EFFECTS OF MOISTURE CONTENT, BULK DENSITY AND TRACTOR FORWARD SPEEDS ON ENERGY REQUIREMENT OF DISC PLOUGH

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1 International Journal of Advanced Research in Engineering and Technology (IJARET) Volume 6, Issue 7, Jul 2015, pp , Article ID: IJARET_06_07_009 Available online at ISSN Print: and ISSN Online: IAEME Publication IJARET EFFECTS OF MOISTURE CONTENT, BULK DENSITY AND TRACTOR FORWARD SPEEDS ON ENERGY REQUIREMENT OF DISC PLOUGH S. O. Nkakini Department of Agricultural/Environmental Engineering, Faculty of Engineering, P. M. B. 5080, Rivers State University of science and Technology Port-Harcourt, Nigeria. Ndor. M. Vurasi Department of Mechanical Engineering, Faculty of Engineering, P. M. B. 5080, Rivers State University of Science and Technology Port-Harcourt, Nigeria ABSTRACT Energy requirement in tillage operations plays a vital role in agricultural mechanization. This hardly comes by since much drudgery is still applied in farming operation in respect to mechanization. This research was conducted at National Root Crops Research Institute (NRCRI) Experimental Farm, Umudike Umuahia, Abia State of Nigeria. Three different tractor forward speeds of 1.94 m/s, 2.22 m/s and 2.5 m/s were employed to determine the needed energy requirements in the ploughing operations. It was observed that total energy expended on ploughing were 36, KJ, 55, KJ and 69, KJ respectively. The results indicated that energy decreased with increase in moisture content level db% and increased with increase in bulk density at various forward speeds. This follows the sloping and rising up of the graphs as the moisture content levels (db %) and bulk density (g/cm 3 ) increased, with highest coefficient of determination R 2 = at tractor forward speed of 1.94 m/s. The result revealed that energy increased as the tractor forward speeds increased with mean energy values of 1, KJ, 2, KJ and 3, KJ. The highest energy was expended at tractor forward speed of 2.5 m/s. It was clear that the ploughing at tractor forward speed of 1.94 m/s requires less energy. Therefore, 1.94 m/s tractor forward speed is preferred to ploughing operation. Key words: Energy requirement, tillage, disc plough, moisture content, bulk density, tractor forward speeds and ploughing 69 editor@iaeme.com

2 S. O. Nkakini Ndor. M. Vurasi Cite this Article: Nkakini, S. O. and Vurasi, N. M. Effects of Moisture Content, Bulk Density and Tractor Forward Speeds on Energy Requirement of Disc Plough. International Journal of Advanced Research in Engineering and Technology, 6(7), 2015, pp INTRODUCTION Tillage as one preliminary and basic step for any agricultural production demands huge amount of energy. Tillage is generally regarded as the most fundamental operation in agricultural production. It can be defined as the cutting, pulverizing and inversion of the soil to create conducive environment for crop growth and good yield [1]. According to researchers tillage operation is any physical loosening of the soil as carried out in a range of cultivations either by hand or mechanical methods [2]. The implement plough is used in farming activities for initial cultivation of soil in preparation for seeds planting. Tillage operation such as ploughing is an effective means of controlling weeds especially perennial weed species, because trash and weeds are buried relatively deeply in the soil. The use of energy is substantial mostly in agriculture where drudgery is set to be reduced to the barest minimum. This is the fact that most farmers still go subsistence farming, reason being that they cannot afford the higher rate of energy consumption including the labour requirement during the process. Energy requirement of a tool during tillage operation is affected by three main factors which are: soil, tool and operational parameters. Hence for proper evaluation of total energy expended, the energy requirement of each factor should be taken into consideration. Factors such as soil texture, soil moisture content, and soil compaction, and tool geometry, tool operating depth, tool forward speed and tool rake angle obviously affect the energy requirement of a tillage operation [3]. Two additional factors such as tools shape and manner of tool movement were reported as factors affecting energy requirement of tillage operations [4]. In tillage operation, energy could be expressed in terms of energy per unit area or per volume of disturbed soil as well as the rate of energy per depth of operation [5, 6]. Soil properties that contribute to tillage energy are moisture content, bulk density, cone index, and soil texture [7, 8]. In fact, in the case of loosing hardpan layer of soil, it becomes obvious that a high energy input is required to improved root development and increased draught tolerance. A significant savings in tillage energy could be achieved through site specific management of soil compaction [9]. Energy requirements of tillage tools are important consideration in selecting tillage system.[7] In agricultural cultivation, there is this problem of determining the energy values or fuel consumption as it is to be used by machineries and other implements. It is of a great important to farmers, to have the full knowledge of the energy required and fuel consumption for any particular farming operation. This has been a renounced problem for farmers. When a predetermined actual energy requirement and fuel consumption are obtained, the farmers can easily choose the best conservation practices to manage farm equipment and operations. This is to say, if agricultural industries or firms can calculate the energy requirements in any farm practices, agricultural operation would be easy and hence increase in productivity editor@iaeme.com

3 Draught Force Requirements of a Disc Plough at Various Tractor Forward Speeds in Loamy Sand Soil, During Ploughing Thus objectives of the research is to determine the energy requirement and the optimal forward speed for disc plough in tillage operation at various tractor forward speeds. The effects of moisture content and bulk density on energy requirements 2. MATERIAL AND METHODS Description of Study Area: The experiment was conducted between September, 2010 and January 2011 at National Root Crops Research Institute (NRCRI) Experimental Farm, in Umudike, Umuahia, Abia State of Nigeria. Umudike is within under the derived tropical humid ecological zone of Nigeria and is 122 m above sea level and lies on latitude N and longitude E. It is approximately 64 km south-east of Owerri and 128 km west of Port Harcourt capital of Rivers State of Nigeria. The weather data during the period of the field operations in terms of rainfall, relative humidity and sunshine for 2010 and January, 2011 were obtained from the Agro-meteorological Department Umudike Station. Annual rainfall in the research area is between 2500 mm to 300 mm per year. The monthly mean weather condition for 2010 to January 2011, when the tillage operations were carried out is also given. The instrument and equipment used are as follows, two tractors of the same model and horse powers, dynamometer, measuring tape, disc plough, stop watch, core sampler, polythene bag for soil sample collection and auger. Experiential design: The experiential layout area is 90 m by 90 m and was designed with three different blocks of 90 m by 27 m each. Each block was divided into 9 trips of 90 m by 2 m wide with a space of 3 m between each strip. Experimental procedure: Ploughing operations were carried out on each of the blocks, 24 hours after each rainfall event. Three replications of ploughing operations were conducted after every rainfall events. The total treatments were 9 20 rainfall events. The sequence of tillage operation was Rainfall event ploughing on block 1, strip 1, block 2, strip 1 and block 3, strip 1. Rainfall event 2: ploughing on block 1, strip 2 block 2, strip 2 and block 3 strip 2. Rainfall event 3: ploughing on block 1, strip 3, block 2, strip 3 and block 3, strip 3. This pattern was followed for the remaining number of rainfall events up to the last day when minimum moisture content was established. Moisture content determination: Soil moisture was replenished only through rainfall. The soil moisture content on each rainfall event was determined gravimetrically (oven dry method). In order to define the relevant soil condition, soil samples were collected from various soil depths before any tillage operation. The soil samples were collected at depth of 0 50 mm, mm, and mm, using soil auger at three replications per sample point. Different spots in the test plot were randomly selected for the soil sample collections for soil moisture content level. The tillage operation started only after each rainfall event. Mws Mds Mc = 100 (1) Mds where, Mc = Moisture Content %, Mws = Mass of wet soil, Mds = Mass of dry soil Determination of Bulk density: The bulk density was obtained using cylindrical cores to collect some soil samples randomly. With Vanier Calliper the diameter and length of cylindrical core were measured. The soil samples were collected at different depths. To determine the bulk density of the soil equation 2 was used editor@iaeme.com

4 S. O. Nkakini Ndor. M. Vurasi Ms Db = g cm Vb 3 / (2) where, Db = Bulk density (g/cm 3 ), Ms = Mass of oven dry soil sample (g), Vb = Volume of core sample (cm 3 ) Determination of Power: When the draught force is given in (Newton) and the speed in (metre per second). The power is then calculated by using equation 3. P = F V (3) Also note that Power can be known from the draught, the area and the force. That is, Force = (Draught Area) N Determination of Energy: Power and energy are related as in equation 4 E = P T (4) where, E = Energy, P = Power, T = Time Determination of draught: To determine draught (p) used in pulling the implement, the equation 5 is applied. P = P 2 P 1 (4) where, P = the draught (N), P 1 = the force required to pull the implement in transportation position, P 2 = the force required to pull the implement during tillage operation. The differences between the force to pull the implement and transportation position determine the required draught 3. RESULTS AND DISCUSSION The moisture content was obtained before any tillage operation. Table 1, shows results of moisture content levels db% and bulk density (g/cm 3 ) of the rainfall events. The rainfall events of 15 th and 6 th days recorded the lowest and highest soil moisture content levels of 1.53% and 24.14% respectively. The lowest and highest bulk densities of 1.61 (g/cm 3 ) and 1.94 (g/cm 3 ) were obtained on 6 th and 11 th days of rainfall events. The drawbar-pull force was determined using trace-tractor techniques. This reflects the force a tractor can generated over the primary forces resisting to movement, consisting of rolling resistance, Table 2, represents the determined mean drawbar-pull forces during ploughing operations at 1.94 m/s, 2.22 m/s and 2.5 m/s forward speeds. The average drawbar-pull force obtained during ploughing operation at forward speed of 1.94 m/s shows the mean drawbar-pull force of N, the highest drawbar-pull force of N and lowest drawbar-pull force of 3, N on 15 th and 6 th days of rainfall events. At tractor forward speed of 2.22 m/s, the mean drawbar-pull force was N. The lowest and highest drawbar-pull forces of N and N were obtained on 4 th and 15 th days of rainfall events. Tractor forward speed of 2.5 m/s recorded mean drawbar-pull force of 5, N, lowest and highest drawbar-pull forces of 5, N and 6, N on 6 th and 15 th days of rainfall events. This has shown that drawbar-pull force increased with increase in ploughing speeds and decreased with increase of moisture content level editor@iaeme.com

5 Draught Force Requirements of a Disc Plough at Various Tractor Forward Speeds in Loamy Sand Soil, During Ploughing This is in line with the findings of others, that said, increasing the speed of operation of disc plough increase the draught of implement[10][11]. Table 1 Mean moisture content (db %) and bulk density (g/cm 3 ) for days of field operations Days Amount of rainfall, mm Soil moisture content db% (0 200 mm) depths Bulk density (g/cm 3 ) (0 200 mm) depths , Determination of energy requirements: Energy requirements were calculated on each day of field operation at three different tractor forward speeds. In Table 3, the calculated total and means energy requirements for ploughing operation at the forward speeds of 1.94 m/s, 2.2 m/s and 2.5 m/s are shown to be 36, KJ, 1, KJ, 55, KJ, 2, KJ and 69, KJ, 3, KJ respectively. The results showed that energy requirements increased with increase in tractor forward speeds. This is in accordance with the findings of others which stated that increasing the forward speeds of operation would increase the draught and energy requirement of the implement[1]. Moisture content level plays a vital role during tillage operations. Its effects on energy expended during tillage operations at different tractor forward speeds were shown in Figures 1 3. At every tractor forward speed, there was a decrease in energy expended with coefficient of determinations of R 2 = 0.698, R 2 = and R 2 = The results displayed the highest coefficient of determination of R 2 = with tractor forward speed of 1.94 m/s editor@iaeme.com

6 S. O. Nkakini Ndor. M. Vurasi Table 2 Determined mean drawbar-pull forces during ploughing for each day of field operation at 1.94 m/s, 2.22 m/s and 2.5 m/s forward speeds Days of field operation Rainfall amount on days of field experiments Average drawbar-pull at 1.94 m/s Average drawbarpull at 2.22 m/s Average drawbar-pull at 2.5 m/s ,58 4, , , ,42 5, , , , , , , , , , , , , , , , ,05 5,06 6, , , , , , , , , , ,94 4,96 6, ,93 4,95 6, , , , , , , , , , , , , , , , , 5,67 6, ,03 5,05 6,10 Mean , , Figures 4 6 showed the effects of bulk density on energy expended during tillage operations at various tractor forward speeds of 1.94 m/s, 2.22 m/s and 2,5 m/s. Energy expended increased with increase in bulk density at these speeds, with coefficient of determinations R 2 = 0.668, R 2 = 0.504, R 2 = The results showed the highest coefficient of determination R 2 at tractor forward speed of 1.94 m/s 3,00 2,50 2,00 1,50 1,00 50 ENERGY VS MOISTURE CONTENT AT 1.94m/s y = x R² = Moisture Content db % Figure 1 The effect of Moisture Content on Energy during tillage operation at 1.94 m/s forward speed 74 editor@iaeme.com

7 Draught Force Requirements of a Disc Plough at Various Tractor Forward Speeds in Loamy Sand Soil, During Ploughing Table 3 Energy requirements of tillage operations at forward speeds of 1.94 m/s, 2.22 m/s and 2.5 m/s. Days of field operations 1.94 m/s 2.22 m/s 2.5 m/s Time (s) Energy ( KJ) Time (s) Energy (KJ) Time (s) Energy (KJ) , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Total 36, KJ 55, KJ 69, KJ Means KJ 2, KJ 3, KJ 4,00 3,50 3,00 2,50 2,00 1,50 1,00 50 ENERGY VS MOISTURE CONTENT AT 2.22m/s y = x R² = Moistuer Content db % Series2 Figure 2 The effect of moisture content on energy during tillage operation at 2.22 m/s forward speed 75 editor@iaeme.com

8 S. O. Nkakini Ndor. M. Vurasi Energy (KJ0 5,00 4,50 4,00 3,50 3,00 2,50 2,00 1,50 1,00 50 Energy Vs Miosture content at 2.5m/s y = x R² = Moisture Content db% Energy Vs Miosture content Linear (Energy Vs Miosture content) Figure 3 The effect of moisture content on energy during tillage operation at 2.5 m/s forward speed. ENERGY Vs BULK DENSITY AT 1.94m/s 3,00 2,50 2,00 1,50 1,00 50 Bulk Density g/cm3 y = x R² = Energy Vs Bulk Density Linear (Energy Vs Bulk Density) Figure 4 The effect of bulk density on energy during tillage operation at 1.94 m/s forward speed 4,00 3,50 3,00 2,50 2,00 1,50 1,00 50 ENERGY VS BULK DENSITY AT 2.22m/s y = x R² = Bulk Density g/cm3 Figure 5 The effect of bulk density on energy during tillage operation at 2.22 m/s forward speed 76 editor@iaeme.com

9 Draught Force Requirements of a Disc Plough at Various Tractor Forward Speeds in Loamy Sand Soil, During Ploughing 5,00 4,00 ENERGY VS BULK DENSITY AT 2.5m/s y = x R² = ,00 2,00 1,00 Linear () Bulk Density g/cm3 Figure 6 The effect of bulk density on energy during tillage operation at 2.5 m/s forward speed. Tables 4 6 show analyses of variance for effects of moisture content levels on energy expended at various tractor forward speeds of 1.94 m/s, 2.22 m/s and 2.5 m/s. The results indicated that there are significant differences (P 0.05) between moisture content levels and energy expended at the respective tractor forward speeds. Table 4 Analysis of variance (ANOVA) for effect of moisture content on energy during tillage at 1.94 m/s tractor forward speed Sources of Variance SS df MS F P-value F crit Between 3.72E E E Within 4.26E E+11 TOTAL 4.14E Table 5 Analysis of variance (ANOVA) for effect of moisture content on energy during tillage at 2.22 m/s tractor forward speed Sources of Variance SS df MS F P-value F crit Between 7.2E E E Within 8.92E E+11 TOTAL 8.36E Figure 7 depicts the trend of energy expended in the various tractor forward speeds during ploughing operation. The energy expended increased with increase in tractor forward speeds. The less energy expended was obtained with tractor forward speed of 1.94 m/s editor@iaeme.com

10 S. O. Nkakini Ndor. M. Vurasi Table 6 Analysis of variance (ANOVA) for effect of moisture content on energy during tillage at 2.5 m/s tractor forward speed. Sources of Variance SS df MS F P-value F crit Between 1.33E E E Within 1.3E E+11 TOTAL 1.46E Forward Speeds at 1.94m/s,2.22m/s,2.5m/s 40,00,00 30,00,00 20,00,00 10,00, Forward Speeds m/s Figure 7 The effect of tractor forward speeds on mean energy expended during tillage operations 4. CONCLUSION This study has determined the various total and means energy expended for three different tractor forward speeds of 1.94 m/s, 2.22 m/s and 2.5 m/s respectively in loamy sand soil of rainforest zone of Nigeria. The results have shown that energy expended decreased with increasing moisture content level at various tractor forward speeds. This is evident from the coefficient of determinations of R 2 = 0.698, R 2 = and R 2 = at tractor forward speeds of 1.94 m/s, 2.22 m/s and 2.5 m/s. The effect of bulk density, revealed increase in energy expended as the bulk densities increase with corresponding increase in tractor forward speeds. The tillage operations, ensured increase in energy expended with increase in tractor forward speeds. The analysis of various parameters on effects of energy expended showed significant difference (p 0.05) between, moisture content levels and energy expended at various tractor forward speeds. In fact, R 2 = stands out for less energy expended. Thus, 1.94 m/s stands the best tractor forward speed for ploughing operations in terms of energy consumption. 5. REFERENCES [1] Grisso, R. D., Yasin, M. and Kocher M. F.. Tillage implements force operating in silty clay loam. Transaction of the ASAE, 39(6), [2] Ahn, P. M. and Hintze, B. No tillage, minimum tillage and their influence on soil properties in: Organic matter management and tillage in humid and subhumid Africa editor@iaeme.com

11 Draught Force Requirements of a Disc Plough at Various Tractor Forward Speeds in Loamy Sand Soil, During Ploughing [3] Nicholson R. H. and Bashford, L. L. Energy requirements for tillage from a reference implement. ASAE Paper No ASAE St. Joseph, MI, U. S. A, [4] Gill, W. R. and Vanden Barg, G. E Soil dynamics in tillage and traction. Agricultural hand book 316. Washington, D. C. USDA-Agric. Res. Service. [5] Darmora, D. P. and Pandey, K. P. Evaluation of performance of furrow openers of combined seed and fertilizer drills. Soil and tillage Research, [6] Chancellor, W. J. Soil Physical properties in Advances in soil Dynamics. Hansen, P. D. ed. ASAE Monograph, [7] Upadlyaya, S. K., Williams, T. H., Kemble, L. J. and Collins, N. E. Energy requirement for chiselling in coastal plain soils. Transactions of the ASAE, 27, 1984, pp [8] Panwar, J. S. and Siemens, J. C. Shear strength and energy of soil failure related to density and moisture. Transactions of the ASAE, 15,1972, pp [9] Raper, R. L. Site specific tillage for site specific compaction: is there a need? Proceeding of the international conference of dry and conservation zone tillage, Beijing, China, [10] Al-Janobi, A. A. and Al-Suhaibani, S. A. Draft of primary of tillage implements in Sandy loan soil. Applied Engineering in Agriculture, 14, 1998, pp [11] Kamel, A. R. and Onwualu, A. P. Energy conservation in tillage operations in Nigeria. State of the Art and Research Needs. Proc. of the NSAE, 18, 1996, pp editor@iaeme.com