Research Scientist Kirsi H. Saarijärvi of MTT Agrifood Research Finland charted the nitrogen emissions caused by intensive grazing in her doctoral dissertation. The topic has not been previously investigated to this extent in boreal conditions.
The experiments were conducted in a 0.7-hectare lysimeter field at MTT Agrifood Research in Maaninka, Finland. A total of 12 basins are placed underneath the field surface, and analyses of the leachates in these basins reveal the nutrient cycle in the pasture. A comparable pasture-size lysimeter field is not known to exist anywhere else in Europe.
The research also involved measuring the ammonia evaporated from the dung and urine of cows by using a chamber process.
LEACHING IS THE KEY ROUTE OF NITROGEN LOSSES
Saarijärvi found that much more nitrogen is left behind on a pasture than in silage cutting fields, since the nitrogen outputs from the pasture are much lower than from silage cutting fields. Most of the nitrogen leaving the pasture is absorbed in the milk produced by the cows grazing in the pasture.
From an ecological perspective, the nitrogen leaching from the soil is the most significant load from dairy pastures.
“The second largest hazard to the environment arises from the ammonia (NH3) evaporating from cow dung and urine, but its volumes have been previously overestimated. The significance of nitrogen loss in surface runoff is low in the conditions prevailing in Finland,” Saarijärvi says.
Nitrous oxide is also emitted into the air from the entire field area, but its emissions are also lower than previously assumed.
NITROGEN PULSE HIGHEST AFTER PASTURE RENEWAL
Saarijärvi stresses that measurements must be carried out throughout the four-year ley rotation in order to gain a representative view of the nitrogen emissions. The nitrogen pulse is especially strong in springtime following pasture renewal.
“The nitrogen accumulated in the ploughed layer is released after pasture renewal. Emissions are smaller in the first years of the rotation, as the grassroots and soil microbes actively bind nitrogen,” Saarijärvi explains.
She found that the springtime nitrogen load is increased since the microbial activity in the soil is not entirely shut down for the winter but merely slows down. Therefore, nitrous oxide resulting from microbial processes in winter is emitted in large quantities as the soil thaws during the spring.
The nitrogen load is greatest in the areas where cattle spend most of the time in the pasture. The watering facility area functions as a congregation area, and it suffers treading damage that destroys the vegetation and soil pore structure, adding to local nitrogen losses.
MANY WAYS TO REDUCE EMISSIONS
The nitrogen emissions from dairy pastures can be reduced by several fairly simple techniques. Saarijärvi notes that emissions can be cut by reducing fertilisation, for example. A white clover mixture, which binds nitrogen directly from the air, can replace fertilisation in good soil conditions.
“The use of protein supplementation for cows should be reduced and the grazing season can be shortened slightly in the autumn. The hot spots of nitrogen cycling can be relieved by moving the watering facility area before the soil around it becomes damaged,” Saarijärvi suggests.
Where possible, it is best to sow the grass in the spring and to use a catch crop that effectively binds the nutrients.
The dissertation of Kirsi H. Saarijärvi, M.Sc. (Agriculture and Forestry), ‘Nitrogen cycling on intensively managed boreal dairy pastures’, will be publicly reviewed at the University of Kuopio on 19 December 2008. Professor Juha Helenius of the University of Helsinki will serve as the Opponent and Docent Helvi Heinonen-Tanski of the University of Kuopio will serve as the Custos.For more information, please contact:
Ulla Jauhiainen | alfa
New insight into why Pierce's disease is so deadly to grapevines
11.06.2018 | University of California - Davis
Where are Europe’s last primary forests?
29.05.2018 | Humboldt-Universität zu Berlin
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
21.06.2018 | Earth Sciences
21.06.2018 | Life Sciences
21.06.2018 | Earth Sciences