Ammonia, Total Reduced Sulfides, and Greenhouse Gases of Pine Chip and Corn Stover Bedding Packs

Abstract

Bedding materials may affect air quality in livestock facilities. Our objective in this study was to compare headspace concentrations of ammonia (NH), total reduced sulfides (TRS), carbon dioxide (CO), methane (CH), and nitrous oxide (NO) when pine wood chips ( spp.) and corn stover ( L.) were mixed in various ratios (0, 10, 20, 30, 40, 60, 80, and 100% pine chips) and used as bedding with manure. Air samples were collected from the headspace of laboratory-scaled bedded manure packs weekly for 42 d. Ammonia concentrations were highest for bedded packs containing 0, 10, and 20% pine chips (equivalent to 501.7, 502.3, and 502.3 mg m, respectively) in the bedding mixture and were lowest when at least 80% pine chips were used as bedding (447.3 and 431.0 mg m, respectively for 80 and 100% pine chip bedding). The highest NH concentrations were observed at Day 28. The highest concentration of TRS was observed when 100% pine chips were used as bedding (11.4 µg m), with high concentrations occurring between Days 7 and 14, and again at Day 35. Greenhouse gases were largely unaffected by bedding material but CH and CO concentrations increased as the bedded packs aged and NO concentrations were highly variable throughout the incubation. We conclude that a mixture of bedding material that contains 30 to 40% pine chips may be the ideal combination to reduce both NH and TRS emissions. All gas concentrations increased as the bedded packs aged, suggesting that frequent cleaning of facilities would improve air quality in the barn, regardless of bedding materials used.

Ammonia, Hydrogen Sulfide, and Greenhouse Gas Emissions from Lab-Scaled Manure Bedpacks with and without Aluminum Sulfate Additions

“…Over the course of the 42-day experiment, the CO2 flux increased for all bedded packs, regardless of treatments. This gradual increase in CO2 flux is consistent with previous studies [17,19,28]. Carbon dioxide is produced during aerobic respiration and indicates biological activity in the bedded packs.…”

“…An ideal pH is between 6.7 and 7.5 [37,38]. Methane production was largely nonexistent until Day 21 of the study (Figure 3), which is consistent with previous studies conducted using simulated bedded packs [17,19]. While ideal conditions for CH 4 production were never achieved during this study, the weekly increases in bedded pack height as urine, feces, and bedding were added each week can be assumed to have made a more anaerobic environment towards the bottom of the bedded packs as the study progressed.…”

“…Beginning on Day 28, an overall decrease in pH of all bedded packs was observed, with the bedded packs containing the 10% alum treatment having significantly lower pH than those that did not receive alum. This decrease in bedded pack pH has been observed in previous studies using this experimental design, although the decrease did not happen until Day 35 in previous studies [17,19]. It is likely caused by an increase in volatile fatty acid (VFA) production as the manure mixture ages, as demonstrated by other researchers [16,29,30].…”

“…Two dose frequencies (once or weekly) and four concentrations of alum (0, 2.5, 5, or 10% alum by mass) were examined. Thirty-two laboratory-scaled simulated bedded packs were constructed and maintained for 42 days, as previously described [16][17][18][19][20][21]. The study was conducted twice (Period 1 and Period 2) for a total of 64 experimental units.…”

“…The bedded packs were housed in four environmental chambers [22] that were maintained at an ambient temperature of 18 • C with a dew point of 12 • C throughout the study. This temperature and dew point were selected to represent conditions during a moderate season in a barn [23], like spring or fall, and have been used in previous studies [16][17][18][19][20][21]. There were eight bedded packs per chamber.…”