Prior Winter Wheat Straw Management Influences Processing Tomato Yield but not Quality

There is some concern by Ontario growers that too much winter wheat (Triticum aestivum L.) straw may have negative effects on the processing tomato (Solanum lycopersicum L.) crop in the following year. An experiment was designed to evaluate the response of processing tomato yield and quality to common winter wheat straw management practices including: 1) control treatment, that is leaving the straw in the field, 2) removing straw after wheat harvest, or 3) leaving the straw in the field and adding a fall application of N fertilizer at 40 kg N ha(-1). The experiment was a split-plot factorial design with wheat straw management as the main-plot factor and spring N fertilizer (0 or 145 kg N ha(-1)) to the tomato crop as the sub-plot factor. Wheat straw treatments were established in the fall of 2006, which was extremely wet; September and October had 20 and 100% more rainfall than the 30 years average. Based on visual observation the following June, there was more wheat residue on the soil surface in the control wheat treatment compared to treatments where the straw was removed or fall N was applied. At harvest, both red and total tomato yields were significantly higher (total yield 98.6 vs. 86.2 T ha(-1)) in the control wheat treatment compared to the other two wheat treatments. Tomato quality parameters (Agtron colour, soluble solids, and pH) were not affected by wheat straw management or spring N treatments. The increased processing tomato yield in the control wheat straw management treatment was likely more affected by increased soil moisture retention during summer dry periods than by N dynamics.