الفهرس 
Water tableOnly 14 pages are availabe for public view
 |  | from | 184 |  |  |
| | | from | 184 | | |
Abstract
SUMMARY AND CONCLUSION
Two experiments were carried out in eighteen double wall concrete lysimeters of the size 1.25 m × 1.25 m in area and 1.25 m deep using the cultivar Faba bean (Vicia Faba L.) and Corn (Zea mays L.) during, 2010 and 2011 seasons, respectively to estimate the contribution of water table to meet the water requirements, the impact soil management practices including compost; and the interaction effect of both them on either faba bean or corn crop. The lysimeters were connected to a tank with Marriotte siphon and a piezometer to maintain the water table level at the desired depths, which consisted of 50, 70 and 90 cm from the soil surface. There were two compost treatments, which consisted without compost and with compost treatments. The amount of compost was 20 Ton per feddan, which mixed with the 30 cm depth from the soil surface. The obtained results could be summarized as follows:-
-):otevapotranspiration (EReference
The values of climatic conditions and reference evapotranspiration (Eto) calculated according to the modified penman equation (mm/day) for faba bean and corn crops were follow the changes in the climatologically norms during the growth season.
-Water use from water table:
The highest water table contribution for faba bean and corn crops value is obtained under the shallowest water table depth (50 cm) and it reduces with increasing the depth of water table from soil surface in with and without compost treatments. Also, the result show that the considered crops (faba bean and corn crops) has different ability to take up water even with the same water table level. The values of water table contribution are increased as the plant progressed then it decreases again till the end of growth season for all studied water table levels through either with or without compost treatments.
Water table contribution significantly increased with compost treatment compared to without compost treatment.
Shereen A. H. Saad.Ph.D.,2014
159
The maximum value of seasonal contribution of water table is obtained at 50 cm water table level with compost treatments, While the minimum value is obtained at 90 cm water table without compost treatment, this for both faba bean and corn crops .
-use from Irrigation water:Water
The irrigation requirements are minimum at the shallowest water table level and increased with increasing the water table depth from soil surface to meet the field capacity of the soil for both faba bean and corn crops and also under with and without compost treatments. The results also indicated that, there was a progressive and consistent increase in irrigation requirements under all considered water table levels in presence of compost practices. Thus, the maximum value is obtained at 90 cm water table with compost treatment, while the minimum value is obtained at 50 cm water table depth without compost treatments. With regard to the trend of the values of water use from irrigation water and its distribution through soil profile layers for faba bean and corn crops under different water table levels, values under 50 and 70 cm water table levels with and without compost treatments decreased from the soil depth 20 to 40 cm but, it increasesd heavily again till 60 cm soil depth during all the growth season. But in case of water table level 90 cm, it almost decreased with increasing the depths of soil profile for e both treatments of compost for faba bean and corn crops.
-):atActual evapotranspiration (E
ETa gradually increase as the plant age progressed to reach the maximum value then it decreased gradually till the end of growth season. But the periods of maximum Eta values changed from treatment to another for both faba bean and corn crops.
There is no high difference between the Eta values at 50, 70 and 90 cm of water table levels. It slightly increased with increasing the depth of water table for both with and without compost treatments.
The values of Eta were increased in the presence of compost at all periods of growth season and under different water table levels comparing with the absent of compost.
Shereen A. H. Saad.Ph.D.,2014
160
The highest values of actual evapotranspiration were obtained under both 90 cm water table level and compost addition, while the lowest ones were obtained at 50 cm water table level without compost addition.
-Crop coefficient (Kc):
The values of Kc for faba bean and corn crops under all the treatments under study increased as the plant age progressed till the maximum value, then Kc values decrease gradually till the end of growth season. The maximum values of Kc changed at all the treatment in either the values or the period which appeared on it for both faba bean and corn crops. The Kc values increased compost addition under all water table levels.
The highest values of Kc for faba bean and corn crops were achieved at the water table level of 90 cm in compost treatment, while the lowest ones were obtained at 50 cm water table level without compost addition.
-:(WE) Water economy
There is a significant effect of contribution of water table levels on water economy for both faba bean and corn crop. The highest value is obtained at 70 cm water table level, while the lowest one was obtained at 90 cm water table. While 50 cm water table levels is in between of them for faba bean and corn crops.
With respect to the effect of compost treatments , there was a significant difference between the values, they increased in compost treatment in contrast to without compost treatment whiche led to the minimum values.
In respect the interaction between water table levels and compost treatments on water economy, the highest value of (WE) was obtained at
07cm water table level in the compost treatment, while the lowest one obtained at 97cm water table level without compost treatment.
-ncy (WUE):Water use efficie
Water table levels or compost treatments or both of them significantly effect on values of water use efficiency.
Shereen A. H. Saad.Ph.D.,2014
161
The highest value of (WUE) was obtained under 70 cm water table level, while the lowest one was found at 90 cm water table level, while 50 cm water table level is in between of them.
Concerning the effect of compost, the highest value was achieved by applying compost.
In respect the interaction between water table levels and compost treatments on water use efficiency, the highest value of WUE was obtained at 07 cm water table level with compost treatment, while the lowest value is obtained at 97cm water table level without compost addition.
-:Nutritional status in the soil profile
Total and available nutrients status, ie, N, P, K, Fe, Mn and Zn in the soil profile was affected significantly by the different levels of water table, compost practices and both of them for either faba bean or corn crop. It is easy to notice that, the highest values of total and available considered nutrients achieved through 70 cm water table level followed by 50 cm and 90 cm water table level.
There is no doubt that compost affected significantly on both total and available nutrients values in all cases of water table levels. Using compost practices exhibited significantly exceeding from total and available nutrients N, P, K, Fe, Mn and Zn under different water table levels against without compost practices.
Concerning, the interaction effect between the water table levels and compost treatment, the highest value of total and available nutrients under studying was obtained at 07 cm water table level with compost addition in all soil profile depth, while the lowest value was obtained at 97cm water table level without compost addition in most of soil depths.
-:in the faba bean and corn crops Nutritional status
The obtained results referred to an increase in N, P, K, Fe, Mn and Zn for all organs of faba bean and corn plants in the treatment of 70 cm water table level comparing with both 90 and 50 cm water table levels regardless the compost addition.
Shereen A. H. Saad.Ph.D.,2014
162
Concerning to the effect of compost addition, the values of nutrients contents in the different parts of faba bean and corn crops indicate that, they increased with compost addition under all water table levels under study.
Referring to the effect of the interaction between both water table levels and compost addition on nutrient content and distribution in faba bean and corn crops, the highest values were found at 70 cm water table level with compost addition in root, stem, leaf, seed and peel for both faba bean and corn plants. While, the lowest values were obtained in most parts of the plant at 90 cm water table level without compost addition.
-:)/plant(g rain yieldG
The obtained results demonstrated that, there were significant differences increasing yield between the water table levels. In addition, substantial increases in faba bean and corn grain yields were found in 70 cm water table level comparative to 50 cm and 90 cm water table levels. The highest values of grain yield that were obtained at 70 cm followed by 50 cm then 90 cm water table levels for both faba bean and corn crops.
Concerning to the effect of compost addition, the values of grain yield in both faba bean and corn crops, they increased with compost addition under all water table levels under study.
The effect of interaction between both water table levels and compost treatments on the grain yield of both faba bean and corn crops showed significant differences between the treatments. The maximum significant increment of grain yield of both faba bean and corn crops was realized at 70 cm water table level with adding compost. But, 90 cm water table without compost practices showed the highest reduction in grain yield for both crops