Biofortification of urochloa brizantha with nitrogen and sulfur and biomass quality

Abstract

The protein quality of pastures in Brazil is low and almost always related to total protein. Determinations of amino acids and soluble proteins are rare. The two main nutrients associated with forage production and quality are nitrogen and sulfur. Both are directly associated with the synthesis of amino acids and proteins, however they are rarely applied together. The objective of the work will be to evaluate the production and protein quality of the pasture with application of nitrogen doses in the presence and absence of sulfur. The experimental design will be completely randomized in factorial 4x2, with 4 replications. The treatments will consist of four doses of N (0, 150, 300 and 450 mg dm-3 of soil), combined with the absence and presence of sulfur (100 mg dm-3 of soil). The following evaluations will be carried out: gas-exchange measurements, chlorophyll a fluorescence, photosynthetic pigments, biometric measurements (tillers, dry matter), accumulation of macronutrients in the shoot biomass, forage bromatology, reserve proteins, qualitative analysis of amino acids. The data will be analyzed using analysis of variance (ANOVA, p <0.05). The mean of the values will be compared using the Tukey test. When the effect of doses is significant, the data will be submitted to regression analysis and adjusted to linear or quadratic function.