Analyses indicated no significant differences in yields between black-plastic-covered perennial system (BP) and matted row (MR) treatments in 2012 and 2013, but the researchers found that yield in BP was significantly lower than in MR in 2014. "Based on the three harvest years, we would recommend two harvest seasons for the BP system, because plants declined for all cultivars in the third year. Plants in the MR system, however, were good for at least three harvest seasons," they said.