Two varieties of soybean were grown in large pots out of doors. At the R2 stage, a state of temporary root anoxia appeared caused by a heavy rainfall and in R3, nitrogen was applied. The nitrogenase activity of the nodules was measured at weekly intervals (ARA test). During the vegetative stage, the number of nodules and their weight increased rapidly, although the anoxia caused a slowing down followed by a recovery in the successive stages (R3–5). The same effect was apparent in consequence of a late nitrogen fertilization; both varieties attaining values close to those of the control 15 days after the treatment. Nitrogenase activity also showed an inhibition caused by the anoxia but it appeared earlier. During the latest stages of the cycle (R6–7), the nitrogen treatment increased the rate of nitrogen fixation in Hodgson 78 only. The use of a multiple regression model allowed a verification that the parameters controlling nitrogen fixation acted in a similar way in both varieties. In the field, the weight of the nodules, both single and total, appeared to be particularly important in determining the total nitrogen fixation rate.

Behaviour of the root nodules in soybean in the presence of nitrogen: the use a statistical simulation model.

BONA, STEFANO;MOSCA, GIULIANO
1991

Abstract

Two varieties of soybean were grown in large pots out of doors. At the R2 stage, a state of temporary root anoxia appeared caused by a heavy rainfall and in R3, nitrogen was applied. The nitrogenase activity of the nodules was measured at weekly intervals (ARA test). During the vegetative stage, the number of nodules and their weight increased rapidly, although the anoxia caused a slowing down followed by a recovery in the successive stages (R3–5). The same effect was apparent in consequence of a late nitrogen fertilization; both varieties attaining values close to those of the control 15 days after the treatment. Nitrogenase activity also showed an inhibition caused by the anoxia but it appeared earlier. During the latest stages of the cycle (R6–7), the nitrogen treatment increased the rate of nitrogen fixation in Hodgson 78 only. The use of a multiple regression model allowed a verification that the parameters controlling nitrogen fixation acted in a similar way in both varieties. In the field, the weight of the nodules, both single and total, appeared to be particularly important in determining the total nitrogen fixation rate.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2511207
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 0
social impact