عمار جابر
30-07-2009, 03:44 PM
Demonstration for
SUMMER ONION TOUR
August 15, 1994, Call Farms, Layton, Utah
by Robert W. Hill, Irrigation Specialist and Glen Stringham, Professor Emeritus
Utah State University, Cooperative Extension Service, Biological & Irrigation Engineering
Note: Surge Flow is a registered trademark of Utah State University
SURGE FLOW TM is a method of applying water in a series of surges to furrows, borders and basins. The system used in this field will automatically save labor, water, improve irrigation efficiency, and can improve yield.
When USU researchers began studies of surge flow, they were looking for a way to automate surface irrigation by decreasing a furrow stream size from the big one needed to get water to the end of the furrow to one just large enough to keep the furrow wet while the root zone filled up. They conceived the idea of the cutback phase and built the equipment to do it. The tremendous advantages of the method in the advance phase were discovered during field tests of the equipment.
CALL FARMS SURGE FLOW DEMONSTRATION FIELD
The surge valve and controller (loaned from P & R Surge Systems, courtesy of Pete Strawick, Rupert, ID) were installed in the field in mid May. Irrigations have been scheduled about every six days since then. Neutron probe access tubes were installed at the head and tail of 2 rows, one on the east and one on the west. Readings are taken prior to and following each irrigation.
The field rows are longer on the east (1100 feet) than on the west (985 feet). The valve is not in the exact center with 64 rows on the east and 56 rows on the west. This gives higher average furrow stream size on the west side of the field. Accordingly the on time was adjusted to be more on the east side than on the west for each of the advance and cutback cycles.
The irrigation on July 14 was evaluated for advance time, furrow flow rates and tailwater runoff. While the flow rates in all furrows were measured, only four furrows (numbers 10 and 11 from the east edge and numbers 11 and 12 from the west edge) were monitored for advance and only the east side for tail water runoff.
Preliminary analysis results are shown in the attached three figures: accumulated advance distance for the first 3 advance cycles (Figure 1), advance and cutback cycle timing and flow rates for row 10 on the east (Figure 2), and flow rates for all furrows (Figure 3). The advance cycles were set to 13 minutes east and 9 minutes west for cycle 1, 16 minutes E and 12 minutes W for cycle 2, 23 minutes E and 17 minutes W for cycle 3 and 35 minutes E and 27 minutes W in cycle 4. The water reached the end of the west side furrows during the third advance cycle but required a fourth advance on the east (Figure 1). Runoff began on the east side during the fourth advance (Figure 2). However, the cutback phase reduced the runoff considerably below what may have occured with continuous flow.
The Calls estimate a water savings of about 40 percent for this field compared to previous methods.
The furrow stream size varied considerably across the field as shown in Figure 3. Much of this was due to trash coming into the open ditch upstream of the buried pipe supply line. This indicates a need for the use of suitable trash screens to improve the field irrigation uniformity.
SURFACE IRRIGATION
In surface methods of irrigation, the soil surface serves two distinct functions. First, it is an infiltration surface. Water must pass through the soil surface into the soil below. The quantity of water that enters the soil soaks in. However, the longer water is on the surface the slower the rate at which it enters. This means that less water infiltrates per unit of time near the end of the irrigation than at the beginning.
The second function of the soil surface is to convey the water from one end of the furrow to the other. Thus, while the soil surface is performing the conveyance function, it also performs the infiltration function. The two cannot be separated. Therefore, since water is on the soil at the beginning of the furrow longer than it is on at the end, more water infiltrates at the beginning than at the end. If a furrow stream is allowed to run long enough to completely fill the root zone at the end of the furrow, too much water is applied at the beginning and losses due to deep percolation occur. Furthermore, excess water must run off at the end of the furrow, and runoff losses occur. These two phenomena are the cause of most of the inefficiency in surface irrigation under conventional practices.
BENEFITS OF SURGE FLOW
1. Water Savings. There are two characteristics of surge flow that help save irrigation water. When water is admitted to the furrow for a given period of time, and then shut off and the furrow allowed to de-water, the intake rate of the furrow is dramatically reduced. Thus, when the second surge of water is admitted to the furrow, less water infiltrates into the soil than would otherwise occur, hence more water is available in the dry portions of the furrow, and advance is more rapid. The combined affect of the reduced infiltration during the advance phase plus the more rapid advance with surge flows, leads to a more uniform distribution of water alone the furrow. In some soils, the same quantity of water normally required to get to the end of one furrow can be spread out over two furrows with surge flow. Thus, the uniformity of application is significantly improved. In some field tests, uniformities of more than 90% have been achieved.
The second water savings characteristic of surge flow comes in the cutback phase. The rapid cycling of the water flow in the cutback phase reduces the flow rate in the furrow, and hence the runoff is reduced during the time needed to completely fill the root zone. In the ideal situation, only enough water would be admitted to the furrow to supply the intake requirements of the furrow. In reality it is difficult to reach the ideal, but some of the available equipment can come close to it.
2. Crop yield is improved due to the improved uniformity of application. Over-watering at the head of the field and under-watering at the end (or over-watering and drowning of the crop due to tail water runoff) are almost eliminated. The crop is much more uniform throughout the length of the field. In 1985, one half of a 35-acre corn field was irrigated with this equipment, and the other half irrigated with siphon tubes. The 17 acres irrigated by SURGE FLOWTM produced 210 bushels of grain per acre (213 bushels is the all-time record for Utah). Using the identical cultural practices except for irrigation, the remaining 18 acres produced 148 bushels per acre.
3. The system operates at low pressures (as low as 1 psi) making expensive, high pressure pumping systems unnecessary and operation costs minimal.
4. Maintenance is relatively simple.
HOW SURGE FLOW WORKS IN FIELD
Surge flow is simply a method of applying water to a field in a series of intermittent surges rather than as a continuous stream. There are two application phases to the surge flow method: a) The "advance phase" where the water advances from the beginning of the furrow to the end of the furrow; and b) the "cutback phase" where the flow rate of the water in the furrow is reduced.
In the advance phase, the cycle time (the time for one complete on/off cycle for a particular furrow or block of furrows) is -relatively long, i.e., 30 minutes or more. In such an advance phase, water is in the furrow for 30 minutes and out for 30 minutes, then back in again and so on until it reaches the end of the furrow. In the advance phase, it is important that the water be out of the furrows long enough that the furrow completely de-waters, or that all of the water disappears from the furrow. Much of the advantage of surging in the advance phase is lost if this is not the case.
During this phase the alternate filling and emptying of the furrow quickly lowers the soil's infiltration capacity, reduces the percolation depth, and smooths the furrow surface. These changes in soil behavior and furrow condition make for more efficient water use in the second, cutback phase.
In the cutback phase, the cycle time is shortened to about 10 to 20 minutes. This means that there will be water in the furrow at all times, infiltrating uniformly, but the average flow rate will be about half that of a conventional continuous application. The objective of the cutback phase is to reduce the time-averaged flow rate in the furrow to less than the instantaneous flow rate entering the furrow.
SURGE EQUIPMENT SUPPLIERS
There are two main suppliers of surge valves and controllers: P & R Surge Systems, Inc., Lubbock, Texas; and Waterman Industries, Inc., Exeter, California.
REFERENCES
Bishop, A. Alvin. A Revolution in Surface Irrigation: Surge Flow. Utah Science, Summer, 1980.
Surge Irrigation Can Cut Waste. World Water, September, 1987, p. 29.
Figure 1
Figure 2
Figure 3
SUMMER ONION TOUR
August 15, 1994, Call Farms, Layton, Utah
by Robert W. Hill, Irrigation Specialist and Glen Stringham, Professor Emeritus
Utah State University, Cooperative Extension Service, Biological & Irrigation Engineering
Note: Surge Flow is a registered trademark of Utah State University
SURGE FLOW TM is a method of applying water in a series of surges to furrows, borders and basins. The system used in this field will automatically save labor, water, improve irrigation efficiency, and can improve yield.
When USU researchers began studies of surge flow, they were looking for a way to automate surface irrigation by decreasing a furrow stream size from the big one needed to get water to the end of the furrow to one just large enough to keep the furrow wet while the root zone filled up. They conceived the idea of the cutback phase and built the equipment to do it. The tremendous advantages of the method in the advance phase were discovered during field tests of the equipment.
CALL FARMS SURGE FLOW DEMONSTRATION FIELD
The surge valve and controller (loaned from P & R Surge Systems, courtesy of Pete Strawick, Rupert, ID) were installed in the field in mid May. Irrigations have been scheduled about every six days since then. Neutron probe access tubes were installed at the head and tail of 2 rows, one on the east and one on the west. Readings are taken prior to and following each irrigation.
The field rows are longer on the east (1100 feet) than on the west (985 feet). The valve is not in the exact center with 64 rows on the east and 56 rows on the west. This gives higher average furrow stream size on the west side of the field. Accordingly the on time was adjusted to be more on the east side than on the west for each of the advance and cutback cycles.
The irrigation on July 14 was evaluated for advance time, furrow flow rates and tailwater runoff. While the flow rates in all furrows were measured, only four furrows (numbers 10 and 11 from the east edge and numbers 11 and 12 from the west edge) were monitored for advance and only the east side for tail water runoff.
Preliminary analysis results are shown in the attached three figures: accumulated advance distance for the first 3 advance cycles (Figure 1), advance and cutback cycle timing and flow rates for row 10 on the east (Figure 2), and flow rates for all furrows (Figure 3). The advance cycles were set to 13 minutes east and 9 minutes west for cycle 1, 16 minutes E and 12 minutes W for cycle 2, 23 minutes E and 17 minutes W for cycle 3 and 35 minutes E and 27 minutes W in cycle 4. The water reached the end of the west side furrows during the third advance cycle but required a fourth advance on the east (Figure 1). Runoff began on the east side during the fourth advance (Figure 2). However, the cutback phase reduced the runoff considerably below what may have occured with continuous flow.
The Calls estimate a water savings of about 40 percent for this field compared to previous methods.
The furrow stream size varied considerably across the field as shown in Figure 3. Much of this was due to trash coming into the open ditch upstream of the buried pipe supply line. This indicates a need for the use of suitable trash screens to improve the field irrigation uniformity.
SURFACE IRRIGATION
In surface methods of irrigation, the soil surface serves two distinct functions. First, it is an infiltration surface. Water must pass through the soil surface into the soil below. The quantity of water that enters the soil soaks in. However, the longer water is on the surface the slower the rate at which it enters. This means that less water infiltrates per unit of time near the end of the irrigation than at the beginning.
The second function of the soil surface is to convey the water from one end of the furrow to the other. Thus, while the soil surface is performing the conveyance function, it also performs the infiltration function. The two cannot be separated. Therefore, since water is on the soil at the beginning of the furrow longer than it is on at the end, more water infiltrates at the beginning than at the end. If a furrow stream is allowed to run long enough to completely fill the root zone at the end of the furrow, too much water is applied at the beginning and losses due to deep percolation occur. Furthermore, excess water must run off at the end of the furrow, and runoff losses occur. These two phenomena are the cause of most of the inefficiency in surface irrigation under conventional practices.
BENEFITS OF SURGE FLOW
1. Water Savings. There are two characteristics of surge flow that help save irrigation water. When water is admitted to the furrow for a given period of time, and then shut off and the furrow allowed to de-water, the intake rate of the furrow is dramatically reduced. Thus, when the second surge of water is admitted to the furrow, less water infiltrates into the soil than would otherwise occur, hence more water is available in the dry portions of the furrow, and advance is more rapid. The combined affect of the reduced infiltration during the advance phase plus the more rapid advance with surge flows, leads to a more uniform distribution of water alone the furrow. In some soils, the same quantity of water normally required to get to the end of one furrow can be spread out over two furrows with surge flow. Thus, the uniformity of application is significantly improved. In some field tests, uniformities of more than 90% have been achieved.
The second water savings characteristic of surge flow comes in the cutback phase. The rapid cycling of the water flow in the cutback phase reduces the flow rate in the furrow, and hence the runoff is reduced during the time needed to completely fill the root zone. In the ideal situation, only enough water would be admitted to the furrow to supply the intake requirements of the furrow. In reality it is difficult to reach the ideal, but some of the available equipment can come close to it.
2. Crop yield is improved due to the improved uniformity of application. Over-watering at the head of the field and under-watering at the end (or over-watering and drowning of the crop due to tail water runoff) are almost eliminated. The crop is much more uniform throughout the length of the field. In 1985, one half of a 35-acre corn field was irrigated with this equipment, and the other half irrigated with siphon tubes. The 17 acres irrigated by SURGE FLOWTM produced 210 bushels of grain per acre (213 bushels is the all-time record for Utah). Using the identical cultural practices except for irrigation, the remaining 18 acres produced 148 bushels per acre.
3. The system operates at low pressures (as low as 1 psi) making expensive, high pressure pumping systems unnecessary and operation costs minimal.
4. Maintenance is relatively simple.
HOW SURGE FLOW WORKS IN FIELD
Surge flow is simply a method of applying water to a field in a series of intermittent surges rather than as a continuous stream. There are two application phases to the surge flow method: a) The "advance phase" where the water advances from the beginning of the furrow to the end of the furrow; and b) the "cutback phase" where the flow rate of the water in the furrow is reduced.
In the advance phase, the cycle time (the time for one complete on/off cycle for a particular furrow or block of furrows) is -relatively long, i.e., 30 minutes or more. In such an advance phase, water is in the furrow for 30 minutes and out for 30 minutes, then back in again and so on until it reaches the end of the furrow. In the advance phase, it is important that the water be out of the furrows long enough that the furrow completely de-waters, or that all of the water disappears from the furrow. Much of the advantage of surging in the advance phase is lost if this is not the case.
During this phase the alternate filling and emptying of the furrow quickly lowers the soil's infiltration capacity, reduces the percolation depth, and smooths the furrow surface. These changes in soil behavior and furrow condition make for more efficient water use in the second, cutback phase.
In the cutback phase, the cycle time is shortened to about 10 to 20 minutes. This means that there will be water in the furrow at all times, infiltrating uniformly, but the average flow rate will be about half that of a conventional continuous application. The objective of the cutback phase is to reduce the time-averaged flow rate in the furrow to less than the instantaneous flow rate entering the furrow.
SURGE EQUIPMENT SUPPLIERS
There are two main suppliers of surge valves and controllers: P & R Surge Systems, Inc., Lubbock, Texas; and Waterman Industries, Inc., Exeter, California.
REFERENCES
Bishop, A. Alvin. A Revolution in Surface Irrigation: Surge Flow. Utah Science, Summer, 1980.
Surge Irrigation Can Cut Waste. World Water, September, 1987, p. 29.
Figure 1
Figure 2
Figure 3