Research Supplement
Microbial responses to undervine treatments Michelle Barry and Kate Orwin
INTRODUCTION WINEGROWERS ARE INCREASINGLY CONCERNED about the impact of weed management practices in the undervine area on soil health, specifically soil microbial health. Winegrower concerns about the effect of weed management in the undervine area on soil health exists alongside concerns about the impact of practice change on yield and fruit ripeness/ composition. Application of herbicides containing glyphosate is the most widely used tool to limit plant and weed growth in the undervine area. In recent times the negative effect of glyphosate on human and environmental health has been publicised, causing winegrowers
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to consider alternative methods of weed control. One such method is undervine mechanical weeding. This method eliminates the need for chemical intervention but increases diesel consumption and labour requirements. Continuous physical disturbance of the soil under vine is not without its disadvantages. Negative effects of undervine mechanical weeding include soil compaction and declines in soil structure and soil biological communities. Lately it has become common practice to combine glyphosate applications with biological stimulants in an effort to mitigate the negative
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effect of glyphosate on soil biology. This project compared the effects of herbicide, undervine mechanical weeding and herbicide buffered with biological stimulants on soil biological communities. Many studies have explored the effect of weed management practices in various agricultural production systems on soil health, but no studies have compared the effect of commonly utilised weed management practices in the undervine area in Aotearoa New Zealand. This project is a response to both winegrower concerns about the impact of undervine management practices on soil microbial