Characterization of Moisture Conservation
Practices on Yield of Sorghum in Holte,
Department of Natural Resource Management, Wolkite University, Ethiopia
Submission: May 01, 2020; Published: May 12, 2020
*Corresponding author: Asrat Fikre, Department of Natural Resource Management, Wolkite University, Ethiopia
How to cite this article: Asrat F. Characterization of Moisture Conservation Practices on Yield of Sorghum in Holte, Southern Ethiopia. Int J Environ Sci Nat
Res. 2020; 24(4): 556143. DOI: 10.19080/IJESNR.2020.24.556143
Water is the common medium for several life processes; it is very limited in semi-arid climatic zone for growth and development. A coping mechanism; water management includes understanding about the release pattern and storage of water by the soil. The emphasis given to the conservation practices in conserving and retaining moisture is very limited in semi-arid zone of southern Ethiopia. The aim of this study is to characterize the three conservation practices in relation to moisture with various soil depths. Erratic rain fall over the season makes harsh for growing vegetations. Indigenous conservation practice in the form of (mona, poteya and targa), trash line and stony with little straw were evaluated for their volumetric moisture content. SAS 9.2 version was used to analyze the data, for instance, there was statistically difference (P ≤0.05) among conservation practices and there was statistically difference between indigenous and trash line conservation practices over the stony with little straw conservation practice over the growing period and depth intervals of the profile.
Water is the common medium for several life processes, lifecycle cease in the absence of water. For instance, in plants, mobility of necessary materials in the plant tissue is hold by soil water. Consequently, water and soil are the primary requirements for the life and growth of plants. However, water availability in soils is restricted, and therefore, its conservation and utilization turn into an indispensable issue . Water management includes understanding about the release pattern and storage of water by the soil. Soil moisture data can be used for water reservoir content and managing, early advice of deficiencies, irrigation planning, and crop yield estimation [1,2]. In the semi-arid area, soil moisture is an important water source for plant growth [3,4] and soil moisture consumption rates were found to depend on vegetation types [5,6].
A limited attention has been given to how soil depth and type of soil and water conservations variation in soil moisture is affected by environmental factors. As depth variations of soil moisture have important implications on agriculture [7-9] and soil erosion [10,11], understanding its dynamic role will provide a scientific basis for the optimization of spatial allocation in the depth basis
crop production efforts. Specifically, soil moisture is an important stable water source for vegetation in the semi-arid environment, understanding soil depth and conservation practices variation on soil moisture is fundamental for the possible optimization of plant growth.
Straw terracing is indigenous moisture conservation practice in the form of mona, poteya and targa construction by the farmers with letting of sorghum/maize stalk with the soil in the previous season . Trash lines are created across the slope using previous seasons crop residues maize, sorghum stalks and other dead vegetative organic materials to control surface runoff, soil erosion and enhance infiltration. Besides, stony with little straw is practiced by farmers as moisture conservation for cultivating crops in stone/rock dominated land.
Holte kebele is located in Derashe special woreda of southern
nation’s nationalities and peoples of Ethiopia. In doing so the
study plots were demarcated with latitude longitude and altitude
of 33.520-33.560, 62.520-62.980 and 1141-1136ma.s.l. (above sea
level) respectively. The area is located in the semi-arid climatic
zone, erratic rainfall  of monthly total from April to July was
217.0mm, 46.7mm, 62.0mm and 7.0mm respectively. The soil
texture in the three conservation types were clay, clay and loam
on indigenous conservation practice, trash line and stony with
little straw respectively. Water shortage is the major constraint
to vegetation growth and agriculture production. The cropping
system in study area is sparse alley cropping of either sorghum or
maize with Acacia or Cordia Africana trees.
For this study three plots with three soil and water conservation
practices (indigenous conservation practices/straw terracing
, trash line conservation practice and stony with little straw
application) were considered. The first two conservations are the
common practices and the last one is practiced in stony farms like
as stone mulch by the peoples of Derashe. The aim of this study
is to characterize three practiced soil and water conservation
measures on soil moisture content and yield of sorghum in Holte
Farmers in semi-arid areas like holte are embracing practices
that enhance agricultural productivity by conserving soil moisture.
For instance, the local peoples have developed indigenous soil
and water conservation practice called indigenous conservation
practice in the form of (mona, poteya and targa) . Mona is
ridge developed for making the basin with the use of minimum
tillage soil in the basin’s catchment. Poteya is a rectangular
structure called basin that enhance time of concentration of the
runoff and Targa is a series of 3-5 poteyas, used as a barrier for
flooding and facilitates to infiltration. These physical soil and
water conservation structures integrated with straw provides
good moisture and soil conservation in derashe area that were
developed through their knowledge to cope the harsh condition
like Konso terracing.
Trash lines are created across the slope using previous seasons
crop residues maize, sorghum stalks and other dead vegetative
organic materials to control surface runoff, soil erosion and
enhance infiltration. Trash lines can be 1m wide that is practiced
by some farmers in the study area; where the sorghum / maize
stalk is consumed as fuel wood.
Whereas, stony with little trash line conservation practice is
commonly practiced in small rock dominated areas of conservation
agriculture land, technically like stone terracing with applying of
sorghum or maize stalk over the terrace (Figure 1).
Soil moisture measurements in the growing seasons were
made by opening the three profile pits from the surface layer to
90cm in 30cm intervals. Soil samples were taken by a moisture
can and core sampler, and stored in sealed plastics when taken
out. Then the sealed plastics were taken to laboratory to measure
SMC (unit: gg−1) by using gravimetric approach. The SMC was
determined using the oven-dry method (24h at 105◦C). Three
sampling profiles were purposefully chosen to obtain the SMC
variation on rock dominated and other conservation lands with
the use of trash line moisture conservation and one site with
indigenous conservation practices. For every stratified depth
interval (30cm for this study) three core sampler data were
obtained on triangular basis for each layer, then the depthaveraged
SMC of each profile pit at each layer was calculated as:
where j is the number of sample measurements at each layer
x, and SMCj is the soil moisture content in layer x calculated by
three sampling profiles. The number of measurement layers at
each layer is 3 with the 3 layers (0-30cm, 31-60cm, and 61-90cm)
in each profile and a total of 27 soil samples were collected from
the three profiles.
Bulk density was determined by dividing dry weight of the
bulk sample that was captured by the core sampler at categorized
layer to volume of soil core. Then averaged bulk density was
obtained for every layer and volumetric soil moisture content
were determined by multiplying gravimetric moisture content
and bulk density, while density of water is 1g/cm3.
According to the result stony plot with little straw retains
a very little moisture than others. This is due to the rocky
characteristics of the plot that have little soil to hold moisture. The
indigenous conservation practice showed a vigorous retention
capability (Figure 2).
The result indicated that indigenous conservation practices
increased significantly (P ≤0.05) soil moisture contents at 0-30cm
as compared to trash line conservation practice and stony with
little straw. This may due to better structured conservation
practices (i.e., mona, poteya and targa) in retaining moisture
and minimizing the evaporation from the soil pores by having
of better mulch than the two practices. It is expected better
retarding capacity of runoff and soil erosion. There was high
surface cracking was observed due to following of long spell of dry
weather after raining. The findings of the present study indicated
that effectiveness of indigenous conservation practice as in-situ
moisture conservation method was highly significant, which
enabled rain water to be held on the surface of land and absorbed
by the soil .
This moisture content was collected when the root of the crop
grows larger and larger to take the moisture (i.e. root >30cm).
As observed from figure 2, moisture content by indigenous
conservation practice was significant with the two.
The analysis of variance revealed that soil moisture content
determined at growing season of sorghum plant was significantly
influenced by conservation practices used. It indicated that
indigenous moisture conservation practices and trash line
moisture conservation practices increased significantly (P ≤0.05)
soil moisture contents at 31-60cm over stony with little straw.
The average moisture content difference among indigenous
conservation practices and trash line were 28 and 27% over stony
with little straw respectively, this may be the little infiltration
capacity of the stone dominated soil. But the variation between
indigenous conservation practice and trash line was only 1%. This
was due to little exposure of the middle layer to evaporation.
The same to the middle depth of the soil profile, moisture
content of 61-90cm depth was significant with in conservation
practices. It indicated that indigenous moisture conservation
practices and trash line moisture conservation practices increased
significantly (P ≤0.05) soil moisture contents at 61-90cm over
stony with little straw.
Generally, the result reveals that indigenous moisture
conservation practices and trash line moisture conservation
practices increased significantly (P ≤0.05) soil moisture contents
of 61- 90cm over stony with little straw. The average moisture
content variation between indigenous moisture conservation
practices and trash line moisture conservation practices over
stony with little straw were 21 and 31% respectively.
The result reveals that there was a positive relationship
between conservation practices (between indigenous and trash
line moisture conservation practices) with depth. This was due
to less effect of evaporation on the deeper soil profile and less
availability of moisture to roots of the plant at deeper horizon.
However, stony with little straw plot showed decrement of
moisture content as the soil depth increasing; this may be due
to youngness of the profile to store moisture in the pores of the
soil. Since stony with little straw plot, the surface has better soil
particle composition to hold more moisture than the deeper. In
general, the stony plot retains less soil moisture content than the
two plots. The following figure showed the relationship in detail
on indigenous conservation practices.
The three soil and water conservation practices in the case
of Holte affect soil moisture, then improved soil water storage
in the profile by enhancing infiltration which was important
in increasing sorghum yield immediately in the given season.
This study revealed that soil and water conservation practices
markedly influences soil moisture at various depths. This result
agreed with other studies [12,13], reported on the significant
responses of soil and water conservation practices to the high
values of soil and runoff losses from an area of low and erratic
rainfall in the semi-arid areas by retaining both soil and moisture
and thereby increased productivity.
The volumetric soil moisture content of indigenous
conservation practice (targa, poteya, mona) shows decrement
from booting to harvesting. This was due to the long dry spell
weather after 50 days after sowing to harvesting in the study
area or high consumption of moisture by roots of the crop even
at harvesting time. However, the leaves of sorghum during grain
harvesting were green over the rest two practices. For this fact,
harvesting time was delayed for five days. Indigenous conservation
practice has great impact on moisture conservation over the other
conservation practices. The relationship between soil depth and
soil moisture content showed direct proportional in the two
practices and inverse proportional with the stony dominated soil
profile. Soil and water conservation methods can influence the
moisture retained by the soil at various depths.