Rate of Work or Farm work capacity (or efficiency) varies by equipment capacity, operator ability, and field and crop conditions.

Work abilities of machine or manual for field work, will be expressed by hours per area, or area per hour, which is called as area capacity.

Work abilities of machine or manual for stationary work, will be expressed by hours per weight, or weight per hour, which is called as material capacity.

In this textbook, Effective Field Capacity is commonly used as hectares or tons per an hour, in a block of field or a unit of material. In the case of farm work by machine, Effective Field Capacity will be expressed the value on a set of machine with operators. In manual farm work, Effective Field Capacity will be expressed the value by a worker.

Also, Work Capacity is defined the reciprocal of Effective Field Capacity, like as hours per a hectare or a ton.

 

1. Effective Field Capacity

Effective Field capacity is the actual rate of land or crop processed in a given time. Effective Field capacity is called as field capacity simply.

1. Effective Field Capacity for field work

 

EFC = A / T                           Eq. 2-1

WC = 1 / EFC = T / A           Eq. 2-2

Where,

symbol	term	unit
EFC	Effective Field Capacity	ha/h
T	Total time required a farm work	h
A	Field area	ha
WC	Work Capacity	h/ha

 

1. Total time required a farm work

Field time is in ASAE defined like as; the time a machine spends in the field measured from the start of functional activity to the time the functional activity for the field is completed.

2. Field area

Field area for effective field capacity is a field block as minimum unit.

3. Example

See Table A-211., A-212., A-213. Standard value of effective field capacity in appendix.

See fm-211.xls

Exercise. 2-1, 2-2, 2-3

2. Effective Field Capacity for stationary work etc.

 

EFC = (P / Y) / T           Eq. 2-3

WC = T / (P / Y)            Eq. 2-4

Where,

symbol	term	unit
EFC	Effective Field Capacity	ha/h
T	Total time required a farm work	h
P	Weight of production, grain etc.	t
Y	Yield or amount per hectare	t/ha
WC	Work Capacity	h/ha

 

1. Weight of production, grain etc.

Weight of production, grain etc. should be in a certain unit expression.

2. Example: Table A-214. Standard Capacity of Grain Dryer in appendix.

Exercise. 2-4

3. Total operating time

 

T = ta + tb + tc + td + te + tf + tg + th + ti          Eq. 2-5

Where,

T	Total operating time
ta	Actual operating time
tb	Turning time
tc	Moving time
td	Regulating time
te	Rest time
tf	Loading or unloading time
tg	Transporting time
th	Waiting time
ti	Supplementing time

Total operating time will be measured by time study. See 2-2-2.

Exercise. 2-5

 

4. Theoretical field capacity

Theoretical field capacity is the rate of performance obtained if a machine performs its function 100% of the time at a given operating speed using 100% of its theoretical width. (Refer ASAE S495)

 

1. Theoretical field capacity

The theoretical field capacity will be led from the following equation.

TFC = Wt * Vt * K          Eq. 2-6

Where,

symbol	term	Unit: 1	Unit: 2
TFC	Theoretical field capacity	ha/h	ha/h
Wt	Theoretical operation width	m	m
Vt	Theoretical operation speed	km/h	m/s
K	Constant	0.1	0.36

We use unit-1 system normally, therefore theoretical field capacity is shown as follows.

 

TFC = Wt * Vt * 0.1          Eq. 2-7

Assume the field, which area is A (ha) and width is equal to Wt (m). Then the field length is equal to A 0.01/ Wt 0.001(km) = 10*A/Wt (km), so the operating time: Tt(h) will be (10*A / Wt)/ Vt (km/h) = 10*A/{Wt*Vt} (h). Therefore, A(ha)/Tt(h) = A/(10*A/{Wt*Vt}) (ha/h) = 0.1* Wt*Vt (ha/h).

TFC = A / Tt                       Eq. 2-7-a 

Tt = 10 * A / (Wt * Vt)       Eq. 2-7-b

 A(ha)=A*10000(m2)＝A*0.01(km2), Wt(m)=Wt*0.001(km), Vt (km/h)= Vt *1000 (m/h) =Vt *1000/3600 (m/s)

See *fm-215.xls*

 

Exercise. 2-6

 

2. Theoretical work capacity

Theoretical work capacity is a reciprocal number of theoretical field capacity.

 

TWC = 1 / TFC            Eq. 2-8

Where, TWC: Theoretical work capacity: (h/ha)

5. How to obtain theoretical operation width and speed

 

1. How to obtain theoretical operation width

Theoretical operation width is the measured width of the working portion of a machine. For row crop machine, it is the average row width times the number of rows.

1. The width of implement (machine width)

It is defined by using machinery standard (usually shown by catalogue).

2. Planned operation width

This operation width is used for making the utilization plan of farm machinery under given detail work circumstances.

For example, in the spraying operations with two stokes on 30 meters width of field, its operation width is estimated as 15m, even if the possible width of the swath sprayer is 20 meters.

We will use above mentioned operation width (W) shown in next table as theoretical operation width (Wt).

Exercise. 2-7

 

2. How to obtain theoretical operation speed

Field speed is defined in ASAE like as; Average rate of machine travel in the field during an uninterrupted period of functional activity. For example, functional activity would be interrupted when the implement is raised out of the soil.

Operation speed is indicated with speed of straight movement of work. The travel speed is varied by the following facts:

1. Condition of soil texture, moisture contents, shape and inclination of the field.

2. The level or rate of operator’s skill

3. The size of tractor and machine

Standard operation speed is shown in Table 215a.

General operation speed is shown in Table A-215b in appendix.

We will use roughly these rated or actual operation speed (V) as theoretical operation speed (Vt). Therefore, theoretical field capacity is shown as follows.

 

TFC (ha/h) = W (m) * V (km/h)* 0.1            Eq. 2-9

Calculated field capacity is obtained by actual operating time (Ta) for the area (A), or by actual width (Wa) and actual speed (Va) as follows, which value is similar to theoretical field capacity.

(i)    Actual operation width (effective operation width): Wa

This is the actual operation width in the field, obtained by the width of the field divided by the number of actual strokes in operation.

 

CFC (ha/h) = A (ha) / Ta (h)                         Eq. 2-10

Assume the field, which area is A (ha) and width is equal to Wa (m). Then the field length is equal to A 0.01/ Wa 0.001(km) = 10*A/Wa (km), so the operating time: Ta(h) will be (10*A / Wa)/ Va (km/h) = 10*A/{Wa*Va} (h). Therefore, A(ha)/Ta(h) = A/(10*A/{Wa*Va}) (ha/h) = 0.1* Wa*Va (ha/h).

CFC (ha/h) = Wa (m) * Va (km/h)* 0.1       Eq. 2-10-a

Table 215a. Theoretical operation width and standard operation speed

Farm work	Field	Work	Machine	Theoretical operation width	Standard operation speed
					（km/h）
Tillage, land preparation	Paddy	Tillage	Bottom-plow, Japanese plow	Shear width	6.0
	Paddy	Tillage	Rotary(<20PS)	Machine width	2.0
	Paddy	Tillage	Rotary(>30PS)	Machine width	2.5
	Paddy	Harrow and puddling	Rotary	Machine width	3.0
	Paddy, upland	Leveling	Tooth harrow	Machine width	7.0
	Paddy	Puddling	Paddy harrow	Machine width	4.0
	Paddy, upland	Harrow and leveling	One-way harrow	Machine width	6.0
	Paddy, upland	Pressing	Culti-packer	Machine width	6.0
	Paddy	Pan braking	Sub-soiler	Planning width	3.6
Fertilizing, Seeding	Paddy, upland	Manure spreading	Manure spreader	Planning width	7.0
	Paddy, upland	Fertilizing	Broad caster	Planning width	6.0
	Paddy, upland	Ridging	Ridge	Row width x Row number	5.0
	Paddy, upland	Fertilizing and seeding	Seed drill	Row width x Row number	6.0
	Paddy	Fertilizing and seeding	Fertilize seeder	Row width x Row number	2.0
	Paddy, upland	Fertilizing and seeding	Fertilize seeder	Row width x Row number	2.5
Trans-planting	Paddy	Rice transplanting	Rice transplanter	Row width x Row number	2.3
	Paddy	Rice transplanting	Rice transplanter (rotary type)	Row width x Row number	3.0
Harvesting	Paddy, upland	Chemical application	Wide swath sprayer	Rated working width	2.5
	Paddy, upland	Chemical application	Boom sprayer	Nozzle interval x its number	5.0
	Paddy, upland	Harvest (rice)	Combine	Cutting width	2.5
	Paddy, upland	Harvest (wheat)	Combine	Cutting width	4.2
	Paddy, upland	Pick and baling	Hay baler	Windrowing width	6.0
	Paddy, upland	Reaping	Binder	Cutting width	6.0

Source: JSAM: Handbook of Bioproduction Machinery, 1996

 

1. Field Efficiency: (or Functional Efficiency)
1. Field Efficiency

Actual effective field capacity is different from theoretical field capacity. For example, actual field operation is including loss times of turning, feeding etc. Therefore, actual effective field capacity might be smaller than theoretical field capacity.

The following equation shows the definition of  field efficiency.

 

ef = EFC / TFC                    Eq. 2-11

or,

EF = EFC / TFC * 100         Eq. 2-12

Also, calculated field efficiency is obtained from Eq. 2-1 and Eq. 2-10 as follows.

 

cef = EFC / CFC = Ta / T                            Eq. 2-13

CEF = EFC / CFC * 100 = Ta / T * 100                Eq. 2-14

tef = CFC / TFC = (Wa/Wt)*(Va/Vt) 

ef =cef * tef 

EFC= TFC * cef *tef

Where,

symbol	term	unit
EFC	Effective Field Capacity	ha/h
TFC	Theoretical Field Capacity	ha/h
CFC	Calculated Field Capacity	ha/h
ef	Field Efficiency in decimal
cef	Calculated Field Efficiency in decimal
tef	Theoretical Calculated Field Efficiency in decimal
EF	Field Efficiency in percentage	%
CEF	Calculated Field Efficiency in percentage	%
Ta	Actual operating time	h
T	Total operating time	h

Exercise. 2-8, 2-9

 

2. Functional efficiency

Functional efficiency is the ratio of the actual effectiveness of a machine to its theoretical effectiveness, expressed in percent. Threshing efficiency of a combine is an example of a functional efficiency.

See Table A-216. Field Efficiency in appendix

 

1. How to obtain the Effective Field Capacity

Actual effective field capacity will be estimated by calculation using theoretical field capacity and field efficiency, when no data of effective field capacity is directly obtained.

1. Daily experience or Past data-base

Farmers know how many hours required for certain farm work by certain machines in their own field. This is Effective Field Capacity.

Data-base is powerful to find the useful data for planning.

Simple data-base will be build up by spread-sheet software, instead of the data-base software like “ACCESS”. See fm-211.xls db-efc-1.

2. Time Study

Motion-and-time study is defined as determining the time necessary to perform motions required for a particular job.

See fm-213.xls

1. Work time for certain farm work

Farm Work will be operated with a certain farm facilities set, and it includes certain machine set and workers.

Example a: A = 0.1 ha, Number of workers = 3 in harvesting

	Term	Machine (min)	Labor (min)	Time required of a set (h)	EFC (ha/h)
ta	Actual operating time	47
tb	Turning time	9
td	Regulating time	4
T	Total time	60	180	1.0	0.1

 

2. Machine or implement

Operating time of machine should be measured, even if it is automatic machine or farm robot.

If more than 2 machine sets are used for a farm work, then accumulated time should be counted for total time. After that, the value should be converted to it on a set.

 

3. Operator and Labor

Total time of manual work without machinery should be the accumulated time of all workers. And the value of time on a worker is shown as Effective Field Capacity of manual work.

 

MH = T * Nw              Eq. 2-15

EFC = A / MH             Eq. 2-16

Where,

symbol	term	unit	Example
	Farm Work	-	Manual weeding
A	Field area	ha	0.1
Nw	Number of workers	-	2
T	Time required	h	1.5
MH	Labor required (Man hours)	h	3.0
EFC	Effective Field Capacity	ha/h	0.033

3. Estimation by calculation

Effective Field capacity and work capacity are estimated by following equation normally.

EFC = TFC * ef                                         Eq. 2-17

Or,    EFC = TFC * EF / 100                     Eq. 2-18

Or,    EFC = CFC * CEF / 100 = CFC * cef       Eq. 2-18-a

EFC = (W * V * 0.1) * ef                 Eq. 2-19

Or,

EFC = (W * V * 0.1) * EF / 100      Eq. 2-20

Or,    EFC = CFC * CEF / 100 = CFC * cef

Also, from Eq. 2-2.

WC = 1 / EFC

Also, from Eq. 2-2.

WC = 1 / EFC

Example:

1. Effective field capacity in case of tillage by power tiller

symbol	term	unit	Example
W	Width	m	0.7
V	Speed	km/h	1.2
TFC	Theoretical Field Capacity	ha/h	0.084
EF	Field Efficiency	%	90.0
EFC	Effective Field Capacity	ha/h	0.0756
WC	Work capacity	h/ha	13.23

See *fm-22.xls*

 

2. Effective field capacity in case of manual weeding

EFC-manual = Area / Time required by one worker

3. Effective field capacity in case of automatic grain dryer

Effective field capacity will be explained in detail, as of machine working time, or as of time required for operator.

Exercise. 2-10, 2-11, 2-12

 

2. What factors affect on the Effective Field Capacity

Even if the area is the same, the field efficiency of plowing varies. The higher ratio of the long side to the short side has larger value of the field efficiency.

As field efficiency varies with shape, size operation method and operator’s skill, the numbers in Table A-232 will be the standard to field the actual effective field capacity form the theoretical field capacity.

1. Machinery
1. Width
2. Speed
3. Power
2. Field condition
1. Size of field
2. Shape of field

The filed size and shape will affect effective field capacity and work capacity, like as shown following equations (Table 23.).

See Table A-232.: Relationships between Field Efficiency and Field Size, in appendix.  fm-232.xls

Exercise. 2-13

 

Table 23. Effect of field size and shape etc. in upland field

Machinery	Operating method	Analytical equations
Rotary	Continuous, turn at each end	T = (x*y)/(v*w) + (x/w) * t1 + tc + td + te
Mount type drill seeder		T = (x*y)/(v*w) + (x/w) * t1 + tc + td + te + tf	tf = (qf*x*y*t4f)/Qf + (qs*x*y*t4s)/Qs
Mount type boom sprayer		T = (x*y)/(v*w) + (x/w) * t1 + tc + td + te + tf + tg	tf + tg = (t4 + t5)*(q*x*y)/Q
Bag unloading type combine		T = (x*y)/(v*w) + (x/w) * t1 + tc + td + te + th

where,

symbol	term	unit
T	Total operating time	h, s
x	Width of field	m
y	Length of field	m
w	Effective operating width	m
v	Effective operating speed	m/s
ta	Actual operating time	h, s
tb	Total turning time	h, s
tc	Moving time in field	h, s
td	Regulating time	h, s
te	Rest time	h, s
tf	Total loading or unloading time	h, s
tg	Total transporting time	h, s
th	Waiting time	h, s
t1	U type turning time	s
t2	Δ type turning time	s
qf	Spreading quantity of fertilizer per unit area	kg/m2
qs	Spreading quantity of seed per unit area	kg/m2
Qf	Fertilizer hopper capacity	kg
Qs	Seed hopper capacity	kg
t4f	Fertilizer loading time	s
t4s	Seed loading time	s
t4	Loading or unloading time	s
t5	Transporting time	s

Example (a): Rotary tillage

In case of plow, total time will be shown as followings:

T = (x*y)/(v*w) +(x/w) * t1 + tc + td + te

where,

symbol	term	unit	Example
x	Width of field	m	49.5
y	Length of field	m	107
w	Operating width	m	1.55
v	0perating speed	m/s	0.38
tc	Moving time in field	s	90
td	Regulating time	s	500
te	Rest time	s	0
t1	U type turning time	s	20
t2	Δ type turning time	s	50

T (s) =1.698 * x * y + 12.9 * x +590                                               Eq. 2-21

T (h) = 0.000472 * x * y + 0.00358 * x + 0.164                              Eq. 2-22

T= 0.000472*A*10000 + 0.00358*100*SQRT (A / m) + 0.164     Eq. 2-23

T=4.72 * A + 0.358 * SQRT (A / m) + 0.164                                  Eq. 2-24

EFC = A / [4.72 * A + 0.358 * SQRT (A / m) +0.164]                   Eq. 2-25

where,

symbol	term		unit
m	Ratio of length and width of field	y / x	-
A	Size of a field	x * y	ha
EFC	Effective Field capacity	A / T	ha/h

 

Fig. 23. shows how the effective field capacity is varied with size and shape of field, which is expressed by the above equation 2-25.

See Table A-23b.   fm-23.xls



Fig. 23. Effective Field Capacity vs. area of a field in Rotary tillage

See Table A-23b. and Fig. A-23 for plowing in appendix.

 

3. Head land
4. Inclination of field
5. Soil condition
1. Soil texture
2. Soil hardness

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2004/7/21