الفهرس 
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Abstract
Two field experiments were conducted during the two successive seasons in Hamoul District, Kafr El-Sheikh Governorate (4 m altitude, 31 42 53- latitude and 31 07 40- longitude) aiming to ”evaluate of using some modern irrigation techniques to improve surface irrigation technique and its effect on nitrogen use efficiency ”A split plot design with three replicates, were used which the main plots was devoted to irrigation treatments i.e.I1- The traditional furrow irrigation technique (all furrows were irrigated)-I2- Alternate furrow irrigation technique (irrigating furrows and left the other furrow)-I3-Gated pipes technique (all furrow were irrigated) -I4- Gated pipes technique (irrigating furrow and left the other furrow),andSub plots were assigned to nitrogen fertilization treatments: N1-The control treatment (0 Kg N Fad-1)-N2-Application the 75% of the recommended dose - N3- Application the recommended dose (135 and 90 Kg N Fad-1) for maize and sugar beet crops respectively.Traditional surface irrigation is used in most of field crops at North Delta as a conventional practice of irrigation at the Egyptian farmers. Developed surface irrigation using gated pipes and alternative furrow irrigation are new methods to be used for irrigation not only in the new land but also in Nile Delta and Valley areas as strategy based on water saving . This tendency is very important because Egypt is suffering from water poverty and high price of nitrogen fertilizers.These irrigation techniques and nitrogen fertilization treatments were applied on maize crop (Sakha 324) in summer growing season 2008 and sugar beet (fareda variety) in winter growing season 2008 / 2009.The results obtained from this investigation can be summarized as follows:5.1. Water applied, stored and Saved with different irrigation techniques: There were clear effect of furrow irrigation techniques on water applied , stored and consumed . The depth of the applied water to maize were 81.5, 68.3, 65.6 and 55.9 cm for traditional surface all furrows (I1) , alternate furrow irrigation (I2) , gated pipes all furrows (I3) and gated pipes alternate furrow (I4) , respectively . , while the depths of water applied to sugar beet were 82.8, 66.2, 64.9 and 51.1cm, for I1, I2, I3, and I4 techniques, respectively.The average depths of water stored in the effective root zone of maize crop are 57, 45.1, 48.6 and 40.2 cm with irrigation techniques of I1, I2, I3, and I4 techniques, respectively. Meanwhile, the highest amount of water stored under maize crop is 57 cm for traditional surface all furrows technique compared with the lowest amount of 40.2 cm for I4 technique. Under sugar beet crop, the average depths of water stored in the effective root zone are 56.9, 40.3. , 47.7 and 34.7 cm for I1, I2, I3, and I4 techniques, respectively. It means that the highest amount of water stored in sugar beet field (56.9 cm) is obtained with I1 technique (control), while the lowest amount of water stored under sugar beet (34.7 cm) is found with I4 technique. Concerning water saving ,under maize crop , using gated pipes method saved more water (31.4 %) , whereas, the traditional alternate furrow irrigation (I2) realize less percentage of water saving (16.2 %) as compared to traditional surface all furrows technique . With regarding to water saving under sugar beet crop, also the highest amount of water saving (38.3 %) was achieved under (I4) treatment , while the lowest one was recorded under (I2) traditional alternate furrow irrigation (20 %). 5.2. Soil moisture extraction patterns: The most moisture extracted by maize and sugar beet roots was within the upper 15cm soil layers and then, it decreased gradually in the deeper layers. The extraction of the soil moisture from the surface layers more than extraction from deepest layers by maize roots with the gated pipes technique which is slightly lower than those recorded with the traditional technique in the deepest layers. 5.3. Water consumptive use as affected by furrow irrigation techniques:The water consumptive use increases with traditional surfaces all furrows (control) technique to the maximum value (54.5 cm), while the minimum value is recorded with I4 technique (39.3 cm.Water consumptive use is affect markedly with increasing nitrogen dose. where the highest value was detected under the recommend dose and I1 while, the lowest one was detected with zero nitrogen and gated pipes I4 for maize and sugar beet crop.4.4. Water application efficiency (WAE) with maize and sugar beet:The highest irrigation application efficiency (74.1%) is achieved by gated pipes for all furrows technique while the lowest value (66.1%) was obtained with the traditional irrigation technique with maize crop. With regard to sugar beet, the values of water application efficiency took the same trend of maize crop.5.5. Moisture distribution efficiency:Using gated pipes all furrows technique (I3) achieved the highest water distribution efficiency (96.04 and 97.2%) under maize and sugar beet, respectively followed by traditional surface irrigation all furrows technique (I1). whereas, the traditional alternative furrow irrigation (I2) achieved the lowest DE values for maize and sugar beet.5.6. Water use efficiency with maize (FWUE and CWUE): The obtained results reveal that the highest value of FWUE (2.01kg grain m-3) was obtained under (I4) and recommended dose of nitrogen (N3). Meanwhile, the lowest value of FWUE (1.25 kg grain m-3) was achieved by the control (I1) under (N3). The highest value of CWUE (2.7kg grain m-3) was achieved under (I4) and (N3), while the lowest one (1.84 kg grain/m3) was recorded with control (I1). It can be observed that the values of CWUE and FWUE gradually increased with increasing nitrogen dose up to 135 Kg fed-1 (N3).5.7. Water use efficiency of sugar beet (FWUE and CWUE): The furrow irrigation techniques highly significantly effected on water use efficiency with roots and white sugar yields. The highest values of FWUE and CWUE for root and white sugar yields were achieved with I4 and N3 while the lowest of both efficiencies for roots or white sugar yield were recorded with I1 techniques and all levels of N application. 5.8.Yield and Yield components: 5.8.1. Maize crop: 5.8.1.1. Maize Yield: There was insignificant effect of irrigation techniques on maize yield. Using gated pipes technique all furrows recorded the highest reduction in grain yield but not insignificant (-6.25 %) as compared to control treatments (I1). These results showed a positive relation between the yield and water applied with each irrigation technique .Increasing nitrogen application levels increased grain and stalk yield of maize. High significant effect is detected on maize yield due to nitrogen fertilization, where the highest grain yield ( 4642 Kg Fed-1 ) is attributed with the highest nitrogen application dose (N3). Grain yield is increased by about 110.9 % and 85.5% for N3 and N2 compared to N1 treatment, respectively. Stalk yield took the same trend of grain yield, where the mean values of stalk yield increased by about 52.3 and 71.3 % for N2 and N3 compared to N1, respectively.The influence of interaction between irrigation treatments and nitrogen fertilization on grain yield was significant for grain yield but insignificant for stalk yield. It can be observed that (I4) achieved the highest grain and stalk yield followed by (I3) under the highest nitrogen application level. 5.8.1.2. Growth parameters: There is significant effect due to irrigation techniques on ear length, plant height, leaf area, First silk and 50% of silk appearance. The ear length with different irrigation techniques can be arranged according to the following descending order: I2 > I1 > I4> I3. The highest mean value of plant height is achieved with (I1) followed by (I4). While the lowest ones are recorded by I3 and I2. The highest mean value of leaf area is obtained under (I4) followed by (I2), while the lowest one was recorded with (I3). But, there is no significant effect for irrigation techniques on ear diameter, 100-grain weight, Chlorophyll and harvest index.Also, nitrogen treatment show high significant effect on ear diameter, ear length, 100-grain weight, plant height, leaf area, Chlorophyll, harvest index, appearance of first silk and 50% of silk which increased with increasing N level up to the recommended dose .The interaction effect between irrigation techniques and nitrogen fertilization rates is significant on ear length, ear diameter, plant height, harvest index, appearance of first silk and 50%. The highest mean value on ear length is obtained under I2 and N3 whereas, the lowest one is detected under I4 and N1. The best treatment for ear diameter was found with N3 under I4 followed by I3. The highest value on maize plant height is achieved by the combination between (I4) and N3. The highest value on harvest index is achieved by the combination between I4 and N2 or N3. The early silk was appeared with gated pipes alternative furrow (I4) and application of recommended dose of nitrogen. The gated pipes alternative furrow (I4) and application of recommended dose of nitrogen (N3) recorded earliest date of 50% silk whereas, I3 and N1 delayed appearance of 50% silk date by about 13 days.There is no significant effect for interaction between irrigation techniques and nitrogen fertilization on100-grain weight, leaf area and Chlorophyll content is not significant.5.8.2 Sugar beet crop: 5.8.2.1. Sugar beet yield (roots, top and white sugar): The yield of roots was insignificantly affected by irrigation techniques. The yield of top and white sugar was highly significantly affected by irrigation techniques. Gated pipes technique produced the highest yield of the roots, shoots and white sugar. Nitrogen treatments exhibited high significant effect on roots, top and white sugar yield. The mean value increased by increasing N level up to the recommended dose. The interaction effect between irrigation methods and nitrogen levels had insignificant relation on root yield and white sugar yield. , While significant relation was found on top. The best treatment was found with the combination between recommended dose of nitrogen and using alternative furrow irrigation with gated pipes I4.5.8.2.2. Growth parameters: There is significant effect due to irrigation techniques on root length, root diameter and (T.S.S.). using of gated pipes for irrigation all furrows or alternative furrows technique leads to elongate the sugar beet roots , while using of (I1) technique result in shortening the roots. Alternative furrow (I2 or I4) irrigated by traditional or gated pipes attained higher values of root diameter. The highest TSS value (19.55 %) was obtained under gated pipes all furrows (I3) followed by I4, while I1 gave the lowest TSS value (17.38 %).There is no significant effect for irrigation techniques on total plant dry weight, leaf area index and chlorophyll.Also, nitrogen show high significant effect on root length, root diameter, total plant dry weight, leaf area index and chlorophyll which increased with increasing N level up to the recommended dose. but (T.S.S.) decreased with increasing N level up to the recommended dos.The interaction effect between irrigation techniques and nitrogen fertilization rates is significant on root length and root diameter. The highest mean values were achieved under alternative furrow irrigation neither surface or gated pipes and the highest level of N application. The highest mean value was achieved under gated pipes alternative furrows (I4), and the recommended dose of nitrogen. 5.8.2.3. Sugar beet purity and quality: The obtained results showed a slight effect of irrigation techniques on K, α-amino N, sugar loss to molasses percentage (SM) and alkalinity coefficient (%) in root juice. Bat Na contents, sucrose percentage, purity percentage of juice extractable sugar (%) and extractability were significantly affected. The highest mean value of Na contents was recorded under I2 treatment followed by I1. whereas, the lowest one was recorded under I4. Gated pipes irrigation techniques (I3) resulted in the highest quality level (85.6 %) followed by I1 and I4, while the lowest juice quality is recorded with I2 technique (79.32%) Regarding nitrogen fertilizer levels, data exhibited highly significant effect .The mean values of K, Na, α-amino-N contents (meq/100g) and sugar loss to molasses percentage (SM) increased with increasing N level up to recommended dose. But the purity, Sucrose percentage, extractable sugar and extractability increased at the low levels of nitrogen fertilizer .There is no significant effete of irrigation techniques or nitrogen fertilizer and their interaction on alkalinity coefficient of sugar beet juice.The interaction effect between irrigation methods and nitrogen fertilizer was significant on Na content in sugar beet juice .the highest mean value was recorded by alternative furrow (I2) and recommended dose of nitrogen.On the other hand, there is no significant effect due to the interaction effect between irrigation treatments and nitrogen fertilization on K, α-amino-N contents, alkalinity coefficient (%), purity percentage, sugar loss to molasses percentage (SM), purity, sucrose percentage, extractable sugar and extractability. 5.9- Nitrogen concentration and its uptake:Nitrogen uptake by maize and sugar beet crops highly significantly affected by irrigation techniques. Nitrogen concentration increased in alternate furrow irrigation treatments (I2 and I4) comparing with traditional irrigation treatment (I1). Also, the nitrogen concentration increased with gated pipes (I3 and I4) comparing with traditional irrigation treatment (I1). The mean values of nitrogen concentration in grains were detected with I4 followed by I3. Also, The N concentration in corn stalks and sugar beet (top and root) took the same behavior of grains. Nitrogen concentration and its uptake highly significantly increased in maize and sugar beet with increasing nitrogen application level from 0 up to the recommended dose The interaction between irrigation and nitrogen fertilization on nitrogen concentration and its uptake were highly significant with maize and sugar beet. I can be observed that gated pipes alternative (I4) was the superior irrigation treatment, and this may attributed to less nitrate leaching, and so increasing nitrogen concentration in root zone, resulting in increasing of nitrogen uptake.5.10-Nitrogen use efficiency:Nitrogen use efficiency value is achieved by N2 is higher than the same obtained by N3, in all irrigation treatments. The highest values of NUE were obtained with irrigation by gated pipes for alternative (I4), followed by I1 and the lowest one was detected under I2 irrigation treatment.5.11- Nitrogen recovery %:Nitrogen recovery increased with increasing N level. The highest value of N recovery % was found under gated pipes alternative (I4) and N3 whereas, the lowest one was found under I2 and N3 with maize and sugar beet.5.12- Available nitrogen remained in soil after harvesting with maize and sugar beet. Irrigation treatments caused significant effect on available nitrogen remained in soil after harvesting.Available nitrogen in soil increased with decreasing irrigated furrows, so the arrangement of irrigation technique according to amounts of available nitrogen were I3, I2 and I1, respectively.Increasing nitrogen application rates led to high significant increase in available nitrogen after harvesting. ConclusionUsing gated pipes technique in irrigating alternative furrows under cultivation of maize and sugar beet crops combined with application of nitrogen recommended dose led to improve water and nitrogen use efficiencies, and save more irrigation water without significant reduction in maize and sugar beet yield specially, under limited of fresh water resources and high price of nitrogen fertilizers.