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- ItemQuantification of nitrogen balance components in a commercial broiler barn(Prague : ČSAZV, 2013) von Bobrutzki, K.; Ammon, S.; Berg, W.; Fiedler, M.Characterizing the respective nitrogen (N) use efficiency requires understanding the N flow of inputs and outputs from a commercial broiler barn. In this study, an N mass balance was performed for one entire growing cycle. The objectives were to quantify, sample, and analyze all N components entering and leaving the barn. The N from feed, chickens, and bedding material was considered as inputs, the outputs included the N accretion in mature broilers, the total N emissions (NTNE), the N accumulation in litter, and the N of mortality. Of particular relevance was the determination of an appropriate method to mirror the heterogenic texture of the litter. Litter samples were collected weekly according to a defined procedure. The major N input was feed N, accounting for 99% of the total N input. After the 36-day growing cycle, the N outputs were portioned as follows: 59% (1741.3 kg N) in mature broilers, 37% (1121.3 kg N) accumulated in litter, and 4% in NTNE (114.3 kg N). The N accumulations in broiler tissue and litter agree well with other studies. The measured emissions were consistently lower compared to other references, due to the fact that these references were mainly based on studies where broilers were raised on built-up litter. In contrast to in situ quantified N emissions in this study, other published values were assumed to be the difference of N between inputs and outputs. This study illustrates that extensive sampling of litter is a prerequisite for calculating litter masses. The accurate specification of the litter texture proved to be crucial within the mass balance approach. With this information, the feasible improvements within management practices can be identified.
- ItemWater use indicators at farm scale: Methodology and case study(Hoboken, NJ : Wiley-Blackwell Publishing Ltd, 2012) Prochnow, A.; Drastig, K.; Klauss, H.; Berg, W.Indicators for water use at farm scale can assist farmers in understanding the water flows on their farms and in optimizing water use by adapting agronomic measures and farm management. The objective of this work is to develop a methodology to estimate water flows at the farm scale, to derive indicators for farm water use, and to apply them in a first case study. After the spatial and temporal boundaries of the farm system and the water flows are defined, three indicators to assess water use at the farm scale are developed: farm water productivity, degree of water utilization, and specific inflow of technical water. Farm water productivity describes the ratio of farm output to water input, where the water input is the total of those water inflows into the farm system that can be assigned to the generation of farm output. Farm output is expressed on a mass basis, food energy basis, and monetary basis. The degree of water utilization characterizes the relationship between productive water to the total water inflow into the farm system, where productive water comprises those water flows that directly contribute to biomass generation via plant and animal metabolism. The specific technical water inflow quantifies the water inflow into the system by technical means relative to the farm area. The application of the methodology in a first case study for a mixed crop-livestock farm with 2869 ha in Germany results in a farm water productivity of 2.30 kg fresh mass per mWinput-3, 1.03 kg dry mass per m Winput-3, 5.96 GJ m Winput-3, and 0.25 € mWinput-3. The degree of water utilization is 0.56. The specific technical water inflow is 36.5 m3 ha-1 year -1. Factors that mainly effect these indicators and general approaches to optimize water use in farms are discussed as well as the further research required for practical implementation.