Publication Date
1985
Location
Kyoto Japan
Description
In a forage cropping system (legume-grass), some of the nitrogen (N) which is fixed symbiotically by legumes is used by the associated grass. However, very few measurements of such transfer have been conducted under field conditions. The objective of this work was to estimate N transfer from alfalfa to associated timothy under field conditions, by using the 15N dilution technique. There was no significant difference in total N (T-N) content in timothy grown alone or in mixture at cut one. However, the effects of associated alfalfa became apparent at cuts two and three where T-N% increased by 15 to 38% over the grass control, respectively. The associated alfalfa significantly increased T-N yield of timothy. N fixed by alfalfa also increased after cut one, with a total of 160 kg N/ha for the entire growing season. The proportion of alfalfa N derived from symbiosis ranged from 66% at cut one to 81 % at cut three. The importance of N transfer from alfalfa to timothy in mixed stands is emphasized. This transfer increased between cuts and contributed 3, 18, and 25% of the T-N yield of timothy in cuts one, two, and three, respectively. Both direct excretion and decomposition of nodulated roots may be involved in this transfer. The degree of the contribution of each pathway varied with clipping times.
Citation
Faris, M A. and Ta, T C., "Study of Nitrogen Transfer from Alfalfa to Associated Timothy Under Field Conditions" (1985). IGC Proceedings (1985-2023). 3.
(URL: https://uknowledge.uky.edu/igc/1985/ses6/3)
Included in
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Study of Nitrogen Transfer from Alfalfa to Associated Timothy Under Field Conditions
Kyoto Japan
In a forage cropping system (legume-grass), some of the nitrogen (N) which is fixed symbiotically by legumes is used by the associated grass. However, very few measurements of such transfer have been conducted under field conditions. The objective of this work was to estimate N transfer from alfalfa to associated timothy under field conditions, by using the 15N dilution technique. There was no significant difference in total N (T-N) content in timothy grown alone or in mixture at cut one. However, the effects of associated alfalfa became apparent at cuts two and three where T-N% increased by 15 to 38% over the grass control, respectively. The associated alfalfa significantly increased T-N yield of timothy. N fixed by alfalfa also increased after cut one, with a total of 160 kg N/ha for the entire growing season. The proportion of alfalfa N derived from symbiosis ranged from 66% at cut one to 81 % at cut three. The importance of N transfer from alfalfa to timothy in mixed stands is emphasized. This transfer increased between cuts and contributed 3, 18, and 25% of the T-N yield of timothy in cuts one, two, and three, respectively. Both direct excretion and decomposition of nodulated roots may be involved in this transfer. The degree of the contribution of each pathway varied with clipping times.
