IRISH COBBLERS.

The yields of the three grades and the percentages of U. S. Grade No. 1 are given in TABLE I and show that in each of the three years that the total yields were the largest when the distances between the hills were the least. However, with the exception of 1922, most of the increases in total yields from closer planting are due to larger percentages of U. S. Grade No. 2 and No. 3, very little difference in the yields of No. 1 existing between the 9 and 12 inch spacings in either 1921 and

1923.

In 1922 the percentage of No. 1 is lower for the 12 than for the 9 inch spacing. The unusually large percentages of No. 1 from the latter might be explained by the fact that the precipitation for May, June, July and August in 1922 was 6.49 inches above normal, with July, probably the most critical month with Cobblers in Connecticut, having almost double the rainfall of the same month in 1921 and 1923. However, this does not explain why the 12 inch spacing should have a smaller percentage of No. 1. That the supply of soil moisture available for the potato plants in July has considerable bearing on the distance to space Cobbler hills, is shown by the results in 1923. Long periods with very little precipitation were experienced in July and early August of that season, and it is the only year in which the yields of No. 1 were larger for the 12 than for the 9 inch spacing.

The average difference in favor of the 9 inch over the 12 inch spacing was 16.4 bushels of No. 1. The average percentage of No. 1 was 1.7 less for the 9 than the 12 inch spacing.

The 18 inch spacing yielded much less than either the 9 or 12 inch in both 1921 and 1922 and therefore it was not deem

ed necessary to repeat it in 1923, a 6 inch spacing being included instead. The latter produced a total yield of slightly more than the 9 and 12 inch spacing, but considerably less No. 1. With plenty of moisture, this result might have been different. However, Stewart (1) working with the varieties Sir Walter Raleigh and Enormous No. 9 for 5 years, found that the average percentages of tubers, weighing 2 or more ounces, were 64.1 and 73.9 for 6 and 15 inch spacing respectively.

(1) Stewart, F. C. Experiments on the spacing of potato plants. New York (Gen

eva) Bul. 474-1920.

In the last analysis, it is generally the financial returns which one considers in deciding the practice to be followed. Therefore, in Table II are given the values of the crops produced. The No. 1 were valued at $1.50 per bushel; the No. 2 at .85 cents; while the No. 3 were considered a negligible item. The net returns are the balances after the cost of the seed at $2.00 per bushel has been deducted.

TABLE II-EFFECT OF DISTANCE BETWEEN HILLS ON THE FINANCIAL RETURNS FROM IRISH COBBLER POTATOES.

From a study of the net returns there seems to be little choice between the 9 and 12 inch spacings, except in 1922, when the former was $50. per acre above the latter. The average for the three years is almost $17. per acre in favor of the 9 inch spacing. The 6 and 18 inch spacings are considerably below either the 9 or 12 inch. Therefore it appears advisable to plant this variety at about 9 or 10 inches under average conditions in this climate.

GREEN MOUNTAINS.

Green Mountains were planted with hills 9, 13, and 20 inches a part in 1921 and 1922, and 6, 9, 12, and 15 inches apart in 1923. Therefore, results are available for 9 and 12-13 inch spacings for three years; for 20 inch spacings for two years; and 6 and 15 inch spacings for one year. These results are shown in table III.

TABLE III-EFFECT OF DISTANCE BETWEEN HILLS ON THE YIELDS AND SIZE OF GREEN MOUNTAIN POTATOES.

The 9 and 12-13 inch spacings will be considered first. In 1921 and 1923 the 9 inch spacings produced a larger total yield and also more No. 1 than the 12-13 inch, the average difference being 33.0 and 14.0 bushels per acre respectively. In 1922, the total yields were practically the same:-260.5 and 262.6, but the 12-13 inch spacing had 23.3 bushels more of No. 1. The averages for the three years show that the closer spacing yield

ed 21.3 more total bushels and 1.6 more No. 1. The percentages of No. 1 were larger for the 12-13 spacing in all years and averaged 5.8 percent above the 9 inch.

The financial returns from the yields of Green Mountains are given in Table IV. These have been calculated in the same manner as for the Cobblers. The net returns were $5.77 greater for the 9 inch spacing, not a significant amount. From this data the conclusion is drawn that it makes very little difference whether Green Mountains are planted at 9 or 12 inches if the No. 2 can be marketed at about 60 percent of the price received for No. 1. As this is not always possible, the 12 inch spacing appears to be the better for average conditions.

The 20 inch spacing gave so little promise of yielding profitable returns in 1921 and 1922 that it was not included in the 1923 trials and 6 and 15 inch spacings were included instead. Neither of the latter gave as large net returns as the 9 or 12 inch spacings in the one year all have been tested.

TABLE IV-EFFECT OF DISTANCE BETWEEN HILLS ON THE FINANCIAL RETURNS FROM GREEN MOUNTAIN POTATOES,

RURAL RUSSETS.

With Russets, the total yields have also decreased as the distance between hills increased. This is also true of the No. 1 if only the plantings of 10 or more inches are considered. In 1923, the only year in which 6 and 9 inch distances were tested, they yielded slightly less No. 1 than the 12 inch. These data are shown in Table V.

TABLE V

EFFECT OF DISTANCE BETWEEN HILLS ON YIELD AND
SIZE OF RURAL RUSSET POTATOES.

To average the results for the three years, three groups have been made, viz:-9-10, 14-16, and 18-23 inch spacings. These groups include all the tests with Russets except the 6 and 12 inch spacings of 1923. The averages for yields, both total and No. 1, as well as the net financial returns are larger for the 9-10 inch than for the 14-16 inch spacing and the latter is superior to the 18-23 inch.