Improvement of clayey soil drainage in Dakahlia governorate [electronic resources].

Includes reference.

Sub-soiling system was conducted in order to alleviate the disadvantage which developed by soil compaction. A comparison made between field treatments which tilled by chisel plough at 20 cm depth and the technique of sub-sailer plough with differences in the sub-soiling depths (25, 50, and 75 cm) and the lateral spaces between sub-soiling ruts (200, 400, and 800 cm). Each techniques of the sub-soiling depth were replicated with all of the different distance of lateral spaces between subsoiling ruts. The aim of the comparison was to indentify the most effective sub-soiling technique which produce more enhancement of soil physical properties, achieve the best distribution of soil moisture content and achieve the highest rate of soil water flux. Results indicated that, the plot of soil which was tilled at 75 cm with a lateral space of 200 cm, recorded t1e lowest moisture content values and exhibited the highest values of soil penetration resistance. It exhibited more enhancement of soil physical properties as the action of the excess loosening occurred from the deep tilling with the narrower lateral space lead to increases soil porosity, improve permeability, decrease soil strength to low values in comparison with their values before sub-soiling. The soil plot which tilled at 50 cm with a lateral space of 200 cm were also achieved more enhancements. Those plots were also recorded high correlation coefficient consideration to the three irrigations. It was found 95.16 and 94.97 % at the first irrigation, 95.54 and 95.47 % at the second irrigation and 95.45 and 95.28% at the third irrigation for the plots of 75 and 50 cm, sub-sailer depth and 200 cm, lateral space respectively.

Summary in Arabic.

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