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Growth dynamics of reed canarygrass ( Phalaris arundinacea L.) and its allocation of biomass and nitrogen below ground in a field receiving daily irrigation and fertilisation

Research paper by Thomas Kätterer, Olof Andrén

Indexed on: 01 May '99Published on: 01 May '99Published in: Nutrient Cycling in Agroecosystems



Abstract

Biomass and nitrogen in the roots, rhizomes, stem bases and litter of reed canarygrass (Phalaris arundinacea L.) were repeatedly estimated by soil coring, and root growth dynamics of this potential energy crop was studied for two years using minirhizotrons. Results are discussed in relation to above-ground biomass and nitrogen fertilisation. Five treatments were used: C0, unfertilised control; C1, fertilised with solid N fertiliser in spring; I1, irrigated daily, fertilised as in C1; IF1 , irrigated as I1 and fertilised daily through a drip-tube system; IF2, as in IF1 but with higher N fertiliser rates. Biomass of below-ground plant parts of reed canarygrass increased between the first and second years. Up to 50% of total plant biomass and nitrogen were recovered below-ground. The highest proportions were found in C0. The calculated annual input via root turnover ranged between 80 and 235 g m-2. In absolute terms, up to 1 kg and 10 g m-2 of biomass and nitrogen, respectively, were found in below-ground plant fractions. High inputs of stubble and accumulated below-ground biomass will occur when the ley is ploughed, which will result in a highly positive soil carbon balance for this crop in comparison with that of conventional crops such as cereals.