SOIL FAUNA POPULATION, SURVEY AND TOXICAN APPLICATION IN THE NILE DELTA, EGYPT

1. SOIL FAUNA POPULATION, SURVEY AND TOXICAN APPLICATION IN THE NILE DELTA, EGYPT TADROS S. MOHSEN Department of Economic Entomology, Faculty of Agriculture, Tanta University, EGYPT. E-mail: tadrosy30@yahoo.com Introduction The present investigation was carried out in the laboratory of the Economic Entomology Department, Faculty of Agriculture, Kafr El-Sheikh, Tanta University, Egypt. It lasted for 3 complete years, materials were collected from nine Governorates and eighteen cities, all from the Nile Delta valley. The chosen Governorates were : Alexandria, Beheira, Dakahlia, Damietta, Gharbia, Kafr El-Sheikh, Menofia, Sharkia and Qualubia. Soil samples were taken every two weeks at two soil levels, the upper (0-15 cm.) and the lower (15-30 cm.). Evaluation of soil microarthropods was carried out using Batteries of Modified Tullegran Funnels for 48 hours. It was found out that total Collembola, as a whole from the nine tested Govenorates, reached 64.07% against 34.43% for Acarina. However that result was not the same in all tested areas, in Gharbia the percentage was 97.22% for Acarina, to 2.78% for Collembola and in Menoufia too, the numbers were 79.27% against 20.75% for Acarina and Collembola respectively. In other Governorates, such as Qualubia the percentage was not far from each other 45.48% to 54.52% for Acrarina and Collembola respectively. In most cases the upper soil strata held the majority of soil Acarina & Collembola. However, that result also differed between the occurrence of Acarina & Collembola from one location to another. Those differences were referred to carbon, pH, E.C., O.M. and the covering vegetation. The occurrence of species was divided to 2 categories, constant species, that occurs in more than 50% of the samples (Weis-Fogh 1948) and, dominant species that constitute 5% or more of the number of individuals (Weis-Fogh 1948, Karppinen, 1958). Toxicant applications; Rup 962, Dimethoate and Kalthane were found to decrease the numbers of soil fauna numbers, but a recovery happened afterwards within 3 months Table (4): Mean of total soil arthropods (Acarina and Collembola) from eight governorates and eighteen cites and some important soil properties. N.B. Statistical analysis showed that the simple correlation between soil fauna and every indicated soil property is non significant. Table (5): Vertical distribution of America and Collembola at two soil depth (0-15 & 15- 30) & (0-30) from eight Governorates, represented the Delta of the river Nile. Table (6): Effect of some insecticides on soil fauna (Acarina and Collembola) existing in three cities in Kafr El-Sheikh Governorate. *Insecticides was used for the control of cotton pets Thrips tabaci (Lind), Aphis gossypii (Glover), Earias insulana (Boisd). Objectives 1- Survey of soil microarthrpods occurring in soil of different city locations at two soil depths (0-15 cm and 15-30 cm), with special reference to soil mites and spring tails. 2- Finding the different degrees of population density in the eight tested governorates (18 cites). 3- Finding if there is any correlation between soil organisms magnitude and some important soil properties. 4- Finding the effect of some toxicants. Insecticides and herbicides on soil organism magnitude and the recovering period. 5- Sensitivity of different fauna groups and/or species to the applied toxic compounds, and finding if these compounds accumulates in some soil mite species. Discussion A. Results indicted in recording (34) Families and (56) species. it was also found that mites and spring tails were the majority of soil organisms (64.07%). On the other hand mites: spring tallies, were (34.43 : 64.07) in most location. B. It was also found that the upper soil strata (0-15 CM) Held the majority of the soil organisms (%) in most tested cities. C. Preparing the total soil fauna magnitude in all tested locations, the following figures would clear up that: Dakahlia (26.60) Kafr El-Sheikh (7.76 %) Behiera (9.04) Damietta 4.71%) Sharkia (3.91%) D. Results indicated some correlation soil mite/collembola magnitude and most of the tested soil properties. E. Application of toxicants proved to decrease soil organisms. However, a recovery happened afterwards, and 90 days was fair enough to raise the magnitude of sot soil fauna groups to its normal level. However, some mites were sensitive to the applied compound, others were resistant, while a third group could not recover even when experiment terminated. On the other hand, the applied herbicides were less toxic than insecticides on the recorded soil organisms. Materials and Methods Batteries of Modified Tullegran funnels adapted with Plilips bulbs,were set up in the laboratory of The Economic Entomology Department, Faculty of Agriculture, Kafr el-Sheikh,Tanta University, Egypt,135 Km to the North East of Cairo,Egypt. Extraction of organisms took place for 48 hrs.,Organisms were received in Petri dishes full of water.Evaluation of he extracted mtes & insects was done by the aid of a binocular microscope.For accurate identification a suitable microscope was used ,and organisms were loaded on slides,using h\Hoyer"s media, slides were sealed by asphaltum for reservations . Results Table (1):Soil fauna orders recorded from some Egyptian soils N.B. Individuals from these orders are recorded at low magnitude and/or limited number, and not from all tested habitat. Table (2,a): Soil fauna groups extracted from most Egyptian soils. N.B. *** Soil fauna groups existing in large numbers, or in other words dominant in any soil sample. ** Soil fauna groups existing in reasonable numbers, or predominant species. * Individuals may not be recorded from every sample. Table (2,b) Conclusion Most investigators and the literature indicates that soil arthropods greatly accelerate decomposition of organic matter and with microflora serve in nutrient cycling. Soil arthropods serve also in the biological control of pests. So, it is recommended to use soil arthropods especially mites as follows: 1. Biological test: To use soil faun as an index of the stability of decomposition of soil toxicant application in soil, side by side with the chemical analysis before recommending the use of any compound in agricultural soils especially urban soils for the best of human, animals and those crops and fruits consumed by man kind. 2. Indicator species: Some soil arthropod species especially mites may indicate activity of soil biology, and in the meantime if there are any toxicant residue, in soil or in other words if these species are absent that would be warning toxic compounds in soil, and in that case the chemical test would be necessary, to confirm that result.