Nitrogen and Sulphur On Marandu Palisadegrass Root System.

Well-developed root systems ensures adequate plant growth and shoot, reduces regrowth period after plants are harvested, increases biomass production and resistance to drought conditions, and promotes nutrients utilization efficiency. The objective of this study was to evaluate the effects of various N and S application rates on roots dry mass and total roots length and surface of Brachiaria brizantha cv. Marandu (Marandu palisadegrass). The experiment was conducted under greenhouse conditions, in Piracicaba, Sao Paulo State, Brazil, from September to December, 2008. Soil was an Entisol that exhibited low organic matter content (0.95%), pH CaCl₂ = 4.0. Treatments consisted of fractionated factorial combination of five N rates (0; 100; 200; 300; and 400 mg dm^-3) and five S rates (0; 10; 20; 30; and 40 mg dm^-3) with four replications. Aboveground forage biomass was harvest three times at 28-d intervals. At the end of the study, root samples were collected and evaluated for dry mass production, and total length and surface area. Maximum roots dry mass (83.65 g/pot) of the Marandu palisadegrass were obtained with 299 mg dm^-3 of N combined with 28 mg dm^-3 of S (10.6:1 ratio). Total root length and surface increased with N rates, with the maximum root surface (5784.28 cm²/pot) being obtained at N rate of 322 mg dm^-3. Results showed that root dry mass was affected by the combination of N and S application, while N showed effects on total roots length and surface.