Efeito de adubações minerais exclusivas e contínuas sôbre a fertilidade do solo Effect of exclusive and continuous application of mineral fertilizers on the fertility of a soil

• Main Author: Coaracy M. Franco
• Format: Article
• Language: English
• Published: Instituto Agronômico de Campinas 1970-01-01
• Series: Bragantia
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87051970000100013
• ISSN: 0006-8705; 1678-4499

Com o objetivo de verificar se o uso contínuo de adubações minerais pesadas, desacompanhadas de adubações orgânicas, poderia prejudicar o solo, foi executado um experimento em vasos "Mitcherlich", com capacidade para 6 kg de terra, nos quais se empregou solo do tipo Podzolizado de Lins e Marília, variação Marília. Nesses vasos foram feitas 10 culturas sucessivas de milho, cujas plantas foram cortadas e pesadas ao atingirem cerca de 80 cm de altura. Os resultados demonstraram que as plantas dos vasos, através dos quais haviam passado quantidades exageradas de adubos minerais, se desenvolveram melhor do que aquelas dos vasos testemunhas.<br>Although largerly employed for economical reasons, it has been suggested that a continuous and exclusive application of mineral fertilizers is deleterious to coffee plantation. To investigate such a possibility, an experiment was carried out in Mitcherlich pots filled with Podzolized soil on Calcareous Sandstone, Marilia variation, which is one of the most commonly used soil for coffee. Ten plantings of corn, used as indicator plants, were made successively in these pots. Plants were harvested when about 80 cm high, and after each harvesting the soil of individual pot was removed, sifted, replaced and heavily fertilized. Prior to new planting, the soil was well watered, dried, then excess o salts being removed by a generous supply of water. A balanced mixture of fertilizer was applied to the plants, as done normally in field cultures. At the end of the experiment, each pot has received a maximum of 440 g of mineral fertilizer which is equivalent to ca. 880 kg of fertilizer applied to an individual coffee plant, under field conditions, in a period of 10 years. Such amount represents roughly a hundredfold dose usually recommended for coffee crop. Nevertheless, corn planted in soils treated with such heavy excess of mineral fertilizer, grew better than those cultivated in control pots. These received only normal level of fertilizers, and had the soil replaced several times during the experiment.