Vermicast as a Fertilizer

Worms have been tirelessly toiling away, building soil in the same manner as their ancestors 600 million years ago.  The work that they do may be one of the most important and undervalued positions, but through their physical action and the castings produced, worms create the elixir for life

(Edwards, 1995).

Then comes the term “vermicast”; Vermicast is an organic/natural fertiliser that is created by using composting earthworms. These earthworms are placed in a container which is filled with compost. The worms make their way through the food and excrete what we call Vermicast. Vermicast enriches the soil and helps to ensure that plants receive all the nutrients they need to grow successfully. Vermicast renews the soil and is used as a natural fertiliser. It is made by recycling organic waste which is transformed into natural fertilizer by using earth worms.

Worms are the great alchemists, concentrating the important plant nutrients such as nitrogen, potassium, phosphorus and calcium into forms that are much more available to the plants than those in the parent materials. The addition of vermicast has consistently improved seed germination, enhanced seedling growth and development and increased plant productivity much more than would be possible from the mere conversion of mineral nutrients into more plant available forms.

Vermicasting can be done on a small scale by homeowners with household organic wastes, on a large-scale by farmers with manure or even by the food industry using organic wastes such as fruit and vegetable cull materials.

Through proper design, Vermicasting is a method of waste handling that:

 

  • is clean, socially acceptable, with little to no odour

  • requires no energy input for aeration

  • reduces the mass of waste by 30%

  • produces a valuable vermicast byproduct

  • even generates worms as fishing bait

CHARACTERISTICS OF VERMICAST

Nutrients

Vermicast nutrient content varies with earthworm feed type, but feeding waste to earthworms does cause nitrogen mineralization, followed by phosphorous and Sulphur mineralization after egestion. A typical nutrient analysis of casts is C:N ratio 12–15:1; 1.5%–2.5% N, 1.25%–2.25% P2O5 and 1%–2%, K2O at 75%–80% moisture content. The slow-release granules structure of earthworm casts allows nutrients to be released relatively slowly in sync with plant needs.

 

Salinity

Ammonium is the main contributor to salinity levels. Earthworms are repelled by salinity levels above 5 mg/g. Therefore, if the starting material is low in salt, the resulting vermicast will be as well. In fresh vermicast, ammonium mineralized in the earthworm gut is nitrified over 2 weeks.

 

Pathogens

Pathogen levels are low in vermicast, which is considered a Type A biosolid when excreted by earthworms. This is a lower pathogen level than in typical composts. Vermicast is low in pathogens because earthworms consume fungi, and aerobic bacteria do not survive low oxygen levels in the gut. Low pathogen levels could also be due to the fact that vermicasting does not build up heat, which allows disease-suppressing organisms to survive the vermicasting process and outcompete pathogens.

 

BENEFITS OF VERMICASTING

Now, what’s not to like about Vermicast? It provides a multitude of services; increasing soil water and nutrient retention, texture, nutrient availability and aiding in disease prevention. Studies show improvements in crop yield, bunch sizes, fruit set, fruit storage, trunk diameters and more. These positive affects have been shown to be measurable for many years following applications.

Greengold Farms Pampanga (GG Farms) is a market leader in low-cost agri-supplies. We provide consulting for Agro-Businesses, Foundations, LGU’s, and Multi-Purpose Cooperatives. We encourage those with a passion for agriculture to improve overall productivity.

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