| European type grapes (Vitis vinifera L.) account for over 90% of all grapes grown in the world. However, an extra so-called "winter-hilling" practice is required for winter protection of grafted vinifera grapes in northern states including Ohio. Winter hilling consists of two tillage activities. The first is to mound soil up to cover the graft union in fall for protection from lethal cold temperatures during winter, and the second is to remove the mounded soil in the next spring for prevention of rooting from the vinifera scion. Due to the intensive soil disturbance associated with winter hilling, any vineyard along a hillside is facing elevated risk for severe soil erosion. Along with soil erosion, any chemicals applied into the vineyard, such as fungicides, insecticides, herbicides and fertilizers, are also more likely to runoff during heavy rainfall. Loss of the fertile surface soil harms grapevines, and offsite movement of chemicals pollutes the environment. Therefore, there is a great research need to find a potential substitute to winter hilling.;In this study, we used simazine treated mulches (STM) to replace winter hilling and explored the following aspects: (1) weed population shifts as affected by winter hilling, (2) the efficiency of STM on weed control and herbicide resistant weed management, (3) grape production variables as affected by STM, including winter protection, nitrogen nutrition, fruit yield and quality, and (4) the potential of mulches as a mitigation tool to reduce chemical offsite movement.;The results indicated that winter hilling increased the number of weed species and density in vinifera vineyards relative to vineyards that had not been hilled. STM overall provided outstanding weed control, largely due to the season-long weed suppression by mulches. Pre-winter application of simazine herbicide resulted in little residual activity by the next spring, and simazine reapplication made in June controlled weeds but was not sufficient for the balance of the growing season. Triazine resistant (TR) common lambsquarters became more prevalent in response to simazine treatment, contributing to the low efficiency of simazine on weed control. However, simazine treated bark suppressed common lambsquarters and did not result in accumulation of a more TR population. These results suggested that STM could be used as a tool for management of TR weeds in vineyards. STM protected the graft union through winter and conserved soil moisture. The effect of STM on grape yield varied on different varieties from year to year, but overall STM either had no effect or increased grape yield. The fruit quality of grape was not affected by STM with the exception that sugar content in juice of Auxerrois was lower than un-mulched treatment one of two years. Lastly, the in-lab simulation trial indicated that straw reduced simazine leaching and runoff by 40% and 68%, respectively, after intensive simulated rainfalls. These results indicated that mulches could be an effective tool to mitigate chemical offsite movement from the vineyard. In conclusion, STM is an integrated management tool with multiple beneficial impacts including winter protection, soil conservation, weed control and chemical runoff mitigation. |
