Agricultural Engineering Research, Volume 10 (1004)

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Application According to Plant Biomass : Sensor Based Distribution of Nitrogen Fertilizer, Growth Regulators, and Fungicides
(2004) Ehlert, Detlef; Dammer, Karl-Heinz; Völker, Ulrich
Recently a mechanical sensor pendulum-meter was developed for meas- uring the crop biomass density in cereal fields. It has a working width of 1 m and is central mounted in front of a tractor. The sensor has finished the stage of research and development and is now market available un- der the name "Crop-meter". To investigate the agronomic potential of the Crop-meter, the sensor was combined with a centrifugal spreader and a field sprayer for the variable rate application of nitrogen fertilizer, growth regulators and fungicides in real time. Based on farm scale strip trials, the effects regarding savings and yield response the new sensor was positive assessed.
Cost Reductions in Natural Fibre Processing : Use of an Optimised Comb Shaker for Fibre Cleaning
(2004) Pecenka, Ralf
There is a demand for high-grade hemp and flax fibres as a raw mate- rial, not only in the automobile industry. Experience in cultivation and harvesting as well as modern processing facilities are needed for Euro- pean farmers to supply the raw fibre materials. A pilot installation has been developed at the Institute of Agricultural Engineering Bornim with which both retted and unretted hemp, flax and linseed straw can be processed. Cost-effectiveness calculations and processing trials have shown that efficient fibre processing and in particular efficient fi- bre cleaning are necessary in order to achieve an attractive straw price for the farmer.
Development of Innovative Ventilation Systems for Fattening Pigs : Part I - Method and First Results
(2004) Häußermann, Angelika; Hartung, Eberhard; Jungbluth, Thomas
The aim of the above named project at the Institute of Agricultural Engi- neering (University Hohenheim) is to develop and to test several innova- tive ventilation systems. The investigations focus on an improved indoor air quality, the reduction of environmentally toxic and greenhouse gases from animal husbandry and the technical use of additional housing and animal parameters to control the indoor air climate within the scope of Precision Livestock Farming. To reach this aim experimental work is done for more than one year in the Hohenheim research facility for fat- tening pigs. The experimental pig facility is subdivided in two compart- ments and features two different feeding systems. For the investigations the research facility was upgraded according to current animal welfare requirements. Furthermore the climate control was equipped with a high pressure water fogging system for humidifying and cooling the air. Addi- tional control parameters which influence the degree and the reaction of the ventilation rate in different ways and which starts e.g. the water fog- ging, are the animal activity and the CO 2 -indoor concentration in the compartment. Based on a continuous data collection with high temporal resolution over four fattening periods, data on the indoor air climate and the emission as well as further side effects are recorded within rotating ventilation strategies in the two compartments. In a following step the emissions of NH3 , CO2 and CH 4 are calculated including the background concentration and the exhaust air concentration of each gas, the water vapour cross sensitivity of the gas analysers and the ventilation rate measured simultaneously. Due to the developed innovative experimental design the evaluation of the control strategies encloses different influenc- ing factors like seasonal effects, measuring sections, the feeding systems, the compartments or the effect on the indoor air climate. Part I of the three-part proceedings explicates mainly the developed experimental lay- out, the operating mode of the control strategies, their technical realisa- tion and the approach of the investigation including the data logging sys- tem. Furthermore the practical functionality of the control strategies is described and pictured within the first selected results. The figures com- pare the indoor temperatures, the ventilation rates and the CO2 -indoor concentrations of both compartments, featuring different ventilation con- trol strategies at the same time. The first results indicate the effectiveness of the different ventilation control strategies. When finishing the practi- cal research work in early summer 2004, the final evaluation of the com- pleted data-set is scheduled subsequently.
Monofermentation of Nutritional Waste in Biogas Plants - Laboratory Investigations
(2004) Adolph, Jan; Beck, Jürgen; Mukengele, Michael; Jungbluth, Thomas
In the following publication a joint project with the partners Ing. Frie- drich Bauer GmbH from Kemmelbach, Austria, Enersys GmbH, Donaueschingen, the Institute of Agricultural Engineering and the Insti- tute of Environmental and Animal Hygiene and Veterinary Medicine (with Animal Clinic), (head: Prof. Dr. R. Böhm), both University of Hohenheim will be presented. In the project a process engineering tech- nique was developed for the anaerobic monofermentation of low - fibre and high - energy material. For a period of 126 days systematic labora- tory investigations have been accomplished in twelve horizontal lab - fermenters with 16 litre net volume. After a starting period of 29 days to adapt the microorganisms to the substrate, the influence of different tem- peratures (mesophilic operation with 40 °C and thermophilic operation with 55 °C) and different organic loading rates (high organic loading with 5.1 kg odm/m³ reactor volume per day and low organic loading with 3.5 kg odm/m³ reactor volume per day) were tested in three experiments. Moreover a two - stage treatment with a doubled organic loading rate of 10.1 kg odm/m³ reactor volume per day was monitored in the methanisa- tion - stage. In this experiment hydrolysis und methanisation were sepa- rated in back to - back reactors. Because of the high energy content of up to 18.3 MJ ME / kg odm the used nutritional waste are predestined for monofermentation in biogas plants with anticipated high gas yields. Comparing the different tempera- ture levels the reactor specific methane yields were equal with approxi- mately 2.12 l CH4 /l reactor volume per day. In the last third the perform- ance of the mesophilic variant decreased down to 50 % of the thermo- philic reactors. Varying the loading rate in interaction with the tempera- ture range the thermophilic variant with high loading rate showed the highest reactor specific methane yields with 2.25 l CH4 /l reactor vol- ume per day in comparison to only 0.86 l CH4 /l reactor volume per day in the mesophilic variant with a low organic loading rate. By dividing the fermentation into a hydrolysis- and a methanogenic step it was possible to stabilise the process.
Monofermentation of Nutritional Waste in Biogas Plants : Pilot - Biogas Plant
(2004) Adolph, Jan; Beck, Jürgen; Jungbluth, Thomas
In a joint project of the partners Ing. Friedrich Bauer GmbH (Kemmelbach, Aus- tria), Enersys GmbH (Donaueschingen, Germany) as general planner, the Biogas - Systemtechnik Deutschland (BST - D company) as constructor and the Institutes of Agricultural Engineering as well as Environmental and Animal Hygiene with Vet- erinary Clinic (head: Prof. Dr. R. Böhm) at Hohenheim University a process engi- neering technique was developed and tested for the anaerobic monofermentation of nutritional wastes with high energy concentrations and low contents of structural components. The research project started with systematic investigations in the bio- gas laboratory of the Institute of Agricultural Engineering at Hohenheim University about monofermentation of nutritional waste to obtain information about the fer- mentation behaviour and the performance of the substrate (compare long version, LANDTECHNIK-NET, volume 01/2004). In a second step intensive process engi- neering and hygienic investigations followed at the pilot biogas plant being erected by Biogas Systemtechnik Deutschland GmbH at Donaueschingen. The general planning was done by Enersys GmbH, Donaueschingen. The trials included two phases in a period of in total 192 days. In phase I the fer- mentation process was started and the tube fermenters of the plant got filled at first exclusively with inoculant material and afterwards they were fed with slowly in- creasing amounts of nutritional waste. After 130 days phase I finished by the end of November 2002. During that time in the tube fermenters 0.971 m3 CH4 m-3 RV d -1 , was produced in average, and in the second fermenter stage 0.431 m3 CH4 m-3 RV -1 were generated under a hydraulic loading rate of 3.18 kg odm m-3 RV d -1 and with a theoretical retention time of the fermentation substrate in both fermenter stages of about 118 d. The gas quality from both fermenter stages reached in average 56.3% CH4 and 36.1% CO2 . Due to a defective temperature measurement device in com- bination with malfunction of the gas counter whose signals were basis for the de- termination of the specific input mass of fresh substrate, the horizontal fermenters got overloaded in the beginning of October. Subsequently the concentration of vola- tile fatty acids increased rapidly up to 16500 ppm, whereby especially the concen- tration of propionic acid strongly increased up to 4690 ppm. As a result the pH - value in the horizontal fermenters dropped down to values of 6.4. By re-inoculating with fermented material from the second fermentation stage methane generation was restarted again. In phase II over a duration of 62 days and after having stabi- lized the process conditions there were generated in average 0.95 m3 CH4 m-3 RV d -1 in the tube fermenters and 0.64 m3 CH4 m-3 RV d-1 in the second fermentation stage with 58.7 % CH4 and 36.6 % CO 2 in the mixed gas. The concentration of volatile fatty acids was at a level of in average 5070 ppm of acidic acid and 3680 ppm of propionic acid. It can be followed that the process has been overloaded due to the high contents of volatile fatty acids. The results from the lab scale investigations and from the pilot plant confirmed that a monofermentation of nutritional waste is feasible but that there are several starting points to optimize the process and the strategies as well concerning aspects of process engineering and fermentation biol- ogy.
The Influence of Chop Length on Compactability, Ensiling and Undesirable Temperature in Maize Silage
(2004) Wagner, Andrea; Leurs, Kristina; Büscher, Wolfgang
Quality losses in maize preservation due to undesirable rises in tempera- ture still cause considerable problems in the practice of dairy cattle feed- ing. These problems must be assumed to grow still more severe in the fu- ture. The aim of the present study has been to determine the quantitative interrelations between maize breed, chop length, and the degree of me- chanical processing. This article presents the experimental design, the methods and the first results of extensive research conducted in the con- text of a doctoral dissertation.
Torque-Controlled Bottom Conveyor Velocity for the Application of Solid Manure : Effect of a DLC System on Longitudinal Distribution
(2004) Kosch, Ralf; Klose, Andree; Van den Weghe, Herman
To improve distribution accuracy during the spreading of solid manure and secondary raw material fertilizer in a longitudinal direction, a DLC (drive line control) system for solid manure spreaders has been developed. A control circuit allows the DLC system to keep the mass flow at the spreading elements constant. For the examination of distribution accuracy in a longitudinal and lateral direction, a spreading trial with collection trays was carried out. Three application rates (5 t, 10 t, 20 t ha-1 ) were examined both with and without the DLC system. The experimental set-up over a driving distance of 120m enabled more detailed insight into the quality of longitudinal distribution on a small scale and over the course of the unloading distance to be gained. The variation coefficients of lateral distribution (VKQ ) ranged between 11.7 % and 16.5 %. At values between 15.6 % and 35.7 %, the variation coefficients of longitudinal distribution (VKL ) were significantly higher both with and without the DLC system. In the test, the DLC system did not have any influence on VKL . Variability was rather caused by small- scale differences than by differences over the examined travel distance. Nevertheless, the DLC system means significant progress since it provides torque control independent of real driving speed, for example.
Tube Feeders for Piglet Rearing : A comparison of two tube feeders with regard to biological performance and behaviour of piglets
(2004) Snell, Hinrich; Schmidt, Christine; Hüttmann, Burkhart; Van den Weghe, Herman
Two types of tube feeders were compared. The first tube feeder (Lean- Machine, Big Dutchman, Vechta) featured a round trough. The feed was metered out through the movement of horizontally arranged bars above the trough. The second machine (PigNic, Big Dutchman, Vechta), how- ever, was equipped with a rectangular, three-bowl trough with a cen- trally arranged metering ring. The feed was significantly drier than in the variant used for comparison. At the LeanMachine tube feeder, more piglets were observed eating than in the other pens. However, this difference was not reflected by produc- tivity. At the LeanMachine, the piglets needed to eat more frequently in order to achieve the same body mass increase as in the other system. With regard to aggressive behaviour and intersucking, however, no sig- nificant differences could be determined.

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