الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Shortage in Nile water resources resulted in using the unconventional sources of water such as drainage water. The Current study is carried out in Kom Oshim district, Tamia, El Fayoum Governorate which was selected to study the soil health in 6 sites: four of them were cultivated with Olive trees in different times and irrigated (DROP irrigation) with a mix of agricultural drainage water and Nile water obtained from the mixing station located at Kobry el Bayomy, Tamia District. The mixing station mix the drainage agricultural water and the Nile water in a ratio of 3:1. The fifth site (control site) was free of plantation (virgin soil) without irrigation. The sixth site located at Al Alam district, Sanours, El Fayoum Governorate irrigated (basin irrigation) with Nile water from Bahr Alaam only for more than 50 years ago and cultivated with alfaalfa crop, was used for comparison. Soil samples were collected during spring, summer and autumn of 2012 from all sites at 30 cm depth of the soil surface from rizhospher area of plantations. Each sample was about 1 Kg there were three samples of each site. Each site samples were mixed together and divided into two volumes and preserved in icebox. One volume is for physical and chemical analysis whiles the other one is for determination of soil fauna.
Water and Soil (physical and chemical) properties, extraction, identification and description of dominance for both nematodes and mites were determined by using the established method referred in the references.
The results can be summarized in the following:
1: Impact of using different irrigation water resources:
a. The Fresh Nile water: In general, the variations in water pH value ranged between 7.23 and 7.29 The minimum value was recorded in summer, while the maximum one was found in winter. The Nile water salinity expressed ECw, shows a narrow variation at each sampling date. The ECw levels recorded the minimum value (0.65 d s/m) in winter period and increased up to the maximum one (0.73 d S/m) during summer. It means that the Nile water is subject to either contaminated with agricultural drainage water at some areas or it is enriched with dissolved salts from the natural ridge sediments along its canal stream.
Concerning the distribution pattern of soluble ions of the Nile Water in the studied soil sites, The general trend of cationic composition follows the descending order of Ca2+ > Na+>Mg2+>K+, while the soluble anions followed the descending order of HCO-3 > Cl- > SO42- The superiority of Na+ content over Mg2+ is probably due to contamination of the agricultural drainage water. The adjusted SAR values ranged between 2.32-2.76, the minimum value was found during spring period. According to the permissible limits for irrigation water scale, the used irrigation Nile water belongs to the first class (< 6.0), which do no problems for soil sodicity. Residual sodium carbonate (RSC) which considered as another character of water sodicity, were not detected.
The N, P, K (Macronutients), Fe, Mn, Zn,Cu, B (Micronutrients) ,Cd , Ni, Pb and Co (Heavy metals). According to their contents, the previous elements are arranged in the descending order of K > N > P > Fe > B >Mn > Zn> Cu > Pb > Ni> Co > Cd. It is worthy to mention that, the contents of the previous elements are laying within the permissible limits for irrigation water.
b. Mixed drainage water: Some areas at El Fayoum Governorate suffer from irrigation water deficiency, especially at the irrigation canal ends during the summer seasons. Data of the chemical analysis for these Mixed irrigation waters show that the pH value ranged between 7.79-7.86. The pH values of the agricultural drainage water still laying within the suitable category for irrigation.
The water salinity, as expressed by ECw, ranged between 1.44-1.63 dS/m for the mixture of the drainage water with the Nile water. According to the salinity classes of the permissible limits for irrigation water, these waters are laying within the second category (0.75-3.00dS/m).
The distribution pattern of soluble cations follows the descending order of Na+ > Ca2+> Mg2+ > K+, while the soluble anions could be arranged as follows Cl- > HCO3- >SO42- The Na+ content reached two folds that of (Ca2+ + Mg2+) content. Also, Cl- dominated the soluble anions, denoting that Na- , Cl- is the probable dominant salt in the studied mixed irrigation water categories. The adjusted SAR values for the mixed irrigation water ranged are 12.52-14.26. According to the permissible limits for irrigation water, the mixed irrigation waters are lying within the third class (> 9.0), denoting the increase and severe problems are expected for soil sodicity.
In General the N, P, K (macronutrients), Fe, Mn, Zn, Cu, B (micronutrients), Cd, Ni, Pb and Co (heavy metals) varied throughout the different studied mixed irrigation waters, the contents of the previous elements, they are arranged in the descending order of K > N > P> Fe > B > Mn > Zn > Cu > Pb > Ni > Co > Cd. It is worthy to mention that, the levels are laying within the permissible limits for irrigation water according to the permissible limits for irrigation water. Regarding the boron content in the Mixed irrigation waters, data reveal that its amounts still within the safe range (< 0.50 mg/L), and no problems are expected due to their usage for irrigation.
2: Degradation of soil properties as affected by using the mixed irrigation water:
Data indicated that silt and clay increased till reached the highest values (27.67 and 53.63%) respectively in 18 years old, in contrast values of coarse and fine sand were higher in virgin and 3 years old than 18 years old. This may leads to a change in soil structure from sandy (virgin and 3 years old) to sandy loam (8 and 13 years old), then to clay (18 years old). Also organic matter increased till reached the highest value (2.13 %) in clay soil in contrast, CaCO3% decreased till reached the lowest values (2.5 and 2.53%) in sandy loam and clay soil respectively.
Regarding some chemical properties i.e. nutrient elements, it could be observed that a slightly increase in the content of N, P, Mn and Cu on the other hand K, Fe and Zn increased gradually till reached the highest value in clay soil (18 years old).
3: Impact of soil texture deterioration from sandy to clay texture on nematodes and mites census:
Occurrence of soil nematodes could be affected by seasons but there were other factors having a great effect on the soil environment such as, irrigating water, chemical and physical soil prosperities, plantations, age of plants, and organic matter. Data revealed that 5 genera of soil nematodes recorded in olive and alfalfa plantations grown in different types of soil and irrigated with different types of water at El Fayoum Governorate. The nematode genera were 2 of plant parasitic nematode (PPN) i.e. Meloidogyne spp. and Pratylenchus spp. while the other 3 were free living nematode (FLN) i.e. Rhabdites spp., Acrobeles spp. and Cephalobes spp.
Regarding the PPN, it could be observed that during spring Meloidogyne spp. and Pratylenchus spp recorded the highest numbers (5965 and 435 individual/1kg.) respectively in olive tree (8 years old), whereas the highest numbers during summer were (2275 and 254 individual/1kg.) and autumn were (1354 and 96 individual/1kg.)in olive tree (13 years old) respectively. The lowest number of Meloidogyne spp. was(120 individual/1kg.) in olive tree (3 and 18 years old) during summer and autumn respectively, while for Pratylenchusspp were (77 and 96 individual/1kg) in olive tree (8 and 13 years old) during summer and autumn respectively. Only Meloidogyne spp. was recorded in olive tree whereas Pratylenchus spp recorded in both plants. Obviously data revealed that marked decrease in the nematode density was observed in the oldest trees in each season and also from spring to autumn season.
Concerning the FLN data revealed that Rhabdites spp. recorded the highest numbers followed by Cephalobes spp. whereas Acrobeles spp. recorded with a few numbers. However in olive trees the highest numbers of Rhabdites spp. were (865 and 993 individual/1kg.) in 3 years old while the lowest numbers were (80 and 113 individual/1kg.) in 18 years old during spring and summer respectively. Rhabdites spp.was superior in its numbers in alfalfa irrigated with Nile water (2160, 1820 and 1404 individual/1kg.) during spring, autumn and summer respectively. Similar trend was observed with Cephalobes spp. Regarding the total numbers of nematodes, it could be observed that PPN decreased from spring to autumn with an average numbers ranged from 1400 to 435 individual/1kg. respectively, this could be due to the plant root activity and soil temperature. from the previous results it could be observed that: irrigating with the mixed drainage irrigation water, soil structure have been changed from sandy structure (Virgin soil and 3 Years) to sandy loam (8 and 13 years) then to clay structure soil (18 years), it means that the soil structure has been changed and the nematode population are affected by soil structure as the population growth was lower in fine textured soil than in coarse textured soil. Soil pore space changes reduce the capillary diameters which affect the population growth. While the soil irrigated with Nile water (50 years) have been changed to clay loam structure. Generally both of PPN and FLN decreased with increasing the age of olive trees, it may be attributed to irrigation with mixed agricultural drainage water.
Data revealed that PPN Meloidogyne spp. was “resident” in olive trees 3 and 18 years old with total nematode percent (2.1 and 3.4%) respectively whereas it was “dominant” in olive trees 8 and 13 years old with total nematode percent (23.5 and 14.9%) respectively. The FLN Rhabdites spp. was “influent” in olive trees 3, 8 years old and alfalfa with a total nematode percent ranged from (6.1 to 8.9%). Acrobeles spp. and Cephalobes spp. were ”resident” in all olive plantations with total nematode percent ranged from (0.02 to 3.3%). Obviously all recorded soil nematodes were “resident” in olive trees 18 years old. Concerning FLN generally it was “resident” in all olive plantations; in contrast it was “dominant” in alfalfa. Nematodes activities cannot be considered in isolation from abiotic environmental conditions. Physical conditions are important and, for both soil-inhabiting and aquatic nematodes, several studies have shown that soil type is more important than time of year or management practices in determining the overall make up of the nematode assemblage.
Occurrence of soil mite taxa could be affected by seasons but there were another factors had a great effect especially which effect on the soil environment such as, irrigating water, chemical and physical soil Properties, plantations, age of plants, and organic matters. Data revealed that 8 genera of soil mite taxa recorded in olive and alfalfa plantations grown in different type of soil and irrigated with different type of water at El Fayoum Governorate. The mite taxa were one of sub order Gamasida i.e. phytosiidae spp. and it is from the Predacious types and one Non-Predacious type i.e. Rodacaridae spp.two of sub order Actinedida i.e. Pygmaphoridae spp.and Canaxida spp. of the Non-Predacious types while the other 4 were of sub order Orbidatidae i.e. Oribatulidae spp., Bellebidae spp., Oppidae app. and Epilohmanniidae spp of the Non-Predacious Types.
The highest numbers were 136 and 76 with a percentage of total mites 47 and 26 % recorded to family Oribatulidae in alfalfa and olive 8 years old respectively. Whereas the lowest numbers of mites were 2 and 4 with a percentage of total mites 0.7 and 1.4 % recorded to family Phytoseiidae and Rhodacaridae for alfalfa plantation.
Obviously the highest numbers of soil mites were recorded with alfalfa plantation in soils irrigated with Nile water.
Generally the following can be concluded as a priority list of measurable biological criteria for invertebrates:
1. Keystone species or ecosystem engineers. where such groups can be identified unambiguously, their abundance, biomass and density may represent the best criteria for quickly and effectively assessing the invertebrate contribution to soil health.
2. Taxonomic diversity at the group level. Assessment of the abundance, biomass and density of all soil invertebrates at the order/class level will provide a simple indication of the ecological complexity of the soil community.
3. Species richness of several dominant and perhaps more taxonomically tractable groups of invertebrates. Again, this will indicate the ecological complexity of the soil community
Inevitably, these three measures will provide only a simple guide to soil health. The real obstacle to evaluating the invertebrate contribution to soil health is a lack of understanding of the links between gross soil processes and the structure of soil organism communities. If we are to understand these processes, then at least one or two major, in-depth studies of the community structure and of the interactions of invertebrates with each other and with micro organisms and their soil environment must be attempted.