The carbon and nitrogen balance on grassland due to management intensity
2005
Stypinski, P., Warsaw Agricultural Univ. (Poland) | Mastalerczuk, G., Warsaw Agricultural Univ. (Poland)
The goal of studies, which were carried out in the years 2000-2002, was to check if grasslands are able to reduce the glasshouse effect by CO2 accumulation. Two field trials were established on black-earth soil on two sites (moderate dry and moderate wet). Three levels of management were used: intensive management (180 kg N haE-1 per year, 6 cuts), moderate (120 kg N, 4 cuts per year), and extensive (90 kg N, 3 cuts per year). A special attention was paid on the C and N content in plants (in different organs) and soil. The C content was measured by spectrophotometer. Plants used nitrogen very effectively (about 90%) and without clear differences between sites and fertilisations. The nitrogen content decreased in the soil, but almost the same quantity of N was found in grass roots; the total balance between N input and output was almost zero. Carbon content increased in the soil (particularly in the dry site) for about one ton per ha per year. Carbon accumulation in plant biomass was higher in the treatment of 180 N compared to extensive use (4.5 t C haE-1 and 3.6 t C haE-1, respectively). A lot of carbon was accumulated in grass roots (5-6.4 t C haE-1, especially in less intensive grassland management). It was concluded that less intensive grassland use is a method for increasing carbon accumulation in plant and soil. It is also a good method to reduce nitrogen losses.
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