Dry matter yield and tissue flow of <em>Cynodon spp,/em>. cv. Tifton 85 in response to nitrogen doses

Abstract

The objective of this study was to determine dry matter production (DMP) and tissue flow of Tifton 85 bermudagrass (Cynodon spp.) under the effect of four doses of nitrogen (NO-O, N1-45, N2-90, N3-135 mg/kg soil) in the form of nitrate of ammonium in a randomized design, with five replications. Nitrogen increased DMP of leaves and stems (p < 0.05), but it did not influence the DMP of roots, stem/leaves ratio and percentage of senescence material (p > 0.05). The DMP of leaves presented quadratic behavior in response to the nutrient up to the dose of 90 mg/kg. With regard to the tissue flow, the highest doses of N caused higher leaf elongation rate, higher leaf emergence rate and larger number of live leaves per tiller (p < 0.05). The rate of senescence was the highest for control (p < 0.05), while the number of tillers per plant did not show any response to N treatments (p > 0.05). For maximum dry matter yield of Tifton 85 bermudagrass, higher doses than the used in this experiment would be necessary, while for stems the maximum yield was reached with 133,5 mg N/kg soil. The 135 mg/kg N dose had greater influence on the tissue flow of the plant. The rate of leaf elongation and number of live leaves per tiller were better correlated with the dry matter yield. A low rate of senescence is of basic importance for the maintenance of a high number of live leaves per tiller. Tifton 85 bermudagrass crude protein provided higher values when 135 mg N/kg soil was used.