Determination of Optimal Combination of Substrates for Vermicast Production Using Locally Available Organic Wastes

Rationale

Soil nutrients is a fundamental factor in agricultural production and essential for the production of foods and fiber that we consume on a daily basis (Farmers.gov, 2023). But soil nutrients are being depleted due to intensive and mismanaged farming. As a result, nitrogen retention has declined by 42%, phosphorus levels have decreased by 27%, and sulfur by 33%. Plants need these nutrients to function properly, including photosynthesis, the production of enzymes, protein synthesis, and more (Melville, 2020). One of the amendments used to improve soil nutrients is vermicompost.  

Vermicompost has long been recognized as one of the most effective methods of increasing crop yields by improving soil physical, chemical, and biological properties (Gopinath, 2010). It was introduced in the Philippines in the 1970s (Guerrero, 2004) and is now being extensively practiced by our local farmers. From substrates that include locally available plant biomass and animal manures, farmers are able to produce volumes of vermicompost. This kind of composting is considered a low-cost technique that transforms organic wastes into biodegraded by-products through the combined action of earthworms and microorganisms (Gomez-Brandon and Dominguez, 2013).

In the study of Ngo (2011), vermicompost is a uniform and odorless material with good physical structure and high microbial activity. It contains quantities of various nutrients and plant growth-regulating substances that are beneficial for plant growth (Roy et al., 2010; Arancon and Edwards, 2011). Numerous studies have found that vermicompost amendments can improve soil chemical properties, increase the availability of nutrients to plants, promote biological activities, and enhance crop yield (Song et al., 2015; Doan et al., 2015; Goswami et al., 2017). These are the promising characteristics of vermicompost in improving the growth and yield of crops.

However, one of the most significant factors affecting the quality of vermicompost is the original raw material (Dominguez, 2004). Substrates have different levels of nutrient content. It depends on the kind of substrate that will be utilized to produce enriched vermicompost because some have low nutrient content while others have high nutrient levels. Therefore, it is important to determine the optimal combination of substrates using different organic wastes or biomass to maximize its quality and crop productivity.

The National Soil and Water Resources Research and Development Center for Hillyland Pedo-Ecological Zone (NSWRRDC HILLPEZ) of the Department of Agriculture – Bureau of Soils and Water Management (DA-BSWM) is mandated to develop knowledge products on cost-efficient practices, environment-friendly technologies, and studies to achieve its objectives. In compliance with this mandate, the center conducted a study that intends to develop a protocol utilizing locally available raw materials. The protocol would feature the optimal combination of substrates to produce quality vermicompost and response of African Night Crawler (ANC) with regard to its weight, size and population.  The study also aims to support the National Soil and Water Resources Research Development Extension and Agenda (NSWRRDEA) of BSWM on Organic Agriculture, and the National Organic Agriculture Program (NOAP) among local farmers by increasing the availability of quality vermicompost, targeting a major Organic Agriculture adaptation problem which is limited number of accredited organic inputs.