obtained from the soil and are generally classified as "nutrients". There are 6 macro nutrients namely N, P, K, S, Ca and Mg. These macro elements are needed by plants in large quantities with a critical content (value) between 2 – 30 g/kg dry weight of plants. These macro nutrients are divided into two, namely primary nutrients (N, P, K) and secondary nutrients (S, Ca, Mg). Primary nutrients are provided in the form of all types of plants and all types of soil. Meanwhile, secondary nutrients are only for certain types of plants and certain types of soil. While micro nutrients consist of 7 elements consisting of 5 elements which are metals namely Fe, Mn, Zn, Cu and Mo, and 2 non-metallic elements namely Cl and B. The need for micro nutrients is relatively small ranging from 0.3 – 50 mg/kg dry plant weight. The combination of macro fertilizers and specific organic fertilizers will maximize plant growth.

Biochar and N2O Emission in Agriculture

Urea Plant

The world's production of urea fertilizer in 2020 will reach around 181 million tons and this type of urea fertilizer is the most widely used. In practice, the use of urea fertilizer is mostly inefficient, so it is wasted and pollutes the environment. It is estimated that the level of loss of urea and pollution to the environment, in use reaches around 40% or 72.4 million tonnes globally. Efforts to improve fertilization efficiency can be done by modifying it to become a slow release fertilizer (SRF), one of which is highly recommended, namely biochar, as a slow release agent, read more details here. In addition, the use of urea causes N2O emissions. N2O (nitrogen monoxide) is a greenhouse gas and air pollutant, N2O is a dangerous gas because it has a stronger effect about 300 times per unit weight than CO2 in a span of 100 years. In air, N2O reacts with oxygen atoms to form NO, and NO then breaks down ozone.

Urea is one of the conventional fertilizers commonly used in agriculture. Urea has a main content in the form of nitrogen which is absorbed by plants in the form of ammonium (NH4+) and nitrate (NO3−). Loss of nitrogen in the fertilizer occurs due to evaporation as ammonia (NH3), immobilization in the pores of the soil or washed by water, both rainwater and irrigation water. In addition to economic losses, environmental pollution due to excess nitrogen also causes a number of negative effects. Nitrogen from urea can also be lost due to complete denitrification of nitrates to produce nitrogen gas (N2) or through incomplete nitrate denitrification to produce nitrogen monoxide (NO) and nitrous oxide (N2O) gases, which evaporate from the soil. Nitrate, nitrogen monoxide (NO) and nitrous oxide (N2O) gases contribute to environmental problems. Nitrates are harmful substances that cause water pollution. Excess concentration of nitrate in drinking water is harmful to health, especially in infants and pregnant women.

Meanwhile, nitrous oxide (N2O) has now become the largest ozone depleting substance emitted in the 21st century. The main source of global nitrous oxide (N2O) emissions is nitrogen-based fertilizers, especially urea fertilizer. The presence of N2O in the lowest region of the atmosphere (troposphere) can cause a greenhouse effect or global warming because N2O traps infrared radiation emitted from the earth's surface and then warms the atmosphere. In addition, N2O can migrate up into the stratosphere where it reacts with oxygen atoms to produce some nitric oxide (NO). Then, the depletion of the ozone layer occurs because NO reacts with stratospheric ozone (O3) to form NO2 and O2. Furthermore, NO2 reacts with O to form NO again. The depletion of the ozone layer increases the amount of UV rays from the sun that reach the earth's surface.

Biochar application has been suggested as a strategy to reduce nitrous oxide (N2O) emissions from agricultural soils while increasing soil carbon (C) stocks, especially in tropical areas. Climate change, especially temperature increase, will affect soil environmental conditions and thereby directly affect soil N2O volume. Related to climate issues, there are two aspects of the role of biochar, namely as a carbon sequestration / carbon sink and reducing nitrous oxide (N2O) emissions, while related to agriculture, namely increasing soil fertility and increasing the productivity of agricultural products. The multi-benefit application of biochar is predicted to become a trend in the bioeconomy era, when the aspects of sustainability, food adequacy and as a climate solution become a complete package in one action.

The effort to minimize the use of urea fertilizer is by modifying it to become a slow release fertilizer with biochar as the slow release agent. The use of excess doses of urea apart from damaging the environment is also a waste. The use of urea can still be used to a certain extent, namely that all of the urea can be absorbed by plants with minimal loss or environmental pollution. When all the nutrients/fertilizer nutrients can be completely absorbed by the plants, it means that there is no residue in the soil, so that damage or environmental pollution can be minimized even avoided. The residue, especially in the long term, will cause severe soil damage. Slow release with close to the rate of absorption of nutrients by plants is a condition that is pursued or NUE (nutrient use efficiency) as much as possible. The technique of modifying urea fertilizer into SRF is the key.