| Autor: |
Morris, Dolen R., Weaver, W. |
| Zdroj: |
Crop Science; November 1983, Vol. 23 Issue: 6 p1111-1114, 4p |
| Abstrakt: |
Nitrogen nutrition of soybeans [Glycine max(L.) Merr.] during pod development is important in determining seed yield. Soybeans utilize leaf N to meet the N needs of developing fruit which may reduce yield potential. A field experiment was undertaken using 15N to test the hypothesis that high N2‐fixing rhizobia would delay mobilization of N from leaves to developing pods. Three strains of Rhizobium japonicum, USDA strains 110, 31, and an ineffective mutant of strain 8‐0, varying in N2‐fixation effectiveness were used as inoculum to determine their influence on the utilization and translocation of N during pod fill. Foliarly applied 15N urea was sprayed onto leaves five times prior to pod formation to label vegetative N. Total application of N was approximately 3 kg/ha. During the first 17 days of pod development approximately 25% of the incorporated 15N was mobilized to the pods regardless of the rhizobial strain. During the final stages of pod development, mobilization of labelled N continued at nearly a linear rate for all rhizobial treatments. for USDA strain 110, there was an insignificant net loss in leaf and petiole N during the first 17 days of pod development which indicated there was an exchange between N2recently fixed and N previously incorporated into leaves. The rate of N2‐fixation by both effective strains of rhizobia increased during pod development. Even though strain 110 fixed more total N than strain 31 the final seed yield for both treatments was similar due to differential partitioning of N. Future research is needed to elucidate the partitioning of N2fixed during pod development and to determine why the better N status of plants inoculated by strain 110 did not result in increased yields. |
| Databáze: |
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