Higher Field Efficiency Research Articles

Comparative Performance Analysis of a Remote-Controlled Paddy Weeder in Varied Soil Conditions

Aim: Remote controlled paddy intercultural equipment was evaluated under sandy, sandy loam and loamy soils in terms of fuel consumption (l/h), field capacity (ha/h) and field efficiency (%).
 Study Design: Field evaluation of robotic paddy weeder.
 Place and Duration of Study: Dr NTR College of Agricultural Engineering, Bapatla. Duration of study was from August, 2023 to September, 2023.
 Methodology: The performance evaluation of weeder was conducted at rotary weeder rotational speed of 160rpm and weeding depth of 50mm in terms of the observations on fuel consumption, field capacity and field efficiency. Weeding operation was carried on 20th day and 40th day after transplanting. Each field test was conducted over a run length of 50m at constant speed and depth in different soils were recorded for all the parameters and each test was replicated thrice to eliminate experimental bias.
 Results & Discussion: The highest fuel consumption was observed as 2.2l/h when weeder was operated in loamy soil on 40 days after transplanting and the lowest was 1.2 l/h when the weeder was operated in sandy soils on 20 days after transplanting. The highest field capacity was observed as 0.098ha/h when weeder was operated in sandy soil on 20 days after transplanting and the lowest was 0.076ha/h when the weeder was operated in loamy soils on 40 days after transplanting. The highest field efficiency was observed as 81.66% when weeder was operated in sandy soil on 20 days after transplanting and the lowest was 63.33% when the weeder was operated in loamy soils on 40 days after transplanting.
 Conclusion: The performance of remote operated paddy weeder is best when operated on 20 days after transplanting when compared with 40 days after transplanting for increasing the productivity.

Performance of Disc and Chisel Ploughs and their Effects on Some Soil Physical Properties

A study was carried out at the University of KhartoumDemonstration Farm in (2007), to study the performance of two tillageimplements: (disc and chisel plough) and their effect on some soilphysical properties. The results showed that the higher values of boththeoretical and effective field capacities were recorded by chisel plough(1.23 ha/hr and 0.90 ha/hr) as compared to disc plough (0.63 ha/hr and0.50 ha/hr). The higher field efficiency was recorded by disc plough(79.37%) as compared to the chisel plough (73.4%). The fuel consumedwhen using the disc plough was (10.60 l/ha) less than that consumed bythe chisel (13.47 l/ha). Tractor wheel slippages ware found to be 10.92%.and 14.1%. The result also showed that both ploughs decreased the soilbulk density values from 1.54 g/cm3 to 1.51 and 1.49 g/cm3 by disc andchisel plough respectively. Particle density was not affected (P > 0.05) byboth implements . The soil porosity values were also increased for bothimplements. The soil moisture content recorded in two depths 0-15 and15-30 cm were higher for chisel plough (6.53% and 6.9%) as compared todisc plough which recorded 6.3% and 6.5% respectively. The infiltrationrate obtained by the disc plough was 22.2 cm/hr while that of chiselplough was (20.1 cm/hr)

Performance of Disc and Chisel Ploughs and their Effects on Some Soil Physical Properties

A study was carried out at the University of KhartoumDemonstration Farm in (2007), to study the performance of two tillageimplements: (disc and chisel plough) and their effect on some soilphysical properties. The results showed that the higher values of boththeoretical and effective field capacities were recorded by chisel plough(1.23 ha/hr and 0.90 ha/hr) as compared to disc plough (0.63 ha/hr and0.50 ha/hr). The higher field efficiency was recorded by disc plough(79.37%) as compared to the chisel plough (73.4%). The fuel consumedwhen using the disc plough was (10.60 l/ha) less than that consumed bythe chisel (13.47 l/ha). Tractor wheel slippages ware found to be 10.92%.and 14.1%. The result also showed that both ploughs decreased the soilbulk density values from 1.54 g/cm3 to 1.51 and 1.49 g/cm3 by disc andchisel plough respectively. Particle density was not affected (P > 0.05) byboth implements . The soil porosity values were also increased for bothimplements. The soil moisture content recorded in two depths 0-15 and15-30 cm were higher for chisel plough (6.53% and 6.9%) as compared todisc plough which recorded 6.3% and 6.5% respectively. The infiltrationrate obtained by the disc plough was 22.2 cm/hr while that of chiselplough was (20.1 cm/hr).

Model development and optimisation of the disc plough efficiency on loamy-sand soil in South-East Nigeria

This study was conducted to model and optimise the efficiency of a disc plough on loamy-sand soil in South-East Nigeria to aid farmers to examine and choose the right ploughing implement based on the soil type for an effective and bountiful production. The operational speed and cutting depth were taken as factors for the study of the plough efficiency. The results revealed that the highest field efficiency of 80% was noted when the plough worked at the cutting depth of 30 cm and a speed of 5 km·h–1 while the lowest efficiency of 68.10% was achieved at a speed of 9 km·h–1 and a depth of 10 cm. The quadratic model was significant for the response (P < 0.05). The results indicated that the coefficient of determination (R2) was 0.98, which specified the high correlation among the factors. The predicted R²Â (0.76) was consistent with the adjusted R²Â of 0.96. The adequacy precision of 24.89 showed a suitable indicator and that the model could navigate the design space. The optimum field efficiency and the desirability of 77.50% and 1.00 were, respectively, obtained at an optimum speed of 7 km·h–1 and a cutting depth of 30 cm. Farmers can, however, assess and select the implements with the aid of the developed model.

DESIGN DEVELOPMENT AND PERFORMANCE EVALUATION OF SOLAR POWERED SPRAYER WITH WATER LEVEL INDICATOR

Currently in Bangladesh farmers use hand operated sprayer or motorized sprayer in agricultural fields. Generally in the agricultural field, traditional or conventional techniques like shoulder mounted spraying system have been used because it is cheaper, easy to use and less costly. Continuous use of traditional energy resources will have high risk of rising in price and energy depletion. Now-a-days there is a great need for ‘’conservation of energy’’ and application of renewable energy. This paper presents the design, development and evaluation of a solar powered spraying system. The specific objectives of this research is to design and fabricate the solar powered sprayer by considering parameters like desired spraying rate, low weight, low cost, faster coverage of area and high field efficiency. A two-nozzle sprayer was fabricated with MS bar frame and 4-wheel trolley with water level indicator which runs on power source as a DC battery (12 volt, 8.2 Ah) via solar panel and runs by a DC motor (12 volt, 2A). The entire unit is portable and is operated by one labor. The design mainly eliminates the shoulder mounting sprayer setup which causes back pain, uses of fossil power which is non-renewable and hazardous and extensive use of manpower. The machine was compared to conventional sprayer and found more efficient. Pump efficiency almost 83.33% found for single nozzle and 93.33% for double nozzle and the sprayer is 58% time saving than manual sprayer. The operating cost of the machine was 802 Tk ha-1 . Also found capital recovery factor, capital consumption and annual cost of the solar operated sprayer were 0.26, Tk 1520 and Tk 41665, respectively.

Evaluation of different tillage interventions under rice-wheat system in a vertisol

In the extensive rice-wheat system of India, harvesting is done mostly by combines, and the paddy residues after harvesting are normally burnt, followed by irrigating the field and intensive tillage prior to sowing of next crop wheat. While in-field, retention of previous crop residues plays an important role, such as it reduces soil erosion from water and wind and increases soil organic carbon. To avoid burning of crop residues ‘Happy Seeder’ was developed by PAU, Ludhiana. It greatly reduces fuel consumption, crop cost establishment and the ability to sow the seed as desired after harvesting, thereby ensuring the possibility of sowing at the optimum time and reducing the irrigation needs. In the present work, five common methods (treatments) were selected for sowing of wheat, which is T1-No-tillage + Happy Seeder, T2-No-tillage + Zero till seed drill, T3-Reduced tillage (disc harrow with one pass) + zero till seed drill, T4-1 × Cultivator + 2 × Disc harrow + Conventional seed-cum-fertilizer drill, T5-2 × Cultivator + 2 × Disc harrow + Raised bed seed drill. With the use of Happy Seeder, sufficient tillage operation time was saved because the machine is used directly after harvesting of paddy field. The highest effective field capacity was found in T5 with 0.48 ha/h, highest field efficiency and seed emergence in T4 with 70.2% & 85.7%, respectively. Maximum grain yield was found in T1 with 42.4 q/ha and minimum in T2 with 37.8 q/ha. Plant population and highest weed density was found in T4 with 143 plants/m² and 67, 69, 75 numbers/m² at 30, 60 and 90 days. The weed count increased with days due to variation in degree of soil manipulation.

Field Performance Evaluation of Power Weeder for Paddy Crop

Weeds are the main significant constraints in paddy production. Weed eradication by using herbicides and weedicides pronounced simple and fast method but is restricted due to its adverse effects on both environment as well as human beings. To overcome these limitations, mechanical weeding can be selected as appropriate weed control measure.Based on this, a modified power weeder was tested for weed control in upland paddy at 20 and 45 days after sowing (DAS) andthe performance was compared with traditional hand weeding and manual operated mechanical weeder (Ambika paddy weeder). The modified power weeder show well prominence in weeding for upland paddy at 20 and 45 DAS and fuel efficient (0.63 to 073 l/h).The power weeder was found at par with the Ambika paddy weeder with a weeding efficiencyof 74.22 % and 86% at 20 and 45 DAS respectively. There was no significant variation in field efficiency for Ambika paddy weeder at 20 &amp; 45 DAS, but the highest field efficiency was shown by paddy power weeder as 70% for 45 DAS.The energy consumption was more in paddy power weeder than Ambikapaddy weeder as 493.64 and 452.40 MJ/ha at20 and 45DAS respectively. The cost of operation per hectare with power weeder amounted to ₹928/-and₹850/-against Ambika paddy weeder as₹2,617/- and₹2,346/- for 20 and 45 DAS respectively. The machine also depicted the energy-cost as 1.88 and 1.87 at 20 and 45 DAS respectively. Whereas the hand weeding showed the highest values in weeding efficiency and field efficiency at 20 and 45 DAS as it was an ideal method of weed control exceptforthe cost of operation.

EFFECT OF TWO TYPES (FURROW OPENERS AND CLOSERS) IN ZERO TILLEGE SEEDER ON SOME MECHANIZATION TRAITS

A field experiment was carried out during the agricultural season (2012-2013) in Moderate Rainfall Area-MRA /Nineveh governorate. Italian Gaspardo Sc250 Seeder modified to ZT farming system used in the cultivation of bread wheat. The experiment included three factors: the first factor was Press wheels with two levels, gang press wheel and mutual press wheel, the second factor was the Opener types with two levels, Hoe (Tine) Opener and inverted (T) Opener, the third one was the seeding depths with two levels (3-4 cm) and (4.1-5 cm). This experiment was implemented with split split plot under randomized complete block design with three replicates where the press wheels represented the main plot while the Openers within subplot and seeding depths were under sub sub plot. The mechanization Traits studied were: (slippage percentage, fuel consumption, field efficiency, power requirements).The results showed a significant effect of gang press wheel in enhanced these mechanization traits: (slippage percentage, fuel consumption, field efficiency, power requirements) compared with mutual press wheel. The results also indicated the less significant value of the Hoe opener. The results again showed the significant effect of (3-4 cm) seeding depth in improving the fallowing traits: (slippage percentage, fuel consumption, field efficiency, power requirements) compared with the depth (4.1-5 cm). The interaction between the two types of press wheels and opener types had a significant effect in mechanization traits. The interaction between gang press wheel with seeding depth (3-4 & 4.1-5 cm) had a significant effect in enhancing mechanical characteristics (Slippage percentage, Fuel consumption, Field efficiency, Power requirement). The dual interaction between the Hoe tine with seeding depth (3-4 cm) recorded the best results for the following traits (Slippage percentage, Fuel consumption, Power requirements) and high field efficiency compared with other treatments. Triple interaction between gang press wheel with Hoe tine and seeding depth (3-4 cm) had best values for the studied traits (Slippage percentage, Fuel consumption, Field efficiency, Power requirements) compared with other treatments.

Development of an automatic tracking system to determine field efficiency of agricultural machines

Field efficiency of machines tells how efficient the farm machines are operating in the field. Measuring of the field efficiency used to be a tedious and laborious work which is not worth to collect for further operational optimization. The objective of this study was to develop an automatic system for monitoring the field activities and then evaluation of the field efficiency of farm machines. The system consisted of a microcontroller to collect working data including position, speed heading, and working status of the machine. The system was installed on a farm tractor with plowing disc to test on two fields with the same size, but in different traveling directions, i.e., lengthwise and crosswise. The results showed lengthwise operation yielded a higher field efficiency due to less number of turning at headlands. The proposed system allowed to collect necessary information for detailed efficiency evaluation of farm machines. This technique enables further utilization of the operational information and benefit to use in the optimization of the farm works.

Comparative assessment of newly designed burial type lowland power cultivator for weed control

Weeds are the major reason for the significant yield reduction in rice cultivation worldwide. Power weeders have been introduced to rice cultivation as an alternative solution for the controversial herbicide applications. The aim of this study was to appraise the newly designed burial type lowland power cultivator through a comparative performance assessment including cost economics. Five weeding methods using Cono-weeder (T1), Modified “Asakura” wooden clog (T2), Rotary power weeder (T3), Newly designed lowland power cultivator (T4) and manual weeding (T5 as the control) were evaluated. The T4 showed a significantly high field capacity of 0.04 ha/h, which is 8 times higher than T5, high field efficiency of 88.30% and weeding efficiency of 62.29% which was similar to the performance of T5. Significantly high performance indexes were observed in T2 and T4 (461.65) followed by T1 and T3. Plant damage percentage, maximum tiller number and the yield did not show any significant variation (p>0.05) among weed control methods assessed. Further, the T4 showed a significantly low cost of weeding of 6583 Rs/ha which was 76% of cost reduction of the T5, and moderately high break-even point of 0.88 ha/yr suggesting that it is appropriate for the medium and large scale farmers. Moreover, T4 showed low fuel consumption (0.556 L/h) and power requirement (0.57 kW) representing 48% and 42% respective reductions over the T3. Further, T4 showed the significant lowest weed re-growth rate which is essential for sustainable weed control. Based on the above results, newly designed burial type power cultivator could be recommended for medium and large scale paddy farming, since it showed high performance compared to other methods assessed. Machine performance could be further improved by high speed, light weight design with efficient turning mechanism. Besides, it is suggested to conduct detailed ergonomic evaluation in future investigations.

EFFECT OF DIFFERENT SPEED OF TWO PLOWS TYPES ON SOME MAGHINARY UNIT PERFORMANCE INDICATORS

This experiment was conducted to evaluate stadying the effect of different speed of two plows types on some machinary unit performance indicators. New Holland TD80 was used in this study.Three machinery speeds included; 2.72,4.34 and 6.23 km.hr-1 which represent main plot and two plows included; moldboard plow and disk plow which represent sub plot were used in this study. slippage percentage, practical productivity, Field efficiency, soil volume disturbs and fuel consumption were measured in this experiment Split plot design.The results can be summarized as Fallow; The 6.26 km.hr-1 speed gave higher practical productivity 0.31 ha.hr-1, higher soil volume disturbs 599.07 &#x0D; m3.hr-1,lowest fuel consumption 30.69 L.hr-1 and higher Field efficiency 60.89%. While speed 2.72 km.hr-1 gave lowest slippage percentage 8.69%.The moldboard plow on the disk plow gave lowest slippage percentage 9.48%, higher practical productivity 0.26 ha.hr-1, higher soil volume disturbs 514.89 m3.hr-1, higher Field efficiency 58.98% and lowest fuel consumption 33.77 L.hr-1. As for the significant of overlap between the speed 6.23 km.hr-1 and the moldboard plow it has impacted significantly in all traits.

Performance evaluation of two planter makes as affected by forward speeds

Two different makes of row crop planters were evaluated for performance by laboratory and field tests. The laboratory test was conducted to investigate the seed rate, uniformity of seed spacing and seed damage during operation, while the field test examined the effective field capacity, field efficiency, planter drive wheel slippage and fuel consumption, and two planting speeds were used (5.5, 8.5km/hr). The experimental study was carried out at the farm of College of Agricultural Studies, where the soil is considered light clay soil. The field was tilled by discing once and harrowing once followed by leveling to prepare a uniform field for the planters work. An average weight of 17 kg/ha and 31.5kg/ha of seeds were discharged during the test from Giad make and Rome make respectively. The seed spacing varying from the theoretical for the two planters, with a noticed minimum seed damage of 0.6% and 0.72% for Giad and Rome make planters respectively. Field evaluation results showed that planter make had significant effect (p&lt;0.05) on seed rate, seed spacing, fuel consumption and effective field capacity. Planting speed had a significant effect on seed rate, fuel consumption and effective field capacity. Interaction effect between planters and planting speed had significant effect (p&lt;0.05) on seed rate and fuel consumption only. The highest fuel consumption and driven wheel slippage were obtained with Giad make planter. Giad make planter gave lower field efficiency compared to Rome make planter at 5.5km/hr forward speed. From the study the two planters were able to effectively meter high seed rate with minimum damage to the seeds. Rome make gave better performance that resulted in lower fuel consumption, wheel slippage and high field efficiency.

STUDY ON THE MECHANIZATION OF BEAN (Phaseolus vulgaris) CROP UNDER EGYPTIAN CONDITIONS

This study aimed to select the proper system of bean crop mechanization to achieve high yield, low grain losses with high field efficiency. The experiments were carried out using pneumatic planter and seed drill in planting operations in addition to the manual method, and tractor mounted mower was used in harvesting operation under different forward speeds and moisture contents compared to the manual method. Also, a Turkish threshing machine was used for threshing the crop at different drum speeds and seed moisture contents. From the obtained data it was concluded that; the pneumatic planter followed by tractor mounted mower and threshing by Turkish machine was considered the proper system for producing dry bean under Egyptian conditions, where as required minimum cost compared to the others. The seed moisture content of 14.86% and forward speed of 2.9 km/h were the proper conditions for harvesting dry bean crop. The threshing drum speed of 10.47m/s and seed moisture content of 11.33 % considered the proper values for threshing bean.

Development of a telemetry and yield-mapping system of olive harvester.

Sensors, communication systems and geo-reference units are required to achieve an optimized management of agricultural inputs with respect to the economic and environmental aspects of olive groves. In this study, three commercial olive harvesters were tracked during two harvesting seasons in Spain and Chile using remote and autonomous equipment that was developed to determine their time efficiency and effective based on canopy shaking for fruit detachment. These harvesters work in intensive/high-density (HD) and super-high-density (SHD) olive orchards. A GNSS (Global Navigation Satellite System) and GSM (Global System for Mobile Communications) device was installed to track these harvesters. The GNSS receiver did not affect the driver’s work schedule. Time elements methodology was adapted to the remote data acquisition system. The effective field capacity and field efficiency were investigated. In addition, the field shape, row length, angle between headland alley and row, and row alley width were measured to determinate the optimum orchard design parameters value. The SHD olive harvester showed significant lower effective field capacity values when alley width was less than 4 m. In addition, a yield monitor was developed and installed on a traditional olive harvester to obtain a yield map from the harvested area. The hedge straddle harvester stood out for its highly effective field capacity; nevertheless, a higher field efficiency was provided by a non-integral lateral canopy shaker. All of the measured orchard parameters have influenced machinery yields, whether effective field capacity or field efficiency. A saving of 40% in effective field capacity was achieved with a reduction from 4 m or higher to 3.5 m in alley width for SHD olive harvester. A yield map was plotted using data that were acquired by a yield monitor, reflecting the yield gradient in spite of the larger differences between tree yields.

DEVELOPMENT AND EVALUATION OF SMALL-SCALE POWER WEEDER

Small-scale power weeders are an important and challenging task in many countries, where the farm size in hectare per capita is very low and is declining over time. Therefore, the development of suitable mechanized weeding methods is an imperative to meet the demand for farmers. An economical mechanical power weeder that can be used as inter and intra-row weeding method was developed and evaluated in triple hybrid 314 variety of maize. Developed power weeder consisted of engine, blades assembly and transmission system. Modified vertical blades were used with the weeder and mounted on a circular rotating element on its horizontal side; the motion was transferred to blades units by amended transmission system. The effect of weeder forward speeds, depth of operation, number of blades and soil moisture content on fuel consumption, plant damage, weeding index, effective field capacity, field efficiency, energy required per unit area and total cost were studied. Three levels of soil moisture content (7.73, 12.28 and 16.18 %), two blades arrangements (two and four vertical blades for each unit), three weeder forward speeds (1.8, 2.1 and 2.4 km/h) and two depths of operation (from 0 to 20 and from 20 to 40 mm) have been chosen. The results showed that, the minimum value of fuel consumption was 0.546 l/h and recorded by using two blades with 1.8 km/h weeder forward speed at depth of operation ranged from 0-20 mm and soil moisture content 16.18 %. The highest field efficiency was 89.88% by using two blades with 1.8 km /h weeder forward speed at depth of operation ranged from 0 to 20 mm and soil moisture content 16.18%. The minimum value of effective field capacity was 0.198 fed/h by using four blades, weeder forward speed 1.8 km/h, soil moisture content 7.73% and under depth of operation ranged from 20-40 mm. The lower value of total cost was 55.09 L.E /fed and was obtained by using two blades with 2.4 km/h weeder forward speed at depth of operation ranged from 0-20 mm and soil moisture content 16.18 %.

Computer Modeling for Prediction of Implement Field Performance Variables

Size selection of agricultural machinery must necessarily base on anticipated performance and anticipated cost. In field machinery selection, the most pertinent variable is size or capacity of the machine. A computer program was developed in C<SUP>++</SUP> programming language, to predicted implement performance parameters are total field time, theoretical field capacity, effective field capacity and field efficiency for 1.0, 1.5 and 2 m width implement at operation speed of 4, 4.5, 5, 5.5 and 6 km/hr. Program was built, compiled and was then debugged. It was found that as speed and implement width increased, the total field time decreased while theoretical field capacity and effective field capacity increased and field efficiency decreased. The highest field efficiency was 85.5% and it was recorded by implement width of 2 m at 4.5 km/hr speed while the lowest field efficiency was 80.7% and it was recorded by implement width of 1 m 6 km/hr. It was concluded that width of plow found to has higher effect than plow operating speed on increasing the effective field capacity, consequently, the field efficiency.

The evaluation of alternative stalk chopping methods in sunflower farming

In this study, the alternative chopping methods were compared in sunflower farming. After harvesting sunflower stalk was chopped with three different methods by using three different stalk chopper machines. Two different rotary type machines (RT1 and RT2) and heavy duty disc harrow (CON) were applied in the experiment. Heavy duty disc harrow used as conventional method. Particle size distribution after chopping, management parameters of the machines and energy requirements were determined in the experiment. Maximum frequency with 37.09% for RT1 and 24.62% for CON were found in the stalk size group of 102 - 173 mm. Whereas, maximum frequency with 31.08% was obtained in the size group of 30 - 101 mm for RT2. The highest fuel consumption (19.28 L.ha-1) was obtained in CON method and the highest field efficiency with 0.886 ha.h-1 was found in RT2. RT1 has 756.1 MJ.ha-1total energy requirements. RT2 has 868.3 MJ.ha-1 and CON has 944.3 MJ.ha-1. The differences among methods in frequency of particle sizes, values of fuel consumption and total energy requirements were found to be statistically significant. Key words: Sunflower, stalk, shedding, chopper, energy.

A COMPARATIVE STUDY OF THE MOST WIDELY HARVESTING SYSTEMS FOR WHEAT CROP IN EGYPT

Field experiments were carried out at the experimental field of Rice Mechanization Center, Meet El-Deeba, Kafer El-Sheikh Governorate during harvesting season of 2007.Five of the most widely wheat harvesting systems were studied on the widely common wheat cultivar (Sakha93): multi-purpose combine harvester, through in combine harvester, hold in combine harvester, Reaper + thresher and double knives mounted mower + thresher to recommend the appropriate system for harvesting wheat crop. The systems were evaluated according to the technical parameters: actual performance rate, field efficiency; cutting efficiency, cleaning efficiency; percentage of the total losses and consumed energy, according to (RNAM 1995) and according to the financial criteria. Overall cost criterion was used to evaluate the tested wheat harvesting systems. The results showed that the combine harvester realized the highest actual performance rate (3.06 fed./h) at all the tested forward and threshing speeds compared with the other studied systems. The highest field efficiency (94.3%) was obtained from the 4 th system and the 5 th system. The highest cutting efficiency (94.3%) was conducted by hold in combine harvester. The highest cleaning efficiency ( 98.7%) resulted from 4 th and 5 th systems at threshing drum speed 35.34 m/s. The lowest percentage of total grain losses averaged (2.27%) resulted from the 3 ed system. The lowest consumed energy per fed. and per ton was achieved by multipurpose combine harvester. The lowest significant total cost (85.72 LE/h) resulted from 4 th system. The overall cost criterion (LE/fed.) was observed from harvesting systems; it includes actual performance rates, consumed energy, cost of total losses grain, and total costs. The lowest value is considered the most appropriate from operation of multi-purpose combine harvester. * Assist . Prof., Ag. Eng. Dept. , Fac . of Ag., Cairo University.

Analytical determination of an optimum mechanical harvesting pattern for high field efficiency and low cost of operation

The width of plot above which, harvesting should be done along four sides and below which, along two sides was determined analytically for different machines. General solutions for break-even widths were found for two objectives, namely for high field efficiency and low cost of operation. The improvement in field efficiency through optimum harvesting pattern has been compared for walking-type and four-wheeled machines and was found to be up to 20%. The harvesting cost also reduced by up to 5%. These improvements in field efficiency and cost of operation were obtained in comparison with the method of harvesting where there is no change-over from four-sided to two-sided cutting at break-even width of plots. Nomographs have been developed for determination of break-even widths of plot for changing from four-sided to two-sided cutting.