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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />3 <br /> <br />for each plant species by periodic weighing of pots. Water treatment was applied in a partially <br />subsurface perforated containers to avoid direct contact between foliage and irrigation water <br />(plants can absorb salts through the leaves). Leaching was kept to a minimum. Plants were <br />planted by seed 2 cm below soil surfaces, grown in a temperature-controlled greenhouse using a <br />24:!:20C day/night temperature regime with an average photon flux density of 400 Jimol m"s-l. <br /> <br />Tall fescue was initially clipped 60 days after planting and then clipped in 20-30 day intervals. <br />Final harvest was 35 days after previous clipping. Both types of birds foot trefoil were initially <br />clipped 120 days after planting and then clipped in 30-35 intervals. Clipping "four" for birdsfoot <br />trefoil was conducted =50 days after previous clipping. Clipping interval regimes were <br />subjectively determined based on visual regrowth, on or about in 30 day intervals, when possible <br />for all species. Generally, clipping was perfonned to an approximate height of 10 cm above soil <br />surface. Plant material was processed at a future date. Approximately 317 days after planting, all <br />plant species were completely harvested 2 cm above the soil surface. Harvested and clipped plant <br />material was oven-dried at 50oC, dry matter (DM) yield recorded, and then ground in a Wiley <br />mill. Plant sub-samples were taken and then wet-acid digested and analyzed for Ca2+, Mg2+, and <br />Na+ by the inductively coupled plasma spectometry. Additional plant sub-samples were extracted <br />with 2% acetic acid and tissue Cl" concentrations were determined potentiometrically, Composite <br />soil samples were made from all replications within each treatment for each species and soil EC <br />(electrical conductivity in dS mol), pH, and soluble Ca2+, Mg2+, Na+, and Cl- concentrations were <br />determined at preplant and postharvest from a saturated soil paste. <br /> <br />Results <br /> <br />General observations <br />Tall fescue thrived and outperfonned both varieties of birds foot trefoil under the test conditions, <br />irrespective of treatment. Narrow-Ieafbirdsfoot trefoil appeared to grow and look better than the <br />broad-Jeaftrefoil under poor growing conditions (i.e., bad soil, poor irrigation water). Salt <br />toxicity symptoms (burning of the leaf margins) and stunting of growth began to appear in all <br />three species shortly after applying "poor If' quality water. <br /> <br />- <br />- <br /> <br />Biomass <br />Tall fescue was clipped ten times throughout the designated growing season, while narrow-and <br />broad-leaf birdsfoot trefoil were clipped six times. Generally, height of all plant species were <br />highest for the following at each clipping: treatments 1>4>2 (data not shown). Individual DM for <br />each clipping and total DM are presented in Table 3 and 4 for all species; a histogram overview of <br />DM production is shown in Figure 1, 2 and 3 for all plant species (final clipping or harvest was <br />higher in on Figures], 2 and 3 because each plant species was clipped to within 2 cm of the soil <br />surface). Tall fescue produced more DM than both varieties of birds foot trefoil at any treatment <br />and did not experience significant decreases in DM among the treatments. Narrow-leafbirdsfoot <br />produced more biomass than broad-Ieafbirdsfoot at any treatment. Moreover, the DM yield <br />appears to be stimulated in narrow-leaf by either "poor" quality water or "poor" quality soil. <br />