The Effects of Treated Wastewater on Soil Nitrogen Dynamics and Winter Wheat Growth under Different Groundwater Depth

Abstract

Sugar beet (Tribal variety) was cultivated in the winter season of 2004/05 in a previously established experimental drainage field at El-Serw Farm, Agricultural Research Station northeastern delta of Egypt near El-Manzala Lake. The experiment included three drain spacing treatments 15, 30, and 60m. The aim was to assess and evaluate the effects of drainage treatments and soil conditions and the extent of their impact on sugar beet yield. The results reveal that, five days after irrigation, the water table levels were 69, 44 and 39 cm and reached 110, 92 and 75 cm before the next irrigation for 15, 30 and 60 m drain spacing treatments, respectively. The water table depth varies depending on the drain spacing. In all layers, the hydraulic conductivity values were higher in 15 m drain spacing treatment than those in 30 or 60 m drain spacing treatments. Soil salinity (ECe) values were relatively affected by drain spacing treatments. In surface layer, the soil salinity value was 3.4, 4.1 and 5.3 dS/m for 15 m, 30 m and 60 m drain spacing treatments, respectively. Results indicate that spacing treatments highly affect sugar beet root diameters and lengths and consequently crop yield. Root diameters increased with decreasing drain spacing; average maximum root diameter was 32 cm, 26 cm and 20 cm for 15 m, 30 m and 60 m drain spacing treatments, respectively. There was an increment in sugar beet production with narrow drains spacing treatments; the yield being 34, 30 and 25 ton/feddan for 15 m, 30 m and 60 m drain spacing, respectively. (1 feddan= 4200m2)