A field study was conducted in heavy clay salt affected soil at 83km along EI-
Salam canal (North plain Husseiniya) to evaluate suitability open drainage system
with 30-m space between the drains with two tillage depths 15 and 25-cm for
improving some physical and chemical properties of soil and to improve its
productivity. The data were collected through two growing season (Berseem, winter of
200012001 and Corn summer of 2001). Soil contents of total and available N.P.K. and some chemical properties (EC, pH, SAR and ESP) were studies. The soil samples were taken from four sites between the drains and the distances 10-m between all samples along the mid- way at depths 0-15,15-30,30-60 and S0-9Ocm. The obtained results showed that, the content of soluble salts EC, pH, SAR and ESP increased with the increase of soil depth and decreased with the increase of tillage depths. Also this decrease was clear in the surface layers compared with the decrease occurred in the down layers. Data show that, both total and available N, P and K decreased with increasing soil depth before and after drained and tillage treatment. This decreased In the N.P.K. values was more clear in the soil profile with drained and tillage depth 25-crn than with tillage depth 15-cm. This decreased may by due to the low content of organic malter and high soli pH values In the lower layers of soil profiles. The high loss of available N and P resulted from down movement of available and organiC matter with leaching water. Data also show that, the available (N) increase with tillage treatments. The calculated relative increases of N. were 7.4 and 20 % with tillage depth 25 and 15-cm of the soil " before tillage and drained. While, the values of the available (P and K) decrease with
tillage treatments, the relative decrease of (P and K) were 18.9 and22.3 %, 71.9 and
52.5% in the soil profile with drained and tillage depth 25-cm and 15-cm. The bulk density of the deeper layers is relatively higher than those of the
upper ones. The lowest bulk density is obtained in the solis provided with open
drainage and tillage depth 25-cm. With respect to the porosity, it was found out that,
the total porosity (E %) Increases with decreasing of the bulk density. The open
drainage system with tillage deep 25-cm is more efficient in Increasing soil hydraulic
conductivity comparing with the other process. Also, hydraulic conductivity increased
with Increasing electrolyte concentration but decreased with increasing SAR. The
lowering of CaC03 % content under open drained and tillage conditions may by due to
the high leaching and movement efficiency than before drained and tillage. The
organic matter's content decreases with increasing soil depth and tillage depth. The
drainage condition appears no effect on texture class because this soil parameter is
considered as initial, but the tillage operation one of the most treatments to be
changed. The regression equations and correlation coefficients (r) between the hydraulic
conductivity and each of EC, CaC03, clay, ESP and ASR. Also, between the
vavailable content of N, P and K and each of EC, ASR, and ESP were
computed. Results , also show that the yields obtained from the soil provided by drainage and tillage are higher than those obtained from the non- drained and tillage
soils.