Intercropping of signal grass and soybean: productive performance of the crops and nutritional characteristics and quality of silage

The objective was to evaluate the culture of signal grass and soybean intercropping or in single cultures on the production of dry matter (DM) and crude protein (CP) and total digestible nutrients (TDN) per ha. It was evaluate, also, contents of CP, neutral detergent fiber (NDF), lignin (LIG), non-fibrous carbohydrates (NFC), NDT, butyric acid and lactic acid, ammonia nitrogen, the content of DM and pH of these silage cultures harvested in two phenological stages (R6 and R7) of the soybean plants. The production of DM was greater in signal grass in single culture, regardless of the vegetative stage. The DM content of signal grass silage in single culture was low in both vegetative stages (19.55 and 19.49%). In silages from signal grass and soybean intercropping and soybean in single culture, the content of DM was higher in the R7 vegetative stage. Regardless of the vegetative stage, soybean in single culture produced higher content of CP, NFC, LIG, TDN and higher amount of CP, followed by signal grass and soybean intercropping and signal grass in single culture, which showed inverse behavior for NDF content. The amount of TDN obtained in signal grass and soybean intercropping and soybean in single culture increased from the R6 to R7 vegetative stage, whereas in signal grass in single culture, decreased with advancing of the crop maturities. In all silages, harvested in the two vegetation stages, the values of pH and butyric acid were high and the values of lactic acid were low. In the R7 stage, ammonia nitrogen level of the silages was lower than the R6. It is feasible to use the signal grass and soybean intercropping for silage production, being recommended to harvesting the crops in R7 vegetative stage of the soybean plants.