The Use of “Indoor Lagoons” for Manure Disposal in High Density Systems of Poultry Management

The successful operation of the “Indoor Lagoon” house at the University of Nebraska was the stimulus for hundreds of inquiries received from poultrymen in over forty states.Most of these people wanted to modify the two square feet of surface and 2.5 cu. ft. of water per bird – allowances used in the original “lagoon” house – to fit their own circumstances.Since no information was available on what effect these modifications would have, the “Microlagoon” system for cages was devised as an experimental attempt to provide several small “lagoons” where such variables as surface area and cubage per bird could be studied. Information on other aspects such as heating, aeration, and combined heating and aeration was also needed. The presently reported experiments were an attempt to supply this much needed and often requested information. It was also hoped that this investigation would provide an estimate of the rate of the dry matter accumulation and the time required from one cleanout to another. Advisor: John L. Adam

The Origin and MgCl2–NaCl Variations in an Athalassic Sag Pond: Insights from Chemical and Isotopic Data

The examination of past and new chemical–isotopic data (2H/1H–18O/16O,11B/10B and87Sr/86Sr ratios) shows the meteoric origin of the Sawa Lake (Muthanna Governorate, Iraq) and its connection with the local aquifers, which feed the lake via the groundwater emerging from its floor through fault systems. The chemical and isotopic evaporation models are traced by geochemical computer codes by using a different composition of some potential inflows to the lake (e.g., the Euphrates River and Dammam aquifer). The main product of the chemical evaporation models is gypsum, as confirmed by the mineralogical examination of the sediment and the surrounding outcrops. A strong18O–2H enrichment is a consequence of the evaporation effect in arid regions; δ18O–Cl models and δ11B = + 23.4‰ exclude the contribution of any seawater-derived fluids. This latter value along with87Sr/86Sr = 0.707989 suggests a mixed origin from the Eocene–Miocene aquifers. The isotope and chemical evaporation paths from the meteorically recharged sources match the lake composition. However, compositional switches from NaCl toward MgCl2occurred in the last decade and are related to post-drought periods, showing that the interaction of the recharging waters with the local soils (Na–Mg exchange and/or the leaching of the top layer salts) have a role in the chemical composition. This demonstrates that the lake is significantly influenced by climatic variations