Plastic mulch has long been a standard practice in vegetable production because it effectively conserves soil moisture and suppresses weeds. However, its widespread use also creates environmental challenges. Plastic residues remain in agricultural soils for years, interfere with soil microorganisms, and contribute to long-term pollution. These concerns have encouraged researchers worldwide to seek biodegradable alternatives that maintain crop performance without generating persistent waste.
The research team from Universitas Quality Berastagi explored two abundant local materials—banana stalks (Musa sp.) and water hyacinth (Eichhornia crassipes). Banana stalks are widely available as agricultural waste, while water hyacinth is considered an invasive aquatic weed that frequently disrupts rivers and lakes. By converting these materials into Organic Mulch Sheets (OMS), the researchers aimed to create a practical product that not only suppresses weeds but also utilizes underused biological resources.
Testing Organic Mulch Under Field Conditions
The study was carried out in vegetable fields in Barusjahe Village, Karo Regency, at an elevation of approximately 1,300 meters above sea level. Researchers compared four treatments:
- No mulch (control)
- Banana stalk mulch
- Water hyacinth mulch
- A 50:50 mixture of banana stalk and water hyacinth mulch
The experiment evaluated several practical indicators, including the mulch's physical properties, durability in the field, soil-covering ability, weed population, weed biomass, and caisim yield. Laboratory testing using a Universal Testing Machine (UTM) at the Faculty of Industrial Engineering, Universitas Sumatera Utara, was also performed to measure the mechanical strength of each mulch material before field application.
Rather than relying only on visual observations, the researchers combined laboratory measurements with field performance to understand how material strength influenced weed suppression under real farming conditions.
Mixed Organic Mulch Delivered the Best Overall Performance
Among all treatments, the 50:50 mixture of banana stalk and water hyacinth consistently produced the strongest overall results.
Key findings include:
- Tensile strength reached 0.9761 MPa.
- Young's modulus measured 15.7532 MPa, indicating strong structural stability.
- The mulch experienced the lowest deterioration rate (45%) during field use.
- Soil coverage effectiveness reached 80%, the highest among all treatments.
- Weed density was reduced to only 28.33 plants, compared with much higher numbers in other treatments.
- Weed biomass averaged only 6.33 grams, making it the most effective treatment for suppressing unwanted vegetation.
In comparison, plots without mulch recorded approximately 140.67 weeds, while plots covered with banana stalk mulch or water hyacinth mulch individually still contained around 44–46 weeds. The researchers observed that the mixed mulch created a denser surface barrier, limiting sunlight from reaching weed seeds and reducing their ability to germinate.
Statistical analysis further confirmed that mulch treatments significantly reduced weed biomass compared with the control treatment. Although the three organic mulch types did not differ significantly from one another in statistical comparisons, all performed substantially better than having no mulch at all.
Weed Control Does Not Automatically Increase Crop Yield
One notable finding was that improved weed suppression did not translate into a statistically significant increase in caisim yield.
According to the study, differences in mulch type did not significantly affect plant weight. The researchers explained that crop productivity depends on multiple interacting factors beyond weed competition, including soil nutrients, moisture availability, environmental conditions, and nutrient dynamics during the decomposition of organic materials. During the early stages of decomposition, organic mulch may temporarily reduce nitrogen availability as soil microorganisms break down plant fibers.
This finding suggests that while organic mulch is highly effective as a weed management strategy, improving vegetable yield requires integrated crop management practices rather than weed suppression alone.
Supporting Sustainable Agriculture Through Local Resources
The research demonstrates how locally available biological waste can become a valuable agricultural input instead of an environmental burden.
Using banana stalks and water hyacinth as mulch materials provides multiple benefits. Farmers can reduce dependence on plastic mulch, lower weed management costs, and make productive use of agricultural residues and invasive aquatic plants. At the same time, biodegradable mulch contributes organic matter back to the soil after decomposition, supporting long-term soil health.
As Theo Nicodemus Tarigan and colleagues from Universitas Quality Berastagi conclude, the 50:50 combination of banana stalk and water hyacinth offers the best balance between mechanical strength, field durability, and weed suppression, making it the most promising organic mulch alternative for caisim cultivation. They also recommend further research involving thicker mulch sheets, longer observation periods across multiple growing seasons, and additional soil analyses to better understand the long-term effects on soil fertility and crop productivity.
Author Profile
Theo Nicodemus Tarigan is a researcher from Universitas Quality Berastagi specializing in agricultural cultivation, sustainable farming technology, and the utilization of organic biomass for environmentally friendly crop production. This research was conducted in collaboration with Chaula Lutfia Saragih and Agus Susanto Ginting, who are also affiliated with Universitas Quality Berastagi.
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