**4. Vermicomposting**

contained 24 plots (2 crops × 3 replicates × 4 treatments). The treatments were (1) SS amended with soil, (2) CM amended with soil, (3) horse manure (HM, **Figure 3**) amended with soil, each at 15 t acre-1, and (4) no‐mulch bare soil used for comparison purposes. The results in **Table 1** revealed that soil amended with SS increased plant biomass production in arugula and mustard by 26 and 21%, respectively, compared to no‐mulch (NM) native bare soil [24].

162 Organic Fertilizers - From Basic Concepts to Applied Outcomes

**Figure 3.** Horse manure obtained from Kentucky horse park, College of Agriculture, University of Kentucky, Lexing‐

**Soil amendment Root weight, g Shoot weight, g Plant weight, g**

SS 74.24 a 290.95 a 365.20 a HM 54.00 b 247.21 b 301.21 b CM 41.64 c 235.60 c 277.23 c NM 30.08 c 240.45 c 270.54 c

SS 61.43 b 426.60 a 488.00 a

ton, Kentucky, USA.

**Arugula**

**Mustard**

In agricultural practices, vermicomposting is the product or process of composting worms, usually red wigglers, white worms, and other earthworms such as *Eudrilus eugeniae* to create a heterogeneous mixture of decomposing vegetable or food waste and animal bedding materials to promote biotransformation of organic waste into organic fertilizer and contribute to sustainable agricultural practices. Researchers, government agencies, and farmers are seeking new ways to manage and utilize agricultural wastes to beneficial use. This way of environmental management could be used as a green technology to bio‐covert plant residues or animal manure residues into nutrient rich in organic fertilizers [29]. Many factors such as available moisture, particle size, and organic content contribute to the growth of earthworms [30]. Earthworms might lose weight and die if they are fed with materials such as rice residues that are rich in lignin, even if the substrate is fortified with nitrogen‐rich amendments to decrease the initial C/N ratio [31]. According to Edwards [32], the basic principle in earthworm breeding systems is to regularly add small batches of wastes in the composting chamber to allow worms to process successive layers of waste.

Data revealed that earthworm growth was lower in treatments that contained high percentages of cow dung (CD). Results also showed that *E. eugeniae* growth was reduced when the proportion of CD in feed substances was increased. This could be due to the earthworm preference of feed substances that may favor rice straw (RS) than CD, and possibly due to inadequate control of ammonia volatilization, resulting from inadequate pre‐treatment of cow manure to remove urea present in the initial material. Similarly, Chan and Griffiths [33] found that earthworms feed that contained untreated pig manure killed the worms within few hours. This is because of the high sensitivity of earthworms to ammonia and presence of high concentrations of cations in livestock manure. Accordingly, availability of pre‐treated cow manure could be used to enhance the reproduction and growth of *E. eugeniae* for use in composting and organic agricultural production.
