| Autor: |
Sims, A. P., Barber, D. J., Folkes, B. F., Walls, D. |
| Předmět: |
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| Zdroj: |
Plant, Cell & Environment; Mar1986, Vol. 9 Issue 2, p111-119, 9p |
| Abstrakt: |
A new technique has been devised for the direct estimation of the contribution of N2-fixation to the total nitrogen of a legume crop. Sealed lysimeters and ancillary equipment are described by which it is possible to enclose in a gas-tight system the roots of some of the plants within the crop, together with their associated core of soil. The normal soil atmosphere can then be replaced by one containing 15N2, thus allowing, from the 15N content of the resulting plants direct calculation of the N2-fixation. Regular monitoring is necessary to ensure that soil O2, CO2 and moisture contents are maintained at normal field levels. The results indicate that the technique is capable of achieving its objectives and, provided the seedlings establish well initially, the resultant plants fully match the field average at final harvest. It has been possible to maintain the labelling of the soil atmosphere sufficiently constant to ensure that reliable and highly reproducible estimates of N2-fixation are obtained. Using Pisum sativum cv. Meteor at densities of 160 plants m-2, fixation accounted for about 90% of the total nitrogen uptake. The limitations and merits of the method are compared with those of the 15N-fertilizer dilution method. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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