Land degradation can be considered in terms of the loss of actual or potential productivity or utility as a result of natural or human factors; it is the decline in land quality or reduction in its productivity. It causes running down of soil organic matter and available water for crop growth. Consequently, implementation of soil and water conservation especially level soil bund is supposed to alleviate the impacts of soil erosion and increase agricultural land production and crop productivity. Based on that the effects of level soil bund was evaluated by conducting on-farm study during the cropping season of 2019 in Eba wakeyo kebele, Nejo District, Western Wollega of Oromia Regional State with the objective of evaluating level soil bund on teff productivity and soil properties. The study involves two factor: level soil bund (with and without) was a main plot and the ages of level soil bund was taken as the sub-plots. The treatment (T1=with bund of six year splited in to 7, T= with bund of 4 year splited in to 7, T3= with bund of 2 year splited in to 7and T4= without splited in to 7) with randomized complete block design. The data was analyzed using general linear model procedures and to separate difference between mean LSD (5%) was used. The level soil bund increased the mean value of soil moisture contents at 0-30 cm and 0-60 cm soil depth, the teff (Eragrostis tef) grain yield increased by 22.85% when compared with controlled block and the teff biomass increased by 24.32%. As the wall, it is concluded that level soil bund improves soil fertility, soil moisture status and teff (Eragrostis tef) grain yield and yield components.
Keywords: Land degradation, Level soil bund, Soil erosion, Soil properties and teff productivity
1.1. Background and Justification
Natural resource degradation and land degradation in particular has negative impact on the economy of developing countries including Ethiopia. This is because; the country heavily depends on their natural resource for food self-sufficient, food security and economic development. Soil erosion and nutrient depletion are the most important forms of land degradation in Ethiopia (Tekle, 1999). Erratic and erosive rainfalls, steep terrain, deforestation, inappropriate land use, land fragmentation, overgrazing and weak management practices are among the factors that cause land degradation in the country (Osman and Sauerborn 2001).
Soil erosions are the serious problem in Ethiopia since agriculture is the major source of livelihood in the country. The average annual rate of soil loss in the country is estimated to be 12 tons/hectare/year, and it can be even higher (300 tons/hectare/year) on steep slopes and in places where the vegetation cover is low (Abera B., 2003). Agricultural activities change the soil chemical, physical, and biological properties, and play the major role for soil degradation mainly due to soil fertility decline because of lack of nutrient inputs (Adimassu etal .2014,).
The sorting action of erosion removes large proportions of the clay and humus from soil, leaving behind the less productive coarse sand, gravel, and in some case even stones, impairing the quality of the remaining topsoil. The removal of this organic matter affects soil properties including texture, structure, nutrient availability and biological activity and makes soil more susceptible to further erosion as its aggregates becomes less stable thus, negatively affecting crop production.
Soil and water conservation measures such as soil bunds and stone bunds are adaptation options to mitigate the problems caused by soil erosion and its consequences. Since 2000, government and nongovernment organizations such as sustainable land management Programme have been promoting agricultural production through the implementation of biological and physical soil and water conservation measures in the degraded of Nejo district. Especially, Construction of level soil bunds has been the major activities that preformed on the croplands. But the long-term effects of those interventions on production have not been investigated. This study assessed the effects of Level Soil Bund (LSB) on teff productivity and selected soil physico- chemical properties.
1.2. Statement of the problem
Soil deterioration and low water quality due to erosion and surface runoff have become severe problems worldwide. Soil erosion is the main driver of land degradation in Ethiopia. In the study area it is a serious problem due to continues cultivation of crops, over grazing, limitations of soil and water conservation practice, termite, poor soil infiltration capacity and high volumes of runoff. This leads to change on a soil properties and reduction of crop land productivity. Based on those phenomena, the lives of local peoples in the study area was under deterioration. Even if the agricultural extensions try to introduce soil and water conservation practices like level soil bund in the area, the spreading out of the structures was poor. Consequently, it is important to conduct a research to assess how level soil bund is effective to improve soil properties and enhance crop productivity in the study area.
1.3. Objective of the study
To evaluate the effects of level soil bund on crop productivity and soil properties a
The specific objectives are
I. To evaluate the effect of level soil bund to improve teff crop yield and yield components
II. To assess the effects of level soil bund soil selected chemical properties
III. To assess the impacts of level soil bund on selected soil physical properties
2. MATERIALS AND METHODS
2.1. Description of the study site
The study was conducted at Nejo district Eba wakeyo kebele which is located in western Wollega zone of the Oromia Regional State at the latitude of 9o5’N and longitude of 35o45’E in western Ethiopia. The site has an elevation of 1735 meters above sea. Nejo, is found at about 498 km west of Addis Ababa.
2.2. Treatments and Experimental Design
For study, Eba wakeyo kebele was selected. For experimental work 28 farmers’ plots a quarter of a hectare each, was selected whereas ,7 plot with level soil bund of six years ,7 plots level soil bunds of four years, 7 plots of two years and 7 plots was without level soil bund and the experimental protocol was 4 treatments which can be conducted as follows:
(1) Pure stand crop on a plot without soil bund of six years (T1)
(2) Pure stand crop on a plot with soil bund of 4 years (T2)
(3) Pure stand crop on a plot with soil bund of 2years (T2)
(4)Pure stand crop on a plot with soil bund (T3)
3.3. Soil sampling and analysis
3.3.1. Monitoring soil chemical properties and physical properties
Composite soil samples was collected for homogeneity of soil from all plots at 0-30cm and 0-60cm using Auger and the selected chemical properties including texture by Bouyoucos hydrometer method (Day, 1965), organic carbon using Walkely and Black method (Neilsan and Sommers, 1917),and total nitrogen using Kjeldahl digestion and distillation method (Bremner and Mulvaney, 1982), available phosphorous (Olsen and Dean (1965), Soil pH was determined at soil: water suspension ratio of 1:2 using a conventional glass electrode pH meter (Jackson,1973) at Bedele Soil Research Center of Oromia Agricultural Research Institute (OARI). Texture: texture determination was carried out using the hydrometer method (Day, 1965).
3.4. Agronomic Data Collection
Biomass: was calculated at harvesting stage by measuring the total biomass using spring balance from three randomly selected samples using a 1 m x 1 m quadrant at each plot. Grain yield: Grain yield from 1 m x 1 m per plot was measured using electronic balance and then adjusted to 12.5 % moisture and converted to hectare basis after oven drying the samples as follows(African journals of plant science)
Where: FW = Field weight harvested from sample plot; AMC = Actual moisture content; RDW = Recommended dry weight (Given) = 87.5; 0.8 = Shelling % (Given). Then the yield per plot is converted into yield per hectare (tones ha-1).
3.5. Data analysis
The collected data from both crop and grazing land were subjected to analysis of variance (ANOVA) using general linear model (GLM) procedures in SAS version 9.2.3 (SAS Institute, 2002). Means that were significantly affected by the treatments were separated using the Least Significant Difference (LSD) test at 5% level of significance.
3. RESULTS AND DISCUSSION
3.1. Soil physical properties
3.1.1. Soil moisture contents
Soil moisture content was affected by soil and water conservation practices. As data presented in (Figure 1) the level soil bund significantly influence the soil moisture content of the study area. Consequently, the higher mean value of soil moisture content of plots with level soil bund of six years were 37% at 30-60 cm and 33 % at 0-30 cm soil depth. On the 4 years, the mean value of soil moisture content were 35.4 % at 30-60 cm and 31.53% at 0-30cm soil depth in the plots with level soil bund while 30.75 % at 0-30 cm and 34.5 % at 0-60cm soil depth in the plots without level soil bund. As the present study level soil bund improves soil moisture content, which is a key factor to improve land production. Also ages of the bund and soil moisture content have positive relationships. As the ages the bund increases the soil moisture content also increases.
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Fig. 1. Soil moisture content affected by level soil bund at 0-30 and 30-60 cm
3.1.2. Soil bulk density and texture
Soil bulk density (BD) (g cm−3) was affected by soil conservation practices. It ranges from 0.91 g cm−3 (level soil bund of six years) to 1.10 g cm−3 (plots without level soil bund) (Table 1). The lower mean BD value under six years level sol bund measures might be the subsequent effects of reduced soil loss and crop residue through erosion; and addition of organic matter from plants. Similar results were reported by (Gebiresilassie et al. 2013; Dulo et al. 2017; Solomon et al. 2017 and Worku 2017) who indicated lower mean soil BD value in conserved farms than non-treated cultivated lands. Data regarding particle size distribution revealed dominantly loam clay textural class which implying that SWC practices (management) alter the soil texture classes.
(Table 1). Mean value of on selected soil physical properties affected by soil bund
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3.2. Soil chemical properties
3.2.1 Soil (pH)
The mean soil pH value was significantly affected by the use of level soil bund at (P<0.05). Also the ages of level soil bund have effects on soil pH value. In general , the higher mean pH value (5) obtained from the plots of level soil bund of six year while ph value (4.5) and (4.17 )obtained from the plots with level soil buds of four and two years respectively. In addition to the lower mean pH value (4) was obtained from the plots without level soil bund (Table.2).
3.2.2. Total nitrogen (TN)
Total nitrogen (TN) contents were significantly different at (P<0.05) among the conservation practices and ages of soil bund (Table 2). The higher mean values of TN (0.25) observed in the plots of level soil bund of six year. The plots of four year and two years gives the mean values of TN (0.24 and 0.21) respectively. While the lower mean value (0.19) obtained from the plots of without level soil bund. The result was match with the finding of (Abay et al. 2016) that reported as the farmlands with physical SWC measures have high TN as compared to the non- conserved.
Table.2 Mean value of on selected soil chemical properties affected by soil bund
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3.2.3. Available phosphorus (AvP)
Available phosphorous (AP) was significantly different at (P<0.05) among the plots of conservation and blocks and ages of soil bund (table 2). The mean values of available phosphorus of the soils sampled from the level soil bund plots were higher than that of non-conserved plots. The higher mean value (7.13 ppm) and the lower mean value (5 ppm) of AvP were observed under the plots of with and without level soil bund, respectively. Also, the ages of bund has an effects on the mean values of available phosphorus since the high value (7.13 ppm ) observed on the plots level soil bund of six years While, the plots of two years so gives the lower value (6.33)
- Quote paper
- Masters of Science in Environmental Science Dessalegn Etana (Author), 2020, Effects of Level Soil Bund and Ages of Bund on Teff Productivity and Soil Properties: At, Nejo District, Oromia Region, Ethiopia, Munich, GRIN Verlag, https://www.grin.com/document/921472