AGRICULTURAL BOTANY. 439 



rotic when sprayed with milk of lime. Grasses were not permanently injured 

 when si)riiyed with 2 to 5 per cent solutions of iron sulphate. 



In another series of experiments the effect of spraying with 0.5 to 15 per cent 

 iron sulphate solutions on plants that had been rather strongly fertilized with 

 lime niter was tested. Even where the smallest amount of iron sulphate was 

 used there was some injury to potatoes and it is believed that the super- 

 abundant lime in the lime niter was in part responsible for this injury. The 

 sensitiveness of mustard to iron sulphate is believed to be due to the stimu- 

 lating effect of the nitrogen in the fertilizer, causing a much more tender 

 growth of the mustard plants. 



Spraying oat fields for the destruction of wild mustard, in which a 20 per 

 cent solution of iron sulphate was used, was without injurious effect to the 

 oat plants. 



K.xperiments in spi-aying potatoes with 2 to 4 per cent solutions of lime 

 nitrogen, kainit, sulphate of magnesia, iron sulphate, milk of lime, humus, 

 Bordeaux mixture, and a copper-humus mixture were made to determine the 

 relative efficiency of the different mixtures in preventing the leaf curl disease 

 as well as the possibility of correcting the lime-magnesia ratio by applying fer- 

 tilizers in this manner. On the variety of potatoes especially subject to dis- 

 ease the yield was increased by all the treatments, except where iron sulphate 

 or milk of lime was used. Where Bordeaux mixture and the humus-copper 

 mixture were compared the highest yield was secured from the plat receiving 

 the humus mixture. 



other cxperinicnts were conducted in the si>raying of oats, peas, horse beans, 

 lupines, serradella, mustard, and potatoes grown on soils poor in lime, in which 

 applications were made of 2 per cent solutions of gypsum, 4 per cent milk of 

 lime, 1 per cent sulphate of magnesia. 1..5 per cent iron sulphate, and 2 per 

 cent humus. Spraying with gypsum was unfavorable in every case except with 

 oats. The plats of serradella, mustard, and potatoes sprayed with sulphate 

 of magnesia gave maximum yields, while peas, horse beans, and lupines when 

 given applications of humus produced the highest yields. 



In conclusion the author states that the yields of all the crops experimented 

 with were increased by spraying and the plants were made more resistant to 

 disease. 



The action of different amounts of copper in the soil on the growth of 

 plants, J. Simon (Landir. Ucr-s. .S/r//.. 77 (1909). Ao. 6, pp. .'//7-.'/^9).— Pot 

 experiments with oats and mustard grown on garden soil, clay, and pure sand 

 containing amounts of copper sulphate varying from 0.01 to 10 per cent are 

 reported. The oat plant was shown to be more resistant to copper sulphate 

 in the soil than mustard, and in general the resistance of the plants was 

 greater the less the absorptive power of the soil for copper sulphate. With 

 the same concentration, injury from the sulphate was least in the garden soil 

 and greatest in the pure sand. 



Experiments with Reflorit, F. Mach (Bo: Landic. Vers. Anst. Augustenb., 

 1901, pp. 20, 28-30). — Reflorit is stated to be essentially a picrate of lime, the 

 sample used in the experiments here reported containing 16.43 per cent of 

 nitrogen. 



Tests of the material on various fungi and on maize, as well as in the treat- 

 ment of plant lice on grapes, showed that under certain conditions and dilutions 

 the Reflorit stimulated the growth of molds and was utilized to a slight extent 

 as a source of nitrogen by corn. A 0.0.5 per cent solution, however, injured the 

 roots of corn. A solution containing 1 i^art of Reflorit to 600 of water produced 

 no effect on plant lice. The author concludes in general that the material can 

 not be expected to give the remarkable results claimed .for it. 



