PLOT K2. ALL K2O IN DOUBLE SULPHATF OF POTASH MAGNESIA.

PLOT K3. K2O DIVIDED BETWEEN SULFATE AND DOUBLE SULFATE.

No differences in growth during the season of 1923 were noted. Sorting data on the primed leaves as taken by Slagg are recorded in Table XIII.

During the first year of this experiment no appreciable effects were seen on the yield and quality of the tobacco. The percentages of the two top grades of plots K1, K2 and K3 were 48%, 51.4% and 50.3%, respectively.

The experiment was conducted during 1924 in the same manner as in 1923. The tobacco on the K2 plot was somewhat taller than on the other plots. Otherwise no differences in growth were noticed.

The tobacco was harvested, stripped, and sorted at the same time as the nitrogen plots. Table XIV gives the sorting data on the plots.

No striking differences in quality were noted in the above plots. Samples were taken from these plots and graded in a manner similar to the other fertilizer plots. These pool ratings are given in Table XV.

TABLE XV. SCHEDULE OF PRICES PER POUND.

From the pooling data recorded in Table XV, it is apparent that there were no differences in quality between the different plots.

Regarding the percentage of the different grades as decimal parts of a pound and applying the corresponding pool prices, the average price per pound was figured for each plot, as given in Table XVI.

TABLE XVI. SUMMARY OF RESULTS FOR 1924 ON POTASH PLOTS.

1 Prices per pound after deducting 11 cents per pound for sorting, sweating, storage and overhead charges.

SUMMARY OF TWO YEARS' COMPARISON OF HIGH GRADE SULFATE WITH DOUBLE SULFATE OF POTASH.

During the two years of this experiment there has been no marked difference in the quality or quantity of the tobacco grown on the different plots. A somewhat larger yield in 1924 on the plots treated with double sulfate is offset by the smaller yield in 1923. Altogether there appears to be little choice between the three treatments. Apparently, if there were occasion to anticipate

that the crop was going to suffer from magnesia hunger the double manure salt could be used to prevent it without serious impairment of the quality or yield of the tobacco. Ordinarily, however, magnesia hunger is not found where reasonably large amounts of organic fertilizers such as cottonseed meal or castor pomace are used. In this case, there would seem to be no advantage in using sulfate of potash magnesia and it has the disadvantage of adding to the bulk of fertilizer and of doubling the quantity of sulphuric acid introduced into the soil. Any conclusions based on experiments of only two years must necessarily be tentative, however.

FRACTIONAL APPLICATION SERIES.

This series was started in 1923 and continued during 1924. There was a double object of the tests (1) to see whether there was any increase in yield or quality above that obtained by the single broadcast application when some of the fertilizer was applied later during the growth of the plants and (2) to see whether a smaller amount applied fractionally would produce as good results as a larger amount applied all at once.

The basal mixture as in N1 was used on all plots, the only variation being in the amount and time of application. The treatments were as follows:

Plots H and H*. Total application 3,000 pounds; 1,400 broadcast, 400 in drill at time of setting, 400 after plants started, 400 at second hoeing, and 400 at later cultivation.

Plots I and I*. Total application 2,000 pounds. None of it broadcast, 400 in drill, 800 at first hoeing, 400 at second hoeing, 400 at later cultivation.

Plot J. 3,000 pounds broadcast.

This to serve as a check on

the above plots and on other plots where 4,000 pounds per acre was applied.

Between 500 and 600 leaves were taken from each plot when harvested and sorted by Slagg in 1923. Data are recorded in Table XVII.

These data show little difference in quality from the three treatments. Three thousand broadcast yielded over 100 pounds more leaf than 3,000 applied fractionally and about 150 lbs. more than 2,000 applied fractionally. There does not appear therefore to be any gain from fractional application as compared with the same amount broadcast and it is questionable whether the reduction in the cost of 2,000 lbs. of fertilizer as compared with 3,000 lbs. would counter-balance the 150 lbs. reduction in yield and the additional cost of labor for later applications.

During the growing season of 1924 it was noted that the growth was not quite so good on the I plots which received only one ton of fertilizer. The tobacco was topped, harvested, stripped and sorted at the same time as that on the nitrogen plots. The sorting records are presented in Table XVIII.