Cover Crop and Pre-Emergence Herbicide Combinations in No-Tillage Fresh Market Cucumber Production

A field study was conducted to determine the effect of various pre-emergence (PRE) herbicide (clomazone, ethalfluralin, and halosulfuron) combinations with or without a winter rye (Secale cereale L.) cover crop on control of smooth crabgrass [Digitaria ischaemum (Schreb. ex Schweig.) Schreb. ex Muhl.] and redroot pigweed (Amaranthus retroflexus L.) in no-tillage 'Daytona' cucumber Cucumis sativus L.) production. Winter rye provided a significant advantage for weed control compared with the no-cover-crop production system. In the absence of herbicides, winter rye reduced redroot pigweed and smooth crabgrass densities up to 69 and 89%, respectively, compared with no winter rye at approximately 60 days after transplanting (DAT). Furthermore, the use of a winter rye cover crop increased the level of weed control achieved by herbicides at 56 DAT in two of three years for each weed species. Winter rye enhanced early marketable cucumber yields (from 2,008 to 6,100 kg·ha⁻¹) under drought conditions in 2002, while winter rye suppressed early marketable yields (from 14,883 to 9,367 kg·ha⁻¹ and 16,117 to 13,600 kg·ha⁻¹ in 2003 and 2004, respectively) when sufficient moisture and cooler spring temperatures were present. During drought conditions in 2002, no-tillage treatments with clomazone ethalfluralin and clomazone+ethalfluralin+halosulfuron produced similar yields; however, under high moisture and cooler conditions in 2003 and 2004, no-tillage treatments with clomazone + ethalfluralin + halosulfuron produced greater early- (~16%) and total-season (~25%) marketable yields than treatments with clomazone+ethalfluralin. Weed control is essential to obtain optimal cucumber productivity, as simple correlations indicated that cucumber yields were highly correlated to smooth crabgrass and redroot pigweed control. Cover crops, such as winter rye, can be integrated in vegetable production systems along with labeled herbicides as a sustainable approach to improved weed management.