Levantamento do estado nutricional de cafezais de São Paulo, pela análise foliar. I- Solo Massapê-salmourão

Abstract

Êste trabalho é o primeiro de uma série para o levantamento da situação geral de nutrição dos cafèzais nos principais tipos de solo do Estado de São Paulo. Foram colhidas amostras de folhas para análise em 107 cafèzais de 20 municípios, compreendendo as variedades Mundo Novo, Bourbon e Caturra, entre 5 e 10 anos de idade. Nas amostras foram determinados 12 elementos essenciais, e os resultados comparados com os níveis limiares conhecidos. As análises para determinação de N, B, Zn, Fe e Mg confirmaram os sintomas de deficiência observados no campo. Os resultados indicam que, para melhorar a produção nesse tipo de solo, deve ser dada atenção ao nitrogênio e boro.

This survey represents the first part of a program for the evaluation of the general nutritional level of coffee fields in main soil groups of the State of São Paulo and it reports the data concerning the massapê¬ -salmourão area of soil (ortho red-yellow podzolic soils, ortho red-yellow latosol and gravelly podzolized soils). A total of 107 leaf samples was taken for analyses in three seasons during 1964: summer (January-February, when the coffee fruit is deve- loping); autumn (April-May, during fruit ripening), and in the spring (September-October, when flowering occurs). The sampling was made in 20 different counties in 5 to 10 years old coffee fields of "Mundo Novo", "Bourbon" or "Caturra" varieties. Analyses were performed for 12 elements. The results obtained were then compared with the threshold level and frequency distribution curve, previously obtained in a general survey of coffee plantations under a wide range of conditions in the State. Leaf analyses of N, B, Zn, Mg, and Fe confirmed the deficiency symptoms observed in the field. Some differences in potassium, manganese and molybdenum content of the leaves from different varieties were found. The percentage of deficient coffee fields changes with the sampling season for most ele- ments. Fluctuations must be taken into account for the foliar diagnoses. The results of this study indicate that for the improvement of the coffee production in these soils, attention should be given to nitrogen and boron.