Thursday, November 8, 2007 - 10:45 AM
337-12
Saltgrass A50 Growth and Quality Responses to Nitrogen and Iron Fertility Management.
William Henry1, D.M. Kopec2, and James Walworth2. (1) Soil, Water and Env. Sci., Univ. of Arizona, Room 303 Bldg 36 Plant Sci Dept, Univ. of Arizona, Tucson, AZ 85721, (2) University of Arizona, Department of Plant Sciences, Forbes Bldg., Room 303, Tucson, AZ 85721
A field study was conducted to determine the effects of applied nitrogen and iron on aspects of growth, color, and overall visual quality to determine the best cultural management scheme for A50 Inland saltgrass (Distichlis spicata). Ammonium sulfate (NH4)2SO4 and ferrous sulfate (FeSO4) were used as the N and Fe sources. Four fertilizer N levels and two Fe fertilizer levels were applied monthly from June to October 2006. Monthly N rates were 0, 48, 97, and 195 kg N ha-1; Fe was applied at 0 and 18 kg ha-1. Four replications of each fertilizer treatment/combination were used in a full-factorial design. Plots were mowed 2-3 times weekly at 7.5 cm. The test was irrigated two to three times weekly to prevent drought stress. Visual evaluations were made to determine color, quality, density, and percent plot canopy composition. Clippings were collected approximately two weeks following each fertilizer application. The best visual turf quality and the highest amount of clippings resulted from application of 48 kg N ha-1, averaged over all Fe levels. The best color ratings, when averaged across both Fe levels, occurred when no nitrogen was applied. Zero application of iron resulted in the best color and quality ratings, although the application of 18 kg Fe ha-1 produced the highest yield of clippings. There was a non-linear relationship for the applications of iron and nitrogen for all visual quality measurement responses of saltgrass A50. Overall, the results show that saltgrass A50 did not respond favorably to Fe applications as overall color and quality diminished over the season. There was no benefit of increasing applied N to above 48 kg ha-1.