الفهرس 
INTRODUCTION
Introduction.Only 14 pages are availabe for public view
 |  | from | 170 |  |  |
| | | from | 170 | | |
Abstract
Field experiments were carried-out at the experimental farm of Water Studies and Research Complex (WSRC), station, National Water Research Center, Toshka – Abu simbel City, Egypt during the two growing seasons. The conducted experiments aimed to study the effect of different irrigation regimes under sprinkler irrigation system on yield and yield components, as well as water relations of wheat and sesame crops.
Reference evapotranspiration were also estimated by some empirical formulas.
The experiments were laid o u t i n split plot design with f i ve replicates and f i ve treatments in wheat experiment, while there was in one factor experiment wi t h five replicates and three treatments in sesame experiment. The main plots were used to express irrigation system (sprinkler). The plot were assigned for irrigation regimes (20, 40, 50, 60 and 75 % ASMD) in wheat experiment, while there were (25, 50 and
75 % depletions of available soil moisture) in sesame experiment.
In the winter seasons of 2010/11 and 2011/12, wheat seeds (Triticum aestivum vulgar, CV Geza 168) were sown on November, 17 with a rate of 60 Kg / fed under sprinkler irrigation systems in the first and the second seasons. Wheat plants were harvested on March, 23 and 21 in the first and the second seasons, respectively, All agronomic practices were following the recommendation of Egyptian Ministry of Agriculture
In the summer seasons of 2011 and 2 0 1 2 sesame seeds (Giza 32, variety) were planted in the 15 and May 17 in the first and the second seasons. And were harvested on September, 13 and 15 in the first and the second seasons, respectively. All agronomic practices were following the recommendation of Egyptian Ministry of Agriculture
The obtained results could be summarized as follows:-
1- Wheat.
1-1. Actual evapotranspiration (ETa) for wheat.
• The actual evapotranspiration vary from growth stage to another through the two growing seasons. These values were increased with increasing available soil moisture.
• The highest values of ETa were recorded in the mid growth stages (3 Jan. to 21 Feb.) followed by development (9 Dec. to 2 Jan.) And late season stages (22 Feb. to 23 Mar.); the lowest values were recorded in the initial stage (17 Nov. to 8 Dec.).
• The average seasonal ETa values were 510.4, 498.9, 463.9, 446.8, 430.3 and 411.8 mm at 20, 25, 40, 50, 60 and 75% ASMD respectively.
• The daily water consumed varied with growth stages. It started small at the initial stages then it increased gradually to reach the peak values at flowering stage (3 Jan. to 21 Feb.), after that it declined.
• The highest value of daily consumptive use (5.21 mm) was obtained during mid stage for 20% SMD treatment.
1. 2. Irrigation water applied.
• The seasonal Irrigation water applied values of wheat plants irrigated at the depletion of 20, 25, 40, 50, 60 and 75% ASMD respectively were 696.7, 688.5, 638.1, 613.0, 602.1 and 568.7 mm under sprinkler irrigation system.
1. 3. Reference evapotranspiration (ETo)
• The seasonal ETo values for wheat crop calculated from Penman Monteith, Modified Penman, Doorenbos and Pruitt, Jensen and Haise, Pan Evaporation, Blaney-Criddle, modified Hargreaves, Makkink, priestly -Taylor, Stephens - Stewart, Turc, and Elbably equations were 640.3, 707.2, 380.2,510.0, 536.6, 314.4 , 761.4 , 528.5 , 411.6 , 335.1 , 261.9 , 320.6 , 521.2 and 420.9 mm, respectively.
• The ETo value estimated by Penman Monteith equation was the superior one that exceeded the actual evapotranspiration (ETa) by 26.8 and 24.04 % in the first and second seasons, respectively.
• The ETo value estimated by Modified Penman equation over estimated the ETo value by 38.6 and 38.5 % While, Evaporation pan equation over estimated the ETo value by 7.6 and 2.5 % and Turc equation over estimated the ETo value by 57.9 and 40.04 % in the first and second seasons, respectively.
• The ETo value estimated by Doorenbos and Pruitt equation under estimated the ETo value by 22.9 and 28.3 % While, Blaney- Criddle under estimated the ETo value by 34 and 43.03 % and Makkink equation under estimated the ETa value by 15.9 and 23.02 % in the first and second seasons, respectively.
• The top five ranked methods which it’s total values has been closer to the total actual evapotranspiration values. The ranked was as the following rating: Elbably (3), Jensen and Haise, Evaporation pan, Modified Hargreaves and Elbably (2) in the first growing season (2010/2011).
• The top five ranked methods in the second growing season (2011/2012). The ranked was as the following rating: Jensen and Haise, Evaporation pan, Modified Hargreaves, Elbably (2) and Makkink.
• Jensen and Haise, modified Hargreaves, evaporation pan and Elbably (2) equations calculated ETo efficiently but Jensen and Haise equation was the most efficient in calculating ETo of wheat crop in Toshka district due to its least under estimation, as it was only 0.08 % as an average value of both seasons.
• During studied the relation between growth stage and the mount of water which Jensen and Haise equation has Identifies interesting notes has been founded , which reflect doubtful results.
• The encouraging results obtained from this notes should be investigated further by using suitable empirical method for each growth stage.
1. 4. Crop evapotranspiration (ETc).
• The seasonal ETc values for wheat crop calculated from Penman Monteith, Modified Penman, Doorenbos and Pruitt, Jensen and Haise, Pan Evaporation, Blaney-Criddle, modified Hargreaves, Makkink, priestly -Taylor, Stephens - Stewart, Turc, and Elbably equations were 510.9, 513.3, 517.7,519.7, 522.6, 504.5 , 524.6 , 510.7 , 505.1 , 511.4 , 506.2 , 518.7 , 510.3 and 561.0 mm, respectively.
1. 5. Crop coefficient (Kc).
• Seasonal averages of wheat kc values were 0.73, 0.66, 1.29, 0.98, 0.92 , 1.79 , 0.67 , 0.90, 1.12 , 1.41 , 1.82, 1.98 , 1.17 and 1.44 using Penman Monteith, Modified Penman, Doorenbos and Pruitt, Jensen and Haise, Evaporation pan, Blaney- Criddle ,Turc , Modified Hargreaves , Makkink, priestly – Taylor , Stephens - Stewart , Elbably (1) , Elbably (2) and Elbably (3) equations, respectively.
• The crop coefficient varies from growth stage to another in the two growing seasons. These values were low at the beginning of the growing season, and reach their peaks in medium growth stage. During the late period, the kc started again to decrease until it reached a lower value at the end of the growing period. This tendency was obtained for both growing seasons.
• The average kc values of wheat in two seasons which calculated by Jensen and Haise equation during growth stages were 0.37 , 1.50 , 1.35 , 0.71 for initial , development , mid season , late season, respectively.
• The seasonal averages of wheat kc values under the same equation were 0.98.
1. 6. Coefficient of water stress (Ks).
• Elbably (2) and makkink equation could be calculate ETo efficiently under water stress but Elbably (2) was the best one to calculate ETo for the two growing seasons in Toshka district .
1. 7. Wheat yield and yield traits
• Irrigation regimes were significant effect on plant height, number of spikes / m2, grains number / spike, grains weight / spike and seed index, in both season.
• Grains yield under sprinkler irrigation in the first season were 2310.0, 2230.2, 2035.3, 1890.4, 1680.0, and 1470.8 kg/fed , While in the second season (2011/2012) were 2355.5 , 2275.5 , 2100.0 , 1920.5 , 1710.5 , and 1495.5 kg/fed for 20 , 25, 40 , 50 , 60 and 75% ASMD, respectively .
• Grains yield and was significantly increased with increasing available soil moisture, in both seasons. However, protein percentage was decreased.
1. 8. Water use efficiency (WUE) and Irrigation water use efficiency (IWUE).
• Increased irrigation regime treatment from 20 to 75 % ASMD decreased water use efficiency by wheat plants from (1.06 to 0.84) and (1.13 to 0.87) in 2010/2011 and 2011 /2012 seasons respectively.
• Increasing the amount of applied irrigation water was accompanied by increasing in total yield / fed but the irrigation water use efficiency decreased as the percentage of ASMD increased.
1. 9. Grain Yield Responses to Water ( Ky):
• The obtained values of ky were higher than 1 and varies with different irrigation regimes and growing seasons.
• A response factor higher than unity indicates that the crop response is very sensitive to water deficit with proportional larger yield reductions when water use is reduced because of stress.
• Each decreased in one unit of water applied corresponding decrease by 1.61 and 1.81 unit of grain yield in the first and second seasons, respectively.
2- Sesame
2-1. Actual evapotranspiration (ETa) for sesame.
• The actual evapotranspiration vary from growth stage to another through the two growing seasons. These values were increased with increasing available soil moisture.
• The highest values of ETa were recorded in the mid growth stages (10 July. to 18 Aug.) followed by development (5 Jun. to 9 Jul.) And late season stages (19 Aug. to 15 Sep.); the lowest values were recorded in the initial stage (15 May. to 4 Jun.).
• The seasonal ETa values were 707.6, 602.0 and 561.4 mm at 25, 50 and 75 % soil moisture depletion from available water, respectively.
• It started small at the initial stages (in May and first of June) then it increased gradually to reach the peak values at flowering stage (July and first of August) after that it declined to reach its minimum values at September.
• The highest value of daily consumptive use (6.75 mm, average value of two seasons) was obtained during mid stage at 25 % ASMD. While the lowest value of daily consumptive use (1.58 mm, average value of two seasons) was obtained during initial stage. The overall average values of daily consumptive use (through the growing season) were 5.63, 5.10 and 4.90 mm at 25, 50 and 75 % ASMD, respectively.
2. 2. Irrigation water applied.
• The seasonal irrigation water applied values for sesame were found to be 949.4, 799.9 and 751.9 mm in the first season (2011) and were 993.7, 884.9 and 814.8 mm in the second season (2012) under sprinkler irrigation system for 25, 50 and 75% ASMD treatments, respectively.
2. 3. Reference evapotranspiration (ETo)
• The seasonal ETo values for wheat crop calculated from Penman Monteith, Modified Penman, Doorenbos and Pruitt, Jensen and Haise, Pan Evaporation, Blaney-Criddle, modified Hargreaves, Makkink, priestly -Taylor, Stephens - Stewart, Turc, and Elbably equations were 1023.7, 1193.6, 779.3,1325.7, 1242.4, 959.9 , 412.4 , 1011.0 , 762.5 , 724.5 , 684.2 , 692.7 , 1135.9 and 914.3 mm, respectively.
• The ETo value estimated by Jensen and Haise equation was the superior one the exceeded the actual evapotranspiration (ETa) by 94.0 and 74.5 %, while Pan Evaporation equation was exceeded by 75.7 and 69.4%. Also the ETo values estimated by Modified Penman equation was exceeded by 72.6 and 59.1% ,While, the ETo values estimated by Turc equation was under estimated the ETa values by 41.1 and 44.3 % in the first and second seasons , respectively.
• The ETo value estimated by Elbably (1) and Stephens - Stewart equation was under the ETa values by 3.9 and 5.03 %, respectively. On the other hand the average seasonal ETo values estimated by Makkink and Doorenbos and Pruitt equation was exceeded the ETa values by 5.8 and 8.2 %, in the first and second seasons, respectively.
• The top five ranked methods which it’s total values has been closer to the total actual evapotranspiration values. The ranked was as the following rating: priestly – Taylor, Elbably (1), Stephens - Stewart, Makkink and Doorenbos and Pruitt equation in the first growing season (2011).
• The top five ranked methods in the second growing season (2012). The ranked was as the following rating: priestly – Taylor, Doorenbos and Pruitt, Makkink, Elbably (1) and Stephens - Stewart equation.
• Calculated ETo values at different sesame growth stages by various equations were not always identical in both seasons.
• Priestly- Taylor, Elbably (1), Stephens- Stewart and Doorenbos and Pruitt equations calculated ETo efficiently but Priestly- Taylor equation was the most efficient in calculating ETo of sesame crop in Toshka district due to its least over estimation, as it was only 0.57 % as an average value of both seasons.
• As the winter seasons, the same notes has been founded during studied the relation between growth stage and the mount of water which Priestly- Taylor equation has Identifies, which reflect doubtful results.
• The encouraging results obtained from this notes should be investigated further by using suitable empirical method for each growth stage.
2. 4. Crop evapotranspiration (ETc).
• The seasonal ETc values for sesame crop calculated from Penman Monteith, Modified Penman, Doorenbos and Pruitt, Jensen and Haise, Pan Evaporation, Blaney-Criddle, modified Hargreaves, Makkink, priestly -Taylor, Stephens - Stewart, Turc, and Elbably equations were 721.2, 719.4, 719.9,721.7, 720.9, 723.7 , 720.3 , 722.7 , 718.9 , 720.8 , 725.8 , 720.1 , 720.0 and 718.7 mm, respectively.
2. 5. Crop coefficient (Kc).
• Seasonal averages of wheat kc values were 0.69, 0.57, 0.92, 0.54, 0.55 , 0.76 , 1.75 , 0.69, 0.90 , 0.95 , 1.04, 1.04 , 0.64 and 0.80 using Penman Monteith, Modified Penman, Doorenbos and Pruitt, Jensen and Haise, Evaporation pan, Blaney- Criddle ,Turc , Modified Hargreaves , Makkink, priestly – Taylor , Stephens - Stewart , Elbably (1) , Elbably (2) and Elbably (3) equations, respectively.
• The crop coefficient varies from growth stage to another in the two growing seasons. These values were low at the beginning of the growing season, and reach their peaks in medium growth stage. During the late period, the kc started again to decrease until it reached a lower value at the end of the growing period. This tendency was obtained for both growing seasons.
• The average kc values of sesame crop in two seasons which calculated by Priestly – Taylor equation during growth stages were 0.27 , 0.94 , 1.12 , 1.45 for initial , development , mid season , late season, respectively.
• The seasonal averages of sesame kc values under the same equation were 0.95.
2. 6. Coefficient of water stress (Ks).
• Elbably (1) and Stephens- Stewart equation could be calculate ETo efficiently under water stress but Stephens- Stewart was the best one to calculate ETo for the two growing seasons in Toshka district.
2. 7. Sesame yield and yield component
• Irrigation regimes were significant effect on plant height, number of plant / m2 , number of branches / plant , number of leaves / plant , number of capsules / plant , dry matter of leaves / plant , dry matter of stem / plant , dry matter of capsules / plant, average number of capsules / plant , average values of sesame length of fruiting zone (cm) , seed weight (g) /plant , seeds index in both season.
• The values of sesame yield in the first season (2011) were 370.44, 360.18 and 344.24 kg/fed for 25, 50 and 75% ASMD, respectively. While in the second season (2012) were 385.25, 366.25 and 350.75 kg/fed for 25, 50 and 75% ASMD, respectively.
• The values of sesame oil content percentage in the first season (2011)were 58.62 , 56.09 and 55.10 % for 25 , 50 and 75% ASMD, respectively .The values of sesame oil content percentage in the second season (2012) were 58.99 , 57.50 and 55.40 % for 25, 50 and 75% ASMD, respectively.
• Grains yield and oil content percentage was significantly increased with increasing available soil moisture, in both seasons.
2. 8. Water use efficiency (WUE) and Irrigation water use efficiency (IWUE).
• Increased irrigation regime treatment from 25 to 75 % SMD increased water use efficiency (WUE) by sesame plants from (0.13 to 0.15) and (0.12 to 0.14) in 2011 and 2012 seasons respectively.
• The values of sesame (IWUE) in the first season (2011) were 0.09, 0.11 and 0.11 kg / m3 for 25, 50 and 75% ASMD, respectively. While it was in the second season (2012) 0.09, 0.10 and 0.10 kg / m3 for 25, 50 and 75% ASMD, respectively.
• increasing the amount of applied irrigation water was accompanied by increasing in total yield / fed , also the irrigation water use efficiency increased as the percentage of SMD increased due to that increasing the mount applied irrigation water was inappropriate with that of yield.
1. 9. Grain Yield Responses to Water ( Ky):
• The obtained values of ky were lower than 1 and varies with different irrigation regimes and growing seasons.
• A response factor lower than unity indicates that the crop is more tolerant to water deficit, and recovers partially from stress, exhibiting less than proportional reductions in yield with reduced water use.
• Each decreased in one unit of water applied corresponding decrease by 0.29 and 0.48 unit of grain yield in the first and second seasons, respectively.
Conclusions
from all previous results, it can be concluded that in Toshka district:-
- Jensen and Haise equation was the most efficient to estimate ETo of wheat crop, while of sesame crop was Priestly- Taylor.
- In order to maximizing wheat and sesame crop productivity it must be increasing available soil moisture through sprinkling irrigation system.
- More investigation should be further by found suitable empirical method for each growth stage.