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1- Body weight was significantly affected by temperature at 49 days in all three experiments. Body weight was higher at the lower temperature (2591 vs 2518 g).2- Body weight was significantly affected by the light regime at 6 weeks of age. Body weight was higher with intermittent light (9L : 3D) compared to continuous light (23L : 1D) (2223 vs 2164 g).3 - As expected, given the differences in body weight at 49 days, at 6 weeks of age daily weight gain was significantly affected by temperature, and by light regime (52.5 vs 50.8 and 50.4 vs 51.8 g respectively).4- Ammonia concentrations increased greatly with the age of the birds. The mean concentrations in experiments 1 and 3 all fell below the recommended for animal threshold limit value of 20 ppm ( but in experiment 2 the mean concentrations of ammonia were higher (28 ppm) than the recommended TLV of 20 ppm.5- Ammonia concentration was significantly greater in rooms with a litter depth of 30 mm (32 ppm) compared with 45mm, (24.2 ppm).6- Ammonia concentration was greater than 'Litterite' than wood shavings after the third week (11.2 vs 7.9 ppm)7- Inspirable dust concentration was significantly greater in rooms at the higher temperature in all the three experiments (10 vs 13.3 mg/m3) and in rooms with near-continuous light in experiment 1 (8.5 vs 5.7 mg/m3).8- Settled dust concentration was significantly greater in rooms at higher temperature in all experiment 2 and 3 (614.5 vs 474.35 mg/m2).9- Ammonia concentration was higher (but NS) in rooms at the higher temperature (21°C) compared with rooms at the low temperature (19°C) in all three trials (19.3 vs 22.3 ppm).10- Stocking density significantly affected ammonia concentrations in the 5th week and from 3-7 weeks of age (8.9 vs 13.3 ppm) (8.5 vs 11.2) respectively. Overall, the lower temperature (19 C), intermittent light, a litter depth of 45mm and a low stocking density (16 birds/m2) led to reduced ammonia and dust concentrations, an increased body weight, and daily weight gain and reduced mortality (NS).

<p>Using the Hooghoudt equation and measured water table depths, together with linear regression method, a long-term drain flow record for a controlled drainage (CD) experiment at the Davis Purdue Agriculture Center was constructed. </p> <p><b> Site description:</b> The Davis Purdue Agricultural Center (DPAC) is a research farm in eastern Indiana. The controlled drainage experimental site is the 0.16 km² field split into four quadrants, northwest (NW), southwest (SW), northeast (NE), and southeast (SE) with areas of 3.5 ha, 3.5 ha, 3.6 ha, and 3.7 ha. This field has a slope of less than 1%. Soils at the site consist of Blount (somewhat poorly drained), Condit (poorly drained), Pewamo (very poorly drained) and a small portion of Glynwood (moderately well drained) series. The drainage system was installed in 2004. Laterals have an approximate depth of 1 m and spacing of 14m. Drainage in the SE and NW quadrants was controlled during some periods while the SW and NE were allowed to freely drain at all times. A more detailed description of the methods can be found in Saadat et al. (2018).</p><br>

This study evaluated the potential of using simple, semi-empirical resistance models for the direct estimation of crop evapotranspiration as an alternative to the traditional approach involving a reference equation and a crop coefficient. It consisted of three major parts. The first part originally aimed at the development of simple expressions for the aerodynamic and surface resistance terms in the Penman-Monteith equation. This goal could not be achieved because of two reasons: First, the determination of aerodynamic resistance was rendered impossible because of problems with the measurements, and, secondly, the values of surface resistance, back-calculated from the Penman-Monteith equation, turned out to be very sensitive to the estimates of aerodynamic resistance. In the second part, two forms of the Penman-Monteith equation and one form of the Shuttleworth-Wallace model were compared to each other and to the traditional KimberlyPenman approach. The analysis showed that (1) it was possible to fit a simple form of the Penman-Monteith equation to measured data, (2) one form of the Penman-Monteith equation allowed a better fit than the KimberlyPenman approach and ( 3) the Shuttleworth-Wallace model provided a slightly better fit to the data than the Penman-Monteith equation. In the third part, the possibility of estimating net radiation and soil heat flux was investigated and a comparison was made between meteorological observations obtained at a grassed weather station and those obtained above an agricultural crop. The results indicated that (1) it was difficult to obtain an accurate estimate of net radiation or soil heat flux for a partial canopy and (2) major differences existed between measurements of vapor pressure deficit and wind speed obtained above an agricultural crop and at a grassed weather station. From the analysis, it is concluded that the benefit of using a semi-empirical form of the Penman-Monteith equation instead of the traditional approach is limited, in particular for the prediction of crop evapotranspiration from limited historical measurements executed at a grassed weather station. As an alternative, the use of an elaborate multi-layer model for the determination of more versatile crop coefficients is suggested.

A method for collecting dinitrogen gas emissions from open pond waste treatment systems was developed. The method was critically tested in a laboratory for sources of air contamination to ensure reliable gas measurements. A laboratory experiment was done to estimate the rate at which dissolved dinitrogen would be stripped out of solution due to non-dinitrogen bubbles rising through the water column. A volumetric mass transfer coefficient for the process was estimated for clean water. The gas collection method was implemented in a partially aerated lagoon treatment system for dinitrogen and methane gas sampling. The volumetric mass transfer coefficient found in the laboratory for clean water was adjusted to compensate for field gas production rates, temperatures and wastewater quality to estimate the rate of stripped dinitrogen from the partially aerated lagoon. The estimated rate of stripped dinitrogen was subtracted from the total measured dinitrogen flux to estimate the dinitrogen produced biologically. Results from laboratory testing revealed that dinitrogen can be measured with low amounts of dinitrogen atmospheric contamination (0.57% N₂) and the preliminary field results suggest that biological denitrification did occur at this lagoon treatment system.

Turfgrass is a major part of the landscape in North Carolina with its acreage equal to 44% of the stateâs harvested crop acreage. Proper irrigation of residential, industrial and commercial turf areas is required to ensure healthy and acceptable turf quality. With increasing competition for water resources and better turf quality, an efficient irrigation control technology is essential in meeting the dual goals of water conservation and turf quality. The objective of the research was to compare two general types of commercially available irrigation control technologies; one based on estimates of evapotranspiration (ET) and the other based on feedback from soil moisture sensors. Water application and turf quality resulting from using these technologies were compared to results from using a standard time-based irrigation schedule. The study also incorporated the effect of irrigation frequency. The experimental area, located at North Carolina State University Lake Wheeler Turf Field Laboratories, Raleigh, North Carolina, consisted of forty 4-m x 4-m plots established to âConfederateâ tall fescue (Festuca arundinacea Schreb) using sod. There were ten treatments combining control type and watering frequency (3 technologies x 3 frequencies + 1 on-demand technology) with four replicates in a randomized complete block design. Technologies included three systems: a time-based system, a soil-moisture-based âadd-onâ system, an ET-based system each with three frequencies: once per week, twice per week and seven days per week irrigation, and a soil-moisture-based âwater on-demandâ system which was allowed to schedule irrigation everyday. Rain sensors were connected to the timer-based and ET-based systems to prevent irrigation in case of rainfall. The add-on soil-moisture-based system applied the least amount of water while the ET-based technology applied the most water averaged across frequencies. Once a week irrigation frequency applied the least amount of water, and daily irrigation frequency applied the most when averaged across all technologies. Minimally acceptable turf quality was met by all the treatments when averaged over the duration of the study period, although during the last month of the study some technologies, especially the timer-based and add-on systems had noticeably drought stressed plots. In general, the ET-based system and the water on-demand system had the best turf quality. The water on-demand system resulted in the best combination of water use efficiency and turf quality. Canopy temperatures were measured once a week and there were significant differences in canopy temperature among treatments averaged over the season. The ET system plots had the lowest canopy temperature while the add-on system plots had the highest canopy temperature. Also there was no significant difference between mean weekly reference ET estimates from an atmometer and Penman-Montieth reference ET estimates using a weather station at the site.