Effect of nitrogen source on barley growing in a high aluminum content soil

Bruno Stange M.1, Edmundo Beratto M.2, Adolfo Montenegro B.2, Amelia Peyrelongue C.2 y Fernando Borie B.1

An experiment in culture cage conditions was conducted in order to test the behaviour of two barley genotypes grown in a soil with a high level of exchangeable aluminum and additions of N-NO3-, N-NH4+ and NH4NO3 as a source of N-fertilization. Results showed an acute deppresing effect of N-NH4+ on barley growth specially in seedling emergence, shoot and root weight, spike number/m2 and grain number spike. On the contrary, N-NO3- addition increased all the parameters above mentioned and NH4NO3 addition showed an intermediate behaviour between N-NH4+ and N-NO3- but it was closer to N-NH4+ These results were in accordance with chemical analysis of the soils which were sampled from plant rhizosphere and with shoot and root analysis. Thus, it was found that N-NH4+ addition produced a significative decrease in soil pH and a concomitant increase in Al and Mn levels. On the other hand, fertilization with N-NO3- showed a high increase in soil pH and an evident decrease in the levels of phytotoxic elements such as Al and Mn. The same trend of such elements were observed in the analysis of shoots and roots from both cultivars.

Keywords: barley, aluminium toxicity, acidity, nitrogen source.
1 Universidad de La Frontera, Casilla 54-D, Temuco, Chile.
2 Centro Regional de Investigación Carillanca (INIA), Casilla 58-O, Temuco, Chile.