Surface Drip Irrigation System Research Articles

THE ROLE OF COMPOST AND WATER STRESS AND THE SYSTEM OF SURFACE AND SUBSURFACE DRIP IRRIGATION VEGETATIVE AND PLANT GROWTH CHARACTERISTICS OF POTATO PLANT

A field experiment was conducted in Ramadi, Anbar province, western Iraq, in soil with a Silt Loam soil during the autumn season 2018, to study the role of compost, water stress and the surface and subsurface drip irrigation system. 50, 75 and 100% of the net irrigation depth. In the design of the splintered splinters, the transactions were divided according to the design of the complete random sections and by three replicates. Each sector was divided into two main parts, in which the compost was distributed. 1 - Without adding 2 - Addition of 10 tons’ e- 1. Each was divided into two secondary pieces. 2. Sub-surface irrigation Each secondary subdivision was divided into three sub-sub-sections as experimental units where irrigation levels 50, 75 and 100% of the net depth of the irrigation were distributed. Use the American Type A evaporation pond at the irrigation time. The results showed that the level of addition of 10 tons e-1 led to a significant increase in all indicators of the study number of air legs and paper area and the weight of the tuber and the number of tubers and the marketable and the total number of 2.38 stem plant -1, 72.75 dm 2, 124.2 g and 4.84 darn plant - 131.46 tons e-1 and 42.95 tons e-1 sequentially. The average number of air stems, paper area, weight of tuber, number of tubers, marketable value and total yield of potato plant at the irrigation level were significantly higher than 100% of the net depth of the broth, reaching 2.41 stem plant-1, 65.92 dm 2, 136.7 g, 4.89, Ton e-1 and 42.55 tons e-1 sequentially. The average number of air stems, paper area, weight of tuber, tubers, marketable, and total of subsurface irrigation was also higher than 2.34 stem plant -1,68.04 dm 2, 147.7 g, 4.79,32.39 tons e-1, and 42. 13 tons e-1 sequentially, genotype and seed priming in improving seedling performance to tolerate salt stress.

Utilization of aquaculture drainage for enhancing onion crop yield under surface and subsurface drip irrigation systems

The main objective of the present study is to improve onion crop yield using aquaculture drainage under surface and subsurface drip irrigation systems. Field experiments are carried out on onion crop under conditions of two different water resources (groundwater and aquaculture drainage), two types of filters (screen filter for groundwater, while screen, sand and combined screen-sand filters for aquaculture drainage) and four different pressures (1.0, 1.2, 1.4 and 1.6 bar). The performance of the tested drip irrigation systems is evaluated based on filtration efficiency, discharge reduction, application efficiency, emitters clogging, emission uniformity, onion yield and water-use efficiency. The obtained experimental results show that irrigation with aquaculture drainage gives the highest onion yield of 19.17 Mg/fed for surface drip irrigation and 17.03 Mg/fed for subsurface drip irrigation compared to groundwater, which gives 17.55 Mg/fed for surface irrigation and 14.20 Mg/fed for subsurface irrigation. Surface drip irrigation achieves the lowest emitter clogging (5.98 % for groundwater and 5.86 % for aquaculture drainage) and the highest emission uniformity (90.22 % for groundwater and 89.91 % for aquaculture drainage) in comparison with a subsurface drip irrigation system that gives the lowest emitter clogging (7.98 % for groundwater and 7.55 % for aquaculture drainage) and the highest emission uniformity (91.04 % for groundwater and 90.54 % for aquaculture drainage) at 1.6 bar pressure. It is recommended to use aquaculture drainage for operating surface drip irrigation systems under pressure of 1.4 bar, using combined screen-sand filters for aquaculture drainage filtration, while screen filter for groundwater filtration.

Surface and Subsurface Drip Irrigation Improving to Cultivate Fennel Plants at Old Land in Nile Valley of Egypt

The object of this study is to improve irrigation system in the old land in Nile Valley in Egypt to diminish the water lost in irrigation process by using the systems of Surface Drip Irrigation (SDI) and Subsurface Drip Irrigation (SSDI). The research also, study the effect of previous systems and drought stress on Fennel growth, yield, essential-oil and and some chemical constituents in two successes seasons. The results showed that in both seasons, SSDI irrigation system increased all characters of vegetative growth, seed yield and essential-oil percentage and yield, compared with the obtained with SDI system. The results also pointed to drought stress inspired a significant decline in all of the growth parameters and the yield of essential-oil at compared with control in SDI system, while the opposite occurred in the SSDI system where 85 % from ETp treatment gave the highest values in growth and essential-oil compared with other treatments. The water productivity (kg/m3) in SSDI system gave the highest values under the same conditions especially at85% of total water applied, in both seasons. Fifteen essential-oil components were recognized about99.81-99.95 % of total contents of essential-oil. The major essential-oil components were Estragol (71.12-75.80 %), D-Limonene (10.18-15.16 %), and Fenchone (5.46-11.45 %).The percentages of these compounds unclear affected by irrigation system and water applied treatments.

PERFORMANCE FIELD EVALUATION OF DRIP IRRIGATION SYSTEMS UNDER CONDITIONS OF THE DESERT REGION IN WESTERN IRAQ

A field experiment was carried out at Al-Saqlawiya township Al-Anbar governorate at north in latitude 33°24´57" and east longitude 43°41´23", during period from 15/10/2018 to 15/1/2019 in order to evaluate the performance of 5 units of surface drip irrigation system, components and periods of use, by the steps recommended by the American Agriculture Engineers Association, at 50 kPa operational pressure. Results showed that there was a disparity in values of emitters actual discharge, uniformity coefficient, emission uniformity and variation percent of discharge. Although the similarity of most measurement conditions such as land area, design, management and the operational pressure except of the periods of using these systems which ranged 2-5 years. The decrease percent of actual discharge values 8.06%, 8.74%, and 19.04% when comparing the actual discharge for the system 1 with the values of systems 2,3 and 4, respectively. While the increase percent of the actual discharge value reached 29.74% when comparing of system 1 with system 5. Uniformity coefficient of system decreased were 5.32%, 19.95%, 3.81% and 7.21%, respectively, and 10.73%,37.25%,7.51% and 14.36% for the decrease percent of emission uniformity comparing the system 1 with the systems 2, 3, 4 and 5, respectively, as for the increase percent for the variation emitters discharge, it were 7.70%, 118.73%, 7.70%, respectively. Non- compliance of users of these systems with regular maintenance of the end of agriculture seasons, poor storage conditions, not maintained at high temperature or cold conditions and increase use periods, all had caused the expansion of emitters' holes, which affected negatively in some values of the followed evaluation standard.

Effects of treated greywater irrigation regimes and mulches on yield of Capsicum chinense under surface drip irrigation system

A field study was conducted to determine the effects of combine treatment of greywater application rates and mulches types on growth and yield of Capsicum chinense in Omu-Aran, Nigeria. Greywater (GW) was treated using a pilot-scale horizontal sub-surface flow constructed wetlands (HSSF CW) vegetated with Canna indica plants. Four irrigation levels (60, 80, 100 and 120% of ETc) and four mulches types (Black plastic film BM, Silver plastic film SM, Rice straw RS and un-mulched Control) were applied to the potted plants. The experiment was laid out in a split-plot design, with main plots as irrigation levels and mulches types as sub-plots. C. indica plants were found to be effective in GW Phytoremediation treatment in CW. The maximum fruit yield was observed for T10 (I100SM) 4666.70 kg/ha due to reflective mulch ability to increase light and heat to plant resulting to a higher yield. Significant difference was observed between the mean yield of I60 and other irrigation regimes, whereas between I80 to I120 there was no significant difference in mean yield recorded. Silver mulch combined with full irrigation with treated greywater effluent was found to be the best of all treatments in the study.

Studies on sustainable sugarcane initiative (SSI) technology in north eastern agro climate zone of Tamil Nadu

Field experiments were conducted at North-eastern Agro Climatic Zone of Tamil Nadu to find out the influence two methods of sugarcane cultivation on cane productivity. The experiments were conducted in farmer’s holdings in hands with sugar factory during 2012 to 2014. Each experimental plot is large sized with more than 0.40 ha non- replicated with sub surface drip irrigation system. The results indicated higher plant height at harvest stage under SSI method (276cm) than conventional system (Sett) of sett planting (247cm).Study found that sugarcane yield was higher under SSI method (143 t ha-1) as compared to conventional method (126 t ha-1) in main crop. Likewise, SSI registered higher sugar yield (15.30 t ha-1) than conventional system (11.48 t ha-1). Total water consumption and water productivity of SSI method showed less water consumption of 1669 mm and more water productivity of 8.57 kg/m3 as compared to conventional system of planting (1787 mm and 7.04 kg/m3 respectively).SSI method of crop establishment also recorded Rs.33,100 as additional income than conventional method with a B: C ratio of in the main crop of 1.97 and 1.80 respectively. Similar trend was also noticed in sugarcane ratoon crop yield, water productivity and net profit.

Evaluation of fertigation management impacts of surface drip irrigation on reducing nitrate leaching using numerical modeling.

The objective of this study was to investigate the impacts of fertigation strategies on nitrate leaching and its uptake into maize plants. Field experimental data were employed to calibrate a numerical model (HYDRUS 2D/3D) for a surface drip irrigation system in a sandy clay loam soil. The calibrated model was used to simulate nitrate plant uptake and its leaching in different fertigation scenarios based on various fertigation durations and different start times of fertigation. Finally, nitrogen plant uptake was compared with maize N requirement during growth stages in two fertigation frequency scenarios. These simulations were also performed in sandy loam soil. The results show that, if fertigation is done at the end of irrigation, nitrate leaching in shorter fertigation duration will be less than the leaching in longer fertigation duration. However, in the case of fertigation at the beginning of irrigation, the nitrate leaching is higher if the fertigation duration is short, and vice versa. Furthermore, reducing the number of fertigation events in the sandy clay loam soil increases the nitrate plant uptake. However, in the sandy loam soil, a lesser number of fertigation events reduce nitrate uptake.

Effect of different sand filter underdrain designs on emitter clogging using reclaimed effluents

Sand media filters are those that achieve a higher retention of organic and inorganic solids, which is why they are usually recommended when reclaimed effluents are used in drip irrigation systems. Sand filters usually differ on the design of their underdrain, where an important pressure drop is produced. However, the effect of the design of sand filter underdrain on emitter clogging has not been widely studied. Three sand media filters with different underdrain designs (collector arms, inserted domes and drainage with porous media) were used for filtering a reclaimed effluent in a surface drip irrigation system. Pressure-compensating emitters with 2.3 l/h nominal emitter discharge were placed every 40 cm in 4 irrigation laterals each measuring 90 m in length. Effluents were chlorinated after being filtered. The filters operated for 1000 h with sand media heights of 20 and 30 cm and filtration velocities of 30 and 60 m/h. At the beginning, after 500 h, and at the end of the experiment the emitter discharge of each one of the 2712 emitters that were installed was experimentally measured under field conditions. On average, there was a statistically significant reduction (p < 0.05) on emitter discharge regarding the initial value of 8.03% at 500 h and 10.84% at 1000 h. Emitter clogging was primarily affected by the interactions between underdrain design, emitter location and irrigation time. Differences on emitter discharge due to underdrain design were only observed at 1000 h, showing a significantly higher flow rate (p < 0.05) those emitters protected with the filter with a collector arm underdrain, despite the fact that this filter did not achieve the highest turbidity removals. Emitter location had also a significant effect after 500 h of operation, being discharge significantly lower (p < 0.05) only in the last 2 m of the laterals, with the minimum values found for the final two drippers. The three filters used in the experiment did not show a significant effect on the percentage of completely clogged emitters, which mainly depended on the interaction between irrigation time and emitter location.

ENERGY CONSUMED, WATER PRODUCTIVITY AND VITAMIN (C) CONCENTRATION OF ORANGE CROP UNDER DIFFERENT IRRIGATION SYSTEMS

Food and water consider the key to life. The aim of this study is to increase water productivity and enhancing the quality of the orange crop (Citrus sinensis Osbeck L.). To a chive that aim, four irrigation systems (conventional surface irrigation (SI), furrow irrigation (FI), surface drip irrigation (SDI) and subsurface drip irrigation (SSDI) under heavy soil (clay) at the north of delta Egypt. Soil water content (SWC), soil temperature and soil EC were measured during the growing season under irrigation systems. At the end of the growth season yield and vitamin C were measured for three randomized samples for each treatment. Also, the energy consumed was estimated for each irrigation system. The results shown that the highest values of soil water content at depth 10 cm and along the distance of 200 cm from steam of tree were achieved under SSDI and SDI which increased SWC by 1.7 % and 1.2 % than SI, respectively and the lowest values of SWC was obtain at FI which decreased by 13.2 % than SI, while, at depth 50 cm the highest values of SWC were under SI, applying FI, SSDI and SDI systems decreased the SWC by 16.9 %, 14.7 % and 7.3% than FI, respectively. At depth 100 cm the highest value of SWC was 31.9 (cm3 cm 3) under FI, which increased by 40.2 % than SI, followed by SSDI and SDI by values 27.9% and 7.7%, respectively. Moreover, the results shown that, subsurface drip irrigation system (SSDI) gave the highest orange yield (6.1 Mg fed-1), followed by the surface drip irrigation (SDI) system of 6 Mg fed-1, while the lowest yield was obtained under SI system (5.2Mg fed -1). FI resulted in the higher yield compared with SI (5.4 Mg fed-1) but at the same time, the lower yield as compared with both the SSDI and SDI systems. On the other hand, SSDI system increased the yield by 40.1 %, followed by SDI by 25.8 % and FI by 8.6 % than SI. The highest concentration of vitamin C was 23.4 mg / 100g under SSDI, followed by values 16.83 and 14.52 (mg/ 100g) under SDI and FI, respectively and the lowest concentration was 12.11 under SI. The highest value of consumptive energy was 1044.4 (kwh / fed. season) achieved under SI, followed by 696.3 (kwh / fed. season) under FI and the lowest values were 613.1 and 642.3 (kwh / fed. season) under SSDI and SI, respectively.

Field Evaluating of Wetting Pattern from Surface Drip Irrigation System for Sand and Sandy Loam Soils

Water distribution through soils from trickle source is very important issue since it affects irrigation efficiency, wetted surface area and wetted soil profile. Many attempts to determine wetting pattern under drip irrigation using mathematical and numerical models were carried out. The verification of the validity of which model will be suitable for Iraqi soils need a detailed study. In this paper, the field work measurements of wetted pattern in two Iraqi soils (sand and sandy loam) were conducted to investigate the validity of the application of wetting pattern formulas predicted by Dawood (2016), Amin and Ekhmaj, (2006) and Schwartzman and Zur (1986). The work was divided into two parts: the first one was the laboratory work of soil texture, field capacity, permanent wilting point, and soil porosity. The second one includes field operations through landing, installation of trickle irrigation system, installation of equipment’s and sensors, adjustment of emitter discharge by the valve on the supply pipe. In each run, initial water content was measured and the system was operated for three continuous hours with three different discharges, discharges were selected as 1, 3 and 6 l/hr. the wetted diameter and depth were recorded hourly during each run test .The field measurements of wetted area were compared with that predicted by the previous studies. The obtained result indicate that the value of the wetted diameter and depth increase with increasing of water contents, the wetted diameter are inversely proportional was saturated hydraulic conductivity, and the wetted depth was directly proportional to the saturated hydraulic conductivity. Amin and Ekhmaj 2006 formula was suitable for wetted depth in sandy loam soil with average error 13.40% and Schwartzman and Zur, 1986 formulas gave a good prediction for wetted diameters with average error 12.79% for same soil. Finally Dawood (2016) formulas were more suitable than others for sand soil with average error for wetted diameter and depth 11.49%, 16.79% respectively.

Effect of Deficit Irrigation, Air injection and Nitrogen Fertilization on Water Productivity of Carrot under Subsurface Drip Irrigation System.

A field study was conducted in 2017-2018 to evaluate the effect of deficit irrigation, air injection and nitrogen fertilization on yield and water productivity of carrot under subsurface drip irrigation system. Experimental treatments were three levels ofdeficit irrigation (60%, 80% and 100%) of full crop water requirements and three types of nitrogen fertilizer(nitric acid(HNO3)48 % N, urea CO(NH2)2 46% N and ammonium nitrate(NH4NO3)33.5% N, with air injection treatment (12% air by volume of water). The results show that the yield and water productivity as well as the length of carrot root significantly increased for air injection treatments. On the other hand, the carrot diameter increase was not significant. The highest value of the carrot root yield (19.487 ton/fed) was obtained due to deficit irrigation 60% (I60%) and ammonium nitrate(NH4NO3)with air injection. Also, treatment of deficit irrigation (I80%) and urea fertilization CO(NH2)2 with air injection resulted 17.437 (ton/ fed) carrot roots which was significantly higher than that of non-air injection treatments. Also,the highest values of water productivity of carrot were 185.189 and 101.376 kg/m3obtained due to(I60%) with (NH4NO3)and co(NH2)2underair injection treatments, respectively. The highest lengths of carrot (cm) were 19.800 and 19.000 (cm)obtained due to (I80%) with CO(NH2)2and (I100%) with (NH4NO3), under air injection treatments, respectively. The highest values of carrotdiameter were 42.153 and 41.260 (mm) obtained due to treatment of full irrigation(I100%) and(NH4NO3) fertilizer withoutair injection and the treatment (I80%) and CO(NH2)2 fertilizer with air injection, respectively. Data from this study indicate that carrot yield and its water productivity can be improved byaerated sub surface drip irrigation system(SSDI).

HERBIGATION MANAGEMENTS FOR MAXIMIZING GREEN BEANS CROP PRODUCTIVITY UNDER DRIP IRRIGATION SYSTEM

A field experiment was conducted at the Experimental Farm at Faculty of Agriculture, Ain Shams University (loam soil); to study herbigation managements for maximizing green beans crop productivity under drip irrigation system. Two application techniques were used for weed control with pre-emergence Pendimethalin herbicide (Stomp 50% EC), the first application technique was injection herbicide through drip irrigation systems (surface and sub-surface) with three concentrations (100%, 75% and 50%) of herbicide recommendation dose (1.7 L/ fed) using venture device, secondly by conventional spraying using knapsack sprayer and control without treatment. The results showed that the best water application efficiency was (96%) and the highest value of water distribution uniformity was (95%) achieved with Sub surface-drip irrigation system. The best weeds control efficiency was (82%) achieved with injection herbicide through sub surface-drip irrigation system with 75% - (1.28 L/fed) - of the herbicide recommendation dose in compare with other treatments, which maximized the benefit from the applied herbicides and obtained high productivity and an export product with high quality. According to the obtained results herbigation with sub-surface irrigation system is an excellent method of controlling weeds for the growers with good management.

UTILIZATION CHEMIGATION TO REDUCE PEAS CONTAMINATION WITH PESTICIDE IN NEW RECLAIMED LANDS

the aim of this study is to reduce Peas contamination with herbicide by applying chemigation in new reclaimed lands through drip irrigation systems. The herbicide (butralin) was injected with recommended rate (2.5 Kg/Fed) through subsurface and surface drip irrigation systems with two flow rates of 8 and 12 l/h/m tube under sandy soil conditions in winter and summer seasons 2016. The results showed that the highest productivity of the peas was (5570 kg / Fed) with water use efficiency (WUE) of (2.31 Kg / m3) and more uniformity under the following conditions: the subsurface drip irrigation system at an flow rate of 8 l / h/m – tube (dripper flow rate of 4 l/h) and 50 cm emitters spacing, injection of the herbicide (butralin). It is wearthly to mention that no (butralin) residues were found in Pea yield produced under subsurface drip irrigation systems (10 cm depth), 50 cm emitters spacing and 8 l/h/m flow rate under the manured sandy soil.

Integrating deficit irrigation into surface and subsurface drip irrigation as a strategy to save water in arid regions

Development of sustainable and efficient irrigation strategies is a priority for producers faced with water shortages. A promising management strategy for improving irrigation water use efficiency (IWUE) is deficit irrigation, which attempts to optimize yield and IWUE. Soil water use, crop yield and IWUE of tomato were evaluated for two consecutive years under two types of irrigation methods (subsurface and surface drip irrigation) and three irrigation strategies: 1.0 of full irrigation supply (T1), 0.8 of full irrigation supply (T2) and 0.6 of full irrigation supply (T3). The results showed that the highest yields were found in the plots irrigated by subsurface drip irrigation at T1 (94.1 ton/ha) and T2 (81.4 ton/ha). Conversely, the fully stressed treatment (T3) reduced the amount of irrigation water by 40%, but significantly decreased mean tomato yield by 25.6% and 26.1% under subsurface and surface drip irrigation, respectively, as compared to T1. The maximum IWUE tended to be higher for subsurface drip than for surface drip irrigation system. The greatest IWUEs were obtained from subsurface drip and surface drip at T3 (19.7 kg/m3 and 18.3 kg/m3), whereas the lowest IWUEs were those estimated in T1 (15.9 kg/m3 and 14.8 kg/m3, respectively). The primary conclusion is that deficit irrigation strategies present certain advantages to crop water management with minimal effects on production and quality, thus contributing to crop sustainability.

MAXIMIZING OF SURFACE IRRIGATION PERFORMANCE ON GROWTH AND PRODUCTION OF COWPEA IN CLAY SOIL

Alternate furrow irrigation (AFI) is gaining interest as a mean of saving water while minimizing loss in crop production. Field experiment was conducted in the Experimental Farm, Faculty of Agriculture, Kafrelsheikh University, Egypt, during growing season of 2016-2017. The present work included the following: Irrigation systems (Furrow surface irrigation and surface drip irrigation (SDI)). However, different techniques had been investigated with surface irrigation (alternative furrow (AFI) and conventional furrow irrigation (CFI) with a furrow length of 20, 30 and 40 m. The experiment was designed as split plot with three replications, where irrigation systems used as the main plot and furrow length as sub-plot. The ranges of mean cowpea yield gained from irrigation system were 932.33, 910.52 and 1179.52 kg/fed for CFI, AFI and SDI respectively. The effect of furrow length and their interaction with irrigation system on yield were non-significant but the irrigation system has significant effect on yield (P<0.01). The maximum and minimum yield was obtained at length of 20 m for SDI and length of 40 m for AFI, which were 34.37 kg and 25.26 kg, respectively. The effect of irrigation system on the water use efficiency (WUE) was significant (p<0.01). The average WUE was decreased from 11.57 to 8.10 kg/m3 when the furrow length increased from 20 m to 40 m. The range of mean values of WUE due to the effect of furrow length from 20 to 40m was highly significant (P<0.01) only. The average of WUE was increased from 5.81 to 9.87 and 13.41 kg/m3 for CFI, AFI and SDI systems, respectively. The highest and lowest values of irrigation depth (ID), water application efficiency (WAE), water distribution efficiency (WDE) and applied water (AW) were 17.65-10.12cm, 75.25-52.46 %, 73.37 -36.45% and 61.20.

English

English

Deficit irrigation and irrigation methods as on-farm strategies to maximize crop water productivity in dry areas

AbstractAn in-situ field study on two types of irrigation methods and three irrigation regimes was conducted in a sandy loam soil located at King Saud University, Riyadh, Saudi Arabia in 2015 and 2016. The study was to assess the effects of different irrigation methods on physiological and yield responses of tomato crops under water shortage conditions. The tested irrigation methods were surface drip irrigation (SDI) and subsurface drip irrigation (SSDI) systems. Irrigation treatments consisted of three strategies: (1) plants were irrigated with a water depth of 100% of the full irrigation supply; (2) plants were irrigated with a water depth of 80% of the full irrigation supply; and (3) plants were irrigated with a water depth of 60% of the full irrigation supply. Results indicated that water shortage significantly affected yield and quality response for each season. Over a 2-year average, yield increase was greatest in T1-SSDI followed by T2-SSDI and then T1-SDI. The yield response factor was 0.95 and 1.05 for SSDI and SDI, respectively. The highest water use efficiency values were obtained in T2-SSDI (16.3 kg m−3) and T1-SSDI (15.6 kg m−3), and the lowest ones, those estimated in T1-SDI (10.9 kg m−3) and T3-SDI (9.5 kg m−3).

Simulating Soil Water Content under Surface and Subsurface Drip Irrigation with Municipal Wastewater

The demand of wastewater for irrigation is gradually increasing due to escalatingcompetition for freshwater by urban, industrial, and agricultural users. To sustain or increase agricultural production, there is a need to adopt highly efficient irrigation technologies such as surface or subsurface drip irrigation systems. Studies related to water distribution under any irrigation system and water quality are important for efficient water and nutrients application. In present study, the water dynamics under surface and subsurface drip irrigation was evaluated by taking cauliflower as a test crop on sandy loam soil. The calibrated model predicted all the parameters close to observed values with RMSE values ranging from 0.05to 0.92. HYDRUS -2D model has ability to predict water distribution with reasonably good accuracy in present crop and soil condition.

THE EFFECT OF WATER STRESS ON NITROGEN STATUS AS WELL AS WATER USE EFFICIENCY OF POTATO CROP UNDER DRIP IRRIGATION SYSTEM

Water and nitrogen management, rate and timing of application are critical factors in optimizing potato tuber yield and quality. This study was conducted to determine the effect of water stress and nitrogen fertilizer levels on canopy water content (CWC), soil water content (SWC), nitrogen uptake, SPAD values, water use efficiency (WUE) and potato yield. Water treatments concluded fully irrigated and water stress. While, nitrogen levels were (N0, N50 and N100). Surface drip irrigation system was used to provide irrigation water requirements. Treatments were irrigated when 35 % of available soil moisture was consumed in soil profile depth. For nitrogen levels (N0, N50 and N100) at water stress conditions, the percentage of irrigation water saved was 11.47 % led to decrease the tuber yield with 31 %, 13.94 % and 25.25 %, respectively.SPAD values were highest in water stress and lowest in the control. In addition, SPAD values were in a positive linear relationships with water and nitrogen treatments as a coefficient of determination with very high (R2= 0.99 and 0.99), respectively. Also, increasing the nitrogen dose led to the increase the nitrogen uptake values.Moreover, nitrogen uptake presented a linear relationships with water regimes at nitrogen levels (0.96 and 0.97), respectively. Also, SPAD values presented linear relationships with nitrogen uptake at well water controlled, stressed and nitrogen levels(R2= 0.99 and 0.99). In conclusions, there were obvious effects of water stress on CWC, SWC, nitrogen uptake and WUE. On the other hand, canopy water content and soil water content could be used to predict potato WUE and yield.

WATER MANAGEMENT AND IMPROVING NITROGEN USE EFFICIENCY UNDER DRIP IRRIGATION SYSTEM FOR MAIZE PRODUCTION ON SANDY SOIL

Agriculture in the semi-arid region of Egypt is highly dependent on irrigation. The water is limited in this region and the prices of mineral fertilizer are exaggerated increases the needed to optimize its efficient use, especially in small-scale farming schemes. Thus irrigation management should be directed towards maintaining optimum moisture and nutrient concentrations within the root zone. If this objective is achieved, crops will take up their maximum amounts of water and nutrients with minimum wastage. Two field experiments, were conducted during summer 2013 and 2014 under surface drip irrigation system at Ali Mubarak experimental farm, El-Bustan area (sandy soil) toevaluate the rates of irrigation water (100% and 75% of ETp ) with Nitrogen applications forms (Urea 46%, Ammonium Sulphate 21% and Ammonium Nitrate 33.5%) compared with the recommended dose (120 N units fed-1) to obtain a formulate interaction among them, which realize the best strategy practices to get the optimum production of maize (Zea mays L.), nitrogen use efficiency and water productivity. The experimental treatments were tested using a split plot design, with three replicates. The main results could be summarized as follows: The highest grain yield (4.12Mg fed-1) was obtained in treatment (100% of ETp × Ammonium Sulphate form). The maximum value of Nitrogen Use Efficiency (NUE) (20.58 kg grains / unit of N applied) and the minimum one was (9.32 kg grains / unit of N applied) were obtained in the following interactions among Ammonium Sulphate and (100% of ETp ) or (75% of ETp ), respectively. The values of Water productivity (WP) were increased with addition the recommended doses of Nitrogen (N) while increased by 103.8%, compared with the control. There are insignificant differences among application of N fertilizer forms on the most studied parameters. Although, the Ammonium Sulphate form consider the best N forms which gave the highest values of the most studied parameters compared to Ammonium nitrate and Urea .