IJERD – International Journal of Environmental and Rural Development (2016) 7-1

Research article
erd

Soil Loss Mitigation by Applying Animal Waste Slurry
SERGIO AZAEL MAY CUEVAS
Graduate School of Agriculture, Tokyo University of Agriculture, Tokyo, Japan
Email: azaelmay@gmail.com

MACHITO MIHARA*Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan
Email: m-mihara@nodai.ac.jp
Received 28 December 2015

Accepted 11 April 2016(*Corresponding Author)

Abstract The application of excreta wastes is beneficial for soil conservation, especially indegraded soils and soils being susceptible to erosion. In this study animal dung was used as aresource for protecting soils against erosion. The objective of this study is to measure theeffectivity of animal waste slurry for mitigating soil loss in leptosol from Mixteca Region,
Mexico. For this purpose, a splash erosion model and a surface runoff model were used. Splasherosion model consisted in stainless steel cores of 1.0 cm long with inside diameter at 1.1 cm.
Soil was placed inside at a dry density of 1.0±0.1 g/cm3. Fifty drops of artificial rain weredripped into the soil inside the core and soil loss was measured. On the other hand, surface
runoff model consisted of a plot of 91 cm x 3.15 cm x 1.4 cm, with a triangular section. Soilwas filled in with the same dry density of raindrop model and 1.2 cm3/s of deionized water wassupplied during one hour on a 12 degrees’ slope. Discharge was collected every ten minutes andsoil loss was measured. As treatment for both models, animal waste slurry was used. Horsedung was collected in the Horsemanship Club of Tokyo University of Agriculture and passed
through a sieve at 212 µm in order to obtain slurry. 2 treatments were set up: the first was cattle
slurry incorporated with soil and the second was crust formed with animal waste slurry; andcontrol. Soil losses were compared among these 2 treatments. Raindrop experiment results
showed that the addition of slurry decreased significantly soil loss rate from 6.4% to 1.3% inslurry incorporated cores and 0.2% in formed bio-crust cores. The same tendency was observedin the slope model experiment, where the application of slurry reduced significantly the soillosses from 558.6 g/m2 to around 60 g/m2 in both plots where slurry was added. Therefore, it
can be concluded that the application of animal waste slurry was effective to reducesignificantly soil losses by protecting the soil against kinetic energy of raindrops, as well asagainst shearing force of runoff on a 12 degrees’ slope in leptosol soil of Mixteca Region.
Keywords slurry, soil erosion, horse dung, leptosol, Mixteca Region

INTRODUCTION
Several studies point that the application of excreta wastes could be beneficial for soil conservation,
especially in degraded soils and soils being susceptible to erosion (Pinamonti and Zorzi, 1996). The
use of compost or mulch blankets as a soil cover could help control soil erosion and provide
sustainable alternatives to disposal for many biomass resources (Faucette et al., 2009).
Mixteca Region is located in Oaxaca State and has an average annual precipitation of 1988 mm
and an average mean temperature of 15.0 ºC (Servicio Meteorológico Nacional, 2010). Oaxaca State is
the main state by numbers of goats (Around 952,000 goats), which represents 10.9% of the national
production (SAGARPA, 2008). Moreover, according to García Hernández (1996), the majority of unitsof production are extensive, where goat dung is left in the croplands. Animal dung was used as aⒸ ISERD136

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resource for protecting soils against soil erosion. For that reason, the objective of this study is tomeasure the effectiveness of animal waste application for mitigation of soil loss by raindrop andsurface runoff and to discuss effective conservation measures with animal waste slurry application
based on the amounts of soil and nitrogen component losses.
METHODOLOGY
For this experiment soil samples from Mixteca Region were used. The samples were collected from arainfed corn field located in a slope of 12 degrees. Physical and chemical properties are summarized inTable 1.
Table 1 Physical and chemical properties of soil experimental design
Soil

Specific
gravity

GravelLeptosol

2.59

5.4

Particle size distribution, %CoarseFine
Silt Claysandsand
25.6
29.9
19.5 19.6

SoiltexturepHEC(μS/cm)

IL(%)

SCL

5.81

15.525.76

For this experiment, as animal waste, horse dung was used. It was obtained from thehorsemanship club of Tokyo University of Agriculture. Analysis of total nitrogen, total phosphorus andcoliform bacteria was conducted (Table 2).
Table 2 Properties of soil and animal waste

Soil

T-N
(mg/kg)920.20T-P(mg/kg)124.28

Coliform bacteria(cfu/g)0Slurry6744.19

13466.06

3.2 x 107

SampleThe preparation of slurry was carried out through the sieving of the horse dung through a sieve of
212 µm to eliminate straw residues. Deionized water was used for this process. Since the slurry had ahigh water content after this process, and for reducing the amount of coliform bacteria (Saito andMihara, 2010), slurry was dried up during four weeks (Fig. 1).

Horse dung fromhorsemanship club ofTokyo NODAI

Sieve of 212 µm
Air dried for four weeks

Horse dung slurry

Fig. 1 Animal waste slurry
For measuring the effectiveness of animal waste slurry, two experiments were carried out. The
first experiment was splash erosion model conducted with the purpose to measure the ability of slurryⒸ ISERD137

IJERD – International Journal of Environmental and Rural Development (2016) 7-1

added soil to decrease erosion by kinetic energy of raindrops. The second experiment was surface
runoff model with the purpose of measure the ability of slurry added soil to decrease surface erosion.
For both experiments, two treatments were applied.
Splash Erosion Experiment
For this experiment stainless steel cores were used, which are averagely 1.0 cm long with an internal
diameter of 1.1 cm. They were filled with soil under a dry density of 1.0 ±0.1 g/cm3 to keep a similar
compaction between samples. Constant water pressure was controlled by means of a Mariotte’s bottle(Fig. 2). A needle from the DIK-6000 rainfall simulator equipment was used for this experiment. The
kinetic energy of raindrops was 2.36 x 10-5J, calculated based in the equation Ek= ½ m v2.
Mariotte’s bottle forkeeping constantpressure

Remaining mass of soilin the core wasmeasured

50 drops of artificial
raindrop were dripped
into the coreFig. 2 Splash erosion modelFor both experiments (Fig. 2), two treatments were defined. In these two treatments, the same
dried mass ratio of soil : slurry was kept at 66:1. The first treatment consisted on incorporating theslurry into the soil by mixing both materials and placing the mixture into the stainless cores(incorporated with soil treatment). The second treatment consisted in placing the soil into the stainlesscore, compacted under the above mentioned dry density, and then covering completely its surface withanimal waste slurry (formed bio-crust treatment).
For each treatment, 10 cores were used. 50 drops of artificial rain (deionized water) were dripped
into every stainless core. Then, the remaining mass of soil inside the core was calculated (Eq. 1).

(1 -𝑅𝑒𝑚𝑎𝑖𝑛𝑒𝑑 𝑠𝑜𝑖𝑙 𝑚𝑎𝑠𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑚𝑒𝑡𝑎𝑙 𝑐𝑜𝑟𝑒
𝐼𝑛𝑖𝑡𝑖𝑎𝑙 𝑠𝑜𝑖𝑙 𝑚𝑎𝑠𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑚𝑒𝑡𝑎𝑙 𝑐𝑜𝑟𝑒) x 100(1)

Surface Runoff Experiment
In this experiment, a triangular-section plot was used. The length was 91.0 cm and the triangularsection had a height of 1.4 cm and a base of 3.1 cm (Fig. 3). Similar to the previous experiment, thecompaction was keep under a dry density of 1.0 ±0.1 g/cm3. And for this experiment the constant
supply of deionized water (1.2 to 1.3 cm3/s) was done by the use of a Mariotte’s bottle during 60
minutes. The slope of this plot was determined as 12 degrees for all the samples.
The percolation water and runoff water was collected every 10 minutes for analyzing the amountof soil loss and the contents of total nitrogen.
Similar to the previous experiment, two treatments were defined for the surface runoff experiment.
The first treatment consisted on incorporating the slurry into the soil by mixing both materials andplacing the mixture into the plots. The second treatment consisted in placing the soil into the plot andthen covering completely its surface with animal waste slurry. In both treatments, dried mass ratio ofsoil : slurry was kept at 66:1 (equivalent to 10 tons of slurry per hectare with a water content of 5.87).
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IJERD – International Journal of Environmental and Rural Development (2016) 7-1Fig. 3 Surface runoff plot model
RESULTS AND DISCUSSION
Splash Erosion Experiment
For every treatment ten stainless cores were used. After the 50 drops were applied, the samples weredried and then the weight inside every can was measure. Figure 4 shows the cores after the experiment.
As can be observed, the cores in control showed a higher dispersion of soil particles.

Control

Incorporated with soil

Formed bio-crust

Fig. 4 Cores after raindrop experiment
After the fifty drops were dripped into the stainless cores, the soil loss rate was calculated. As canbe observed in Fig. 5, control samples showed a higher dispersion of soil particles caused by theimpact of raindrops compared to the treatments were animal waste slurry was added into the soil.
The average soil loss in control was 6.4%. The incorporation of slurry into the soil reduced thesoil loss to 1.3%, and the application of slurry into the surface reduced the soil loss until a 0.2%. It was
found that there was a significant difference between the control samples and the treatment with slurry.
However, there was no significant difference between treatments. This can suggest that either way of
applying slurry, being incorporated into the soil as a mixture or just applied on the surface is effective
for reducing soil loss caused by the raindrop energy.

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Soil loss rate (%)

8A**

642B**B**

0Control

Incorporated
Treatment

Bio-crustFig. 5 Soil loss rate between treatment

Surface Runoff Experiment
The collection of runoff samples was carried out every ten minutes during one hour in the surface
runoff experiment as shown in Fig. 6.

Control

Incorporated with soil

Formed bio-crust

Fig. 6 Runoff experiment plots
Figure 7 shows the results of the samples after being analyzed for cumulative soil losses and totalnitrogen. Fig. 7(c) showed that there was no significant difference in the amount of discharge among
treatments during the hour the experiment last. However, as can be observe in figure 7(a), control plot
presented a much higher amount of soil losses, compared to the plots where slurry had been added.
Concerning the amount of total nitrogen, in Fig. 7(b) can be observe that control plot shows a higher
amount of nitrogen released, compared to treatments where slurry has been added. So even if slurry
contains nitrogen, when added to the soil there was a fewer release of nitrogen into the runoff water
samples.
It is considered that between the treatments, the addition of slurry, incorporated to the soil as well
as applied in the surface to form a bio-crust significantly reduced the amount of soil losses compared tothe control plot, in both the raindrop experiment and the runoff model. This could be due to thecohesion force produced by adding organic materials of animal waste slurry into the soil particles
being beyond the kinetic energy of raindrops or shearing force of surface runoff.

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600
550500450400350
300
250200150
10050
0

Cumulative amount of T-N losses(g/m2)

Cumulative amount of soil losses(g/m2)A**

Control
Incorporated
Formed biocrust

B**
B**
01020

30

4050

0.20
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00

A**
B**
C**
Control
Incorporated

10602030405060

Time (min)Time (min)3500

Discharge (ml)

3000
2500
2000
1500

Control

1000

Incorporated

500
0102030405060Time (min)Fig. 7 Analysis of runoff experiment samples
CONCLUSION
Adding slurry into the soil, incorporated or applied on the surface, reduced splash erosion rate
significantly in leptosol of Mixteca Region, as well as soil and nitrogen loss in the surface runoff. This
could be because the addition of organic matter into the soil in the form of slurry improved the soil
aggregation (Six, 1998), making it stronger against the kinetic energy of raindrops or the shearing
forces of surface runoff. However, future research has to be conducted in order to ensure that theaddition of slurry is not harmful for the environment. Furthermore, from a view point of nitrogen loss
in the runoff experiment, formed bio-crust may be recommendable to apply as a conservation strategy
above the incorporation of slurry into the soil.
REFERENCES
Faucette, L.B., Scholl, B., Bieghley, R.E. and Governo, J. 2009. Large-scale performance and design forconstruction activity erosion control best management practices. Journal of Environmental Quality, 38, 12481254.
García Hernández, A. 1996. La caprinocltura en la mixteca oaxaqueña. Ciencias, 44. Universidad Nacional
Autónoma de México.
Pinamonti, F. and Zorzi, G. 1996. Experiences of compost use in agriculture and in land reclamation projects.
The Science of Composting, I, 517-527.
SAGARPA. 2008. Sistema de información agricola y pesquera SIAP.
Saito, Y, and Mihara, M. 2010. Management of manure taking into account of E. coli loss from farmland. IJERDInternational Journal of Environmental and Rural Development, 1 (1), 175-180.
Servicio Meteorológico Nacional, México. 2010. Climatological normal values for Coicoyán de las Flores,
Mixteca Region, 1951-2010.
Six, J., Elliott, E.T., Paustian, K. and Doran, J.W. 1998. Aggregation and soil organic matter accumulation incultivated and native grassland soils. Soil Sci. Soc. Am. J. 62, 1377.
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