2014 ASHS Annual Conference

Growing cucurbit crops in a more sustainable way involves multiple management practices.  Cover crops are often incorporated into the soil before planting the cash crop.  However, they can also be “rolled” and used as a ground cover throughout the growing season.  The cash crop is then planted in small, tilled strips within the residue.  This “strip-tillage” technique provides a weed-controlling, moisture-retaining mat that does not need to be removed at the season’s end, as plastic mulch does.  The reduction in tillage can improve soil structure and health.  Row covers can be placed over newly planted seedlings to provide a better microclimate and a physical barrier to pests.  Row covers can help prevent the spread of bacterial wilt, a disease caused by the bacterium Erwinia tracheiphila, spread by cucumber beetles.  This study investigated how tillage and row covers affected plant size, yield, and soil health in organic and conventionally grown summer squash (Cucurbita pepo) and muskmelon (Cucumis melo).  The first year of this two-year study was conducted in 2013 at the Muscatine Island Research Farm in Muscatine, Iowa on sandy soil.  We used a double split-plot, randomized design with four replications. The field treatments included two cucurbit crops (Athena muskmelon and Lioness summer squash), two farming methods (organic and conventional), two tillage treatments (conventional tillage with black plastic and strip-tillage into rolled rye), and two row cover treatments (no row covers and row covers).  Row cover treatments tended to produce more plant vegetation but not higher marketable yields when compared to treatments without row covers.  Row covers helped reduce the number of insecticide sprays needed in squash, and reduced the presence of bacterial wilt in melons.  Strip-tillage treatments produced smaller plants and smaller marketable yields compared to conventionally tilled treatments.  The effects of tillage and row cover use did not depend on the method of farming (organic versus conventional).  Strip-tillage tended to reduce between-row weed pressure early in the season when compared to the conventionally tilled treatments due to the presence of the rolled rye mulch between rows in the strip-tillage treatments.  Strip-tillage treatments had lower soil microbial biomass than conventionally tilled treatments.  Conventional tillage with black plastic mulch increases soil temperature compared to strip-tillage into rolled rye, which likely lead to the increased growth of these warm season crops.