Scientific registration no : 43 Symposium no : 27 Presentation : poster Morphological Changes of Newly Reclaimed Soils In Egypt Cultivated For Different Periods Modifications morphologiques au cours du temps de sols réhabilités pour la culture en Egypte GOBRAN Omar 1), EL-BARBARY Serry 2) 1) Dept. of Soil Sci., Menofiya University, Shibin El-Kom, Egypt. 2) Soil & Water Res. Inst., Agric. Res. Center, Giza, Egypt. Abstract: The aim of this study was to follow up the changes which might take place in some morphological features and physio-chemical of newly reclaimed soils in both desertic eastern and western sites of Nile Delta. The field morphology rating system for evaluation of the pedological development was employed. Twenty three profiles were selected to cover almost all periods of the land use. Data revealed that the morphological features for the assigned areas, changed according to the period of cultivation. The magnitude of alterations in the surface layers was higher than that in the subsurfaces ones.the Relative Horizon Distinctness (RHD) and the Relative Profile Development (RPD) ratings partially increased with advancing the land use period. Results showed that the soils cultivated for 30 years had higher values of RHD and RPD. This indicates that such soils attained clearer horizontation and greater pedological development than the case of the virgin land and the soils cultivated for shorter periods. In regard to the changes of some physio-chemical properties, results generally, revealed increases of fine fractions content, as well as F.C, C.E.C, Ex.(Ca+Mg) and O.M content with increasing the period of cultivation. Introduction : One of the major aims in agricultural policy of Egypt is to increase the cultivated areas by horizontal expansion, to cope with the over increasing demands of the over growing population. To fulfill the horizontal expansion aim, the desert lands are more concerned. Among of these lands the areas located in the eastern and western sites of the Nile Delta. The main object of the current work is to follow up changes which might take place in morphological and some physio-chemical characteristics of the new reclaimed soils in both desertic eastern and western sites of Nile Delta, upon cultivation, and in particular their hearing on profile development, Accordingly suitable suggestions could be attained to help in planning the reclaimation process and to understanding how to deal with these soils for agricultural use. 1
Materials And Methods : The eastern part of the studied areas is situated at longitudes 31o 45 west and 32o 20 east; and latitudes 31o north and 30o 30 south. While the western part of the studied areas is situated at longitudes 29o 45 west and 30o 45 east; and latitudes 31o north and 30o 30 south, (Fig.1). Twenty three profiles were selected from six regions representing new reclaimed soils in both the desertic fringes on eastern and western sites of Nile Delta. The soil profiles were morphologically described according to F.A.O (1970). Samples of representative soil profiles were collected according to the vertical morphological variations. Some physio-chemical characteristics were determined according to Black (1965) and Page (1982). Evaluation of soil development was assessed using the field morphology rating scale which is proposed by Bilzi and Ciolkosz (1977). Results And Discussion : Data in Table (1) reveal that the morphological features examined, for the assigned areas, changed according to the period of cultivation. The magnitude of alterations in the surface layers is higher than that in the subsurface ones. Cultivation of the new reclaimed soils resulted generally in making their colour darker and improving each of texture, structure, stickiness, plasticity and friability. For example, the original land of El-Salhiya area featured by dark yellowish brown (moist) and light yellowish (dry), sandy, single grains, non sticky, non plastic and friable or loose characteristics had been changed to dark brown (moist) and dark yellowish brown (dry), sandy loam, moderate medium subangular blocky structure, sticky, plastic and firm hard dry after 30 years of cultivation. The same changes, approximately, were observed as a result of cultivation processes in El-Moullake, El-Nobariya and south Tahrir areas. Also, the 2
virgin soil of north Tahrir area featured by light yellowish brown (moist) and yellow (dry), sandy clay loam, weak fine granular structure, slightly sticky and slightly plastic characteristics had been changed to brownish yellow (moist) and very pale brown (dry), clay loam, moderate medium subangular blocky structure, sticky and plastic after 30 years of cultivation. The values of the RHD of the studied profiles are listed in Table (2). It appears that the virgin profiles of El-Moullake, El- Salhiya and San El-Hagar areas are characterized by partially high horizontation, On other hand, the virgin profiles of El- Nobariya, North Tahrir and South Tahrir areas have the lowest RHD values indicating slight horizontation or differences between the individual horizons. Also, values of RHD in soils cultivated for last stage of land use appears distinctness of the surface layer in comparison to the subsequent. The soils cultivated for 30 years in studied areas which have a high values of RHD indicated that the differences noted between the horizons are greater than that of the virgin and other cultivated soils. The high RHD ratings for last stage of land use could be attributed to the intensive anthropic influences through longer cultivated period. Values of RPD ratings of the studied profiles in different studied areas are listed in Table (2). It can be seen that the profiles of virgin plots have the lowest RPD ratings. The Relative Profile Development ratings partially increased with increasing the land use period. Results show that the soils cultivated for 30 years have higher values of RPD. This indicates that such soils attained, relatively, greater pedological development than the case of the virgin land and the cultivated soils for shorter periods, On the other hand, the subsequent deep layers of those soils remained mostly unchanged. In regard to the changes of some physio-chemical properties as a result of cultivation processes, the analytical data of surface layers of virgin land and the cultivated soils in different studied areas are given in Table (3). These data show increases of fine fraction and organic matter content, as well as F.C., C.E.C and Ex.(Ca + Mg) with increasing the period of cultivation in all studied areas. This might be due to the sedimentation of fine particles carried by the irrigation water and cultivation practice, and both to surface additions of organic manures and plant residue. With regard increase of Ex.(Ca + Mg) is may be due to the leaching of soluble salts of Na and K easily more than that of Ca and Mg by irrigation water with presence of carbonate and gypsum. On the other hand, T.S.S, Ex. (Na + K), CaCO3 and gypsum levels correspondently decreased as a result of cultivation in most studied areas. The decrease of salinity and gypsum with increasing time of cultivation can be explained by the removal of these components from the inital open textured soil by irrigation. The decrease of CaCO3 is due to the increase in its solubility caused by the application of orrigation water and enhanced by the presence of CO2 evaluated through decomposition of organic matter.the relatively increase of salts and carbonate as well as exchangeable cations within soil surface as a result of cultivation in some areas is may be due to the combined action of evaporation, plant transpiration and redistribution of salts by irrigation water. The previous factors are effectively with presence of the ground water table near to the soil surface in cultivated soils than that of in virgin soil under the dry conditions. These results, partially, are in agreement with Badawi (1976) and Amer (1991). References: 3
Amer, A.M. (1991). " The effect of cultivation period on the physical properties of arid reclaimed soil". Egypt. J. Soil Sci. 31. No. 4, pp 421-436. Badawi, A.M. (1976). " Improvement of sandy and sandy calcareous soils in the A.R.E.". Ph.D. thesis, Fac., of Agric., Cairo Univ., Egypt. Bilzi, A.F. and Ciolkosz, E.J. (1977). "A field morphology rating scale for evaluating pedological development", Soil Sci., 124, 1: 46-48. Black, C.A. (1965). "Methods of soil analysis" Amer. of Agron. Inc. Pub., Madison, Wisconsin, U.S.A. F.A.O, (1970). " Guidelines to soil description ". F.A.O, Publications, Rome. Page, A.L."Ed", (1982). " Methods of soil analysis " Part 2, Soil Sci. Soc. Amer., Inc. Publ., Madison, Wisconsin, U.S.A. Keywords : morphological properties of soil, sandy soils, pedological development, anthropic influences. Mots clés : propriétés morphologiques, sols sableux, évolution pédologique, influences anthropiques 4