622 EXPERIMENT STATION EECORD. 



question of whether the rotation of crops maintains the productive power of 

 the soil by avoiding injurj^ from possible toxic excreta from plant roots. 



Plant food combinations for sundry crops, J. L. Hills ( Vermont Sta. Circ. 7, 

 pp. IJf). — This is a summary of the more important information originally 

 publishetl in Bulletin 116 of the station (E. S. R., 17, p. 230). 



Experiments with lime nitrogen alone and mixed with lime niter, H. G. 

 SoDERBAUM (Meddcl. Centralamt. Forsoksv. Jordhruksomrddet, 1911, No. 50, 

 pp. 13, figs. 2; K. Landtbr. Akad. Handl. och Tidskr., 50 {1911), No. 8, pp. 

 701-710, figs. 2). — In order to overcome the injurious effect of lime nitrogen on 

 young plants, it has been suggested to use it in mixtures with lime nitrate. 

 The author made pot experiments on oats with these materials separately and 

 in mixtures of 1 and 2 parts of lime nitrogen to 1 of lime nitrate applied 

 as top-dressing or thoroughly mixed with the soil before seeding, the soil in 

 every case receiving a basal fertilizer supplying the necessary amounts of other 

 fertilizing constituents. 



When the materials were mixed with the soil before seeding, the lime nitrate 

 was as effective as sodium nitrate in increasing the yield. Lime nitrogen also 

 gave good results and produced a slightly greater yield of grain than sodium 

 nitrate. No injurious effects from its use were observed. Mixtures of lime 

 nitrogen and lime nitrate gave somewhat better results than either material 

 separately. The best mixture appeared to be 2 parts of lime nitrogen to 

 1 part of lime nitrate. When applied as top-dressing the fertilizing effect 

 of the 2 nitrates was appreciably increased. Lime nitrogen, however, ap- 

 plied as top-dressing proved injurious and in some cases killed the plants. 

 The yields with lime nitrogen applied in this way were less than without 

 nitrogen. A mixture of 1 part of lime nitrogen to 1 of lime nitrate was 

 the least injurious, but even with this the increase in yield was very small. 



The phosphate nutrition of plants, A. Baguley (Jour. Agr. ScL, .'/ {1912). 

 No. 3, pp. 318-322, fig. 1; aJ)s. in Jour. Soc. Ghem. Indus., 31 {1912), No. If, 

 p. 195). — Comparative tests of normal orthophosphates of calcium, iron, and 

 aluminum were made with oats, peas, and Swedish turnips grown on artificial 

 soils of sand and chalk. 



Better results were, as a rule, obtained with iron and aluminum phosphates 

 than with calcium phosphate or even with sui:)erphosphate. Experiments were 

 also made with iron and calcium phosphates which had been ignited and ex- 

 tracted with boiling water. It was found that this treatment affected the 

 availability of the phosphates to a considerable extent. The insoluble calcium 

 phosphate was much less effective than iron phosphate in the case of oats, but 

 there was little difference in the case of Swedish turnips and peas. These 

 results are in accord with those of H. G. Soderbaum and t». N. Prianishnikov 

 (E. S. R., 14, p. 434; 18, p. 539). 



Fertilizing' value of certain phosphates, H. G. Soderbaum {Meddel. Cen- 

 traJanst. Forsoksv. Jordhruksomrddet, 1912, No. 56, pp. 18, figs. J/; K. Landtbr. 

 Akad. Handl. och. Tidskr., 51 {1912), No. 1, pp. 42-56, figs. 4).— The relative 

 value of Tunis phosphate, bone precipitate from a gelatin factory, so-called 

 Palmaer phosphate (electrically precipitated dicalcium phosphate), artificial 

 ferric phosphate, and so-called Bernard phosphate (calcined low grade Belgian 

 raw phosphate) was tested in pot experiments with oats. 



Taking the action of sui^erphosphate as 100, the relative action of the Tunis 

 phosphate was 22.2 and of bone precipitate from 111.2 to 116.6. Slowly precipi- 

 tated dicalcium phosphate was somewhat less effective than the ordinary kind. 

 The increase of yield produced by the ferric phosphate was at best only about 

 one-fifth that produced by superphosphate. The Bernard phosphate was en- 

 tirely without effect. 



