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Poster Presentations


Poster Presentations


Impact of application timing and crop row spacing on fungicide penetration into a soybean canopy and grain yield

Presenter: S. P. Conley

All authors and affiliations: S. Hanna, S. P. CONLEY, G. Shaner, and J. Santini. Departments of Agronomy and Botany and Plant Pathology, Purdue University

The objectives of this experiment were to quantify the impact of crop row spacing and spray application timing on canopy penetration and coverage and the impact of fungicide application timing on crop yield and crop injury caused by sprayer wheels. Experimental design was a randomized complete block with three replications. The main factors were crop row spacing (76, 38, and 19 cm) and Quilt fungicide application timing (unsprayed or applications at growth stage R1, R3, R5, R3+R5, or R1+R3+R5). Spray canopy coverage was quantified at 30-cm height increments in the soybean canopy. Plots were 13.7 91.4 m. The experiment was conducted at three locations in Indiana and utilized field-scale equipment. Crop row spacing did not affect spray canopy coverage at any application timing; however, coverage differed at the 30-cm height increments. Grain yield was 7% greater in the 19- and 38-cm row spacing than in the 76-cm row spacing in the nonwheel track area; however, yield was similar among all row spacings in the wheel track area due to wheel track damage to the crop. Fungicide application time affected neither soybean yield nor frogeye leaf spot severity. Averaged across the 19- and 38-cm row spacings, grain yield was greater in the nonwheel track than in the wheel track areas at the R3 (7.0%), R5 (7.2%), R3+R5 (9.6%), and R1+R3+R5 (5.2%) application timings. Wheel track damage and seed input costs are factors to consider when planning for multiple pesticide applications after soybean has reached R1.

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