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Poster Presentations


Poster Presentations


Sprayer traffic effects on reproductive-stage soybean planted at three row spacings

Presenter: D. Holshouser

All authors and affiliations: D. HOLSHOUSER (1) and R. Taylor (2). (1) Virginia Tech - Tidewater AREC, Suffolk, VA; and (2) University of Delaware, Newark, DE

The impact of sprayer traffic on reproductive-stage soybean yield has not fully been investigated. Furthermore, planting date, row spacing, and environment may influence the extent of yield loss. The objective of this research was to determine the yield loss caused by sprayer traffic to reproductive-stage soybean planted in three row widths and two planting dates. Experiments were conducted during 2005 and 2006 in Suffolk, VA, and in 2006 in Georgetown, DE. Soybean was planted in May (Suffolk), early June (Georgetown, 2006), and late June (Suffolk). Three row spacings were used: 7.5, 15, and 30 or 36 inches. Traffic treatments, with and without fungicide (Quadris - azoxystrobin), were applied at the R4 to R5 (late pod to early seed formation) stage. In 2005, traffic treatments destroyed four of sixteen 7.5-inch rows and two of eight 15-inch rows in the plot (25% of total harvested plot area). No rows were destroyed in the wider row spacing. Traffic reduced May-planted soybean yield 12.5 and 20% per plot in 7.5- and 15-inch rows, respectively. In June-planted soybean, yield was reduced 28 and 25% per plot in 7.5- and 15-inch rows, respectively. From these data, there appears to be yield compensation from adjoining rows in 7.5-inch soybean planted in May, less compensation in May-planted 15-inch rows, and no compensation in June-planted soybeans, regardless of row spacing. Results from 2006 will be presented at the symposium.

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