As indicated in the above diagram, the plan of the experiments of 1895 varied somewhat from those of the first year, and additional changes have been made the present season. Since 1894, the second belts of each plot, at first used as a check, have each been converted into experiment belts by the addition of different chemicals to their soils, the check of Plot II. receiving an application of corrosive sublimate, that of III., powdered copper sulphate, and IV., lime. Gas-lime, kainit, and wood ashes had all proved worthless as preventives of club-root, and the half and quarter-amount applications, at least, had presumably lost most of their characteristic properties by the end of two years. These substances, therefore, were not likely to alter the effect of others that might be added to the same belts, and had probably ceased to have any influence upon the plants grown there. The belts to which half and quarter-amounts of wood-ashes had been applied in 1894 were treated with common salt in 1895. Two of the cultural belts also received new treatment in 1895, that of Plot II., with Bordeaux in 1894, received half as much corrosive sublimate as was applied at the same time to the first check belt of the same plot. In like manner the cultural belt of Plot III. received a halfstrength application of powdered copper sulphate. The tops produced by the second crop in 1895 were spread upon the soil of the cultural belt of Plot I., while the roots were applied to that of Plot III. In April of the present year, sulphur was applied to the soil of three belts in varying amounts; to the first check belt of Plot I., at the rate of 300 pounds per acre, and the full-strength kainit belt of 1894 received twice as much-600 pounds per acre-while to the fullstrength ashes belt of 1894, 1,200 pounds per acre was applied. The half-amount gas-lime belt was reserved for testing the susceptibility to club-root of various members of the mustard family, wild and cultivated. Beet and potato experiments were introduced upon the halfamount kainit and ashes belts of Plots III, and IV. None of the belts were sprayed, and the foliage of the first crop was infested but little by fungi. The bacterial blight began to be manifest at about the time the crop was harvested, and all the belts seemed to be infested in about the same degree. By June 1st, or about five weeks after the turnips were sown, the presence of the root disease was evident in a majority of the belts. In certain ones all the plants were so severely infested that but little growth had been made above ground after the third week. Others had developed as much foliage as the uninfested plants, but that they were clubbed was recognized by the more or less wilted appearance of their leaves, which were of a much deeper shade of green than is usually assumed by healthy turnip plants. The cultural belt of Plot I., treated with a dressing of turnip leaves in 1895, and that of Plot III., treated in like manner with turnip roots, were conspicuous for their greatly increased foliage. Sulphur applied in 1896 nowhere gave evidence of having diminished the degree of clubbing, and none of the substances applied previous to 1896, with the exception of air-slaked lime, appeared to have been of any practical value as club-root preventives. The first crop was harvested June 18th, and the turnips were badly scabbed, so much so that any attempts to separate and weigh those free from the scab was regarded as a waste of time. Upon the new land (Plot I., Series IV.) the scab was much less than upon the old land. A large percentage of the roots when cut open showed a discoloration or a watery appearance just below the crown, and some were hollow in the center. All such turnips, when left upon the ground for a few days, turned dark, became slimy, and gave off a very offensive odor. Everything points to bacteria as the cause of this rapid decay. A bushel or so taken to the laboratory for study quickly spoiled, the ordinary soft-rot fungus Rhizopus nigricans Ehr. taking an active part in the destruction. The results of the harvest of the first crop are given in terms of sound and clubbed roots in the accompanying table (Figure 6): The percentage of clubbed roots in each belt is herewith given (Figure 7): A comparison of the first crop of 1896 with that of the average of the four preceding crops shows, for the four check belts, a decided increase in the percentage of clubbing, as indicated in the following table: In the limed belts there is seen to be a marked falling off in the percentage of clubbing from that of the average of the four preceding crops, as the following table shows: The first crops produced upon the limed belts in 1895 and 1896 were both practically free from clubbing. There were 2.77 per cent. of clubbed roots in the first crop of 1895 in the full-amount belt and none in 1896, although the yield was more than double that of the corresponding crop of the preceding year. There was an increase of clubbing in the half-amount belt, and a decrease in the quarter-amount belt, but the difference was less than one per cent. in either case. The percentage of clubbed roots in the second crop produced in the limed belts in 1895 was greater than the first in 1896 by 14.84 per cent. in the half-amount belt, and 6.36 per cent. in the quarter-amount belt. In neither the second crop of 1895. nor the first of 1896 was there clubbing in the full-amount belt. In the two check belts of Plot IV., treated in November, 1894, with lime at the rate of 600 and 300 bushels per acre, respectively, the percentage of clubbed roots was much lower than in the surrounding belts. The clubbing was somewhat less than in the first crop of 1895, but considerably greater than in the second of 1895. Compared with the average of the two preceding crops, the percentage of clubbed roots in the first crop of 1896 upon the full-amount belt will be seen. to be almost the same, but in the half-amount belt it is considerably increased. A comparison of the percentage of clubbing in the gas-lime belts for the first four crops and for the first crop of 1896 is given below :: There is seen to have been a noticeable decrease in the percentage of clubbing in the full-amount belt and a corresponding increase in the quarter-amount belt. In the half-amount belt, as previously stated, no turnips were grown the present season. In Plot III., the first kainit belt had been treated with sulphur, while the second was devoted to beets, so that only the quarter-amount belt remained in condition to have its first crop for 1896 compared with those preceding it upon the same area. The percentage of clubbing in the quarter-amount belt was considerably higher than that of the average of the four preceding crops, as the following table shows: Average of first four crops........... Per Cent. 83.39 98.32 The first ashes belt of Plot IV. was treated with sulphur, and potatoes were grown upon the second. The quarter-amount belt, to which salt at the rate of 300 pounds per acre had been applied in 1895, showed an increase in the percentage of clubbed roots, as indicated below: Average of first four crops................................ Per Cent. 68.81 89.55 |