تأثير الإضافة المتقطعة للماء من مصدر تنقيط على حركة الماء و توزيع الرطوبة في تربة طباقية

الملخص EN

The aim of this research is to study the effect of intermittent water applicationon the wetting pattern and soil moisture distribution for homogeneous andlayered soils under trickle source.

Thirty experiments were conducted to monitorthe advance of the wetting front in the soil profiles.

Measurements of soilmoisture content were also made at selected locations to evaluate the moisturedistribution in soil.

Four types of soil profiles were built; the first was sandy loamsoil, the second was silty clay loam soil, the third was (silty clay loam/ sandyloam) layered soil, and the fourth was (sandy loam/ silty clay loam) layered soil.

Three water application rates were used for each soil profile.

Three continuousor intermittent applications were used; continuous applications, equallyintermittent applications, and different intermittent applications.

In addition, several cylindrical infiltration tests were conducted to describe somecharacteristics of each soil.

Empirical relations to predict each of vertical (under trickle source) andhorizontal (at soil surface) wetting front advance were found in this study.

Empirical relations to predict the percentage of applied water volume inhorizontal strips as a function of soil depth and in vertical strips as a function ofhorizontal distance from the trickle emitter were also found.

The study showedthat the wetted soil volume increases as either the water application rateincreases, or the intermittent application ratio increases.

Also, it showed that theratio of horizontal advance to vertical advance of wetting front increases as eitherthe water application rate increases, or the intermittent application ratiodecreases.

The study demonstrated that the accumulated ratio of waterapplication volume at a certain soil depth from trickle source increases as theintermittent application ratio decreases.

Also, it demonstrated that theaccumulated ratio of water application volume at a certain horizontal distancefrom trickle source decreases as the intermittent application ratio decreases.