**5.1 Effect of vermicompost on the soil physiochemical properties**

Addition of vermicompost improves soil physico-chemical properties viz. soil structure, soil water holding capacity, penetration resistance, bulk density, soil organic carbon, aggregation, nutrient content, etc. According to the findings of various long term research addition of vermicompost reduces the bulk density of the soil and increases the water holding capacity of soil [25]. Aksakal et al. [26] found that when vermicompost was added in the soil, the mean bulk density, and mean total porosity were the least. Air permeability rose and penetration resistance reduced dramatically as wet aggregate stability improved and bulk density reduced. Increased microbial population and activity led in the development of aggregates and increased soil porosity, resulting in decreased particle and bulk densities. Physicochemical characteristics such as pH, electrical conductivity (EC), porosity, moisture content, water holding capacity, and chemical properties like nitrogen, phosphorous, potassium, calcium, and magnesium were all found to be significantly improved in vermicompost treated soil, while the corresponding physicochemical values in control soil were minimal in rice crop [27]. Vermicompost has indeed been found to have significant concentration of total and bioavailable nitrogen, phosphorus, potassium (NPK), and micronutrients, as well as microbial and enzyme activity and growth regulators [28]. Polysaccharides appeared to be abundant in vermicompost [29]. Polysaccharide worked as a cementing ingredient in the soil, causing aggregate stability, which helped to establish and maintain the soil structure for improved aeration, water retention, drainage, and aerobic conditions. The preservation of soil structure is essential for root elongation and nutrient uptake. The inclusion of mucus secretion and microorganisms from the earthworm's gut improves the soil's aggregate stability. The absorbent organic matter in vermicomposts increases the soil's water retention capacity by holding only the quantity of water required by the plant roots [30]. Vermicomposts have been found to have a higher base exchange capacity and a higher oxidation potential rise [31]. The C/N ratio of vermicompost is usually lower, indicating that it is more suited for use as a soil amendment. By altering the physiochemical parameters of the soil, vermicompost was able to limit the loss of nutrients through leaching [32]. Humic acid and biologically active compounds like plant growth regulators are abundant in vermicompost [33]. Humic acid has been proven to improve nutrient accretion in situations where nutrients are scarce or when additional nutrients are provided. Humic acids may have a hormone-like effect on plant growth and productivity as a result of their involvement in cell respiration, photosynthesis, oxidative phosphorylation, biogenesis, and a variety of other enzymatic functions.

### **5.2 Effect of vermicompost on the soil biological properties**

Biological properties of soil can be enhanced through application of vermicompost. Recent studies founded that soil biological characteristics viz. soil organic carbon as well as soil microbial biomass, enzymatic activity, population of different beneficial microorganism, hormones, etc. significantly enhanced with application of vermicompost [34]. The activity of the dehydrogenase enzyme, which is commonly employed to quantify the respiratory activity of microbial communities, was shown to be higher in vermicompost than in commercial medium [35]. Application of vermicompost


#### **Table 4.**

*Effect of vermicompost on physiochemical properties of soil on different crops.*


#### **Table 5.**

*Comparison between the effect of vermicompost and conventional compost on different nutrient content of the Amaranthus viridis production.*

improved the nitrogen status of soil by introducing the beneficial microorganism in the rhizosphere of the plant which ultimately enhances the nitrogenase activity in soil, which is the enzyme responsible for nitrogen fixation (**Tables 4** and **5**).

#### **5.3 Effect of vermicompost on the soil fertility**

Vermicompost has a great importance to increase the soil fertility level. In recent years organic amendments are getting more importance for nutrient management and sustainable crop production since the long-term use of inorganic fertilizer lacking organic additives has the ability to ruin soil qualities [34]. Long-term treatment of balanced inorganic fertilizers led to reduced soil bulk density, improved total porosity, and higher water-holding capacity. Inorganic fertilizers also promoted soil aggregation in deeper soil layers and raised maize and wheat grain and straw yields [38]. In their research, using farmyard manure (organic fertilizer) instead of inorganic fertilizer improved soil qualities in a similar way. Furthermore, compost provides substantially higher boosts in soil organic carbon as well as some plant nutrients when compared to mineral fertilizers [39, 40]. Thus, using vermicompost improves overall soil fertility by improving numerous soil physical, chemical, and biological qualities.

*Vermicomposting: A Step towards Sustainability DOI: http://dx.doi.org/10.5772/intechopen.102641*

#### **Figure 11.**

*Effect of vermicompost on growth parameters of Phaseolus vulgaris (20 DAS). Source: Ref. [34]. T1: Control (without application of inorganic NPK or vermicompost), T2: 100% recommended dose of NPK (20:80:40 kg ha−1), T3: 100% recommended dose of vermicompost (5 t ha−1), and T4: 50% vermicompost supplemented with 50% NPK (W/W).*

#### **5.4 Effect of vermicompost on plant growth and development**

Vermicompost promotes the growth and development of a variety of plant species, especially various horticulture crops, that is, sweet corn, tomato, strawberry [41], cereals crop rice [27], wheat, sorghum [32], fruit crops papaya [42], and pineapple [43]. Several growth and yield metrics viz. stem diameter, plant height, marketable yield per plant, mean leaf number, and total plant biomass of tomato plant were recorded significantly higher with the application of vermicompost (**Figure 11**).

The increase in growth and development of plant is due to the improving action of vermicompost application on soil physical, chemical, and biological properties which ultimately improves the overall soil fertility, which enhances the plant growth and development. Vermicompost has been demonstrated to improve plant dry weight [44] and uptake of plant N [45] serve as a naturally available, slow released sources of plant nutrients.

#### **5.5 Effect of vermicompost on plant diseases**

Various studies had showed that vermicompost is useful for remedies of different plant diseases. Many plant diseases caused by soil-borne, foliar plant pathogens, and pests have been suppressed by vermicompost products, which have been proven to be effective as organic fertilizers and biological control agents. In conventional agriculture, excessive and repeated use of chemical pesticides resulted in "biological resistance" in crop diseases and pests. As a result, significantly higher doses are now needed to inhibit them for the growth of high-yielding crops that are more sensitive to pests and diseases [46]. A study was conducted to compared the inhibition performance of two different methods, in which two nonconventional chemicals ZnSO4 and oxalic acid, as well as the bio-control agent *Pseudomonas syringae*, were practiced as foliar sprays and seed coatings, respectively, against collar rot of chickpea caused by *Sclerotium rolfsii*, with the combination of vermicompost substitution. When compared to controls, vermicompost substitutes reduced chickpea mortality significantly, but inhibition was much more efficient for treatments that included pre inoculation with nonconventional pesticides as foliar sprays against pathogen [47]. Vermicompost applications suppressed


#### **Table 6.**

*Effect of different types of earthworm species on heavy metal reductions of industrial sludge.*

the tomato late blight caused by *Phytophthora brassicae*, *Phytophthora nicotianae*, and tomato Fusarium wilt produced by *Fusarium lycopersici*, as described by. Earthworm has stimulatory effect on soil microbial activities thus it suppressed the plant diseases more potentially than aerobic compost. There is a lot of research on the suppression effect of organic matter amendments in soils, with gratifying levels of reduction in plant parasitic nematode infestations. There are few scholarly publications on the suppressing effect of solid vermicomposts on numbers and outbreaks of plant parasitic nematodes relative to OM and thermophilic compost additives. Solid vermicompost applications for control of plant parasitic nematode populations have been studied [48]. Solid vermicomposts ranging from 2 to 8 kg ha−1 were applied to tomatoes, peppers, strawberries, and grapes in field treatments. They were able to suppress plant parasitic nematodes with great success. These researchers investigated the suppression capacity of plant parasitic nematodes in vermicomposts made from paper waste, food waste, and cattle manure under field circumstances and found considerable suppression.
