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This study was done on wetlands of Manzala Lake, northeastern Nile Delta of Egypt, to evaluate the changes of some soil properties after rehabilitation and cropping for 10 years. Soil samples (0-80 cm depth) were collected randomly from selected sites in 4 reference wetlands sites and 4 cultivated sites with rice and cotton. Soil properties showed marked variation across the soil profiles. The obtained results showed that cultivation significantly accounted for the variance in soil properties between reference and cultivated wetland. Bulk density (Bd), hydraulic conductivity (K) and the electric conductivity (EC) were decreased while; total porosity (Tp), available water capacity (AWC) and organic matter (OM) were increased under cultivated areas compared with the reference wetlands. A significant difference in most of these soil properties under both rice and cotton was found between cultivation periods. The results also show that soil properties varied according to the cultivated crop. This study indicated a trend toward progressive soil development following wetland revegetation. Development of wetlands should be done.

A field experiment was conducted at the Agricultural Experiments and Researches Station, Faculty of Agriculture, Cairo University, Giza, Egypt, during 2008 season. The study aimed to investigate the effect of skipping irrigation water at some corn growth stages with the application of surface cover on grain yield, some yield attributes and water use efficiency. Five irrigation treatments were applied, viz. control treatment (T 1 ), skipping irrigation at, the vegetative stage (T 2 ), grain filling stage (T 3 ), during both vegetative and grain filling stages (T 4 ) and after every irrigation event throughout the crop growth period (T 5 ). Results showed that skipping irrigation was combined with a reduction in yield components and yield. The highest and lowest reductions in the yield were recorded with T 5 and T 2, respectively compared to T 1 . Water deficit during vegetative stage had little effect on yield components and grain yield of corn. Mulched soil increased corn yield and its components compared with un-mulched one. Seasonal water evapotranspiration (ETa) was affected by skipping irrigation. The control (T 1 ), recorded the highest (ETa) value while, (T 5 ) recorded the lowest one. Mulching reduced (ETa) and increased water use efficiency (WUE). The highest (WUE) was achieved with (T 2 ) followed by (T 4 ) and (T 5 ), under un-mulched and mulched soil, compared with (T 1 ). Mulch enhanced the (WUE) as compared to the un-mulched one at all studied growth stages.

A field experiment was conducted to evaluate the effect of three tillage and three manure treatments on some soil physical properties, grain yield and some yield components of corn. The tillage treatments were no tillage (To), chisel plough to 10 cm (T 1 ) , and to 20 cm (T 2 ) soil depth. The manure treatments were, cattle manure (M 1 ), rice straw (M 2 ), and (½ cattle manure + ½ rice straw) (M 3 ). Measurements of soil bulk density (Bd) and soil penetration resistance (PR) were taken to quantify the ploughing depth. Available water capacity (AWC) was calculated for all treatments. The measurements were taken twice, after ploughing and before harvest. Yield and yield components (weight of 100 grain yield (gm), weight of ear (gm), and grain yield/fed.) were obtained. The data showed that the lowest (Bd) and (PR) were obtained in the surface layer of T 2 and M 2 treatments while, the highest (AWC) was recorded in T 0 and M 2 treatments. The results also showed that the highest 100 grain weight, ear weight and grain yield were obtained with T 2 as compared with T 1 and To. However, the difference among the ploughing treatments was not significant. Application of manure showed that the highest 100 grain weight, ear weight and grain yield of corn were recorded with (M 2 ) comparing with (M1) and (M3) treatments. Interaction effect between ploughing depth and manure treatments influenced the grain yield, and the yield components. The combination treatment (T 2 M 2 ) recorded the highest 100 grain weight, ear weight and grain yield. A significant difference between (T 2 M 2 ) and (T 2 M 3 ) was obtained. These results concluded that the combination of soil ploughing to 20 cm depth with the application of rice straw increased corn grain yield. This increase is due to the effect of tillage and the incorporation of rice straw on the improvement of the soil physical properties.

One of the factors critical to seed germination and plant development is good tilth. This study was conducted to calculate the tilth index (T1) under different tillage practices and two crops, wheat and faba bean in order to determine the optimum tilth index value for maximum yield of wheat and faba bean crops. Tillage practices applied were traditional tillage by different chisel ploughing passes {two (P2), four (P4), six (P6) and eight passes (P8)} and moldboard plough (Pm). Tilth index was calculated following the model suggested by . Five soil physical properties, soil bulk density, cone index, aggregate uniformity coefficient organic matter content, and plasticity index were determined for each tillage system to quantify (T1) according to the model. The calculated values of the tilth index were varied with tillage practices. The tilth index increased as ploughing passes increased. Tilth index increased from 0.52 to 0.67 under (P2) and (P8), respectively. However, the highest value was obtained with the moldboard plough (0.71).Yield of wheat and Faba bean also varied according to the tillage practices and to the (TI) values. The highest yield of wheat was obtained with (Pm) treatment which corresponds to (TI) value of 0.71, while Faba bean yield increased with (P6) treatment which corresponds to (TI) value of 0.59.It is concluded that the tilth index can be used to describe the physical conditions of the soil and as an indicator for the most effective tillage practices that achieve the maximum yield for a certain crop.