Preparation and characterization of vermicompost made from different sources of materials

The study was conducted during 2020, at Fedis district of East Hararghe Zone, Oromia National Regional State; Ethiopia. Composting is a process where waste organic materials derived from plants and/or animals are decomposed by microbial action under aeration to produce a friable homogenous product that is added to soil. Biological, chemical and physical degradation of the soil and reduced yields of the most major crops at Fadis district was the major problem of the area .This was deuto the reliance of farmers on chemical fertilizer alone, and continuous depletion of soil organic matter. Thus why this study was designed with the objectives of to prepare and characterize nutrient composition of different vermicompost and to identify quality vermicompost for crop production. Different source of materials like Wheat, Sorghum, Soybean residues, Haricot bean, Maize stock, chick pea, Finger millet, Groundnut residues, Rhodes grass and Bracharia were used to prepare vermicompost. The collected substrates were chopped and added to the worm bin. Animal manure was added to all substrates in equal amount. The ratio of 1:2was used and Pit method was used for vermi compost preparation. Composite vermi compost sample were analyzed for essential nutrients and chemical properties of compost. The Electrical conductivity of vermicompost under this study was falls in the ranges of 3.22 dS m--6.7 dS m-1 this alkalinity range is suitable for growth of most crops. According to result (Figure 1), the pH value was in the ranges of 7.2-8.4. A pH greater than 8.5 and electrical conductivity of 8 dS m-1 were found to harm both plants and earthworms. Out of all analyzed vermicompost, the highest total nitrogen (TN3.21%) was recorded from vermicompost made from ground nut, soybean (2.93%) and haricot bean (2.73%) substrates and the highest available phosphorus (787.75 mg/kgV. Compost) and 787.75mg/kg Compost) was obtained from vermicompost of haricot bean and chick pea followed by wheat (715.93) respectively. This was the tripled and doubled of TN% available in the soil and conventional compost. Their variation might be attributed to nature of different substrates. Vermi compost made from haricot bean was rich in all essential nutrients and other quality parameters and the most quality vermicompost for plant growth followed by soya bean and chick pea. Research Article Preparation and characterization of vermicompost made from different sources of materials


Introduction
Environmental degradation is a major threat challenging the worldwide, and the extensive use of chemical fertilizers contributes largely to the deterioration of the environment, loss of soil fertility, less agricultural productivity, soil degradation and Climate change due to a number of reasons. For instance production of degradable organic waste and its safe disposal infl uence on soil fertility [1]. Meanwhile the transformation of degraded soils by protecting topsoil and sustainability of productive soils is a major concern at the international level.
Ecological Agriculture", which is by defi nition different from "Organic Farming" that was focused mainly on production of chemical free foods. Ecological agriculture emphasizes on total protection of food, farm & human ecosystems while improving soil fertility & development of secondary source of income for the farmers [2]. Heavy use of agrochemicals since the "green revolution" of the 1960s boosted food productivity at the cost of environment & society. It killed the benefi cial soil organisms & destroyed their natural fertility, impaired the power of 'biological resistance' in crops making them more susceptible to pests & diseases. Chemically grown foods have adversely affected human health. The scientifi c community all over the world is desperately looking for an economically viable, socially safe & environmentally sustainable alternative to the agrochemicals is vermicompost [3].
Vermicomposting is defi ned as a bio-oxidative process in which detritions earthworms interact with microorganisms and other fauna within the decomposer community, thus accelerating the stabilization of organic matter (OM) and greatly modifying its physical and biochemical properties of soil (Domínguez, 2004 [4]. Red worms are local endemic species therefore appears to be appropriate for vermicomposting; as such species are well adapted to different environmental conditions. Vermicomposting differs from composting in several ways [5]. A mesophilic process utilizes microorganisms and earthworms that are active at 10°C to 32°C (not ambient temperature but temperature within the pile of moist organic material). The process is faster than composting; because the material passes through the earthworm gut that diverse biological processes involved in the recycling and recovery of waste components is of increasing importance for more sustainable production and consumption systems. In short, earthworms through a type of biological alchemy are capable of transforming garbage into "gold" [6,7].
According to Ruz-Jerez and Tillman R [8], Vermicompost is an excellent soil additive made up of digested compost and Worm castings are much higher in nutrients and microbial life; therefore, considered as a higher value product and Worm castings product contain up to 5 times the plant available nutrients found in average potting soil mixes. Chemical analysis of the castings was conducted and found that it contains 5 times the available nitrogen, 7 times the available potash and 1.5 times more calcium than that found in 15 cm of good top soil. In addition, the nutrient life is up to 6 times more in comparison to the other types of compost.
According to Reinecke, et al. [9] report phosphorous while passage through gut of worms is converted to the plant available forms that it is usually considered as a limiting element for plant growth. Therefore, any process that signifi cantly increases phosphorous availability through plants and organic matter is  To identify quality vermicompost of different sources that contains high composition of essential nutrients.

Location
The study was conducted at Fedis district of East Hararghe Zone, Oromia Regional State; Ethiopia. It is located in the

Climate and rain fall
According to FWANRDO (2017/18) report, the district has two basic agro-climatic conditions, namely Midland (39%), and lowland (61%). The district experience mean annual maximum and minimum rainfall, mean annual maximum and minimum temperature in the area were 850 to 650mm, 30.4°C, and 10.0°C, respectively. Accordingly, the district has a bimodal rainfall distribution pattern with heavy rains from April to June and long and erratic rains from August to October.

Design of vermiculture
The worm bin where the worms live and produce compost, shallow boxes were constructed in the house with the dimension of 0.5m of height, 0.6m of width and 1m of length from concrete cement.

Experimental materials and vermicompost preparation
The treatments consist of eleven types of feed materials were used as a treatment which undergone partial fermentation

Parameters and test methods
The pH and Electrical Conductivity (EC) was analyzed using the -potentiometry (1:2.5) methods. And organic carbon was analyzed by using -Walkley and Black methods

Data analysis
The collected data was subjected to SAS software 9.1 version And the data was summarized and presented using graphs.

Vermicompost analysis result
The collected vermicompost samples were analyzed for

Electrical Conductivity (EC) in ds/m, Total nitrogen % and soil pH
Electrical Conductivity (Ec) in ds/m : To identify the salinity hazard of a vermicompost, Electrical Conductivity (EC) measurements was conducted. The salt content can thus be estimated from the electrical conductivity of a vermicompost suspension in distilled water. The highest (6.7ds/m) and lowest (3.22ds/m) EC was obtained from wheat and chick pea straw respectively. This fi nding is in line with (Richards, 1954) [13], vermicompost made from Sorghum and mixed straw showed slightly saline while from haricot bean, grasses, and maize straw showed moderately saline. The increased EC(electrical conductivity) during the period of the vermicomposting processes is in consistence with that of earlier workers [14,15], which was probably due to the degradation of organic matter releasing minerals such as exchangeable Ca, Mg, K, and P in the available forms, that is, in the form of cations in the vermicompost [16,17].

Soil reaction of vermicompost (pH)
According to result  [19,20] obtained similar results in which the pH status of vermicompost was ranged from 6.8-8.41. Also Padmavathiamma, et al. 2008 [21] reported that the pH of vermicompost ranged from neutral to alkaline.
A pH greater than 8.5 and electrical conductivity of 8 dS m -1 were found to harm earthworms. Alkalinity and salinity are harmful to both earthworms and microorganism [22]. Thus
The variation of TN among the vermicompost attributed to the substrates digested by worms. Because different types of straw were contains different nitrogen contents. This was in line with the fi nding of S.Kalantari, et al. [23] reported that, 3.5TN% of the total nitrogen was recorded from vermicomost.
George W. Dickerson [20] also obtain the total nitrogen recorded in vermicompost 1.94%. The current result also in line with the fi nding of [18] rating of total nitrogen in a soil, the TN(total nitrogen) in a vermicompost made from all substrates was high (>0.25%) and signifi cantly greater than in a soil. Therefore vermicompost application to soil could increase total nitrogen. It was in agreements with studies of (Tigist, et al. 2017) revealed application of vermicompost could increase total nitrogen in a soil. Vermicompost made from groundnut, soybean and haricot bean was rich in TN% than the rest compost made from other materials Figure 3.

Available phosphorus
The analyzed result revealed that, the highest available phosphorus (787.75 mg/kgV. Compost) and 787.75mg/kg V.compost) was measured/obtained from vermicompost made from haricot bean and chick pea followed by wheat (715.93) respectively. And the lowest value was recorded from the vermi compost made from groundnut substrate/residues (406.88 mg/kgV. Compost) followed by Rhodes grass (512.44 mg/ kgV. Compost) and maize stock (525.5 mg/ of kgV. Compost) respectively. Their variation might be attributed to nature of the substrates. The enhanced P level in vermicompost suggests phosphorous mineralization during the process. The worms during vermicomposting converted the insoluble P into soluble forms with the help of P-solubilizing microorganisms through phosphatases present in the gut, making it more available to plants (Padmavathiamma, et al. 2008, Ghosh, et al. 1999).
When the values compared to soil, available phosphorous from vermicompost made from all substrates, especially from haricot bean vermicompost was very high. The current study was in agreement with the fi ndings of Nagavallemma KP, et al. [24] reported that the available phosphorous in vermicompost was much higher than the soil and conventional compost. Thus, application of vermicompost could increase P content of the soil if the soil is defi cient with phosphorus Figure 4.

Available potassium (K)
According to the result above on Figure 5, the highest available potassium was measured from vermi compost made from Elephant grass (133500 K2Omg/kg V.Compost) substrates followed by fi nger millet (110000 K2Omg/kg V.Compost), wheat and groundnut respectively. And the lowest available potassium was obtained from sorghum treatments/residues followed by maize stock treatments.
According to previously, conducted study the available potassium in vermicompost was stated by S.Kalantari, et al. Dickerson [20] has close relation to this study which was 0.7% and 8.3g/kg when converted to similar unit. In addition to this the result obtained in this study is available in range stated by Nagavallemma KP, et al. [24] which was 1500-7300mg/kg of vermicompost.    Vermicompost made from groundnut, soybean and haricot bean was rich in TN% than the rest compost made from other materials respectively. The highest (3.21%) total nitrogen was recorded from vermicompost made from ground nut, followed by soybean (2.93%), haricot bean (2.73%) and chick pea (2.62%) substrates/residues respectively. And the lowest total nitrogen was obtained from maize stock (1.15%) Elephant grass. TN% of current study was in the ranges of 1.15%-3.21%. Available phosphorus of vermicompost from different source of material was falls in the range of 406.88p mg/kgV. Compost-787.75 P mg/kg Compost. The highest available potassium was measured from vermi compost made from Elephant grass (133500 Kmg/ kg Compost) substrates followed by fi nger millet (110000 K2Omg/kg Compost), wheat and groundnut respectively. And the lowest available potassium was obtained from sorghum treatments/residues followed by maize stock treatments. The CEC of all vermicompost under this study was in a ranges of (54.24 cmol+kg-vermi compost (57.15cmol+ kg/V.compost).

Conclusion and recommendation
According to this study, vermi compost made from Haricot bean was the most quality vermicompost than the rest in terms of all quality parameters followed vermi compost of Chick pea substrates. According to this study, around 1.2t/ha of vermicompost can replaces the commercial fertilizer (blanket recommendation.) This fi nding is in line with Derrib kifl e, et al. [25] Therefore, vermicompost could be used as source of macro nutrients and organic fertilizers for soils defi cient with macro nutrients [26][27][28][29][30][31][32][33].