São relatados os efeitos produzidos pela aplicação de bórax na cultura da batatinha (Solatium tuberosum L.), em solos de várzea irrigada do Vale do Paraíba. Quatro doses de bórax - 10, 20, 30 e 40 kg/ha - foram aplicadas de três maneiras distintas: no sulco de plantio, em cobertura (vinte dias após a germinação) e parceladamente em 4 pulverizações foliares semanais. As melhores doses de bórax foram as de 10 e 20 kg/ha, aplicadas no sulco de plantio, em mistura com os demais adubos. As aplicações em pulverização provocaram sintomas de toxidez nas folhas, notadamente as de maiores doses.

The production of potato plants (Solatium tuberosum L.) grown in alluvial soils of the Rio Paraíba Valey in the State of São Paulo, is not always correlated with high N-P-K fertilization. This has been reported to be due to boron deficiency in these soils. The effect of addition of boron at different rates (10, 20, 30 and 40 kg of borax / ha) applied in mixture with common NPK formulation in the furrow at planting time, as side dressing or by spraying, was studied in an area where symptoms of deficiency was observed in Aquila potato variety, in the previous year. An increase in the production of about 20 % was obtained with the addition of 10 or 20 kg of borax / ha in mixtures with NPK fertilizing formulation but not with the two higher doses. The same amount of borax applied by spraying also increased yield but at a lesser extent and the side dressing technique was less effective than the other two methods of application of borax.

São apresentados resultados experimentais de adubação do arroz (Oryza sativa, L.) em solos irrigados de várzea do Vale do Paraíba. Foram estudados, em cinco níveis, os efeitos do nitrogênio em solos argilosos e os do fósforo em solos orgânicos. Aumentos significativos de produção, provocados tanto pelo nitrogênio como pelo fósforo, foram obtidos na maioria dos ensaios efetuados.

A study was made on the effects of phosphorous and nitrogenous fertilization on rice (Oryza sativa) cultivated in flooded soils in the State of São Paulo (Brazil). Experiments for nitrogen were carried out in clayey lowland and for phosphorus, in organic lawland soils. A significant increase in production of rice was obtained either with nitrogenous or phosphorous fertilizer applications in most of the experiments.

Efeitos das adubações nitrogenada e fosfatada, da calagem e da aplicação de micronutrientes foram investigados através de ensaios de campo em cultura de arroz (Oryza sativa L.), em solos do Vale do Paraíba, no Estado de São Paulo. Os níveis de nitrogênio e fósforo foram de 0, 40 e 80 kg/ha; para o calcário, em solos orgânicos, de 5 t/ha, e nos argilosos de 3 t/ha; os micronutrientes entraram nas dosagens usuais. Os resultados mostraram sempre grande reação ao nitrogênio, inclusive à dose de 80 kg/ha. Para o fósforo, as reações foram muito menores, e somente em parte dos casos houve aumento de produção. Não se observou reação ao calcário e aos micronutrientes.

Thirtheen experiments were carried out at several places in the Paraíba Valey, São Paulo State, to study the effects of nitrogen, phosphorus and micronutrients fertilization, as well as of liming, on rice production. Nitrogen and phosphorus were applied at the levels of nihil, 40, and 80 kg/ha. Lime was applied at the levels of 5 and 3 t/ha in the organic and clayey soils, respectively. Seeds of the variety "Iguape-agulha" were utilized. Cultivation was under flooding system. Planting was done directly with the seeds. The results showed a great response of rice production to nitrogen fertilizer, wich was considerable even at higher dosis. Only in 6 out of the thirteen experiments, there was some response to phosphorus. No response to micronutrients or to liming could be noticed.