Inhibiton of Yellow Nutsedge (Cyperus esculentus L.) and Bermudagrass (Cynodon dactylon (L.) Pers) by a Mulch Derived from Rye (Secale cereale L.) in grapevines

Abstract

A B S T R A C TTwo field trials (Los Andes 1998-1999 and Santiago 2004-2005) were carried out to determine growth inhibition of yellow nutsedge (Cyperus esculentus L.) and bermudagrass (Cynodon dactylon (L.) Pers.), growing on the plantation row, by mulch derived from a rye (Secale cereale L.) cover crop established between grapevine (Vitis vinifera L.) rows on overhead (cv. Flame Seedless) and vertical (cv. Cabernet Sauvignon) training. Spring mowing of the rye sown in the fall allowed for developing a thick and long lasting mulch along the grape rows. Nutsedge and bermudagrass control was 81 and 82%, respectively, and was more effective than conventional chemical (in the row) + mechanical (between rows) control. Glyphosate at 2% for nutsedge and 1% for bermudagrass control, applied twice (October and December), was insufficient to control either perennial weed adequately. Total broadleaved and grass/sedge weed control was 67.3 and 43.0% more effective with the rye mulch than with conventional treatments at Los Andes and Santiago, respectively. Perennial weed control levels could be explained as the new foliage of yellow nutsedge and bermudagrass was particularly susceptible to the shading provided by the rye mulch assembled prior to mid spring shoot emergence, and this effect remained active up until the beginning of autumn. The subsequent rye foliage mowing at the vegetative stage fully expressed the allelopathic effect produced by this local rye cultivar. The use of rye cover crop management and mulch could be applied as an effective weed control technique in conventional, as well as organic deciduous tree orchards. Key words: mulch, cover crop, rye, Cynodon dactylon, Cyperus esculentus, grapevines.INTRODUCTIONWeeds that grow in orchards represent one of the main restrictions to the growth and development of the trees. Perennial species that have some type of vegetative reproduction are the most difficult to control, whether by mechanical methods or with herbicides (FAO, 1986). Among this group of invasive weeds, the yellow nutsedge and bermudagrass have been identified as among the most harmful species of weeds at a global level. They are especially problematic when they grow in the tree rows of fruit and vine orchards (Johnson and Talbert, 1989; Ormeno, 2005). Cover crops planted between orchard rows are an efficient and sustainable alternative to manage the soil in temperate climates. In effect, the use of a cover crop between orchard rows has extensive application, especially in California, USA, where it now covers 20% of cultivated vineyard areas (Ingels and Klonski, 1998). One of the main applications of cover crops is for the management and control of weeds (Elmore et al., 1998).Of the great variety of vegetal species that can be used as cover crops, rye is one of the most appropriate (Bottenberg et al., 1997; Ormeno, 1999). This grass is a winter cereal used marginally as a flour grain and as supplementary forage. It is very rustic, given that not only is it tolerant to low temperatures and soil moisture, but it also posses high foliar and subterranean condition against insects and diseases, and is itself an allelopathic crop on weeds (Barnes and Putnam, 1983;