Aluminum Tolerances of Ten Warm-season Turfgrasses

Acid soils are abundant in tropical and subtropical regions and account for approximately 40 percent of arable land in the world. Next to oxygen and silicon, aluminum (Al) is the third most abundant element in soils and is the main toxic factor for plant growth in acidic soils. Therefore, two glasshouse studies were conducted to determine the influence of Al on root and shoot mass and nutrient uptake of ten warmseason turfgrass species. Turfgrasses selected included ‘Pensacola’ bahiagrass (Paspalum notatum Flugge.), buffalograss (Buchloe dactyloides [Nutt] Engelm.), ‘Isle’ seashore paspalum (Paspalum vaginatum Swartz.), centipedegrass (Eremochloa ophiuroides (Munro) Hack.), common carpetgrass (Axonopus affinis Chase.), ‘Princess 77’ dactylon bermudagrass (Cynodon dactylon var. dactylon), ‘Meyer’ Japanese lawngrass (Zoysia japonica Steud.), manilagrass (Zoysia matrella (L.) Merr.), ‘Raleigh’ St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze.), and ‘TifEagle’ hybrid bermudagrass (Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy). In study I, Al was applied at 240, 480, and 720 μm and phosphorus (P) was applied at 0.425 kg ha-1 day-1, while in study II, Al was applied at 480, 960, and 1440 μm and P application levels were reduced to 0.0425 kg ha-1 day-1. Root and shoot samples were separated, dried, and weighed at the conclusion of both studies and tissue samples were analyzed for nutrients (N, P, K, Ca) and Al concentrations. Japanese lawngrass, manilagrass, and centipedegrass experienced the least root growth reductions as Al increased. These species increased 1%, 24%, and 23% in relative root growth at 480 μm of Al. At the same concentration, St. Augustinegrass and seashore paspalum decreased relative root growth by 31% and 30%. As Al increased to 1440 μm, all species, except for carpetgrass (15% increase) and manilagrass (30% increase), exhibited a reduction in relative root growth. Significant differences were reported for relative P recovery. Japanese lawngrass increased relative root P recovery (5%) and manilagrass minimized relative root P recovery (15%), while buffalograss and bahiagrass decreased relative root P recovery by 72% and 35%, respectively.