The objective of this study was to evaluate the nutritional value of Tifton 85 grass (Cynodon dactylon (L) Pers) cultivated in a vertical flow constructed wetland (VFCW) system treating raw sewage. The VFCW operated according to the French system, but with only the first stage and two units in parallel, using a small footprint of 0.6 m2 per inhabitant. Wastewater feeding and resting periods were of seven days each. To evaluate the yield and nutritional value of the Tifton 85 cultivated, samples were collected after 30, 45, 60, 75 and 90 days of growth. They showed yields of 16, 28, 36, 36 and 38 t·ha−1 of dry matter (DM), respectively. The crude protein content decreased sharply during 60 days, however, with values of 29, 23, 15, 15 and 15% DM for the same days, respectively. The results indicate that Tifton 85 could be used for hay production and, to obtain better yield and quality, when used to treat raw wastewater, the forage should be cut after between 45 and 60 days of growth.
The study evaluated the nutritional value of Tifton 85 grass cultivated in a vertical flow constructed wetland system treating raw sewage.
The nutritional values of Tifton 85 were considered suitable for animal feeding.
The recommended Tifton 85 harvest time period was between 45 and 60 days of growth, because crude protein content decreased after this.