Published on International Journal of Biology, Physics & Mathematics
Publication Date: June 5, 2019
Nweke, I. A., Ejinkonye, C. & Ogugua, U.V.
Department of Soil Science Chukwuemeka Odumegwu Ojukwu University, Nigeria
College of Agriculture and Environmental Science, South Africa University, South Africa
Journal Full Text PDF: Impact of Two Contrasting Vermicomposts on the Fertility Status of a Sandy Soil.
Vermicompost contains chemical nutrients of which has a positive effect on soil and crop life cycle. The study investigated the effect of fruit and vegetable vermicomposts respectively on the chemical characteristics of a sandy soil. The results of the study reveals that the vermicomposts studied increased the macro-nutrient (P, N, Ca Mg K and Na) contents of the sandy soil. The pH of the soil which was very acidic was increased to alkaline (9.09) by vegetable vermicompost (VGC) and neutral level (7.07) by fruit vermicompost (FVC). The OC and MC content of the soil showed elevated levels which were almost double the value recorded in the initial soil before vermicompost treatment. The two vermicomposts mediated over two fold increase in electrical conductivity, 251% for FVC and 100% for VGC respectively. When the two vermicomposts are compared the effect of VGC were more effective on pH, N, Ca, Mg, K, Na and MC of the soil compared with FVC results that was more effective on P, OC and EC contents of the sandy soil. The findings of the present study reveal that the vermicompost from biodegradable wastes has a great future for poor resource farmers and food production generally in the study zone. Hence soil prone to excessive leaching and erodible like sandy soil will no longer be a barrier to crop production when amended with vermicompost as its fertility status will be increased and erodibility greatly reduced.
Keywords: Electrical conductivity, exchangeable bases, organic matter, available phosphorous, sandy soil.
Sandy soils pose many challenges to agricultural productivity in humid tropical climate and areas where there are seasonal hot dry climate. They are noted to have low water and nutrient holding capacity due to their low organic matter content and cation exchange capacity (CEC). Their plant available water according to the report of Allen (2007) is ≤ 50 -110mm per meter of soil couple with the fact that due to high soil temperatures in the tropics, soil organic carbon is rapidly lost (Jabbagy and Jackson 2000). The storage capacity for carbon of sandy soil is typically less than 1% because of the low potential to protect carbon from microbial activity (Six et al., 2006). The actual soil carbon content is however much lower than this due to low plant productivity, thus low carbon input rates. Farmers reliant on sandy soils need carefully designed and well integrated water and nutrient management system to increase their productivity and reduce adverse effects on ground water and soil acidity. The fertility of sandy soil can be upgraded through the help of alternative measure such as the use of vermicompost.
Vermicompost is finely divided mature organic matter with high level of plant nutrient availability increased surface area, aeration and drainage, microbial activity and water hold capacity, high porosity etc stabilized by interactions between earthworms and microorganisms (Nweke 2013; Aracon et al., 2008). Soils amended with vermicompost have the capacity according to the works of the following authors, Atiyeh et al. (2002), Arancon et al. (2003), Posstma et al. (2003), Perner et al. (2006), Mba and Nweke (2009) to improve soil moisture, soil aggregation, CEC, higher level of plant growth hormones and humic acids, higher microbial population and activity and less root pathogen or soil borne diseases as well as overall improvement in crop growth and yield (Arancon, et al., 2004; Nweke 2016). This study therefore, attempts to examine the influence of two contrasting vermicomposts on the fertility status of a sandy soil.
2. Materials and Methods
2.1 Study Environment
The experiment was set up at Faculty of Agriculture Chukwuemeka Odumegwu Ojukwu University Igbariam Campus Anambra State. The area is located between the Latitude 5’40 and 6’45N and longitude 6’40 to 7’20E.
2.2 Collection of Materials
The soil sample that was used for the experiment was collected from the Faculty of Agriculture Chukwuemeka Odumegwu Ojukwu University Igbariam campus. The soil was collected using shovel 15-20cm deep after scraping off 0-5cm from the Faculty of Agriculture premises in a plastic container. After the collection of the soil sample, dirty particles, stones and hard clods where carefully removed, aim is to ensure of fine silt before using it for the experiment. 300g of soil was weighed using weighing balance, 10 polythene bags was brought the 10 polythene bags was divided into 2, each 5 polythene bag contained 300g of sandy soil mixed with 50g fruit vermicompost (FVC) and the other 5 bags containing same measurement 300g of soil sample was also mixed with 50g vegetable vermicompost (VGC). The experiment was incubated for 2 months. The chemical properties of soil before incubation are recorded in Table 1. At the end of the study an aliquot of the sample was used to analyze for the chemical properties of soil based on the principles of Black (1965)
Table 1. Chemical properties of sandy soil before incubation with vermicompost
2.3 Data analysis
Data generated were subjected to T-Test analysis and mean values were compared using LSD at 5% alpha level.
The nutrient content of the soil sample before incubation with the vermicompost showed that the chemical properties tested were at their lowest level (Table 1). The pH of the soil was 4.48; the available phosphorous (P) content of the soil was 10.80mgkg-1. The values of total nitrogen 0.03% (TN), organic carbon 0.49% (OC), and exchangeable bases (Ca2+, Mg2+, K+, and Na+) were generally low. The exchangeable acidity (EA), electrical conductivity (EC) and moisture content (MC) were 0.72 cmolkg-1, 110.00 µscm-1 and 16.78 % respectively. The soil contains low level of major nutrient elements. Hence the studied soil is considered poor in these essential plant nutrients.
The result presented in Table 2 showed that the mean value of soil pH measured in water (H2O) for VGC was 9.09 of which is alkaline, while FVC value obtained recorded neutral pH. The application of fruit vermicompost and vegetable vermicompost that was used to amend sandy soil respectively showed that there was great increase in the mean pH value of VGC and FVC. The available P value recorded from Table 2 in FVC was 0.82mgkg-1 higher than the value obtained from VGC. The value obtained from percentage nitrogen (N) from FVC showed that fruit vermicompost that was added to the soil sample (sandy soil) recorded low value compared to the VGC vermicompost. Organic carbon (OC) content showed that there was slight increase in FVC with the value of 0.042% while in the VGC the value obtained were low.
The Ca value from the result in Table 3 showed that both vegetable vermicompost and fruit vermicompost had great impact on the sandy soil. Mg of value 9.44cmolkg-1 recorded in VGC showed that the application of the vermicompost added to the soil sample contributed positively in Mg content of VGC than in FVC. The available K value in both FVC and VGC was low but FVC showed little change in value. For the Na; the value showed that there was slight increase in VGC than FVC. From Table 3 the study showed that the mean value of soil EA in FVC is greater than the value in VGC. The highest EC value was obtained from VGC (Table 3). Percentage moisture content (MC) result in the study showed higher value in VGC compared to FVC in the soil sample (sandy soil).
Table 2 Effect of two contracting vermicompost on sandy soil
Table 3 Effect of two contracting vermicompost on the parameters of sandy soil
The studied soil is acidic in reaction according to the ratings of USDA-SCS (1974) and Chude et al. (2012) who considered soils of pH 4.8-5.1 to be strongly acidic in reaction. The low levels of exchangeable bases (Ca, Mg, K and Na) of the studied soil which are below their critical levels of 2.0-5.0 cmol+kg-1 moderate (Ca), 3.0-8.8 cmol+kg-1 very low to high (Mg), 2.0 cmol+kg-1 (K) (USDA, 1986) indicated that the studied soil is of low base status. This suggests appropriate amendment to provide the deficit between the inherent basic nutrients status, the amount removed by the crops and leaching losses for good crop performance. Since most of the parameters are at their lowest levels it is expected that the studied soil will benefit from vermicompost treatment because vermicompost is known to influence soil parameters positively. The implication of this is that appropriate soil amendment should be practised to realise optimum production capacity of the soil.
The findings from the study showed that there was great effect of FVC and VGC on the soil studied. This was in agreement with the report of (Lazcano et al., 2010). An increased pH range between7.07-9.09 seems to encourage mineralization of plant available nutrient observed in the study through the assistance of microbial decomposition of the vermicomposts. This invariable lead to increased EC status of the soil which could be due to reduced permeability and leaching of the soluble salts. The high OC recorded in the incubated soil visa vie the initial soil may be due to decomposition of OC compound from vermicompost. Soils with low OC have been reported to have low ability to hold cations in the exchangeable forms (Krasilinikoff et al., 2002). Increased moisture content (MC) in vermicompost amended sandy soil probably may be attributed to aggregation of the soil particles by the actions of microorganisms in the vermicompost which provide cementing action between the soil particles. Parthasarathi et al. (2008) observed that composted and worm-worked sludge increased the available soil moisture of a sandy loam soil from 10.5% to 54.4% and 31.6% respectively. In comparison of the two vermicomposts the impact of VGC on the properties of sandy soil was more effective compared to the FVC. Vermicompost emerges as one of the most feasible alternative techniques compared to conventional aerobic composting. This process is not only rapid, easily controllable, cost effective, energy saving, and zero waste, but also accomplishes the most efficient recycling of organic waste and nutrient.
From the findings of the study VGC performed better than the FVC in nutrient release content. The use of organic material has long been recognized in agriculture as beneficial for plant growth, yield, maintenance of soil fertility and soil amendment. Since worm worked vegetable waste and fruit waste are all use as organic manure which is chemically free and environmental safe, cheap, effortless and affordable, it is advised that farmers should make use of vermicompost in the production of crops and soil amendment.