Assessment of Soil Damage for Biomass Production in Slope Area Used as Agricultural Land in Tanggetada District, Kolaka Regency

This study aimed to assess the soil degradation level for biomass production in sloping areas used as agricultural land. This research was conducted in Tanggetada District, Kolaka Regency. This research was conducted using a field survey method with a slope class approach which is used as agricultural land with a slope of 8-15%, 15-25%, 25-45%, and > 45%. The results of the study show that the status of soil damage in sloped areas used as agricultural land in Tanggetada District, Kolaka Regency, for slope classes 8-15%, 15-25%, and 25-45% included in the lightly damaged category while slope classes >45% included in the moderately damaged category. The limiting factors for soil damage status at this location are surface rock

crops (BPS, 2021). Based on the interpretation of land use maps and topographic land maps, Farmers in Tanggetada Subdistrict used farmers as agricultural land with slope classes of 8-15%, 15-25%, 25-45%, and >45% covering an area of 7,302.81 Ha. Using land with steep slopes as agricultural land will cause soil damage for agricultural purposes. Biomass production in a sloping area used as agricultural land in Tanggetada District, Kolaka Regency.

B. Literature Review 1. Soil Biomass
Biomass is organic material derived from plants and animals composed of carbon (C), hydrogen (H), and oxygen (O) atoms. Biomass also includes gases and liquids from non-fossil materials and the degradation of organic matter. Biomass is formed from the interaction of carbon dioxide (CO2), air, water, soil, and sunlight (Basu, 2010). Biomass is an environmentally friendly energy source whose carbon source comes from CO2in the air. Combustion of biomass produces the same amount of CO2as is absorbed by the photosynthesis process (Reed and Das, 1988).

Slope
The slope of the slope is a specific height difference in the relief that exists in a landform. The land's slope shows the area's character that must be considered in the direction of land use. Each region's land slope is different but generally can be classified into several groups (Sinery, Rudolf, Hermanus, Samsul dan Devi, 2019). According to Gunawan (2011), the land slope class is classified into five types. a. Mountainous with a slope of more than 45% (greater than 24°) b. Hilly with a slope of 25-45% or 14°-24° c. Wavy with a slope of 15-25% or 8°-14° d. Sloping with a slope of 8-15% or 5-8° e. Flat with a slope of 0-8% or 0-5° The slope of the slope is very influential in the process of weathering and soil development, washing, and transport of soil. Soil erosion by water on sloping areas also causes the soil to erode and be transported, ultimately leaving less fertile soil so that soil and plant productivity decreases (Septianugraha and Abraham, 2014).

Soil Damage
Soil damage is a process or phenomenon of a decrease in the capacity of the soil to support life with the loss or decline of the function of the soil, both its function as a source of plant nutrients and its function as a matrix where plant roots are anchored and where water is stored. The process of soil damage is a process or phenomenon of a decrease in the ability of the soil to support life at this time or in the future caused by human activities (Roy, 2012). The land is a resource that is the mainstay in the socio-economic activities of the community, especially in developing countries. However, land resources are not sustainable resources. Land resources have changed due to natural processes and human activities. Changes due to natural processes are caused by changes in the earth's surface due to geomorphology. The ongoing geomorphological process will have a direct or indirect impact on the earth's surface's physical condition. The geomorphological process will result in a decrease in the quality and carrying capacity of the land, which in turn will cause land degradation.
Meanwhile, land degradation caused by human activities occurs due to the use of the environment by humans who ignore environmental balance. Land degradation is the loss or reduction of the potential use of land to support life. The loss or change in appearance causes it not to be replaced by others (Siregar, 2010).

Research Location
This research was conducted in March 2022. The study was located in Tanggetada District, Kolaka Regency, Southeast Sulawesi Province, and the sample analysis was carried out at the Analytical Laboratory of Halu Oleo University, Kendari.

Research procedure
This research was conducted using a field survey method with a slope class approach which is used as agricultural land with a slope of 8-15%, 15-25%, 25-45%, and >45%, identify the characteristics of the land.   Method scoring is carried out by considering the relative frequency of soil classified as damaged in one land unit and then used to determine the category of soil damage status.

D. Result and Discussion
The causes of soil damage are caused by the nature of the soil and human activities that cause the land to be disturbed/damaged and unable to function anymore. Activities that use land and other natural resources uncontrollably can cause damage to the soil for biomass production, thereby reducing the quality and function of the soil, which in turn can threaten the survival of humans and other living things. Microbial Count <10 2 cfu/g Soil damage analysis. Analysis of soil damage status for each level of the slope is described in the following table: Based on observational data on soil damage used as agricultural land on slopes of 8-15%, including mild damage with inhibiting factors for bulk density and soil porosity. The ideal for biomass production is below 1.4 g/cm 3 . One factor that affects plant growth is the high and low density of the soil. The denser the soil, the more difficult it will be for plant growth (Haridjaja, O., Hidayat, Y., dan Maryamah, L.S., 2010).

Table 6. Soil Damage Status on slope class 15-25%
The status of soil damage on slopes of 15-25% is categorized as lightly damaged with inhibiting factors bulk density, porosity, and redox. The more sloping soil is, the more intensive erosion occurs, which causes loss of organic matter and nutrients in that location. The low content of organic matter will affect the density, soil porosity, redox, and the number of microbes in the soil. The density of the soil is an indication of the density of the soil. The denser the soil, the higher the weight of its contents, which means it is more difficult to pass water or penetrate plant roots. (Hardjowigeno, 1993 pass water flow (permeability) or the speed of water flow to pass through the soil mass (percolation). The status of soil damage on slopes of 25-45% is included in the category of light damage with inhibiting factors for bulk density and permeability. The value of density and permeability have implications for the ability of plant roots to reach water in the soil. This occurs due to intensive land use activities without any processing in the tillage layer, thus increasing soil density and bulk density. Arifin (2010) states that continuous intensive soil management without resting the soil and without adding organic matter damages the soil structure. This results in a decrease in soil permeability.
The increase in soil density is due to agricultural activities, which also affects the increase in soil density. Overall, the survey results show that the value of soil fill density increases with increasing soil depth, both in locations that produce high production and locations with low production. This follows Hardjowigeno (2003) statement that the higher bulk density causes the soil density to increase, and aeration and drainage are disturbed. Soil damage status on slopes >45% has moderate damage status with inhibiting factors: surface rock, bulk density, permeability, redox, and Total microbes. Soil with a slope of > 45% will experience high erosion, affecting the soil properties that affect biomass production. Andrian, Supriadi dan Purba M., (2014) and Kasmawati, Hasanah U., dan Rahman, A., (2016) stated that the more sloping the slope of the soil, the greater the water flow velocity on the surface so that the erosion of parts of the soil is more significant. Dela & Mardiatno (2012) stated that the flow velocity would increase with the more excellent slope value, and the carrying capacity of the crushed soil particles would be higher so that the erosion process would be even greater. One of the inhibiting factors at this location is the number of microbes. Microbes are one of the critical factors in the soil ecosystem because they can affect the cycle and availability of nutrients for plants and the stability of soil structure. Biomass formation is also influenced by many other factors, namely temperature and humidity (Joergensen, R.G., P.C Brookes and D.S Jenkinson, 1990). The ideal microbial count for biomass production is more significant than 10 2 cfu/g soil. Soil with high micro-organisms will accelerate the process of biomass decomposition that plants can utilize.

E. Conclusion
Based on the results of the assessment of the status of soil damage on sloped areas used as agricultural land in Tanggetada District, Kolaka Regency, for the slope class 8-15%, 15-25%, and 25-45%, including the category of mild damage while the slope class >45% belongs to the damaged category. Currently. The limiting factors for soil damage status at this location are surface rock, number of microbes, bulk density, permeability, and redox.