Measuring Dew and Its Effect on Ammonia Volatilization from Surface‐Applied Broiler Litter in the Southeastern United States

Abstract

Core Ideas Dew deposition is often overlooked in humid regions but may play an important role in nutrient cycling for surface‐applied fertilizers and broiler litter. Dew accumulated during the measurement period accounted for 6% of the precipitation measured with heaviest dew recorded in the spring and winter months. Under laboratory conditions, simulated dew led to increased ammonia loss for surface‐applied broiler litter. Incorporation of dew as a significant weather variable may better aid in predicting NH3 loss using simulation models. Dew deposition is often overlooked in humid regions, such as the southeastern USA, but may play an important role in nutrient cycling for surface‐applied fertilizers and broiler litter. The objectives of this study were to measure dew in a pasture and to evaluate the effect of simulated dew on NH3 volatilization in a laboratory study. A microlysimeter method was used to measure dew in a tall fescue (Festuca arundinacea Schreb.) and bermudagrass (Cynodon dactylon L.) pasture over 206 d. In the 206 d measured, 119 d received dew with an average dew fall of 0.19 mm and greater events observed in the cooler spring and fall months. Dew accumulated during the measurement period accounted for 6% of the precipitation measured. Under lab conditions, the effect of simulated, daily dew (0.2 mm) on NH3 volatilization from surface‐applied broiler litter to air‐dry soil was evaluated under diurnal fluctuations of temperature (6–27°C) and relative humidity (26–91%) for 15 d. Dew application significantly increased NH3 volatilization losses (31% of the applied NH4–N and 5% of the applied total nitrogen [TN]) when compared with NH3 losses in the absence of dew (15% of the applied NH4–N and 2.4% of the applied TN). These results suggest that dew may affect NH3 losses from surface‐applied broiler litter under dry field conditions.

Mornings with the highest non‐rainfall water during 2 years of measurements in the Negev–Ecological implications

“…Publications during the last decades yielded numerous NRW values, out of which many of them also challenged the common view regarding its potential maximum magnitude. Of special interest are those reports that contradicted the well‐established theoretical threshold for dew formation of 0.45 mm (Monteith, 1957), reporting substantially higher values of ≥0 8 mm (Pan & Wang, 2014; Uclés et al, 2015) and even >1.0 mm (Cassity‐Duffey & Cabrera, 2016; Kaseke et al, 2011; Kosmas et al, 2001; Shanyengana et al, 2003). This was not the case during the current research during which the 0.45 mm threshold was only surpassed by fog.…”

“…Numerous publications reported however also high daily NRW, which surpass the threshold amounts of NRW required for soil biocrusts. These included values between 0.5 and 1.0 mm (Graf et al, 2008; 0.5 mm, Li et al, 2013; 0.5 mm, Sharma, 1976; 0.58 mm, Fritschen & Doraiswamy, 1973; 0.62 mm, Jia et al, 2019; 0.62 mm, Verhoef et al, 2006; 0.70 mm, Uclés et al, 2015; 0.80 mm, Pan & Wang, 2014; 0.86 mm), but also values higher than 1 mm and up to 5 mm (Kaseke et al, 2011; 1.1 mm, Cassity‐Duffey & Cabrera, 2016; 1.3 mm, Shanyengana et al, 2003; 3.3 mm, Kosmas et al, 2001; 5.0 mm).…”

Atmospheric water infiltration intensity in non-rainfall periods under conditionsof varied soil moisture

“…This is an effect that comes about due to the formation of dew, hoarfrost, soil-water vapour condensation and atmospheric water adsorption (Alishaev, 2013;Janik et al, 2014;Zhang et al, 2015). The importance of these processes in the water balance of the soil surface layer is demonstrated not only in arid (desert) areas, but also in humid regions (Cassity-Duffey and Cabrera, 2016). Infiltration in nonrainfall periods is defined as being the water flux from the atmosphere through the plane of soil surface (further on in the paper it is denoted with the symbol E R ).…”