Wednesday, November 15, 2006
285-22

Bahiagrass Genotypic Root Variation and its Effect on Soil Nitrogen.

Cheryl Mackowiak, University of Florida - Agricultural Research Center, University of Florida-NFREC, 155 Research Rd., Qunicy, FL 32351 and Ann Blount, University of Florida, NFREC, 3925 Hwy 71, Marianna, FL 32446.

Bahiagrass (Paspalum notatum Flugge) is the major summer pasture forage in Florida and throughout the U.S. southern coastal plain. It has a deep, extensive perennial root system that can be utilized in best management practices to protect water quality.  Improving 'Pensacola' bahiagrass above-ground yield via recurrent phenotypic selection procedure has had an unknown effect on rooting structure form and function.  Bahiagrass cultivars (‘Tifton 9’, ‘Argentine’, ‘Paraguay 22’ and ‘Pensacola’) and two experimental breeding lines (RRPS Cycle 23 and Tifton 7) were evaluated for rhizome-stolon mass, root mass and nutrient uptake.  Both, diploid and tetraploid lines were tested since ploidy level is believed to influence the size and possibly the capacity of the rhizome-stolons to store nutrients. Bahiagrass genotypes were planted at the North Florida Research and Education Center, Quincy, FL in 2002. In 2003 and 2006 plots were cored to examine rhizome-stolon and root production under low fertility. During establishment (2003), Tifton-9 had the greatest stolon and total root mass (0 to 120 cm soil depth) but by 2006, Paraguay 22 and Pensacola had significantly greater total root mass than RRPS Cycle 23, and Pensacola also had greater root mass at the 80 to 105 cm soil depth than RRPS Cycle 23.  There were no significant differences among the other cultivars at this or other tested soil depths.  Improved subsoil nitrate capture tends to be greater with more deeply rooted plants.  Experimental breeding lines, such as RRPS Cycle 23 that are developed for above ground growth will not likely enhance nutrient removal unless root and storage components are also selected for.  Simultaneously selecting for below ground attributes such as those observed in Pensacola will complement progress in forage yield while also enhancing nutrient recovery.

Back to Nitrogen and Micro Nutrient Fertility Management
Back to S04 Soil Fertility & Plant Nutrition

Back to The ASA-CSSA-SSSA International Annual Meetings (November 12-16, 2006)