Author name:
طالب صبر حريجة العسكري
Supervisor name:
داخل راضي نديوي | محمد عبد الله عبد الكريم
Abstract:
Theoretical foundations for research included the estimations of reference evapotranspiration (ETo) in the midmost Euphrates region and southern Iraq by applying seven mathematical models as well as CROPWAT 8.0 and CLIMWAT software using two sets of climatic data for periods 1970 - 2002 and 2004 - 2010.The results could be summarized as follow : - 1. The annual mean of ETo calculated by the Penman - Monteith equation (PM) for the meteorological stations of Nasiriya, Amarah, Semawa, Najaf, Diwaniya and Kerballa were (6.00, 6.20, 5.92,5.97,6.13,5.74) mm day - 1 respectively, during the first measurement period, and (6.47, 6.08, 5.86, 5.98, 6.13, 5.65) mm day - 1 respectively, during the second period. Also, the ETo estimated by CROPWAT 8.0 and imported by CLIMWAT software have showed the same trend of PM calculations with overestimate reached (6.10, 5.93) % during the first and secondperiods for CROPWAT 8.0 software, and underestimate for ETo reached 8.16 %during the first period for CLIMWAT software compared to PM calculations.2. The statistical criterions for evaluating the performance of six empiricalequations of the original versions were compared with the Penman - Monteithequation revealed that the variations in their performance with relativelypreference for temperature - based equations in comparison with radiation - basedequations. Blancy - Criddle (1950) equation (BC) has proved superiorperformance in Nasiriya, Semawa, Najaf, Diwaniya and Kerballa stations duringboth periods, also in Amarah station during the second period and declining itsperformance for the benefit of Kharrufa equation (1985) (K) during the firstperiod of measurement.3. The calibration process of the six empirical equations including : Hargreaves - Samani (1985) (HS), Makkink (1957) (M) , Priestley - Taylor (1972)(PT),andHargreaves (1975) (H) in addition to BC and K equations were made bysubstituting recalibrated constant values for the original constant values afterthese constant had modified to fit PM calculations and it used a set of statisticalcriterions to verify the validity of calibration and its ability to reduce theestimates errors compared to the original formulas. As the indices ofconcordance (D), confidence (C), correlation (r) and regression (R2) togetherwith the Nash - Sutcliffe Efficiency(NSE), standard deviation ratio (RSR). meanabsolute error (MAE), root mean square error (RMSE), relative error (RE)indicators and the ratio between both average estimations of ETo (r) are used toassess the validation of calibration and optimization which revealed thatconfidence became high in modified equations with reducing the estimation errorof ETo due to approach the values of these criterions from optimal value, then,they had improved efficiency of the six equations to simulate the values of EToare more accuracy than original formulae.4. The proposed new constants for the estimation of the ETo with : BC was 1.37for the time periods from January to April and 1.39 for May to December insteadof the original constant 1 : 41, HS was for the time periods from Octoberto March and for April to September instead of the original constantb0.0023, K was for June - July and for remained months instead of theoriginal constant 0.34, M are for the time periods from November to Mayand for June to October instead of the original constant 0.61, the equationsPT and H were 1.96 and 0 0.0165 for the period of December - May and 2.61and 0.0178 for the period from June to November instead of the originalconstants of 1.26 and 0.0135 respectively and equationsThe side applied to the study has included the implementation of the fieldexperiment for the cultivation of sunflower crop through the loop spring 2013 inprivate farm lies according to the geographical positioning system (GPS) withinthe coordinates (606,366.3437642), (606320, 3437729), (606353, 3437749),(606400, 3437660), is located in Batah town, Thi Qar province, at a distance of 17km west of the city of Nasiriyah, up 5 meters from the sea surface. The mainobjective of experiment included the following : i. Measuring ETo for the study through the crop growing seasonii. To determine the crop coefficient (Kc) and the actual water consumption(ETa) of sunflower crop in the Batah areaiii. . To asses effect of irrigation scheduling and fertilizer application as well astheir combinations on the growth indicators, nutrient uptake, dry matter,crop yields, the crop water use efficiency and water productivity.iv. Evaluating impact of irrigation scheduling and fertilizer application besidestheir combinations on some of soil physical properties at the end season.A field experiment was carried out using factorial experiment in a randomizedcomplete block design (RCBD) Layout with three replications in two factors, nineirrigation Scheduling treatments were assigned to the main plots and four fertilizertreatments were assigned to the subplots. Sunflower seeds (flame) were planted onMarch 23 with plant density 61538 plant ha - 1; the harvest operation was conductedon 18 / July / 2013.The irrigation Scheduling was achieved based on replenish root zone to theborders of field capacity when it reach the percentage of management allowabledepletion (MAD) identified about 55% of total available water (TAW), taking intoaccount the diversity of the effective depth of the root zone according to the stagesof growth, . The experiment involved Irrigation scheduling of the sunflower basedby calculating ETa using Kc which adjusted in situ multiplying by ETo thatestimated by PM equation (S1) ,original BC equation (S2) and adjusted K equation(S3) using meteorological data for real time that collected from agrometeorologicalstation nearby the field. PM equation (S6) using historicalmeteorological data and from pan evaporation with applied (FAO 56, 1998) tocalculate pan coefficient (S4). Whereas, irrigation Scheduling based on soil waterbalance according to daily measurements of soil moisture and adjusted daily onthe basis of changes in moisture content (soil water balance) (S5), fixed irrigationinterval and variable irrigation depth (S7), different irrigation interval and variableirrigation depth (S8) and soil water balance for bare soil (S9). Also the studyincluded four fertilization treatments were used ( F : mineral fertilizer, C : Compost,M : mineral fertilizer + Compost , N : non fertilization). The results showed thefollow : c1. The maximum value of ETo during season growth of sunflower crops accordingto field measurements has increased significantly when using evaporation pan,which gave the highest average rate of 8.81 mm day - 1 in comparison with PMequation that recorded the lowest value of ETo with mean equal to 8.00 mm day - 1,while BC and K gave 8.66 and 8.14 mm day - 1 respectively.2. The converged seasonal mean of Kc value for sunflower crops during growthseason were 0.864, 0.862, 0.863, 0.861, 0.862, 0.862, 0.861, 0.862 for S1 - S8treatments respectively, while the Kc varied in different stages of growth, thehigher value of Kc was 1.213 observed during the flowering stage, followed bytwo phases of vegetative growth and maturity with mean 0.796, 0.494respectively, whereas the lowest values (0.350) was recorded in the initial stage3. The ETa values were variable with various irrigation Scheduling treatments,the treatments (S1 - S8) gave mean ( 876.86, 938.98, 885.57, 943.40, 898.47,949.05, 835.61, 839.76) mm Season - 1 respectively, the mean values of ETa aredistributed as 52.28% during flowering stage, 23.38% through maturity, 18.97%during vegetative growth stage and 5.36% in the initial stage4. The Irrigation scheduling of the sunflower based on S5 treatment caused toincrement of water consumption by transpiration during flowering stage to reach83% from total ETa depth, whereas The Irrigation scheduling based on S7treatment caused to increment of water consumption by evaporation during thesame stage to reach 29% from total ETa depth.5. The results demonstrated that all Irrigation scheduling have been showed astrong relationship with water balance measurement (S5), by R2 is greater than0.91 and r greater than 0.95, also, the results showed there was a preference to therevised K equation to calculate ETa of sunflower crops in the region according toindicators of regression model each of the R2, slope and intercept which amountedto 0.9395, 0.9875, - 0.0144 respectively.6. The overall mean of net irrigation depth was 874.6 mm season - 1 ranged from941 mm season - 1 for S4 treatment to 800 mm season - 1 for S7 . the addition ofwater was 14 applications for S1 - S4 treatments and 15, 13, 12 applications for S5,S8, S7 respectively.7. The lowest nitrogen concentration in the leaves of Sunflower crops duringflowering stage related to decrease water supply at S7 (27.69 g kg - 1) , then, itincreased to maximum value ( 31.48 g kg - 1) when irrigation Scheduling based onS1 followed by S3, S5, S2, S4 treatments,. As respect with maturation stages theS5 treatment gave maximum mean (26.81 g kg - 1) was significantly superiorcompared to all treatments except S1 and it gave increment in nitrogenconcentration equal to 22% in comparison with S8 which recorded lowest nitrogenconcentration (21.94 g kg - 1). The results showed the F treatment was significantlysuperior followed by M treatment which gave average 34.43, 33.42 g kg - 1 duringflowering stage and 28.69, 26.48 g kg - 1 during maturation stage respectively.8. Increasing irrigation depth due to an application S4 and S6 treatments andIncreasing the irrigation frequency for S5 treatment led to significant increment inthe bulk density for 0 - 15 cm depth with mean 1.393, 1.384, 1.386 M m - 3respectively, the bulk density decreased steadily with decreasing of irrigationddepth and irrigation interval until reach their lowest level (1.350 M m - 3) at S7treatment. The bulk density was significantly decreasing when C and M treatmentswere applied with means of equal to (1.362, 1.364) M m - 3 respectively, atmagnitude 1% higher than their initial values. Also the results showed theirrigation scheduling treatments and fertilizer application as well as theircombinations failed to exhibit any significant influence on bulk density for depths15 - 30 cm and 30 - 45 cm.9. The results showed a significant increase in the soil penetration resistance forsoil with high watery supply (S4 and S6), while that status is significantlydecreased under treatment of low watery supply (S7, S8 and S1), the soils withmedium watery supply causing the pattern moderate between the two, also, thisepithet is significantly reduced when you add compost with an average of 708.09kPa, while there was a significant increase resulted from control treatment andaddition of chemical fertilizer alone, the proportion of 31.81 and 18.41%sequentially compared with the addition of compost.10. The results showed the possibility basic infiltration rate for most treatmentsunder the category (moderately slow) according to Landor (1991), by the mean ofbasic infiltration rate was 1. cm h - 1 ranged between 0. to 3. cm h - 1, whereasbasic infiltration rate for S4N and S9 decreased to 0.6 , 0.51 cm h - 1 respectively,thus it can be classified into (slow) while it increased greater than 2.0 cm h - 1 forS1C, S1M, S2M, S5C, S7F, S7M,S7C, S8M treatments which refer to moderateinfiltration rate according to the same classification . C and M fertilization led toimprove soil physical properties, which in turn positively affected the infiltrationrate with increment in magnitude (5 , 56) % respectively, compared to Ftreatment.11. Treatment of F gave a significant superior in most morphologicalcharacteristics and yield components, the efficiency of F treatment for productionwas 37.45 % followed by M and C treatments were achieved 24.66, 19.24 %respectively, compared to N treatment.12. Treatment F achieved highest yield of grains 1945.80 kg ha - 1, an increasing was24.32% in comparison with N treatment which gave lowest yield of grains reached1367.24 kg ha - 1, also there were a significant increase in crop water use efficiencyand water productivity are associated with application of F and M fertilization13. The productivity characteristics of sunflower were significantly affected byirrigation Scheduling treatments, The highest seed yield 1893.8 kg ha - 1and thehighest dry matter 5246.2 kg ha - 1were obtained under S5 treatment, while the S7treatment recorded lowest values of these indicators (1512.5 and 3765.4) kg ha - 1 respectively,14. The application of Irrigation scheduling based on S5, S1 and S3 treatments achieved a significant increase in crop water use efficiency and water productivity, the mean of first parameter was (0.219, 0.216, 0.216) kg m - 3 respectively, and themean of the second parameter was (0.228, 0.220, 0.219) kg m - 3 respectively.
