Xylem resistance to drought-induced cavitation is a key trait of plant water relations. This study assesses the genetic variation expressed for stem cavitation resistance within a population of a riparian species, the European black poplar (Populus nigra L.), and explores its relationships with xylem anatomy, water-use efficiency (WUE), and growth. Sixteen structural and physiological traits re...

center pivot irrigation system is used as a modern irrigation method in different parts of iran. unfortunately due to lack of proper design and hydraulic shortcomings of the system in several agricultural lands in iran, the efficiency of the center pivot irrigation system is low or unacceptable. low system efficiency results in non-uniformity of water distribution along the lateral and on the c...

Hydraulic traits were studied in temperate, woody evergreens in a high-elevation heath community to test for trade-offs between the delivery of water to canopies at rates sufficient to sustain photosynthesis and protection against disruption to vascular transport caused by freeze-thaw-induced embolism. Freeze-thaw-induced loss in hydraulic conductivity was studied in relation to xylem anatomy, ...

Transroot osmotic water flux (Jos) and radial hydraulic conductivity (Lpr) in onion roots were greatly increased by three means; infiltration of roots by pressurization, repetition of osmosis and chilling at 5 degrees C. Jos was strongly reduced by the water channel inhibitor HgCl2 (91%) and the K+ channel inhibitor nonyltriethylammonium (C9, 75%), which actually made the membrane potential of ...

This paper describes the scientific principles of Darcy’s law and hydraulic resistance as they relate to the in-ground dispersal of onsite wastewater effluent. A clear understanding of how water moves into the ground via dispersal trenches is needed to facilitate proper system design and effect some standardization of dispersal trench sizing and design. Hydraulic conductivity of the media, hydr...

In these notes on drainage design procedure, three drain spacing formulae are considered suitable for designing sub-surface drainage systems. The Hooghoudt and the Kirkham-Toksoz formulae have been developed for steady state conditions and the Glover formula is applicable to the transient state condition. The steady state condition implies that the surface inflow is equal to the outflow through...

Hydraulic conductivities of sands with different gradation and grain shape were estimated experimentally at a relative density (Dr) of about 40 % and a 22 ± 2 °C of constant temperature. Narli Sand (NS) with 0.67 of sphericity (S) and 0.72 of roundness (R), and Crushed Stone Sand (CSS) with 0.55 of S and 0.15 of R values were artificially graded into sixteen different grain-size fractions (4.75...

Koot - Hamoodi are two units from seventh units out of 1&2 irrigation and drainage network in Dasht-Azadeghan project where was past about 7 years from their operation. Results of the studies were showed before construction of network; ground water table in considered of this area was high and more than 90% of these lands were high and too high in saline and alkaline. After construction and ope...