Effect of Animal Droppings on Thermal Properties of Dispersed Porous System

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					Trends Soil Sci Plant Nutr 2012 3(1): 13-18

                               Trends in Soil Science & Plant Nutrition
                                                Journal

                                                                www.academyjournals.net

                                                                                                                                   Original Article

           Effect of Animal Droppings on Thermal Properties of Dispersed Porous System.

                                                 Edem, I.D*1, EKO, P.M 2. and John, N.M3
                                   1
                                    Department of Soil Science University of Uyo, P.M. B.1017, Uyo, Akwa Ibom State, Nigeria.
                                     2
                                       Department of Animal Science University of Uyo, P.M. B.1017, Uyo, Akwa Ibom State,
                                     3
                                       Department of Soil Science University of Calabar, Cross River State, Nigeria.

                                Received: 05.08.2012             Accepted: 16.08.2012            Published:06.09.2012


Abstract

Four locations of sand, loam, Laterite and black-earth were chosen to best represent the area of interest and organic materials of chicken
dropping, cow and goat dung were applied to the soil in order to evaluate the effect of animal manure inclusion (at 20,40 & 60 percent to
soil) on soil physical indices and heat flow within the soil system. There was minimal soil disturbance during installation. Soil profile and
surface conditions were carefully reconstructed with four different levels of organic materials to soil proportion; 1:5, 2: 5, 4:5 and control.
And soils were repacked to the original bulk density such that there was no significant change in thermal regime of the soil. Generally, the
trend of thermal conductivity for different soils followed the order of sand > loam > clay > black earth (soil from dump site). The changes
between 20 and 50 % were not significant for goat dung but significantly different in cow dung. When chicken dropping was added to the
soils at different rates, 20 % inclusion was similar to the conductivity of the control; further increase in the rate significantly (P< 0.05)
reduced the soils conductivity. In as much as the dark colour soil is due to dominant organic material, the temperature of these soils is
greatly affected by the relatively high specific heat and low conductivity of a given organic material.

Keywords: Soil Temperature; Thermal Conductivity; Heat Capacity; Heat Flow; Organic Material.


*
 Corresponding Author: Edem ID, email: dennis.edem@gmail.com Phone: +2348027031426



    INTRODUCTION

     Soil temperature is a very important soil property that                   content rate of decomposition, nutrients availability and plant
has direct effect on plant. It varies in time and in space and is              productivity (David and Janssen 2006). While organic
a factor of primary importance in determining the rate and                     material in the soil serves as a nutrient reservoir that can
direction of soil physical processes and of energy and mass                    slowly be incorporated into the mineral soil by
exchange with the atmosphere. The amount of heat reaching                      decomposition (Hungerford et.al. 1990). Biological process
the soil from heat source depends upon the heat intensity and                  such as N mineralization can also be enhanced following heat
absorption of the heat by the soil. Thermal conductivity                       transfer (Ketterings et al. 2000).
according to Hillel (1982) is the amount of heat transferred                       The objectives of this research were to evaluate the
through a unit area in a unit time under a unit temperature                    changes in soils’ physical and chemical characteristics and to
gradient.                                                                      assess the interaction of heat flow in an effort to understand
     Soil depth and mass influence heat behaviour, regulate                    how the transports of matter and energy occur simultaneously
physical soil protection, and affect nutrient pool size. Soil                  and independent in the soil.
temperature can affects the nitrogen (N) and carbon ( C)

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Trends Soil Sci Plant Nutr 2012 3(1): 13-18                                                                            I.D. Edem et al.
MATERIALS AND METHODS                                                    a smoothed side of the pits with its top flush with the surface.
                                                                         Insulated brass of 0.5 cm diameter by 15 cm long with
     Study Site                                                          pointed and sealed ends, each housing an appropriate
     Treatment units were located within Uyo metropolis, the             temperature sensor were pushed through the holes in the
Akwa Ibom state capital, South Eastern Nigeria. The area is              reference board into the soil. The hold was then back filled
located between latitudes 400 301 and 50 31N and longitudes              and the measured animal dung was applied and left for 14
70 311 and 80 201 E and altitude 65 m from the sea level. The            day to equilibrate. The sensor was pushed into the hole,
area is divided into two distinct seasons, the wet or rainy and          ensuring that there was a good contact between the sensor
dry seasons. The wet or rainy season begins from April and               and the surrounding soil. And the measurement depth (15
lasts till October. It is characterized by heavy rainfall of             cm) corresponded to the center of the sensor (Bristow et al.
about 2500-4000 mm per annum. The rainfall intensity is                  2001).
very high and there is evidenced of high leaching and erosion                Heat was imposed on the back filled treated soils where
associated with slope and rainfall factors in the area. The dry          20 cm lead wire was buried at 15 cm depth as the sensor to
season starts from November and lasts till March. It is                  minimize errors cause by heat conduction towards the sensor.
characterized by high temperature with a mean annual                     Data recorded at the data logger output device were recorded
temperature of 280C. The highest temperature is experienced              from all the installations and then fitted into heat capacity
between Januarys through March, the period described by                  equation of Hillel (1982).
Enwezor et al. (1990) as over head passage of the sun. The                   Heat capacity - C = ζmCm + ζoCo + ζwCw                   (1)
relative humidity is between 70% and 80%. The landscape is               Where,
generally undulating to steep hills while the vegetation is                  ζm, ζo, ζw are volume fraction of mineral matter,
mainly: the tropical rain forest. The soils are derived from             organic matter and water
sandy parent materials which are weathered with low activity                 respectively and Cm, Co, Cw, = refers to the heat
clay (Udo and Sobulo 1981).                                              capacities of the same constituent
                                                                         thermal conductivity Ќ was also calculated from Ќ =
     Measurement Principles and Procedures                               Qd/A+∆T (2) where, Q = Thermistor readings
     Experimental Treatments                                                                    d = effective depth
     This research was conducted at four locations of sand,                                    A = cross sectional area of the soil
loam, Laterite and black earth (dump site) with different                                     ∆T = temperature difference
inclusion of organic materials following heating. Animal
droppings were dried, crushed and sieved through 8 mm                         Sample Processing and Analysis
sieve openings, and the following measurement were made                       Soil bulk density was determined based on the total mass
for each of the materials; 5kg/25kg soil (20 %), 10kg/25kg               and volume of each sample. Air-dried soils were sieved to <
soil (40%), 20kg/25kg soil (60 %) and control ( 0 %). The                2 mm, and subsamples were used for the following analyses;
textural class of the soils was also determined.                         Particle size distribution was analysed using the hydrometer
                                                                         method (Day 1965) following H2O2 oxidation of organic
     Installation                                                        matter and dispersion with sodium hexametaphosphate. The
     Four locations were chosen to best represent the area of            soil pH was measured in 1:2.5 (w/v) of veil: wafer with glass
interest. Physical properties of the soil; reflectivity, presence        electrode on a pH meter. Organic carbon was determined by
of woody debris, vegetation, and organic matter were                     the wet oxidation method (Walkley and Black, 1934).
considered because they have significant influence on the                Exchangeable contents of the soils were determined by
surface energy balance and therefore on the surface and sub-             extraction with 1N ammonium acetate (NH4OAc) at pH 7.
surface temperature (Valzano et at. 1997).                               Exchangeable Ca and Mg in the extract were determined by
     There was minimal soil disturbance during installation.             an atomic absorption spectrophotometer and K and Na by
Soil profile and surface conditions were carefully                       flame photometry. Cation exchange capacity (CEC) was
reconstructed with four different levels of organic materials            calculated as the sum of the exchangeable potassium,
to soil proportion; 1:5, 2: 5, 4:5 and control, and soils were           calcium, magnesium and sodium. Total N and total P were
repacked to the original bulk density such that there was no             determined by digestion of the soil with H2SO4 and H2O2.
significant change in thermal regime of the soil.                        For all samples the concentration of P was determined
     Insertion of temperature sensor was in accordance to the            colorimetrically in filtered samples by the molybdenum-blue
method described by Fritschen and Gay (1979). Mini pits                  method (Murphy and Riley 1962), while total N was
were dug in each of the locations to 50 cm and a board of                determined by the Kjeldahl method. All analyses were
predrilled holes at selected increment was then pushed up to             carried out in duplicate.
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Trends Soil Sci Plant Nutr 2012 3(1): 13-18                                                                               I.D. Edem et al.
    RESULTS AND DISCUSSION                                               increased in sand 8.95, loam 31.52, Laterite 28.26 and black
                                                                         earth 10.41 10-3 calcm-3 with an average specific heat of
     The selected soil properties under different proportion of          19.79 10-3calcm-3
organic material from the four sites within the zone (data not
shown) revealed that, the particle size analysis with the                Table 1 Variation in specific heat capacity of soils at
exception of the sandy location generally decreased the sand             different proportion of organic materials
contents in the topsoils while the clay contents were                                    Specific heat capacity (10-3cal/cm3)
increased, giving rise to sandy clay loam to sandy clay                                                                      Black
                                                                          Materials OM %   Sand       Loam       Laterite earth      Mean
texture. In all, application of organic material did not modify
the texture of the soils because of the intrincity of soil                soil only   0       21.982   39.546    15.562     68.319   36.352
texture.                                                                  CD          20      3.813    28.889    27.115     8.212    17.007
     The specific heat capacity of any substance is the                   CD          40      1.937    13.906    6.864      4.800    6.877
calories of heat required to raise one gram one degree on the             CD          60      5.587    31.519    15.628     6.032    14.691
centigrade scale. The heat capacity of a soil is its specific                         Mean    3.779    24.771    16.536     6.348    12.858
heat times its mass. The contribution of organic materials and            CH          20      14.489   57.304    15.119     14.862   25.443
                                                                          CH          40      10.677   12.642    9.667      6.646    9.908
water in the soil greatly influenced the relatively specific heat         CH          60      46.316   13.383    17.757     6.893    21.087
capacity of a given soil. It may be seen from the data in Table
1 that specific heats of various solid soil constituents differ                       Mean    23.827   27.776    14.181     9.467    18.813
greatly at different proportion of added organic materials.               GD          20      4.559    19.349    15.365     8.923    12.049
     Before addition of organic material in the soils, the                GD          40      2.669    9.439     9.791      9.231    7.782
                                                                          GD          60      8.947    31.519    28.267     10.408   19.785
specific heat capacity of Sand, Loam, Laterite and Black
earth were 21.89, 39.55, 15.56 and 36.35 10-3 calcm-3                                 Mean    5.392    20.102    17.808     9.521    13.206
respectively. At 20 % inclusion of cow dung, specific heat
capacity varied from 3.81–28.89 10-3 calcm-3 with a mean
of 17.01 10-3 calcm-3 the corresponding values at 40 %                        Specific Heat Capacity-Organic Material Interactions
inclusion were 1.94, 13.91, 6.86 and 4.80 10-3 calcm-3 for                    The interaction of specific heat capacity x organic
Sand, Loam , Laterite and black earth respectively, with a               material was established by plotting. A study (Figure 1) of
mean specific capacity of 6.88 10-3 calcm-3 . But 60 %                   specific heat capacity x organic material means of different
inclusion of cow dung varied the specific heat capacity from             soils combined into a single graph showed that significant
5.59 - 31.52 10-3 calcm-3 with a mean value of 14.69 10-3                high specific heat capacity (              10-3calcm-3) were
calcm-3                                                                  observed in Black earth before organic material applications,
     It was found that, 20 % chicken dropping reduced the                also when 20 % chicken dropping was added to Loam and 60
specific heat capacity of sand to 14.49 10-3calcm-3 , Laterite           % in sand soil types. The specific heat capacity pattern from
to 15.12 10-3calcm-3 and black earth to 14.86 10-3calcm-3                those other combinations were below 35 10-3calcm-3 even
,
  and increased loam to 57.30 10-3calcm-3 . When the                     in the free state. Despite the sudden increase in specific heat
proportion of the dropping was increased to 40 %, specific               capacity of loam on addition of 20 % chicken dropping,
heat capacity further reduced to 10.68, 12.64, 9.67, and                 subsequent increase inclusion of dropping reduced specific
6.65 10-3calcm-3 in sand, loam, Laterite and black earth                 heat more the 50 %. The data from black earth support the
respectively. When the ratio of chicken dropping was                     hypothesis of low heat capacity of peat soil due to high
increased to 4:5 (dropping / soil), specific heats raised                proportion of aeration pores.
correspondingly to 46.32 10-3calcm-3 in sand, 13.38 10-
3
  calcm-3 in loam and 17.78 10-3calcm-3 in Laterite, and
slightly to 6.89 10-3calcm-3 in black earth with a mean                       Soils’ Thermal Conductivity
specific heat of 21.09 10-3calcm-3 .                                          The amount of heat reaching the soil from heat source
     When 20 and 40 % of goat dung were added to the soil ,              depends upon the heat intensity and absorption of the heat by
specific heat capacity significantly and respectively reduced            the soil. Thermal conductivity according to Hillel (1982) is
to 4.56 and 2.67 10-3 calcm-3 in sand, 19.35 and 9.44 10-3               the amount of heat transferred through a unit area in a unit
calcm-3 in loam, while in Laterite, specific heats were 15.37            time under a unit temperature gradient. The temperature of
and 9.79 10-3calcm-3 whereas specific heats capacity for                 soil is determined to a considerable extent by its own
black earth were 8.92 and 9.23 10-3calcm-3 .As the                       properties .It depends upon factors responsible for
proportion was increased to 60 %, specific heat equally                  differences in intensity of absorption of heat such as colour.

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Trends Soil Sci Plant Nutr 2012 3(1): 13-18                                                                                             I.D. Edem et al.
                                                                                    Table 2 Changes in Thermal conductivity (500C) of soils
                                                                               at different level of Organic Materials inclusion (%)

                                                                                                        Thermal conductivity (10-6 cal/cm/sec0C)
                                                                                             Org.
                                                                                             matter                                       Black
                                                                                Materials    %          Sand      Loam       Laterite     earth    Mean
                                                                                soil only    0          9.455     14.463     4.473        20.692   12.271
                                                                                CD           20         7.848     13.596     8.486        3.792    8.431
                                                                                CD           50         8.667     7.259      2.417        2.600    5.236
                                                                                CD           80         40.446    27.843     7.656        3.331    19.819
                                                                                             Mean       16.604    15.790     5.758        7.604    11.439
                                                                                CH           20         1.962     27.193     4.629        6.067    9.963
                                                                                CH           50         1.529     7.259      3.491        3.467    3.936
                                                                                CH           80         4.667     11.137     10.208       3.807    7.455
Figure 1 Specific heat-organic material interactions in different soils                      Mean       2.719     15.196     6.109        4.447    7.118
                                                                                GD           20         2.825     7.769      4.629        4.334    4.889
     Another factor is differences in specific heat of the soil                 GD           50         2.167     4.839      3.491        5.200    3.924
such as compaction and moisture content and next is                             GD           80         7.584     27.843     15.312       6.663    14.350
variation in heat conductivity. Therefore, these results
                                                                                           Mean      4.192     13.484    7.811      5.399          7.721
provide a semi-quantitative interpretation of observed
                                                                               CD= cow dung, GD = goat dung , CH = chicken dropping
influences of soil surface condition, including the presence of
organic materials on the soil’s thermal regime.
     At this point, attention of this study is called to
differences in heat conductivity resulting from addition of
organic material at different proportions. The significance of
the heat conductivity of various soils is shown by data of
Table 2 and Figures 2-8.




                                                                               Figure 3 Thermal conductivity in different soils with chicken dropping

                                                                                    Application of cow dung to soils results in a
                                                                               progressively increasing thermal conductivity in sand from
                                                                               7.848 (10-6 cal/cm/sec0C) at 20 % inclusion to 8.667 and
                                                                               40.446 (10-6 cal/cm/sec0C) at 40 and 60 % inclusions
Figure 2 Thermal conductivity in different soils with Goat dung
                                                                               respectively. Relatively, high amount of heat (more than in
                                                                               20 and 40 % inclusions) was conducted in sand when there
                                                                               was no addition of this organic material. Thermal
                                                                               conductivity in Loam, Laterite and Black earth were
                                                                               irregularly distributed with cow dung application. These
                                                                               irregular patterns of conductivity emphasize the importance

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Trends Soil Sci Plant Nutr 2012 3(1): 13-18                                                                                  I.D. Edem et al.
of curing the organic materials in the respective soils before         changes in heat conductivity were noticed when chicken
heat application and measurement.                                      dropping was added to soils. The highest conductivity in sand
                                                                       was observed at 60 % inclusion. The same premise held for
                                                                       Loam and inversely related in Black earth. There was no
                                                                       significant change in lateritic soil.
                                                                            Generally, the trend of thermal conductivity for different
                                                                       organic materials (Figs. 5-8) revealed that 60 % goat and cow
                                                                       dung were significantly higher than the control. The changes
                                                                       between 20 and 40 % were not significant for goat dung but
                                                                       significantly different in cow dung. When chicken dropping
                                                                       was added to the soils at different rates, 20 % inclusion was
                                                                       similar to the conductivity of the control, further increase in
                                                                       the rate significantly (P< 0.05) reduced the soils conductivity.
                                                                       In as much as the dark colour soil is due to organic material,
                                                                       the temperature of these soils is greatly affected by the
                                                                       relatively high specific heat and low conductivity of a given
Figure 4 Thermal conductivity in different soils with Cow dung         organic material. The thermal conductivities of specific soil
                                                                       constituents differ very markedly (Figure 8).
     Depending on organic material quantity and soil type,
60% chicken dropping to soil reduced thermal conductivity
from 9.455 (10-6 cal/cm/sec0C) to 4.667 (10-6 cal/cm/sec0C)
in sandy soil. Whereas 40% inclusion of droppings further
reduced heat conductivity to 1.529 (10 -6cal/cm/sec0C) and
1.962(10-6 cal/cm/sec0C) with 20% dropping. The result in
loam revealed that 20 % dropping increased the conductivity
to 27.193 (10-6 cal/cm/sec0C), and suddenly dropped to 7.259
(10-6 cal/cm/sec0C) at 40 % inclusion and to 11.137 (10 -6
cal/cm/sec0C) on addition of 60 % chicken dropping to the
soil. Changes in thermal conductivity for Laterite at different
chicken dropping compositions show significant high thermal
conductivity at 60 % dropping and changes at 20 % and 40 %
inclusions were not significantly different from the thermal
conductivity before addition. Results for black earth soil type
without chicken manure showed thermal conductivity of                  Figure 5 Comparison of Thermal conductivity at different rate of Goat dung
20.692 (10-6 cal/cm/sec0C) and significant conductivity
decline during the manure addition at various proportion
     Thermal conductivity of goat dung dropped in all the
soils at 40 % inclusion. Increase in thermal conductivity was
observed in loamy and lateritic soils at 60 % addition of
dung.

    Comparison of Thermal Conductivity in Different
Soils
    As shown in Figure 2, thermal conductivity of goat dung
at 20 % inclusion was significantly lower than the control
and 60 % treatments in sand. The treatment of 60 % showed
highly significant thermal conductivity followed by control in
loam soil. There was no difference in thermal conductivity of
Lateritic soil except at 60 % inclusion. The reverse was true
in Black earth soil, thermal conductivity declined                     Figure 6 Comparison of Thermal conductivity at different rate of chicken
                                                                       dropping
immediately as goat dung was applied. Furthermore,

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Trends Soil Sci Plant Nutr 2012 3(1): 13-18                                                                                              I.D. Edem et al.
                                                                                 Steady and regular thermal conductivity from these soils is
                                                                                 not widespread occurrence on addition of droppings. It may
                                                                                 have been affected by bulk density and wetness as well as the
                                                                                 internal sources and sinks of heat operating at a time. The
                                                                                 space-average thermal conductivity of these soils depends
                                                                                 upon its mineral composition and organic matter content as
                                                                                 well as water content, hence low thermal conductivity. This
                                                                                 explains the fact that soils dominant of sand fractions have
                                                                                 higher specific heat capacities than those dominated with
                                                                                 organic materials and emphasizes the need for organic
                                                                                 material inclusion in arable soil in order to check earlier
                                                                                 warm up of soils during sunny days.

Figure 7 Comparison of Thermal conductivity at different rate of Cow dung             ACKNOWLEDGEMENTS

                                                                                     The authors thanks BGI Resources laboratory LTD PHC.
                                                                                 For providing the needed equipments and analysis of data
                                                                                 and Mrs. May Innih Dennis for her valuable comments.

                                                                                      REFERENCES

                                                                                 Bristow KL, Kluitenberg GJ, Goding CJ, Fitzgerald TS, 2001. "A small
                                                                                      multi-needle probe for measuring soil thermal properties, water content
                                                                                      and electrical conductivity". Computers and Electronics in Agriculture
                                                                                      31 (3): 265–280. doi:10.1016/S0168-1699(00)00186-1 Retrieved from
                                                                                      "http://en.wikipedia.org/wiki/Soil_thermal_properties
                                                                                 Daniel Hillel, 1980. Fundamental of Soil physics. Academic Press, New
                                                                                      York.
                                                                                 Davidson EA, and Janssen IA. 2006. Temperature sensitivity of soil carbon
                                                                                      decomposition and feedbacks to climate change. Nature 440, 165–173.
                                                                                 Day PR, 1965. Particle fractionation and Particle size analysis. Pages 454-
                                                                                      567 in C. A. Black (ed) method of analysis: No. 9 Monogr. Ser. Part 1
                                                                                      American Society of Agronomy
                                                                                 Enwezor WO, Udo EJ, Ayorade WA, Adepuju J, and Chude VO, 1990. A
                                                                                      Review of Soil and Fertilizer use Research in Nigeria. In: Literature
                                                                                      Review on Soil Fertility Investigation in Nigeria. Federal Ministry of
Figure 8 Trend of thermal conductivity of various organic materials                   Agriculture and Natural Resources., Lagos, pp.53-100
                                                                                 Fritchen LI, and Gay LW, 1979. Environmental instrumentation. Springer-
                                                                                      Verlag,New York.
     CONCLUSION                                                                  Hungerford RD, Harrington MG, Frandsen WH, Ryan RC, and Niehoff JG,
                                                                                      1991. Influence of fire no factors that affect site productivity.
     Results from the study have shown that organic manure                            Symposium on management and productivity of western – Montana
                                                                                      forest soils.
inclusion at any rate significantly dampen heat transfer in                      Ketterings QM, Bigham JM, Laperche V, 2000. Changes in soil mineralogy
black-earth, whereas improved           heat conductivity was                         and texture caused by slash-and-burn fires in Sumatra, Indonesia. Soil
noticed in soils fortified with animal manure. Organic                                Science Society of America Journal 64: 1108–1117
amendments are require to improving the thermal regime and                       Udo EJ, and Sobulo SA, 1981. Acid sands of southern Nigeria. Soil Science
                                                                                      Society of Nigeria spec. Publication Monogr. No. 1: 615
physico-chemical indices of the studied soils (except black                      Valzano IP, Greene RSB, Murphy BW, 1997. Direct effect of Stubble
earth). The optimum thermal conductivity of 8.66 x 10-6                               Burning in a direct drill tillage system. Soil and Tillage Research 142:
cal/cm/sec/0C was achieved at 40 % CD inclusion in sandy                              209-219
soil and this will greatly improve germination and the growth                    Walkey A, and IA. Black, 1934. An Examination of the method for
                                                                                      determining soil organic matter a proposed modification of the chromic
of arable crops grown on acid sands.                                                  acid titration methods. Soil Science 37: 29-38
Therefore, 20-40 % organic amendments is recommended for
lateritic soil as these will ameliorate heavy fine particles and
hence improved the production capacity of this soil .


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