| Abstrakt: |
To investigate the potential for increasing Falkland Island Whitegrass [Cortaderia pilosa (D'Urv.) Hack.] pasture production through application of nitrogen (N) fertilizer, two hydroponic experiments were conducted. First, 5 mg 1[sup −1] N was supplied to plants as nitrate (NO[sup −][sub 3]), urea [CO (NH[sub 2])[sub 2]], ammonium (NH[sup +][sub 4]), or a nine parts NH[sup +][sub 4]: one part NO[sup −][sub 3] mixture. At harvest, plants grown in a NO[sup −][sub 3] medium had about half the biomass of plants grown in a NH[sup +][sub 4] medium. In the second experiment plants were supplied with 1, 3, 10, 30 or 100 mg 1[sup −1] NH[sup +][sub 4]-N. Plants at 1 and 3 mg 1[sup −1] N had the largest biomass of young root and the lowest shoot-root ratios. Leaf extension rate was low in the 1 mg 1[sup −1] N treatment. Plants given 10 mg 1[sup −1] N had the greatest proportion of green shoot material but little root growth; while those at 100 mg 1[sup −1] N produced very little shoot and root biomass. Preferential assimilation of NH[sup +][sub 4]-N and a low N requirement make Whitegrass well adapted to dominating vegetation on much of the Falkland Islands. To investigate the potential for increasing Falkland Island Whitegrass [Cortaderia pilosa (D'Urv.) Hack.] pasture production through application of nitrogen (N) fertilizer, two hydroponic experiments were conducted. First, 5 mg 1[sup −1] N was supplied to plants as nitrate (NO[sup −][sub 3]), urea [CO (NH[sub 2])[sub 2]], ammonium (NH[sup +][sub 4]), or a nine parts NH[sup +][sub 4]: one part NO[sup −][sub 3] mixture. At harvest, plants grown in a NO[sup −][sub 3] medium had about half the biomass of plants grown in a NH[sup +][sub 4] medium. In the second experiment plants were supplied with 1, 3, 10, 30 or 100 mg 1[sup −1] NH[sup +][sub 4]-N. Plants at 1 and 3 mg 1[sup −1] N had the largest biomass of young root and the lowest... [ABSTRACT FROM AUTHOR] |
