Efeito do uso contínuo de certos adubos azotados, sôbre o ph do solo
Influence of the continuous use of certain nitrogenous fertilizers on the soil reaction
O. S. Neves; G. P. Viégas; E. S. Freire * * Contratado pelo Conselho Nacional de Pesquisas, para colaborar com técnicos do Instituto Agronômico.
SUMMARY
The authors report partial results obtained in some longterm experiments and show that at least in certain zones of the State of São Paulo there is a tendency for the soils to become more acid. This happens whether they are cropped without or with nitrogenous fertilizers and whether these are applied as ammonia or nitrate-N. In this sense, the difference between the two forms is that nitrate-N does not generally change the march of acidification, whereas ammonia-N hastens appreciably this natural process. Consequently, lime, which should be used in any case, must be applied more often where ammonia-N is employed. The unit of ammonia-N is normally much cheaper, so that it permits the expense with the additional liming. By maintaining the soil reaction at a suitable level, the farmer is enabled to obtain higher yields and to choose, taking into account other factors, the nitrogenous fertilizers that answer the requirements of his farm.
Texto completo disponível apenas em PDF.
Full text available only in PDF format.
Recebida para publicação em 18 de janeiro de 1980.
Datas de Publicação
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Publicação nesta coleção
14 Abr 2010 -
Data do Fascículo
1960
