More Climate Protection for Organic Fertilization

Thorsten Scheile studied agricultural sciences at the University of Göttingen. For his master thesis, written at the IAPN and supervised by former Junior Prof. Senbayram, he experimented with various combinations of salts and their effects on reducing ammonia emissions caused by the application of cattle slurry.

Photo: agrarzeitung 2014

Mr. Scheile, for your commitment to a more climate-friendly agriculture, you have been awarded the 2014 sponsorship grant. What are the most important results of your master thesis?

The most important result is that addition of potassium, respectively magnesium salts to cattle slurry was shown to significantly reduce ammonia emissions after application of cattle slurry to the soil. Even though these effects varied depending on the properties of the tested soils, they were clearly discernible in all cases. The results were achieved in several series of pot trials; the simulated technique was near-ground trailing-hose application.

Which scientific challenges did you encounter during your investigations?

One challenge I faced was how to properly adapt the experimental design to the questions I wanted to answer, and by using the technology at hand. As I’ve already stated, we did use pot trials, but we wanted to create experimental conditions as close as possible to real-life conditions out in the field. Our pots were filled with sieved soil. We added various concentrations of the tested salts to the cattle slurry and we then applied strips of these mixtures onto the potted soils, simulating trailing-hose fertilization. All pots were sealed gastight and connected to a gas chromatograph, using computer-assisted online gas sampling and data collection in order to record the trace gases emitted. Ammonia was collected in numerous gas washing bottles, which were exchanged once a day, during the entire course of the study. So on the practical side, the study was quite labor-intensive, and it created a lot of data requiring evaluation. But it was well worth the effort.

Based on your results, is it possible to formulate specific recommendations for agricultural practice, or is further research necessary in order to do so?

As nice as it would be to present specific recommendations for agricultural practice, that’s not really where we’re at yet. We conducted our trials under laboratory conditions, with a gastight continuous flow system, which reduced air movement to a constant and limited flow. For real-life ammonia-emissions, external influences such as temperature or irradiation during the application of slurry are of great importance. Research needs to be continued under real-life conditions. However, there is also a need to investigate the physicochemical mechanisms leading to the reduction of emissions by the salts.

How did you like working at IAPN?

I totally enjoyed working at IAPN. The technical assistants were extremely helpful and I also enjoyed working with state-of-technology research equipment.

What’s next in your career?

Since April 2014 I’ve been working to complete my PhD at the Institute of Grassland Science here at the University of Göttingen. My new topic are nutrient cycles on extensive pastures. What I want to find out about is the measurable influence of various types of vegetation and animal species on nutrient cycles.

Thank you very much for this conversation, and lots of good luck for your work!

News article: Distinguished: Master Thesis by Thorsten Scheile