2007 Research Report. Laura L. Van Eerd University of Guelph Ridgetown Campus. Prepared for the Ontario Tomato Research Institute.

Transcription

1 Research Report Laura L. Van Eerd University of Guelph Ridgetown Campus Prepared for the Ontario Tomato Research Institute 1 November 2007

2 2007 Research Report. Laura L. Van Eerd Assistant Professor Mike Zink Research Technician University of Guelph, Ridgetown Campus Ridgetown, ON N0P 2C fax: fax: The financial and in-kind contribution of the following organizations to this Environmental Management research program was greatly appreciated: Ontario Tomato Research Institute Ontario Ministry of Agriculture and Food Agri-Food Laboratories Ltd. A&L Laboratories Inc. CanGrow Inc. Summer Job Service Human Resources Development Canada Summer Experience Program Processing tomato quality was determined by Steve Loewen and Richard Wright; their contribution to this research is greatly appreciated. We sincerely thank our summer research assistants: Brad Vannieuwenhuyze, Geraldina de Regt, Lindsey Cartier, Michelle Verbeek, Dan English, Matt O Halloran, and Mel Geluk, for their hard work and attention to detail. The small plot yields presented in this report are for comparative purposes only and may not accurately reflect commercial yields. We welcome any questions, comments, concerns on this report, particularly suggestions on how to improve or make the trials more meaningful.

3 2007 Research Report. Laura L. Van Eerd University of Guelph Ridgetown Campus Executive Summary 2007: Three winter wheat management practices 1) no 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 nitrogen fertilizer at 30 lb N/ac were established in 2006 to evaluated to the impact on the following year s processing tomato crop. Both red and total tomato yields were significantly higher with no wheat treatment compared to either removing straw or adding fall nitrogen. Quality (colour, soluble solids, and ph) were not affected by wheat management or nitrogen treatments Removing wheat straw or application of fall nitrogen (30 lb N/ac) is not recommended because 1) there is an added expense to these practices and 2) there is yield penalty compared to leaving wheat straw in the field. The increased processing tomato yield when wheat straw was present was likely more due to increased soil moisture retention during summer dry periods than due to nitrogen dynamics. Introduction: There is some concern by processing tomato growers that too much winter wheat stubble may have negative effects on the next year s tomato crop. Therefore, some growers bale the wheat straw to remove it from the field. Other growers leave the straw in the field but apply fall nitrogen fertilizer to encourage soil organisms to break down the straw. There is little knowledge about the impact of these winter wheat management practices on processing tomato yield and quality. Therefore, an experiment was designed to evaluate if the aforementioned practices are beneficial compared to leaving the wheat straw in the field (no treatment). Objectives: To evaluate the impact of wheat management on tomato yield and quality. Assess nitrogen dynamics in a wheat-tomato rotation. Methods: ROTATION: 2006 harvest winter wheat 2007 processing tomatoes CROP: Tomatoes Plant population: 12000plants/ac Row spacing: 5 ft between beds with twin rows 18 in apart Variety: CC337 Plant spacing: 18 in DESIGN: Randomized complete block design Replications: 4 Plot width: 20 ft Plot length: 26 ft

4 PEST CONTROL was according to typical Ontario production practices. TREATMENTS: Fall 2006 Trial established after winter wheat harvest Wheat treatments 1) no treatment left wheat straw in the field 2) wheat straw removed 3) wheat straw left and added 30 lb N/ac of ammonium nitrate Spring 2007 Planted processing tomatoes Tomato treatments 1) no nitrogen fertilizer applied 2) grower rate of 130 lb N/ac The zero N treatment was included to exaggerate the potential impact of N try up by the wheat straw and to follow soil N dynamics. Tomatoes were harvested to determine red, green and total yields. Red tomatoes were processed to determine processing quality parameters (colour, soluble solids, and ph). Table 1. Site characteristics. Characteristic Ridgetown Campus Wheat treatment applied 18 Sept 2006 Fall tillage 10 Oct 2006 Planting date 22 May 2007 Harvest date 30 Aug 2007 Monthly rainfall: Sept. October May June July August Soil characteristics: ph 6.1 Soil texture Sandy loam % sand:silt:clay 54:29:17 % OM 4.4 CEC (MEQ/1 00g) 17.6 P (ppm) 25 K (ppm) 62 Ca (ppm) 2582 Mg (ppm) 141 Observations 2007: Fall 2006 had higher than average rain fall. For instance, September and October 2006 had 20% and 100% more rainfall than the 30 year average. This would have had an impact on N dynamics and break down of straw residue in the fall.

5 There was more wheat residue on the soil surface in the no treatment control compared to when straw was removed or when fall N was applied (Photo 1). There was no visual differences in wheat residue between the straw removed and fall N treatments. a) b) c) Photo 1. Wheat residue on 20 June and 6 July 2007 in a) no treatment straw left in field, b) straw removed, and c) straw + fall N.

6 By blossoming, zero nitrogen fertilizer plots looked less green and somewhat smaller leaves and plants. Visibly, there were no observed differences in plant growth between wheat treatments. By fruit set and to maturity, similar trends were observed with less green somewhat smaller leaves and plants, but very little to no visible difference in the fruit. Likewise, there were no visible differences in fruit between wheat treatments. Results 2007: YIELDS (Table 2): Overall, total tomato yields were acceptable at over 36 t/ac. Ethrol was not used. The tomatoes were harvested a bit early with approximately 27% green, but there was no difference in percent greens between treatments. Both red and total tomato yields were significantly higher with no wheat treatment compared to either removing straw or adding fall nitrogen. But there was no difference between removing straw or adding fall nitrogen in red and total tomato yields. Green yields were not different between wheat treatments. But there were more greens when nitrogen fertilizer applied to the tomatoes. Table 2. Impact of winter wheat management and N fertilizer on processing tomato yields. Tomatoes N rate (lb/ac) Wheat residue treatment Yield (t/ac) Red Green Total 130 No treatment 32.8 a 14.9 a 47.7 a 130 Straw removed 28.4 b 12.1 b 40.5 b 130 Straw + fall N 26.4 b 10.8 b 37.2 b 0 No treatment 30.9 b 9.4 b 40.3 b 0 Straw removed 26.7 b 10.2 b 36.9 b 0 Straw + fall N 28.9 b 10.3 b 39.2 b QUALITY (Table 3): The different wheat treatments did not impact any of the tomato quality parameters (soluble solids, ph, Agtron). Nitrogen fertilizer did not impact any tomato quality measurement.

7 Table 3. Impact of winter wheat management and N fertilizer on processing tomato yields. Tomatoes N rate (lb/ac) Wheat residue treatment Quality parameters Agtron Soluble solids ph 130 No treatment Straw removed Straw + fall N No treatment Straw removed Straw + fall N SOIL NITROGEN (Table 4). Soil mineral nitrogen content in the following spring at tomato planting was not different with any of the wheat management treatments. Therefore, the fall applied N either leached away or was used to break down the straw. Table 4. Impact of winter wheat management on soil mineral nitrogen at planting. Mineral Wheat residue Soil depth Nitrogen treatment Nitrate-N No treatment (NO 3 -N) Straw removed Straw + fall N Ammonium No treatment (NH 4 -N) Straw removed Straw + fall N GENERAL 2007 CONCLUSIONS: Removing wheat straw or application of fall nitrogen (30 lb N/ac) is not recommended because 1) there is an added expense to these practices and 2) there is yield penalty compared to leaving wheat straw in the field. The increased processing tomato yield when wheat straw was present was likely more due to increased soil moisture retention during summer dry periods than due to nitrogen dynamics.