Influence of limestone and phosphogypsum on bahiagrass growth and development
1993
Rechcigl, J.E. | Mislevy, P. | Alva, A.K.
Liming of soil to attain a target pH of 5.5 has been believed to be an essential practice of bahiagrass (Paspalum notatum Fluegge) management. A study was conducted to evaluate the response of bahiagrass grown on a virgin Ona fine sand (sandy, siliceous, hyperthermic Typic Haplaquod) of pH 4.5 to application of either calcitic limestone (0, 1.1, 2.2, 3.3, 4.4, or 6.6 Mg ha-1) or phosphogypsum (2.2 or 4.4 Mg ha-1). 'Pensacola' bahiagrass was seeded in August 1987. Treatments were replicated four times in a randomized complete-block design. Although the addition of 6.6 Mg lime ha-1 increased soil solution pH from 4.5 to 6.0 and decreased the activity of monomeric Al from 45 to 17 micromolar, root growth down to the 90-cm sampling depth and dry matter yields during 3 yr were not improved by liming. Application of phosphogypsum also reduced both root growth and dry matter yields. Soil pH (0-15 cm) 41 mo after the application of various amendments averaged 4.5 for the control, 4.2 for the 4.4 Mg phosphogypsum ha-1 treatment, and 6.0 for the 6.6 Mg limestone ha-1 treatment. Soil pH averaged 5.1 and 5.2 at the 45- to 60- and 75- to 90-cm depths, respectively, regardless of treatments. Exchangeable Al averaged 35.4 mg kg-1 at the 0- to 15-cm depth and 23.4 mg kg-1 at the 75- to 90-cm depth in unamended treatments. Aluminum saturation in 1990 ranged from 48.2 to 85.5% on the control plots. Lime application decreased exchangeable Al and Al saturation percentage by 10-fold in the upper 15 cm. This study showed no significant increases in forage yield of bahiagrass from increasing the soil pH above 4.5.
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