Sôbre uma modificação no método de Neubauer

Abstract

A MODIFICATION OF THE NEUBAUER'S METHOD This paper reports the data obtained, from a modification of the Neubauer method, as compared to the data obtained from the original one. The modification consistec of using smaller crystallizing dishes, and both a very small number of seedling and weight of soil. Thus, there were seeded 25 rice grains in 20 g of soil, very well mixed with 40 g of beach washed sand, in crystallizing dishes having 8C mm in diameter and 20 mm in height. Eighteen days after germination, the seedling were pulled out, their roots washed dried, ashed and its potassium determined by the flame photometer method. The results were compared with the data obtained from an experiment carried on with the same soil samples, at the same time, according to the usual Neubauer technique. Both methods are practically equivalent, as can be seen from the data on Table I in Results and Conclusions, in the Portuguese text. The main advantages of the modified method over the usual Neubauer method may be summarized as follows: reduction of both the soil sample weight from 100 to 20 g and the washed sand from 350 g to 70 g; the room taken by the crystallizing dishes is less than one third; the number of seedlings is reduced to one forth (from 100 to 25) and it takes less work for the handling of the experiment in all its steps.