الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 209 |  |  |
| | | from | 209 | | |
Abstract
Two field experiments were conducted during the two successive seasons of summer 2011 and winter 2011/2012 in Hamoul District, Kafr El-Sheikh Governorate (4 m altitude, 31° 25- 31--latitude and 31° 04- 23-- longitude) aiming to improve nitrogen utilization efficiency under gated pipes irrigation technique. A Split Block (Strip) design with three replicates, were used where the main plots was devoted to irrigation treatments i.e. I1- The traditional furrow irrigation technique (Irrigation every furrows). I2- Gated pipes technique (Irrigation every furrows) . I3- Gated pipe alternate technique (alternative furrows irrigation), and the sub plots were assigned to forms and methods of nitrogen fertilizer application i.e., N1-The control treatment (0 Kg N Fed-1) . N2- Urea (CO (NH2)2) applied by dressing method. N3- Ammonium nitrate (NH4NO3) applied by dressing method. N4- Urea applied with irrigation water. N5- Ammonium nitrate applied with irrigation water. Application of nitrogen was at the recommended dose (135 and 90 Kg N Fed-1) for maize and sugar beet crops, respectively, Urea and ammonium nitrate fertilizer (applied with irrigation water) added with irrigation water through modified fertilizer unit connected to a pump machine under furrow irrigation techniques. The fertilizer unit consists of PVC tank (50 liter) connected to suction pipes through steel valve. The fertilizers (salt) dissolved in water then transported through delivery pipes. This fertigation process had low cost that included the cost of PVC tank and valve. These irrigation techniques and nitrogen fertilization treatments were applied on maize crop (Sakha 324) in summer growing season 2011 and sugar beet (TORO GERMANY) in winter growing season 2011/2012. The results obtained from this investigation can be summarized as follows: 5.1. Applied, stored and Saved water as affected by different irrigation techniques: There were clear effect of furrow irrigation techniques on applied water, stored and consumed. The depth of the applied water (Irrigation water applied (IW) and ground water contribution (S) ) to maize were 85.29, 68.45 and 59.05 cm for traditional surface all furrows (I1) , gated pipes all furrows (I2) and gated pipes alternate furrow (I3) , respectively. while the depths of water applied to sugar beet were 84.18 , 68.07 and 54.20 cm, for I1, I2 and I3 techniques, respectively. Using gated pipes method for irrigating maize and sugar beet crop resulted in less amount of water applied compared to traditional furrow irrigation method. Gated pipes technique saved irrigation water by 19.74 and 30.77 % with maize and 19.13 and 35.62 % with sugar beet crop for I2 and I3, respectively. The average depths of water stored in the effective root zone of maize crop were 56.42, 51.11 and 42.99 cm with irrigation techniques of I1, I2, and I3, respectively. Meanwhile, the highest amount of water stored under maize crop is 56.42 cm for traditional surface all furrows technique compared to the lowest amount (42.99 cm) for I3 technique. Under sugar beet crop, the average depths of water stored in the effective root zone are 51.79, 47.82 and 36.76 cm for I1, I2 and I3 techniques, respectively. It means that the highest amount of water stored in sugar beet field (51.79 cm) is obtained with I1 technique (control), while the lowest amount of water stored under sugar beet (36.76 cm) is found with I3 technique. Concerning water saving ,under maize crop , the alternative furrows irrigation by gated pipes technique (I3) saved irrigation water amounted by (30.77%) , whereas, the irrigation all furrows under gated pipes (I2) realize less percentage of water saving (19.74%) as compared to traditional surface all furrows technique . With regarding to water saving under sugar beet crop, also the highest amount of water saving (35.62%) was achieved under (I3) treatment , while the lowest one was recorded under (I2) gated pipes irrigation all furrow (19.13%). 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 was more than the 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 increased with traditional furrow irrigation technique (control) to the maximum value (56.19 cm), while the minimum value is recorded with I3 technique (42.11cm) with maize crop. Water consumptive use are affected markedly with increasing nitrogen utilization, where the highest value was detected from interaction between application of urea applied with irrigation water (N4) and I1 while the lowest one was detected from combination between zero application of nitrogen and alternate furrows irrigation by gated pipes technique I3 for maize and sugar beet crop. 4.4. Irrigation application efficiency for maize and sugar beet: The highest irrigation application efficiency (74.7 %) is achieved by gated pipes for all furrows technique while the lowest value (66.2 %) 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. Fluctuation of groundwater table during the growing season of maize and sugar beet crop & and ground ater contribution: Gated pipes furrow irrigation techniques (I2) and (I3) recorded the maximum values of water table depth, respectively, while the lowest values of water table depth were obtained with traditional furrow irrigation technique (I1) under (N1) zero application of nitrogen. The mean values of the water table depth were increased with decreasing percentage of soil moisture. Also, the water table depth is decreased with the Field head of the experiment under all the studied irrigation systems treatments for maize and sugar beet. The less contribution of groundwater table (S) was obtained under traditional furrow irrigation (I1), which was found to be 13.97 cm (as an average). The highest groundwater contribution was obtained under (I3) alternate furrow irrigation method under gated pipes (14.39 cm. 5.6. Field and crop water use efficiency (FWUE and CWUE): The obtained results revealed that the highest values of (CWUE and FWUE) were obtained under (I3) treatment and (N4) urea applied with irrigation water under maize crop. Whereas, the lowest mean value was detected under most of irrigation technique and zero nitrogen. With regard to sugar beet, the values of irrigation application efficiency took the same trend of maize crop. 5.7.Yield and Yield components: 5.7.1. Maize crop: 5.7.1.1. Growth parameters: There was a significant effect due to irrigation techniques on ear length and plant height. The alternate furrows which irrigated by gated pipes achieved the highest mean value of ear length. While the traditional furrow irrigation method achieved the lowest one. The longest plant height was achieved under gated pipes when irrigating all furrows (I2) followed by traditional irrigation for all furrows I1. On the other hand, there was no significant effect for irrigation techniques on ear diameter, 100-grain weight, Chlorophyll, leaf area, number of rows and number of grains per row. Nitrogen treatments showed high significant effect on ear diameter, ear length, 100-grain weight, plant height, leaf area, chlorophyll, number of rows and number of grains per row. The highest mean values (ear length, leaf area, 100-grain weight, Chlorophyll, number of rows and number of grains per row) were detected under (N4) urea applied with irrigation water. While the highest ear diameter was accompanied with (N3) ammonium nitrate applied by dressing methods and the highest mean value of plant height was detected under (N5) ammonium nitrate applied with irrigation water. The interaction effect between irrigation techniques and nitrogen fertilization was significant on ear length, ear diameter, 100-grain weight and number of grains per row. The highest mean value on ear length was obtained under I3 and N4 .The best treatment for ear diameter was found with I1 and N3 followed by I2 and N4. The highest value on number of grains per row was achieved by the combination between (I1) and N4, followed by I2 and N4. The highest value on 100-grain weight was achieved by the combination between I2 under N4. There was insignificant effect for interaction between irrigation techniques and nitrogen fertilization on plant height, leaf area, number of rows and chlorophyll content is not significant. 5.7.1.2. Maize Yield: There was insignificant effect of irrigation techniques on maize yield and significant effect due to furrow irrigation treatments on stalk yield. Using gated pipes technique in irrigating all furrows recorded an increase in the grain yield by (3.3%) as compared to control treatments. The grain yield is reflection of stalk yield, so it is logically that maize grain yield took the same trend of stalk yield. The high significant effect due to forms and methods of application nitrogen fertilizer application where the highest grain yield was accompanied with (N3) ammonium nitrate applied by dressing method, since it produced the highest mean value of maize grain yield (4285.3 Kg Fed-1) followed by (N4) urea applied with irrigation water(4199.8 Kg Fed-1). The grain yield is reflection of stalk yield, so it is logically that maize grain yield took the same trend of stalk yield. Grain yield was increased by about 62.1%, 59.7%, 58.8%, and 45.8% for N3, N4, N2, and N5 compared to N1 treatment, respectively. Stalk yield took the same trend of grain yield, where the mean values of stalk yield increased by about 154%, 138.2%, 121.1% and 100.5% for N3, N4, N2, and N5 compared to N1, respectively. Regarding the interaction between furrow irrigation and nitrogen fertilization treatments on maize grain yield and stalk yield. It can be observed that gated pipes technique irrigating all furrows (I2) under N3 achieved the highest grain and stalk yields followed by treatment (I3) alternate furrows which irrigated by gated pipes under N4 than traditional furrow irrigation treatment (I1) under N3. 5.7.2 Sugar beet crop: 5.7.2.1. Growth parameters: There was 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 led to elongate the sugar beet roots, while using of (I1) technique resulted in shortening the roots. Gated pipes for irrigation all furrows or alternative furrows technique attained higher values of root diameter. The highest TSS value (13.93%) was obtained under (I1) followed by (I3), while (I2) gave the lowest TSS value (11.8 %). There was insignificant effect for irrigation techniques on leaf area index and chlorophyll. Nitrogen showed high significant effect on root length, root diameter, total Soluble Solids (T.S.S.), leaf area index and chlorophyll. The highest mean values (root length, root diameter, leaf area index and chlorophyll) were detected under (N4) urea applied with irrigation water but the highest TSS value (15.33%) was obtained under (N1) . The interaction effect between irrigation techniques and nitrogen fertilization was significant on root length, root diameter, TSS and leaf area index. The highest mean value on root length and leaf area index were obtained under I3 and N4 .The best treatment for root diameter was found with I2 and N4 . The highest value on TSS was achieved by the combination between I3 and N1. There was insignificant effect for interaction between irrigation techniques and nitrogen fertilization on chlorophyll content. 5.7.2.2. Sugar beet yield (roots, top and white sugar): The yield of roots, top and white sugar was highly significantly affected by irrigation techniques. Gated pipes technique produced the highest yield of the roots and shoots. While the highest value on white sugar was achieved by I1, followed by I2. Using gated pipes technique in irrigating all furrows increased yield of roots by (9.3%) as compared to control treatments. The roots yield was reflection of tops yield, so it is logically that roots yield took the same trend of tops yield. Nitrogen treatments exhibited high significant effect on roots, top and white sugar yield. Roots yield was increased by about 72.5%, 65.3%, 62.8%, and 62.4% for N4, N5, N2, and N3 compared to N1 treatment, respectively. The mean values of tops yield increased by about 127.3%, 119%, 111% and 92.6% for N5, N3, N4, and N2 compared to N1, respectively. The mean values of extractable sugar yield increased by about 46.5%, 29.4%, 20.9% and 11.9% for N4, N2, N5, and N3 compared to N1, respectively. The interaction effect between irrigation methods and nitrogen fertilization had significant relation on root yield, top yield and extractable sugar yield. The best treatment was found with the combination between urea applied with irrigation water and using alternative furrow irrigation by gated pipes I3 with root yield and extractable sugar yield. The highest value of top yield was achieved by the combination between I2 under N5. 5.7.2.3. Sugar beet purity and quality: The obtained results showed a significant effect of irrigation techniques on Na, K, α-amino N, sucrose percentage, sugar loss to molasses percentage (SM), extractable sugar (%), extractability(%), purity percentage and alkalinity coefficient (%) in root juice. The highest mean value of Na, K , α-amino N and sugar loss to molasses percentage (SM) were recorded under I3 treatment followed by I2. Whereas, the lowest one was recorded under I1. Gated pipes irrigation techniques (I2) resulted in the highest alkalinity coefficient (%) followed by I1. The highest mean value of sucrose percentage, extractable sugar (%), extractability(%) and purity percentage were recorded under I1 treatment. Regarding nitrogen fertilizer treatment, data exhibited highly significant effect. On the other hand, α-amino N and alkalinity coefficient were insignificantly affected. The highest mean value of K, Na (meq/100g) and sugar loss to molasses percentage (SM) were detected under (N4) urea applied with irrigation water but the highest value of purity percentage, sucrose percentage, extractable sugar (%) and extractability(%) was obtained under (N1). The interaction effect between irrigation methods and nitrogen fertilizer was significant on α-amino N, sucrose percentage, sugar loss to molasses percentage (SM), extractable sugar (%), extractability(%), purity percentage and alkalinity coefficient (%) in root juice. The highest mean value of α-amino N was recorded by I3 under N1, the highest mean value of alkalinity coefficient (%) was recorded by I2 under N1, the highest mean value sucrose percentage was recorded by I3 under N1 followed by N4, the highest mean value of sugar loss to molasses percentage was recorded by I3 under N5 and the highest mean value of extractable sugar (%), extractability (%) and purity percentage were recorded by I1 under N1. On the other hand, there was insignificant effect due to the interaction effect between irrigation treatments on Na and K contents. 5.8- Nitrogen concentration and its uptake: Nitrogen uptake by maize and sugar beet crops highly significantly affected by irrigation techniques. Nitrogen concentration increased with decreasing applied water by gated pipes (I2 and I3) comparing with traditional irrigation treatment (I1). The mean values of nitrogen concentration in grains were detected with I2 followed by I3. Also, The N concentration and its uptake by corn stalks and sugar beet (top and root) took the same behavior of grains. The highest mean values of nitrogen concentration in grains and stalks of maize and root of sugar beet were detected with N4 followed by N3. The highest mean values of nitrogen concentration in tops were detected with N5 followed by N4. The highest mean values of nitrogen uptake in grains and roots were detected with N4 followed by N3. Also, the highest mean values of nitrogen uptake by stalks and tops were detected with N3 followed by N4. The interaction between irrigation and nitrogen fertilization on nitrogen concentration and its uptake were highly significant with maize and sugar beet. On the other hand, nitrogen uptakes in grains were insignificantly affected. The mean values of nitrogen concentration and nitrogen uptake in grains and stalks with maize were detected under I2 with N4. On the other hand, the mean values of nitrogen uptake by maize stalks were detected under I2 with N3. On the other hand, the mean values of nitrogen concentration and nitrogen uptake by roots of sugar beet were detected under I3 with N4, and the mean values of nitrogen concentration and nitrogen uptake in tops of sugar beet were detected under I3 with N5, and this may attributed to less nitrate leaching, and so increasing nitrogen concentration in root zone, resulting in increasing of nitrogen uptake. 5.9-Nitrogen use efficiency and Nitrogen recovery %: Nitrogen use efficiency value with maize was achieved by N3 which be higher than the same obtained by N4, in all irrigation treatments. The highest values of nitrogen use efficiency were obtained by (I2) under (N3), followed by (I3) under (N4), followed by (I1) under (N3). Nitrogen recovery took the same trend of nitrogen use efficiency . On the other hand, the highest values of nitrogen use efficiency with sugar beet were obtained (I3) under (N4), followed by (I2) under (N5) and followed by (I1) under (N4). The highest value of N recovery % was found under I3 and N4, followed by (I2) under (N4) and followed by (I1) under (N3). 5.10- 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 I2, I3 and I1, respectively. The highest value of available nitrogen was found under N5, followed by N4. The interaction between irrigation and nitrogen fertilization available nitrogen were highly significant with maize and sugar beet yield. The highest value was found under I2 and N5. 5.11- Nitrogen balance in soil with maize and sugar beet. Expected N losses% from the soil with maize yield increased with increasing amount of irrigation water. The highest values (42.8%) of N losses were obtained with I1 and N5. Whereas, the less amount of nitrogen losses (26%) were detected under gated pipes irrigation technique. N Used % with maize yield was increased with decreasing the amount of irrigation water. The highest values (74 %) of N Used % was obtained with I2 technique, followed by (I3). Whereas, the lowest mean value was detected under I1. This may be due to the large amount of water that leaching nitrogen to main drains. The highest values (9.15 %) of N contribution Used % was obtained with I2 technique. Whereas, the lowest mean value was detected under I1. Sugar beet yield took the same trend of nitrogen balance with maize yield. 5.12- Nitrogen concentration in irrigation water on furrow length. N-added with irrigation water resulted in improves of distribution fertilization efficiency. Also, there were no obvious differences between nitrogen concentrations in irrigation water at furrow length with both fertilizer N-types. 5.13- Nitrogen in groundwater. Nitrogen concentrations in the groundwater, before fertilizer application, ranged from 4.54 to 9.85 ppm in both seasons. These concentrations were increased after fertilizers application. Nitrogen concentration in groundwater with maize plant was higher than sugar beet plant. This is due to high rate of nitrogen application with maize plant (120 kg fed-1) than sugar beet plant (90 kg fed-1). After fertilization, nitrogen concentration in groundwater with gated pipe furrow was higher than other treatments. This is due to high residual of nitrogen in the soil under gated pipe compared with other treatments. This may be due to the large amount of water that leaching of nitrogen to main drains. 5.14- Economical efficiency with maize and sugar beet. Net income from water unit and economical efficiency increased with gated pipes (I2 and I3) comparing with traditional furrow irrigation treatment (I1). Moreover, (I2) under (N3) recorded the maximum values of net income from water unit (2.34 and 2.16 L.E/m3 water) and economical efficiency (2.60 and 2.45) with (I3) under (N4) and (I2) under (N4), respectively), while the lowest values of the abovementioned parameters were obtained with (I1) under (N1) zero application of nitrogen by maize yield. Sugar beet yield took the same trend of net income from water unit and economical efficiency with maize yield. Conclusion Using gated pipe technique combination with application of urea applied with irrigation water led to improve water, irrigation application efficiency, contribution of groundwater table, nitrogen efficiencies, saving more water, net income, net income from water unit and economical efficiency compared to traditional furrow irrigation method without observed reduction in maize crop and sugar beet yield.