The findings arrive at a time when sustainable agriculture has become a growing priority. Farmers across Indonesia and many other countries are increasingly encouraged to reduce dependence on synthetic fertilizers because of their long-term effects on soil quality, production costs, and environmental health. Organic fertilizers produced from livestock waste offer a promising solution by recycling agricultural by-products while improving soil fertility.
Pakcoy, also known as bok choy, is one of the most popular leafy vegetables in Indonesia. It is widely consumed because of its nutritional value, containing vitamins A, B, and C, calcium, phosphorus, iron, protein, and dietary fiber. Rising consumer demand has increased the need for efficient and environmentally friendly cultivation practices that can sustain production without degrading agricultural land.
According to the researchers from Universitas Methodist Indonesia, improving soil fertility through organic fertilization could help farmers increase yields while reducing waste from livestock farming. Cow manure, which is often considered agricultural waste, can become a valuable resource when properly managed. Rabbit urine, another livestock by-product, has also attracted attention because of its relatively high nitrogen content, making it a potential liquid organic fertilizer.
To evaluate the effectiveness of both materials, the research team carried out a field experiment in Sunggal District, North Sumatra. They cultivated Nauli F1 pakcoy using a factorial randomized block design that compared four rates of cow manure with three concentrations of fermented rabbit urine fertilizer.
The cow manure treatments consisted of:
- No cow manure
- 1 kilogram per plot
- 2 kilograms per plot
- 3 kilograms per plot
Meanwhile, rabbit urine fertilizer was applied at concentrations of:
- 40 milliliters per plot
- 50 milliliters per plot
- 60 milliliters per plot
Throughout the growing period, the researchers monitored plant height, leaf number, and total harvest weight. The collected data were analyzed statistically to determine whether the fertilizer treatments produced meaningful differences in plant performance.
The results clearly demonstrated that cow manure played the dominant role in improving pakcoy growth.
Among all treatments, 2 kilograms of cow manure per plot, equivalent to approximately 20 tons per hectare, consistently produced the best overall performance.
The study reported several important findings:
- Plant height increased significantly with cow manure application.
- Plants produced more leaves than those grown without manure.
- Harvest weight reached its highest level at approximately 1,345.89 grams per plot under the 2-kilogram treatment.
- Increasing manure beyond the optimal level did not improve production and instead began to reduce plant performance.
- Rabbit urine liquid fertilizer showed no statistically significant effect on plant height, leaf number, or harvest weight.
- Combining cow manure with rabbit urine fertilizer did not produce additional benefits beyond those achieved with cow manure alone.
The researchers explain that cow manure improves both the physical and chemical properties of soil. It loosens compacted soil, increases water retention, and creates better conditions for root development. Healthier roots absorb nutrients more efficiently, particularly nitrogen, which is essential for leaf development and overall plant growth.
Nitrogen also supports photosynthesis, enabling plants to produce more biomass. As leaf production increases, the plant captures more sunlight, resulting in stronger vegetative growth and heavier harvests.
However, the research also highlights that more fertilizer is not always better. Applying cow manure above the optimal level appeared to reduce growth, likely because excessive organic matter increased soil moisture to the point that root health was affected. Poor root conditions reduce nutrient uptake and ultimately lower crop productivity.
In contrast, the rabbit urine fertilizer did not deliver measurable improvements during the experiment. Although rabbit urine contains valuable nutrients, particularly nitrogen, the concentrations tested in this study were apparently insufficient to influence pakcoy growth significantly.
The authors suggest that future research should investigate higher application rates to determine whether stronger concentrations could produce different results.
According to Pantas Simanjuntak and colleagues from Universitas Methodist Indonesia, properly applied cow manure can become an effective organic fertilizer that simultaneously improves soil fertility and increases pakcoy production. The researchers emphasize that the observed benefits were achieved without relying on additional chemical fertilizers, supporting more sustainable vegetable farming practices.
The practical implications extend beyond pakcoy cultivation. Livestock waste is widely available in rural communities, and transforming cow manure into organic fertilizer can reduce environmental pollution while lowering production costs for farmers. This circular approach also supports government initiatives promoting sustainable agriculture and responsible waste management.
For agricultural extension officers, policymakers, and agribusiness practitioners, the study offers evidence-based recommendations for improving vegetable production using locally available organic resources. Farmers seeking to reduce fertilizer expenses may benefit from applying approximately 20 tons of cow manure per hectare, while further evidence is still needed before recommending rabbit urine fertilizer at higher concentrations.
As demand for sustainably produced vegetables continues to grow, research such as this provides practical guidance that balances productivity with environmental responsibility. Rather than relying exclusively on synthetic inputs, farmers may achieve strong yields by optimizing organic fertilization strategies that improve long-term soil health.
Author Profile
Pantas Simanjuntak, together with Efbertias Sitorus, Lince Romauli Panataria, Meylin Kristina Saragih, and Arie Bagus Lase, is affiliated with the Faculty of Agriculture, Universitas Methodist Indonesia. Their research focuses on agronomy, crop production, sustainable agriculture, soil fertility, and the application of organic fertilizers to improve horticultural productivity.
Source
Article Title: Growth and Production Response of Pakcoy (Brassica rapa L.) Plants to the Application of Cow Manure and Liquid Organic Fertilizer (POC) from Rabbit Urine
Journal: Formosa Journal of Science and Technology (FJST)
Publication Year: 2026
DOI: https://doi.org/10.55927/fjst.v5i6.97
Official Journal: https://journalfjst.my.id/index.php/fjst
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