The Iraqi Journal of Agricultural Sciences

9

Authors: S.S. AL.Zobae A.H. AL.Sheikhly

A field experiment was conducted in Al-Raid Experimental station, Ministry of Water Resources, 20 km west of Baghdad, during autumn season 2008, in silt clay loam soil classified at Typic torriflvent, to study the effect of water irrigation quality, soil mulching on some physical properties under drip irrigation system. The Experimental design was Factorial Experiment with RCBD in three replicates. The study includes two factors: 1- Water quality, which includes three factors: a- Irrigation with river water (WR) ( 1.1 ds. m-1). b- Irrigation with saline water (WS) ( 4.5 ds. m-1). c- Alternate irrigation (WA).2- Soil mulching includes two factors: a- Soil mulching with black polyethylene (M). b- With out mulching (W). The results can be summarized as follows: The irrigation treatments effected the soil physical properties at 0-20 cm depth. It was found that the MWD decreased to 0.603, 0.476 and 0.303 mm for all treatments respectively compared with the value of 0.65mm at the beginning of the experiment. Soil bulk density was effected by alternate and saline water treatments, the values were 1.33 and 1.39 Mgm . m-1 respectively compared with the value of 1.30 Mgm . m-1 at the beginning of the experiment, while the bulk density of the river water treatment was not effected.The saturated hydraulic conductivity effected by the irrigation treatments, it was 3.263 , 2.547 and 1.677 cm . hr-1 for all treatments respectively compared with 3.30 cm hr at the beginning of the experiment. The soil penetration effected by irrigation treatments. It was found that the values were 1.61, 1.82 and 1.93 Kg . cm-1 for all treatment at 25% moisture level compared with the value 1.40 Kg . cm-1 at the beginning of the experiment. Mulching did not appears any significant difference in mean wet diameter, hydraulic conductivity and density, but significant difference in penetration

10

Authors: Ayad H. Abbas Ahmed S. Muhaimeed

Water content of the surface horizon & root zone is a main key for any agriculture, hydrological & environmental issues, for this reason, big concern has been dell with statues & amount of soil water by many different ways, which remote sensing technique is one of it. To know the possibility of using remote sensing to investigate soil water parameters, relationships between remote sensing data taken by landsat satellite (ETM+) and some soil water content parameters has been studied for ten soil units selected from north Kut project located at the left of Tigris river, which showed different soil status. The aim of this study was to build statistical models to predict some soil water content parameters using Remote Sensing & GIS techniques. The results showed that there were significant relationships between remote sensing data and the field data of each of available water “as volume θv & mass θm percentage”, water saturation percentage θs and field soil moisture for the surface horizons of the tested sites with coefficient of determination (R2) values: 0.986; 0.989; 1.000 and 0.962 respectively. Fittings (R2) values for predicted and tested parameters were: 0.923; 0.889; 0.998; and 0.946 respectively which revealed that it is possible to use remote sensing data to predict soil water content parameters because of the direct effect of soil water on electromagnetic energy reflection from soil surface. Its a good chance to produce digital soil water content maps with high coverage area that can use in the geospatial software’s to predict and build many water relations for the soil – plant – atmosphere continuum .

12

Authors: Salloom B. Salim Lurna S. Kudayr

To determine the contribution from a shallow water table to the evapotranspiration process over the growing season or wheat under different depletion rates and Irrigation depth, a field study was carried out during 2008/2009 at the field of the College of Agriculture Baghdad. Three levels of depletion rates %50, %70, and %90 from available moisture and three Irrigation depths of the effective root zone, 0-30 cm from planting to the end of growing season, 0-30 cm from planting to flowering stage then 0-60 cm from flowering stage to the end of growing season and 0-60 cm from planting to the end of growing season. Amount of Irrigation water was applied to satisfy water depletion in soil over the grawing season. 'Water content deficit was determined by gravimetric method. Calculated water content deficit was based on measurements of soil water content by gravimetric method. Contribution from the water table during each Irrigation was calculated from changes in water content and hydraulic head measured before and after Irrigation for each layer between the end or root zone and the water table. Flux calculation was based on Richard equation and similar to Salim(2003) approach. It was found that at %50 depletion rate from available moisture water table contributed 78, 69, 25 mm during growing season which consitituted %17.6 , %14.5 , %4.7 from the total evapotranspiration for the 0-30 cm, 0-30 then 0-60 cm and 0-60 em irrigation depths, respectively. At (%70 depletion from available moisture water table contributed 87, 74, 33 mrn which consitituted %J20.0, % 15.8, %6.4 from total evapotranspiration for 0-30 cm, 0-30 then 0-60 cm and 0-60 cmirrigation depths, respectively. At %90 depletion (rom the available moisture water table contribution 93,79, 37 mm which consititutcd %20.8, %17.0, %7.2 of the total evapotranspiration for 0-30 cm, 0-30 then 0-60 cm and 0-60 cm irrigation depths, respectively. Results of this study showed that contribution of the water table increased with increased depletion rate of the available water in the root zone. Higher contribution from the water table occurred under 0-30 cm irrigation compared with 0-30 cm, 0-30 then 0-60 cm and 0-60 cm irrigation depths. Lower matric suction values were obtained at 0-30 cm due to evaporation and transpiration process resulting in higher gradient values.

12

Authors: H.W. Al - Jutheri N.S. Ali

Three field experiments were conducted on a fields at Babylon Governorate in a silty clay loam soil to study the effect of integrated application of mineral and organic-bio fertilizers under different irrigation systems (furrow , sprinkler , and drip irrigation) on potato tuber productivity and water use efficiency ( WUE) .Treatments included three rates of mineral fertilizers 0,50,and 100% of (300 KgN.ha-1+100 Kg P. ha-1) ,10 Mg ha-1 organic fertilizer (organo fert.), 950 Kg ha-1 bio fertilizer(Al-Muaferbio), organic+ bio fertilizers, and control treatment(without neither organic nor bio.). Results indicated that 100% rate of mineral fertilizers +organic-bio gave the highest tuber yield and and WUE. Mineral fertilizer (100%) increased tuber yield by 38,47, and 49% compared to the control (0 mineral) for furrow, sprinkler and drip irrigation systems respectively. Besides, this treatment (100% rate of mineral fertilizer) resulted in WUE of 7.17, 10.81, and 24.39 Kg m-3 for furrow, sprinkler and drip irrigation systems, respectively.Organic fertilizer , bio fertilizer and bio +organic fertilizers increased tuber yield productivity by (32.9,56.0,&78.8% ),(29.3,50.3,&73.8% ) and (27.6,46.5,&64.7%) for furrow, sprinkler and drip irrigation systems , respectively. Furthermore, Bio + 50% mineral fertilizer or organic fertilizer application gave potato tuber yield similar to 100% rate of mineral fertilizer. Therefore, it can be concluded that bio or organic fertilizers can partly substitute mineral fertilizers.

14

Authors: Ali J. Kadhim

The soil hydraulic characteristics , the soil water content and unsaturated hydraulic conductivity are essential to many agriculture and environmental applications. There are many important methods to estimate the soil water content and unsaturated hydraulic conductivity (K), and used this technique to predict the equation parameters (θr ,θs , α ,m ,n). Three models( van Genuchten – Mualem m= 1-1/n , van Genuchten – Burdine m=1-2/n and Brooks & Corey n→∞) were fitted with soil moisture retention data using RETC Code .The RETC code was developed at US salinity laboratory and it used world –wide in many papers at now. Method this program allows to compare three models from the input of moisture retention curve data. In this study , calculated three relationship water content vs pressure head , relative unsaturated hydraulic conductivity with water content and pressure head respectively .And , used various closed – form analytical models for predicting the hydraulic conductivity. Van – Genuchten derived equation Mualem (1976) with a new model for predicting from the soil water retention curve . Equation Mualem's derivation leads to a simple integral formula for predicting the unsaturated hydraulic conductivity. The three model gave an excellent description of soil moisture data with van Genuchten , Mualem model (m=1-1/n) being superior over the other models having the highest coefficient of determination R2 =0.9843 and lowest sum of squares of residual SSQ = 0.0031 .

17

Authors: J.N. Abdul-Rahman A.H. Al-sheikhly

A field experiment was performed to study the effect of irrigation interval, irrigation level and emitter discharge on infiltration rate in clayey soil, which was planted with okra by using drip irrigation system. The study was designed as a factorial experiment within split-plot design using RCBD in three replicates, A(irrigation interval) was put in main plots and combination between B(irrigation level) and C ( emitter discharge) was put in sub-main plots. The results showed a decrease in infiltration rate and accumulative infiltration at the end of growing season in all treatments in comparison with infiltration rate and accumulative infiltration before planting. Decreasing ratios were 58.7% - 63.7 and 60% - 64% for 3 days and 5 days irrigation interval treatments, respectively. The values of cumulative infiltration were15.5 – 17.3 cm and 14.9 – 16.7 cm for 3 days and 5 days irrigation interval treatments , respectively . the results showed a decrease in the infiltration rate (i) of 5 days irrigation interval in comparison with 3 days irrigation interval . Bulk density of soil profile (0 – 50 cm deep) increased at the end of growing season for all treatments in comparison with their values before planting. Increasing ratios of bulk density for treatments irrigated every three days (3 days irrigation interval) were 10.2% - 12.4% . On the other hand, the increasing ratios of bulk density of soils of the treatments irrigated in 5 days interval, were 11.7% – 14.6%. Saturated hydraulic conductivity (Ks) (as soil profile depth average) decreased in treatments of 3 and 5 days irrigation intervals in comparison with hydraulic conductivity of soil profile befor planting. The decreasing ratios of Ks were 64.7% - 68.9% and 66.6% - 69.9 for both irrigation intervals, respectively. Mean weight diameter decreased at (0 – 30 cm deep) of soils treatments in comparison with MWD values befor planting. The decreasing ratios ranged from 4.4% - 19.6% and 8% - 36.1% in irrigation intervals of 3 days and 5 days, respectively . The values of sorptivity (S) were 0.194 – 0.243 cm min -½ and 0.177 – 0.233 cm min -½ for 3 days and 5 days irrigation interval treatments . The results showed a decrease in (A) values in comparison with Ks .