مشاهدة النسخة كاملة : Water resources
عمار جابر
02-08-2009, 10:36 PM
Water resources
Annual internal water resources: 1,227 cu m per capita (1998); Sector withdrawals - Domestic 4%; Industrial 1%; Agricultural 94%. Desertification and the civil war have caused major shortages of water supply throughout central and southern provinces. Supplies in Khartoum are frequently disrupted; contamination of water supplies in the rural areas is widespread. The total water resources for the Sudan, including internal surface and ground water resources as well as natural external resources are 149 cu km per year (2003) The Nile River is subject to a treaty between Egypt and Sudan.
Nile River transboundary between Egypt and Sudan :
- Total natural discharge (average): 84 cu km per year
Sharing by treaty:
- Egypt : 55.5 cu km per year,
- Sudan : 18.5 cu km per year,
Losses by evaporation of storage: 10 cu km per year
عمار جابر
02-08-2009, 10:39 PM
Rainfall:
Autumn is the main rainy season, extending from May to October with precipitation ranging between less than 50 mm in the extreme north to more than 1500 mm in the extreme south. The rainfall,
however, is characterized with significant variations in distribution as well as in timing and location thereby magnifying the risks of localized crop production. To avert this risk mechanized rainfed production schemes have been spread all over central Sudan. Apart from agriculture the rains replenish the underground reserve and provide the scattered wadis and water points with annual quantities to support the enormous wealth of livestock and wild life.
عمار جابر
02-08-2009, 10:44 PM
Nile Water:
Sudan is a meeting point of river tributaries that emanate from the Ethiopian plateau and the region of the Great lakes. The Blue Nile with its tributaries Dinder and Rahad together with the Atbara flow from the east annually providing some 66 milliards cubic metres (md. c. m.). On the other hand Bahr El Jebel commences from Lake Victoria with permanent rains, but the greater part of the runoff is lost in the Sudd area inside the Sudan, bringing some 15 md. c.m. at Malakal. The Sobat River which joins the Nile at Malakal flows from the Ethiopian plateau and is being fed from tributaries inside and outside the Sudan. However, about 8 md. c.m. of Sobat runoff estimated at 13 md. c.m. are lost in the Sudd area of Sobat and Mashar. Almost all the water flow of Bahr El Ghazal River estimated at 14 md. c.m. are lost in the Sudd area of Bahr El Ghazal, leaving only half a md. c.m. to join the White Nile at lake No.
The big variation in the Blue Nile flow between the high river during the flood season and the low river during the months from March to May have necessitated the construction of dams to store water for irrigation and for the generation of hydro-electrical power. At present there are three dams: Sennar (1 md. c.m.), Roseires (3.4 md. c.m.) and Khashm El Girba (1.3 md. c.m.). However the accumulated silt in the dam lakes has reduced the storage capacity by 25% in Roseires Dam and by 40% in both Sennar and Khashm El Girba dams. A project is now being implemented to heighten Roseires dam to increase the storage capacity to 7.3 md. c.m. and also to construct Siteit Dam across upper Atbara River to install additional storage capacity for irrigation projects.
Sudan is now utilizing about 14.6 md. c.m. of its share of Nile water for irrigation, of which 9.5 md c.m. are from the Blue Nile, 1.7 md. c.m. from Atbara River, 1.8 md. c.m. from the White Nile and 1.6 md. c.m from the main Nile. The heightening of Roseires Dam and the construction of the new dams will enable the country to fully utilize its share of the Nile water which stands currently at 20.5 md. c.m. at Sennar, according to the Nile Water Agreement of 1959. During the early eighties Sudan and Egypt launched a joint project to excavate Jonglei canal and bypass part of the Sudd region, thereby sparing some 4 md. c.m. to be divided equally between the two countries. However, the project was hampered by the civil strife which started in 1983.
عمار جابر
02-08-2009, 11:11 PM
ESTIMATING AGRICULTURAL FIELD MACHINERY COSTS
Agricultural engineers and economists use a variety of engineering and economic principles in calculating a machine's use and costs. An effective farm manager must also know these principles and apply them when deciding to buy, lease, rent or share machinery.
The most accurate method of determining machine costs is complete records of the actual costs incurred. Estimating costs is an alternative. When estimating costs, methods that require more data specific to your situation, the more accurate will be the estimate. The state custom rate guides provide some indication of machines costs based on what is being charged (Wisconsin Custom Rate Guide, 2004). The guides do not take into account your specific conditions, which may be quite different for you. Data in the guide may be impacted by the supply and demand of custom operators in a geographical area.
Available machine cost tables provide an estimate based assumed input data such as machine list price, recommended acreage, fuel price, and labor. These tables often do not use of information specific to your operation. A frequently used table is the Minnesota Machine Cost Estimates published annually (Lazarus and Selley, 2005). They obtained list prices from machinery dealer surveys and used American Society of Agricultural and Biological Engineers machinery data and formulas (ASABE, 2006).
This article, a revision of an earlier bulletin, is designed to provide farm managers with an additional and more accurate tool for their management decisions permitting input of data specific to your operation ( Schuler and Frank, 1991). A series of tables and two worksheets, one for tractors and one for other machines, was developed to help estimate machine costs using the ASABE data and formulas. A computer spreadsheet is also available to make the estimates which are available through the author. Once you can accurately estimate the machine's costs, you can make regarding purchases, leases, rentals and sharing that will meet the needs of your operation.
A discussion of the various components of machinery costs and the procedures for calculating them follows. When you make machinery management decisions, this will help you to estimate machine costs systematically.
عمار جابر
02-08-2009, 11:19 PM
TYPES OF COSTS
Costs of agricultural machines fall into two categories.
Fixed (ownership) costs are incurred regardless of the number of acres or hours of use annually. Fixed costs include depreciation, interest, insurance, shelter and, in some cases, taxes.
Variable (operating) costs vary with the hours of machine use. They include fuel, lubricants, repair and maintenance, and labor.
Fixed costs
Machinery loses value due to wear, age and obsolescence. The loss in value due to age and obsolescence is called depreciation. Machines depreciate each year regardless of the hours of use. Therefore, depreciation is considered a fixed cost. The change in a machine's value divided by the number of years of ownership can be considered annual depreciation.
NOTE: Depreciation for tax purposes must be determined differently and is not discussed here.
You can use various methods to determine a machine's value at the end of a specific period of time. This article uses a schedule that considers the value of machinery on the open market.
Interest on money spent on machinery is another fixed cost. This may be a cash cost when you borrow money or an opportunity cost when you buy machinery with money that you've saved. Since interest cost does not vary with machine use, it is a fixed cost. A rate of 8 percent of the remaining machine value is used here for estimating interest cost.
Housing and insurance are also fixed costs. We use a rate of 2 percent of the machine's list price.
Table 1 allows you to estimate fixed machine costs based on a machine's age and category. To determine the fixed costs, multiply the percentage for the appropriate machine age and category from Table 1 times the purchase price. For example, a new $30,000 tractor would have an estimated fixed cost of $13,671 (30,000 times 0.4557, from Table 1) for the first year. During the sixth year of ownership, the fixed cost is $2,367 ($30,000 times 0.0789, from Table 1). The assigned categories for additional machines are found in Table 2.
Table 1. Annual fixed costs in percent of list price by machine category and age.
(Interest rate is 8 percent and housing, etc. is 2 percent.) 2006 ASAE Standards
Age
(yrs)
Equipment Categories
1
Tractors
2
Combines
S.P. Windrowers
3
Forage Harvester
Balers, Blowers
4
Other Field Machine
1
45.57
51.19
57.92
54.61
2
11.01
11.85
10.37
11.15
3
10.13
10.49
9.18
9.86
4
9.32
9.28
8.12
8.71
5
8.57
8.22
7.19
7.70
6
7.89
7.27
6.36
6.81
7
7.26
6.43
5.63
6.02
8
6.68
5.69
4.98
5.32
9
6.14
5.04
4.41
4.70
10
5.65
4.46
3.90
4.16
11
5.20
3.95
3.45
3.68
12
4.78
3.49
3.06
3.25
13
4.40
3.09
2.71
2.87
14
4.05
2.74
2.39
2.54
15
3.72
2.42
2.12
2.24
To determine average fixed costs for a selected machine life, you must average these costs over the machine life. The average fixed costs per year for a machine with a 7-year life is the sum of the first seven values in Table 1, divided by 7 and multiplied by the machine's value. An example: For a tractor, the sum of the first seven values is 99.75 percent. Dividing by 7, the average annual rate is 14.25 percent
Table 2. Remaining value groups, wear-out life, and total repairs to wear-out life.
(Source: 2006 ASAE Standards)
Machinery
Remaining Value & Fixed Cost Group No.
Estimated Wear-out Life (hrs)
Total Repairs in Wear-out Life (% of list price)
Tractor
Two-wheel dr.
Four-wheel dr.
1
1
12,000
16,000
100
80
Tillage
Moldboard pl
Offset disk
Tandem disk
Chisel plow
Subsoiler
Field culti.
Spring tooth
Rolling packer
Rotary hoe
Rolling harrow
Row cultivar
4
4
4
4
4
4
4
4
4
4
4
2,000
2,000
2,000
2,000
2,000
2,000
2,000
2,000
2,000
2,000
2,000
100
60
60
75
75
70
70
40
60
40
80
Planting
Planter
Grain drill
4
4
1,500
1,500
75
75
Harvesting
Picker sheller
Combine
Pull type
Self prop.
Mower cond.
Sickle
Rotary
Rake
Baler
Large rect.
Large round
Forage harv.
Pull type
Self-prop
Potato
4
2
2
4
4
4
3
3
3
3
4
2,000
2,000
3,000
2,500
2,500
2,500
3,000
1,500
2,500
4,000
2,500
70
60
40
80
100
60
75
90
65
50
70
Other
Fert. spreader
Boom sprayer
blower
wagon
4
4
3
4
1,200
1,500
1,500
3,000
80
70
45
80
عمار جابر
02-08-2009, 11:20 PM
Table 1 can also be used to estimate the fixed costs of used machinery. The average fixed costs for the period of ownership can be estimated by using the average percent for the period. For example, if you buy the $30,000 tractor used at 5 years of age and plan to own it for 7 years, then the average annual fixed cost is based on the average for years 6 through 12 from Table 1. In this case, the annual fixed percent is 6.23 percent, and the costs are $1,869 ($30,000 times 0.0623).
Table 3 was developed from Table 1 to provide the cumulative average annual fixed costs, in percent. For the $30,000 tractor, the average fixed cost would be $4,275 per year ($30,000 times 0.1425 from Table 3) for the first 7 years of ownership. You would use this value in the machine's cost calculations.
Since you will use most tractors for several different operations, you must know the fixed costs per hour in order to distribute these costs among all operations. To do this, divide the tractor's fixed costs by the estimated hours the tractor is used for all purposes during the year. Multiply the result by the number of hours the machine requires the tractor each year.
Table 3. Cumulative average annual fixed costs in percent
of list price by machine category and age.
Age
(yrs)
Equipment Categories
1
Tractors
2
Combines
S.P. Windrowers
3
Forage Harvester
Balers, Blowers
4
Other Field Machines
1
45.57
51.19
57.92
54.61
2
28.29
31.52
34.14
32.88
3
22.24
24.51
25.82
25.21
4
19.01
20.70
21.40
21.08
5
16.92
18.21
18.56
18.41
6
15.41
16.38
16.52
16.47
7
14.25
14.96
14.97
14.98
8
13.30
13.80
13.72
13.77
9
12.51
12.83
12.68
12.76
10
11.82
11.99
11.81
11.90
11
11.22
11.26
11.05
11.16
12
10.68
10.61
10.38
10.50
13
10.20
10.04
9.79
9.91
14
9.76
9.51
9.26
9.38
15
9.36
9.04
8.79
8.91
عمار جابر
02-08-2009, 11:23 PM
Variable costs
Repair costs
Repair costs depend on hours of annual use and are difficult to predict because operators differ greatly in the levels of repair and maintenance they do. Table 4 estimates repair costs based on annual use and length of ownership. The values in the table are the percent of the machine’s list price to be used to determine the repair for the life of the machine.
For example, consider a $7,500 moldboard plow that is used 100 hours per year. From Table 4, the average repair cost for a 7-year life and an annual use of 100 acres is 15.3 percent of the purchase price. For this plow, the life time repair costs are $1148 (0.153 times $7,500). The annual costs are $1148 divided by seven years, $164. Repair costs beyond the wear-out life are not included in Table 4.
Wear-out life, based on the number of hours of operation listed in Table 2, estimates the useful life of a machine that has had average care and maintenance. Beyond this life, repair and maintenance costs become excessive.
Table 4. Average accumulated costs as a percent of list price for the life of the machine.
(Source: 2006 ASAE Standards)
Machine
Annual Hours
7-year Life
10-year Life
15-year Life
Tractor, 2-wheel Drive
200
400
600
800
1.4
5.4
12.3
22.0
2.8
11.1
25.2
44.4
6.3
25.2
56.7
100.8
Tractor, 4-wheel Drive
200
400
600
800
0.6
2.4
5.3
9.4
1.2
4.8
10.8
19.2
2.7
10.8
24.3
43.2
Moldboard Plow
50
100
150
200
4.4
15.3
31.7
53.1
8.3
29.0
60.2
101.0
17.3
60.2
*
*
Chisel Plow and Subsoiler
50
100
150
200
6.4
17.0
30.0
44.8
10.6
28.0
49.4
73.9
18.7
49.4
*
*
Disk
50
100
150
200
3.0
9.8
19.6
31.9
5.5
18.0
35.9
58.5
11.0
35.9
*
*
Field Cultivator and Spring-tooth Harrow
50
100
150
200
6.3
16.4
28.9
43.2
10.2
27.0
47.6
71.3
18.0
27.1
*
*
Roller Packer and Harrow
50
100
150
200
4.1
10.1
17.0
24.8
6.5
16.0
27.1
39.4
11.0
27.1
*
*
Row Cultivator
50
100
150
200
1.7
7.8
18.9
35.6
3.7
17.0
41.5
78.1
9.0
41.5
*
*
Rotary Hoe
50
100
150
200
5.3
14.0
24.6
36.8
8.7
23.0
40.6
60.7
15.5
40.6
*
*
Planting Equipment
50
100
150
200
3.5
15.1
35.5
64.9
7.5
32.0
74.9
*
17.5
74.9
*
*
Corn Picker and Sheller
50
100
150
200
1.3
6.2
15.1
30.4
2.8
14.0
35.6
68.9
7.2
36.6
*
*
Combine, Pull-type
50
100
150
200
1.1
5.3
13.4
26.0
2.4
12.0
30.5
59.1
6.2
30.5
*
*
Combine, Self-propelled
50
100
150
200
0.4
1.9
4.4
8.1
0.9
4.0
9.4
17.1
2.2
9.4
22.0
40.2
Mower-cond.
sickle
50
100
150
200
3.4
10.2
19.5
30.8
5.9
18.0
34.4
54.6
11.4
34.4
65.9
*
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