Evaluation of Ammonium Sulfate Nitrate in Virginia Snap Bean Production
IPNI-2009-USA-VA22
02 Feb 2010
Project Description
The current N management regime recommended for Virginia snap bean production includes a total of 40 to 80 lbs. N/acre in two splits. For this study, we will apply ½ of the nitrogen rate pre-plant incorporated and the remaining ½ N rate approximately 2 weeks after emergence in banded treatments.
Methodology
Test Material: Sulf-N 26 (26-0-0-14S)
Soil: Bojac sandy loam (65% sand, 25% silt, 10% clay; 0.75% organic matter).
Climate: Mean annual precipitation = 43 inches/year; Mean annual temperature = 59°F; Frost free days = 210 days.
Water Availability: Irrigated using traveling guns.
Methods: Nitrogen (N) sources will include Sulf-N 26, liquid urea-ammonium nitrate (UAN; 32% N) and ammonium nitrate (AN; 34% N). Sulf-N and AN will be weighed out and broadcast applied by hand to plots. Liquid UAN will be applied with a calibrated backpack CO2 sprayer and broadcast nozzles.
The current N management regime recommended for Virginia snap bean production includes a total of 40 to 80 lbs. N/acre in two splits. For this study, we will apply ½ of the nitrogen rate pre-plant incorporated and the remaining ½ N rate approximately 2 weeks after emergence in banded treatments. Post-emergent bands will not be incorporated using tillage. Two treatments will include sulfur, applied as gypsum, to test for sulfur response. The following treatment structure will be used:
 | Application Timing | | | |
| Source | Pre-Plant Incorporated | 2 wk emergence Band | Total | Total |
| -------------------lbs. N/ac-------------------- | --lbs. S/ac-- | ||
| Check | 0 | 0 | 0 | 0 |
| SULF-N | 20 | 20 | 40 | 21.5 |
| SULF-N | 40 | 40 | 80 | 43 |
| SULF-N | 60 | 60 | 120 | 64.5 |
| UAN | 20 | 20 | 40 | 0 |
| UAN | 40 | 40 | 80 | 0 |
| UAN | 60 | 60 | 120 | 0 |
| AN | 20 | 20 | 40 | 0 |
| AN | 40 | 40 | 80 | 0 |
| AN | 60 | 60 | 120 | 0 |
| UAN-S | 40 | 40 | 80 | 43 |
| AN-S | 40 | 40 | 80 | 43 |
Phosphorus, potassium, other macro and micronutrients, and production practices will be based on Virginia Cooperative Extension Recommendations. All plots will be replicated 4 times. Conventionally tilled ‘Bronco’ snap beans will be planted 4 rows wide on a 36” row spacing with 30 feet long plots. Statistically the experiment will be a randomized complete block design arranged in a factorial arrangement of 3 N sources (Sulf-N, UAN, and AN) × 3 N rates (40, 80, and 120 lbs N/acre) + 2 sulfur comparisons (AN-S and UAN-S) + a 0-N control × 4 replications = 48 plots. The middle two rows of each plot will be harvested and pods will be graded according to size.