Nutrient Cycling in Agroecosystems 61: 273–281, 2001. 273  2001 Kluwer Academic Publishers. Printed in the Netherlands. 15 Plant recovery of N-labelled nitrogen applied to reed canary grass grown for biomass 1, 1 1 2 * Anneli Partala , Timo Mela , Martti Esala and Elise Ketoja 1 Plant Production Research, Crops and Soil, Agricultural Research Centre of Finland ( MTT), FIN-31600 2 Jokioinen, Finland; Data and Information Services, Agricultural Research Centre of Finland ( MTT), FIN- * 31600 Jokioinen, Finland; Author for correspondence Received 18 April 2000; accepted in revised form 22 November 2000 15 Key words: Bioenergy, Biomass, N-labelled N, Nitrogen cycling, Phalaris arundinacea L. Abstract Reed canary grass ( Phalaris arundinacea L.) is a potential crop for production of bioenergy and biomass in 15 northern Europe. In this study labelled N was used to follow the fate of applied N in roots and shoots of reed 15 21 canary grass during a year. Two rates of N fertiliser were applied in spring 1995 and 1996 to a clay (50 kg ha 21 21 21 and 100 kg ha ) and an organic soil (30 kg ha and 60 kg ha ). The data did not indicate significant differences between recoveries of nitrogen following application of fertiliser at recommended and half of the recommended rates. The recovery of added N in shoots was highest at midsummer. The median values were 68% and 58% in organic soil and 42% and 65% in clay soil, in 1995 and 1996 respectively. Some of the N utilised by shoots was remobilised to the roots during autumn. The highest median recovery of applied N in roots was 19% in clay soil in October 1996, corresponding to a 13 percentage unit increase in recovery during autumn. In contrast, the lowest remobilisation was recorded after a rainy spring in clay soil, being only 3 percentage units. During winter the loss of N and fertiliser N from the shoots continued, and consequently the total N content in shoots was about half of that for autumn. In spring, one year after N application, the shoots contained 9–20% of applied N. The data suggest both intensive uptake and remobilisation of fertiliser N during over a year, following delayed harvest, and indicate the importance of the rhizome system in N turnover. Introduction bearing on the need for fertiliser application. More- over, little knowledge exists on the role of the rhi- Reed canary grass has been considered to be a field zome in plant nutrient cycling and fertiliser manage- crop of remarkable potential in northern Europe for ment, which is of particular importance as it affects biomass production for the pulp and paper industry as production costs, product quality and the environ- well as for bioenergy (Mela et al. 1994; Pahkala et al. ment. 1996; Venendaal et al. 1997). In central Europe Mis- Uptake of fertiliser nitrogen is usually studied using 15 canthus is considered to be a more profitable biomass N techniques. These have revealed that the effect of crop (Himken et al. 1997). Substitution of fossil fuels season and soil type on nitrogen recovery of winter with such biomass crops would help to achieve the wheat, Triticum aestivum L., is marked (Macdonald et emission limitations set by the parties at the conven- al. 1997; Recous et al. 1988; Haynes 1999). Nitrogen tion on climate change in Kyoto (Paustian et al. 1998; recovery in winter wheat ranges between 46 and 87% UNFCCC 1998). New cultivation practice, delayed (Powlson et al. 1992). In Finland recovery of fertiliser harvest after the melting of the snow cover in the N in spring wheat was reported to be 15–25% and spring, has been developed in order to meet the 60–70% under dry conditions and under conditions of quality requirements set by the industry. Plant nutrient ample moisture, respectively (Esala 1991). However, cycling is a major research focus because of its there is much more information available on recovery