FOLLOW-UP OF CHANGES IN SOIL PROPERTIES AS A RESULT OF LONG PERIODS OF LAND USE IN EL-FAYOUM GOVERNORATE, EGYPT

ABSTRACT
The main objective of this study was concentrated in monitoring the changes in some soils properties as a result of various agricultural practices in the long term of land use (0. virgin soil, 8 and 20 year) on some chemical and physical properties of sandy and loamy soils, at El- Fayoum Governorate, Egypt.
In this study, four locations were chosen from district Yousef Al Seddik. i.,e Sydna ELkhder Village, Sydna Moussa Village and Yousef ELSedeq Village where, these three locations representing sandy soil. The fourth location was chosen at EL-Wlaa Village to represent loamy texture soil. Nine soil profiles at soil depths of  0–30 and 30-60 cm were chosen from each location to representative the three application periods. Samples of irrigation water resources were taken from each region i.e. Bahr Qarun Wadi Al-Rayyan Lake, for the first three locations and (Yousef Al-Siddiq region,) irrigated by the water of Bahr Qaroun.
The obtained data showed that soil salinity (EC) was increased up 4.96-9.1, 5.42-14.8, 14.6-24.2 and 15.0-24.8 dSm^-1, soil pH decreased from 7.9 to 7.7, 8.05 to 7.5 , 7.9 to7.51 and 8.1 to 7.2, O.M content (%) increased and reached to 0.34-0.85, 0.74-0.9, 0.68-0.97and 0.67-0.94%, the content of total calcium carbonates tend to decrease to reach 30.2 to 16.4, 20.5 to 14.5, 22.2 to 14.3 and 11.3 to 5.6% for the surface layers after 20 years of agricultural practices compared to virgin soil at Sydna ELkhder Village, Sydna Moussa Village, Yousef ELSedeq Village, and EL-Wlaa Village areas, respectively.
Soil texture changed from sand in the virgin soils to sandy loam at Sydna ELkhder Village, Sydna Moussa Village and Yousef ELSedeq Village. While, it changed from loamy to clay loam in EL-Wlaa Village.
Data showed also, that in all sandy locations area the quickly drainable pores (Q.D.P) and slowly drainable pores (S.D.P)were decreased while, water holding pores (W.H.P), fine capillary pores (F.C.P) and total porosity were increased, the bulk density was decreased from 1.66 to 1.31, 1.62 to 1.38, 0.63 to 1.35 and 1.35 to 1.28 g/cm³, hydraulic conductivity was decreased from, 15.5 to 10.5, 14.6 to 10.5, 14.5 to 10.5 and 9.7 to 5.02 cm h¹, at so, penetration resistance was decreased from 50.7 to 42.3, 50.5 to 45.2, 50.4 to 44.2, and 44.2 to 38.2 kg cm² in the surface layers after 20 years of applying agricultural practices at Sydna ELkhder Village, Sydna Moussa Village, Yousef ELSedeq Village and EL-Wlaa Village locations, respectively.
Soil moisture constituents as field capacity (F.C), wilting point (W. P) and available water (A.W) are high after 20 years of agricultural practices. It can be concluded that, agricultural practices can have many beneficial effects such as decreasing bulk density, hydraulic conductivity, penetration resistance, total calcium carbonate and pH. On Contrary, the total porosity, ECe, O.M and soil moisture constant were increased.
Finally, found from this study that the only negative impact of the exploitation of the soil for long periods is to increase in soil salinity, which results from a decrease in the class of irrigation water used. This effect can be addressed by exploiting those lands by cultivating these lands with salt-tolerant crops.