Nitrogen Fertilization Effect on Phosphorus Remediation Potential of Three Perennial Warm-Season Forages
- Y. C. Newman *a,
- S. Agyin-Birikorangb,
- M. B. Adjeic,
- J. M. Scholberge,
- M. L. Silveirac,
- J. M. B. Vendraminic,
- J. E. Rechcigld and
- L. E. Sollenbergera
- a Agronomy Dep., P.O. Box 110500, Univ. of Florida, Gainesville, FL 32611-0300
b Dep. of Soil and Water Sci., P.O. Box 110510, Univ. of Florida, Gainesville, FL 32611-0510
c Range Cattle Research and Education Center, Univ. of Florida, 3401 Experiment Station, Ona, FL 33865
e Wageningen Univ., Biological Farming Systems, Marijkeweg 22, 6709 PG, Wageningen, the Netherlands
d Gulf Coast Research and Education Center, Univ. of Florida, 14625 CR 672 Wimauma, FL
Warm-season C4 grasses are capable of removing excess soil nutrients because of their high yield potential and nutrient uptake efficiency. Bahiagrass (Paspalum notatum Flügge), limpograss [Hemarthria altissima (Poir.) Stapf & Hubb], and stargrass (Cynodon nlemfuensis Vanderyst), three commonly used pasture grasses in South-Central Florida, were grown to examine the effect of increasing N rates on herbage production and soil P removal. Nitrogen was applied at rates of 67, 90, and 134 kg N ha−1 harvest−1, representing 1, 1.3, and 2 times the recommended N fertilizer application rate for hay production. During 3 yr of evaluation, all three grasses showed a positive P-removal potential that increased with increasing N fertilizer application. Phosphorus removed by forages over the 3-yr period for the highest N application rate was 106, 132, and 147 kg ha−1 for limpograss, bahiagrass, and stargrass, respectively. Mehlich 1 extractable P from the Ap horizon of all plots decreased by as much as 80% of the initial P load over the study period; only ∼15 to 17% of which appeared to leach to subsurface horizons. Nitrogen application enhanced P uptake and consequently reduced P transport to deep (>13 cm) soil depths. These data indicate that stargrass, bahiagrass, and limpograss managed intensively for hay production represent effective options in removing excess soil P from P-impacted sites.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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