1030 EXPERIMENT STATION RECOBD. 



phate correspondingly int'reaseil. The profluet thus obtained is better adapted to 

 the manufacture of superpliosphates than the crude material. 



Some observations on ammonium-magnesium phosphate, E. Selliek (Rev. 

 Gen. Chim. Appl, 5 {1902), p. 77; abs. in Giem. Ztg., 26 {1902), No. 22, ReperL, p. 

 73). — The author found in the course of experiments that ammonium-magnesium 

 phosphate is not completely decomposed by magnesia at boiling temperature. 



On the use of sulphate of ammonia, W. Hasselman {Meded. Proefstat. Suikerriet 

 West Jam, 1902, No. -5,5, pp. 7). — A brief discussion of the absorptive power of the soil 

 for ammonium sulphate, and its effect on capillary rise of water, nitrification, and 

 the calcium carbonate of the soil. 



The action of potash on plant life, H. Wilfarth and G. Wimmer {Arh. Deut. 

 Landw. GeselL, 1902, No. 6S, pp. 106, figs. 14)- — This is a detailed account of pot 

 experiments with potatoes, tobacco, buckwheat, mustard, chicory, oats, and sugar 

 beets. The method used was essentially that of Hellriegel, modified to secure better 

 aeration and to prevent loss of fertilizing matter in drainage. The soil used was a 

 sand-peat mixture very poor in potash. The results obtained show that potash is 

 absolutely essential to plants, and is needed throughout the period of growth. The 

 yields increased in proportion to the amount of potash applied until the maximum, 

 determined by the size of the pot or the water supply, was reached. Beyond this 

 point the effect of an increased application of potash was shown, not in an increase 

 of yield, but in an increase of potash content of the plant. The greater the amount 

 of potash available in the soil, the greater the amount taken up by the plant, espe- 

 cially by the leaves and straw, the potash content of the seeds, roots, and tubers 

 remaining remarkably constant with variations in the supply of potash, and increasing 

 only when a large excess of potash was applied. It was shown that the potash was 

 very completely taken up by the plant, whether needed for growth or not. Even 

 when potash was applied in excess far beyond the point of increasing the yield it 

 was largely (90 to 95 per cent) taken up by the plant. Potash appeared to be espe- 

 cially necessary for such plants as potatoes, sugar beets, etc., which produce organs 

 which store up reserves of starch, sugar, and fat. Small potatoes poor in starch and 

 small sugar beets poor in sugar were produced when there was a deficiency of potash. 

 A deficiency of potash also retarded the development of grain in case of cereals and 

 buckwheat. In the case of such crops many of the seeds were imperfectly developed 

 or abortive. Plants suffering from potash hunger have a generally sickly appearance 

 as distinguished from their appearance when suffering from lack of phosphoric acid 

 or nitrogen. In the latter cases the plants are small but normal in all parts. Plants 

 insufficiently supplied with potash, especially potatoes and beets, appeared to be 

 very susceptible to rot. Potash deficiency has a characteristic effect on the leaves of 

 plants, especially as regards coloring. The spaces between the leaf veins show first 

 characteristic Vjrownish stripes, followed later by white spots, causing a peculiar 

 crinkling, and finally the leaves dry up, with a more or less brown color. No such 

 appearance was noted in case of deficiency of phosphoric acid or nitrogen. 



The experiments on the possibility of substituting soda for potash were not entirely 

 conclusive and are being continued, but they indicated that while soda is taken up to 

 a considerable extent by plants, and exerts some influence, it can not perform the 

 functions of potash in plant growth. 



The results of experiments with kainit and 40 per cent potash salt, Bach- 

 MANN {Filhiing's Landw. Zig., .51 {1902), No. 4, j)p. 147-1,55). — With rye the results 

 as a rule favored the 40 per cent salt, both on limed and unlimed soil; with oats and 

 barley they were not conclusive. 



Potash fertilizers on soils rich in potash, L. Grandeau {.Tour. Agr. Prat., n. 

 Sir., 3 {1902), No. 10, pp. S09-311). — Experiments by Maercker are briefly reviewed, 

 which afford a striking illustration of the fact that the need of the application of 

 potassic fertilizers is determined by the assimilable and not by the total potash 



