Effects of mulching and herbicide on weediness and yield in cultivated lingonberry (Vaccinium vitis-idaea L.)

Lingonberry (Vaccinium vitis-idaea L.) cvs "Sussi"; and "Sanna"; were cultivated on mineral soil with four different soil surface treatments (Sphagnum peat mulch, sand mulch, plastic mulch and herbicide 3-syclohexyl-5, 6-trimethylenurasil (lenasil)). Amount of annual weeds, plant coverage and yield were observed over five years. Weeds were most abundant in the first two observation years. Sand mulch was the least efficient for the control of annual weeds for both cultivars, whereas lenasil was the most efficient for "Sussi";, and peat mulch for "Sanna";. The plant coverage increased steadily throughout the years in the "Sussi"; plots, especially in plots mulched with peat. The spreading of "Sanna"; was slower in all treatments. It was best in plots mulched with peat or sand. Overall, "Sanna"; was more productive, with the highest yield on sand mulch and the lowest on lenasil-treated plots. "Sussi";, instead, yielded best on lenasil plots and poorest on sand.