Cover crop et soil reclamation
Signal grass provides a good ground cover, improves fertility as well as soil structure in banana plantations and in many other environments (Vézina, 2015; Boddey et al., 1996). Signal grass deep and dense root system prevent soil erosion, it facilitates water infiltration, decreases leaching of soluble nutrients and sequesters high amounts of C in the soil (358 tons C/ha)(Saraiva et al., 2014; Boddey et al., 1996). It was also reported to be valuable cover crop in upland rice systems. Growing signal grass before rice produced higher rice grain yield with application of Ammonium sulfate and nitrification inhibitor (Rosolem et al., 2005). It was successfully used in tomato no-tillage systems to reduce weeds and improve soil structure (Silva Hirata et al., 2009).
Signal grass could be used for reclamation of sites contaminated with lead, nearby highways and urban areas where Pb contamination is likely to have occurred. Signal grass has been found considerably more tolerant to Pb than Rhodes grass (Chloris gayana), resulting in a 50 % reduction of Pb (Kopittke et al., 2007).
Weed potential and weed controller
It was shown that germinating seeds and leachates of green parts of signal grass had allelopathic effects on Phalaris canariensis, Lactuca sativa (standard species) and Melinis minutiflora. This could enhance its invasive potential in the Cerrados of Brazil (Barbosa et al., 2008).
It is used in China to make dense pasture cover for the control of the invasive, poisonous, Chromolaena odorata in China (Wu et al., 1991 cited by Cook et al., 2005). Among treatments, digging out of Chromolaena followed by burning and planting with signal grass was the most effective (Rusdy et al., 2013).
In banana agroecosystems, in the french West Indies, the cover crop signal grass (Brachiaria decumbens), is increasingly used to control weeds and to improve physical soil properties (Mollot et al.,2014). In these agroecosystems, it was shown that signal grass could enhance the number of Solenopsis geminata, a predator of the banana weevil (Cosmopolitus sordidus) and thus contributes to control this pest (Mollot et al., 2012).