Assessing the Potential of Bioengineering Superior Forage Grasses as Erosion and Landslide Control in the Upper Watershed Areas of Petungkriyono

Petungkriyono District, located in the highlands of Pekalongan, is an area prone to landslides and erosion. A physical vulnerability mapping study conducted by Arissaldi, T. et al. (2022) revealed that this region has three levels of physical vulnerability: low (0.0228 km²), moderate (73.88 km²), and high (10.27 km²). Additionally, Pratama, M.A. et al. (2022) found that the Kupang Watershed, which originates in Petungkriyono, has an erosion rate of 63,720.681 tons/ha/year, categorized as severe. These conditions threaten the livelihood sustainability of the local population, most of whom depend on agriculture and plantations.

Bioengineering as a Sustainable Solution

Bioengineering, or biological engineering, offers a sustainable solution to address erosion and landslides in Petungkriyono. This approach utilizes biological systems and living organisms to solve environmental issues. One promising method is optimizing the use of forage grasses, which are already common in this area.

However, why have naturally growing grasses not significantly reduced erosion and landslides? The answer lies in the lack of a specific design that considers erosion control and soil stabilization aspects. With specially designed grass planting, its effectiveness in reducing landslide risks could significantly increase.

Root Systems of Grasses for Erosion Control

Grass root systems have significant potential in reducing erosion and landslides. For example, elephant grass (Pennisetum purpureum Schaum), which is the most common grass species in Petungkriyono, has roots that can reach depths of 3-4.5 meters. These roots can bind soil particles, form networks, reduce erosion, and enhance soil fertility. Research by Satriagasa, C.M. et al. (2020) showed that elephant grass cover could reduce surface runoff by up to 98.85% on sloping land.

Economic and Environmental Sustainability

In addition to controlling erosion, superior forage grasses can enhance the economic sustainability of Petungkriyono’s residents. With high-quality animal feed, livestock development can be optimized, ultimately increasing farmers’ and ranchers’ income. In 2023, Yayasan Relung Indonesia conducted trials on planting four types of superior forage grasses—Gama Umami, Pakchong, Biovitas, and Odot—in Dusun Dranan, Yosorejo Village. Initial results indicated that these grasses not only grew well but also improved soil structure and increased organic matter content.

Environmentally, planting superior forage grasses can support sustainability by improving soil quality and increasing biodiversity. Lal et al. (1998) noted that grass planting could increase soil organic matter content by 0.1% to 0.3% per year in tropical and subtropical regions. Strong grass roots can also improve soil structure and increase water infiltration capacity.

Integrated Watershed Management Strategy

Bioengineering with superior grasses can also be part of an integrated watershed management strategy. Steps such as mapping critical areas, selecting appropriate grass species, and training farmers in planting and maintaining superior grasses are essential to ensuring the success of this approach. Regular monitoring and evaluation are also necessary to assess the effectiveness of grass planting in reducing erosion and landslides.

Conclusion

With an integrated approach based on bioengineering principles, erosion and landslide control in Petungkriyono is expected to not only reduce disaster risk but also improve the quality of life for local communities. The success of this program can serve as a model for other areas facing similar challenges, contributing to environmental conservation and sustainable economic development in various regions.

References:

• Arissaldi, T., et al. (2022). Mapping of physical landslide vulnerability in Petungkriyono District. *Journal of Geographical Sciences*.
• Pratama, M.A., et al. (2022). Analysis of land erosion hazard levels in the Kupang Watershed. *Journal of Soil and Water Conservation*.
• Satriagasa, C.M., et al. (2020). Effectiveness of elephant grass cover in reducing surface runoff and erosion. *Journal of Environmental Management*.
• Tamta, S., et al. (2023). Potential of Napier grass roots and shoots in capturing soil erosion and runoff in Himalayan Mollisols. *Journal of Soil and Water Conservation*.
• Conant, R.T., Paustian, K., & Elliott, E.T. (2001). Grassland management and conversion into grassland: Effects on soil carbon. *Global Change Biology*, 7(4), 323-337. doi:10.1046/j.1365-2486.2001.00401.x
• Lal, R., Kimble, J.M., Follett, R.F., & Cole, C.V. (1998). The potential of U.S. cropland to sequester carbon and mitigate the greenhouse effect. *Geoderma*, 82(1-3), 59-95. doi:10.1016/S0016-7061(97)00042-4
• Derner, J.D., Schuman, G.E., & Hart, R.H. (2006). Impact of perennial grasses on soil organic matter in the Great Plains. *Soil Science Society of America Journal*, 70(2), 626-634. doi:10.2136/sssaj2005.0175

Contributor:

Meiardhy mujianto