137 I. A. C. Double Strength Fertilizer 10-8-10....... 669

2.601

The products of a given manufacturer are more adequately judged on the record over a period of years than on the results of a single inspection. If the data given in Table XV is combined with similar data for the preceding three years and compared with the total number of samples of each manufacturer's goods analyzed in this four-year period, we find that of approximately one thousand samples, about one hundred have shown deficiencies in money value of more than $1.00 per ton. In other words, purchasers have obtained commercial values substantially equal to guaranties, or in excess of the same, in about 90 per cent of the purchases represented. This is shown in more detail in the accompanying tabulation, Table XVI. A manufacturer's name does not appear unless ten or more official samples have been analyzed in the four-year period, and the figures refer to individual samples and not to averages.

1 Based on average of two analyses. Based on average of three analyses.

About 70 per cent of the two hundred and eighty-two samples examined have carried guaranties of ammonia of 4 per cent or over. A tabulation for the last four years shows the distribution of ammonia grades and indicates a decrease in the proportion of low nitrogen goods.

THE "NEW ENGLAND STANDARD NINE."

The number of grades represented by the two hundred and eighty-two samples of complete fertilizers and two of the group containing potash and phosphoric acid only is seventy-four. The number of samples falling in the "Standard Nine" grades is ninetysix; but, if several grades closely corresponding to these are included, the number is increased to one hundred and twentyseven. What proportion of the total tonnage in this State is represented by the "Standard Nine" cannot be stated at this time. Less than one-half of the samples examined have fallen in the selected grades or those closely corresponding thereto. In the following summary the "Standard Nine” grades are indicated in full face type.

QUALITY OF THE NITROGEN IN MIXED FERTILIZERS.

The nitrogen derived from nitrates and from ammonium salts is soluble in water and its utilization by plants is relatively rapid and complete. A portion of the organic nitrogen may also be soluble in water and this is presumably more readily utilized by plants than that portion which is insoluble. For many years it has been the practice of agricultural chemists to evaluate approximately the insoluble organic nitrogen of fertilizers. Two methods are employed for this purpose, both of which depend upon the action of dilute solutions of permanganate of potash upon the nitrogenous material under examination, the one an alkaline solution, the other a neutral solution. The results do not measure the availability of the insoluble nitrogen in the generally accepted sense of that term, but they parallel vegetation tests to the extent that low activity values indicate forms of nitrogen which show poor crop-producing power.

In judging the quality of the insoluble nitrogen it is our practice to apply the alkaline permanganate method in all cases where the amount of the insoluble exceeds 3/10 of one per cent. If less than 50 per cent activity is shown, the neutral method is used, check determinations being made in both cases. Activity values of less than 50 per cent by the alkaline method and less than 80 per cent by the neutral method are interpreted as indicating inferior forms of nitrogenous material.

Four samples this year showed results for active insoluble nitrogen less than the limits just quoted. In two of them the actual amounts of insoluble nitrogen were small (0.3 to 0.4), constituting only about 1/10 and 1/4 respectively of the total nitrogen, and judgment was suspended. In Super-Alphano (127) and Woodruff's Home Mixture (23188), the insoluble nitrogen constituted 3/5 and 2/5 respectively of the total, and the activity figures were 44.4 and 41.8 per cent respectively by the alkaline method and 55 and 74.2 per cent respectively by the neutral method.