562 EXPEEIMENT STATION RECORD. 



materially from tho,<c due to a lack of potash. Nitrogen in insufficient quantities 

 was cnaracterized by yellow leaves, and a lack of phosphoric acid by dark green 

 leaves. Sugar beets grown in soil lacking either nitrogen or phosphoric acid remained 

 small, but did not decompose, and also contained a normal percentage of sugar. A 

 heavy application of nitrogen when potash was lacking reduced the percentage of 

 tubers and seed and also the percentage of starch, as comj^ared with results ol)tained 

 from light applications under the same conditions. This was esj^ecially noticeable 

 with i)otatoes and beets. The percentages in these tests were based upon the entire 

 plant. 



The (juantity of water transpired per gram of dry matter produced was found to 

 increase when potash was applied. This result is considered due to the check in 

 plant growth as soon as the potash supply has been used up, in which case the pro- 

 duction of dry matter is arrested, while the transpiration continues. The quantity 

 of water transpired under normal conditions for each gram of dry matter produced 

 by the entire plant, as determined in these experiments, was as follows: Potatoes 200 

 to 230, tobacco 300 to 370, buckwheat 400, mustard 500, chicory 400, and oats 460 gm. 



The various potash salts used, with the exception of potassium nitrate, did not 

 cause any marked differences in the results. With potatoes potassium sulphate and 

 potassium chlorid gave practically equal yields, but the starch content of the tubers 

 was in favor of the sulphate. The effect of potash on starch formation was studied, 

 and the results obtained showed that for each gram of potash taken up by the plant 

 potatoes i)roduced 36 gm. of starch, buckwheat 31, and oats 29. The sugar content 

 in Ijeets Avas subject to greater fluctuations than the starch content in the other 

 plants, the range being from 8 gm. of sugar for every gram of potash taken up by the 

 entire plant when no potash was given to 25 gm. when sufficient iwtash was supplied. 



The effects of insufficient potash, phosphoric acid, and nitrogen were also compared. 

 A beet grown in soil lacking i)otash weighed 26 gm. and contained only 2^ per cent 

 of sugar, while a beet grown in soil lacking phosphoric acid weighed only 14 gm. 

 but contained 14 per cent of sugar, and one grown with insufficient nitrogen weighed 

 15 gm. and contained 17 per cent of sugar. Based on the dry matter in plants the 

 sugar content was 2, 22, and 33 per cent for the beets groAvn on soil lacking potash, 

 phosphoric acid, and nitrogen, respectively. 



In studying the quantity of potash taken up by plants when present in more than 

 necessary quantities it was found that the dry matter of the leaves of jiotatoes, 

 tobacco, buckwheat, and mustard contained 5, 3, 2, and Si per cent, respectively. In 

 the dry matter of sugar-beet leaves 5^ jier cent of potash was found. In the seed and 

 tubers the relation was foimd quite different. In the case of the greatest lack of pot- 

 ash the tubers of potatoes contained from 1.2 to 1.9 per cent of potash in the dry 

 matter, the seed of tobacco 1.4 per cent, buckwheat 0.7 per cent, mustard 1 per cent, 

 and oats 0.9 per cent. When the potash supply was increased, even until it reached 

 a surplus, these figures were not increased to any great extent. Very large quanti- 

 ties of potash, however, caused a marked increase in the potash content of potato 

 tul)ers, and in the case of chicory and sugar beets the potash content in the roots rose 

 with the quantity of potash ajiplied to the soil. Considering the total amount of pot- 

 ash taken up by the plant it is shown that without potash fertilization from 56 to 81 

 per cent occurred in the tubers, and when potash was applied in increasing quanti- 

 ties, the percentage rose to 93 but fell back to 70 when the application was in excess 

 of the needs of the plant. In sugar beets receiving no potash from 10 to 20 per cent 

 of the total potash taken up was found in the root, while in samples grown on a soil 

 having received a normal supply it reached 44 per cent. Chicory contained 29 per 

 cent of the total jxjtash in the roots when no potash was applied and 77 per cent 

 when a liberal api)lication was made. The percentage of total potash of the plant in 

 buckwheat and oats is quite constant, being 39 and 58 per cent, respectively, but an 

 excess of potash in the soil caused a marked decrease. In the case of mustard the 



