1276 CivKKALS AXD rUl.Sl'; CKUl'S 



series of investigations was undertaken by the writer with the specific 

 object of studying and explaining this special behaviour of barley. The 

 article sets out the results of these experiments. 84 glass vessels were used, 

 50 cm. high and 25 cm. in diameter, each containing 28 kilograms of sandy .soil, 

 plus 1. 17 grms. of potassium cliloride and 0.50 grms. of sodium chloride, which 

 corresponds to 134 lbs. of K.^O per acre. The}^ were divided into 3 groups 

 of 27 vessels each, manured with 3 different kinds of phosphates : superphos- 

 phate, basic slag and bone meal, in the respective proportions of 3.65 grms. 

 'J.2'] grms. and 3.45 grms. per vessel, which corresponds to 134 lbs. of P2O5 

 per acre. To each phosphate there was afterwards added one of the 3 

 nitrogenous manures : sodium nitrate, ammonium chloride and ammonium 

 sulphate, in the proportions of 4.50 grms., 2.80 grms. and 3.48 grms. respec- 

 tively, which corresponds to 134 lbs of nitrogen per acre. 



Each grou]) of 27 vessels was thus in turn subdivided into 3 groups of 

 9, differing in the nature of the nitrogenous manure ; these 9 vessels were 

 finally divided into 3 groups of 3, one of which received no further treat- 

 ment, while the other 2 received an addition of magnesium sulphate and 

 magnesium carbonate (magnesite) respectively, in the proportion of i grm. 

 and 3.44 grms. Finally three pots were manured with nitrate of soda, with- 

 out phosphates. 



The barley was sown on the 4th May 1915 and the first seedlings ap- 

 peared on the nth. Towards the end of the same month, in the series: 

 superphosphate, ammoniacal salts, sulphate of magnesia, it was observable 

 that the leaves were yellowing and a stoppage of growth was taking place, 

 followed in some instances by the death of the plant. These pathological 

 symptoms developed with greater intensity in the case of the ammonium 

 chloride, and less strongly in the presence of annnonium sulphate. When, 

 however, the crisis had once been successfully passed, the plants started 

 growing and developing again normally. In the series : superphosphate, 

 ammoniacal salts, magnesium carbonate, no pathological effect was observed. 

 The crop, collected on the 12th Augusr, gave the results set out in the Table 

 annexed. 



The figures compiled in the Table confirm what was already perfectly 

 obvious 3 weeks after sowing. Both in the superphosphate and in the bone 

 meal series, the ammoniacal salts produced results inferior so those brought 

 about by nitrate, and this difference is still more notable if the superphos- 

 phate alone is taken into account. Taking as equal to 100 the crop ob- 

 tained by the use of nitrate, we have for the ammoniacal salts an average 

 of 90 to 80, dropping even to Oo in unfavourable cases. It is interesting to 

 note that with ammonium chloride better results are obtained on the whole 

 than with sul])hate, in spite of the serious symptoms of i)oisoning met with 

 in the early phases of growth of the seedlings. In the series : bone meal, 

 ammoniacal salts, the magnesium carbonate raises the yield, while in the 

 series : bone meal, nitrate of soda, it cau.ses a marked diminution. 



If we now examine the basic slag series, the picture presented is quite 

 a different one. All the differences, more or less marked, between the 



