Band 137. Nr. 23. XXXIX. Jahrgang. I. Bd. Nr. 23. 



Botanisches Cenlxalblatt 



Referierendes Organ 



der 



Association Internationale des Botanistes 

 für das Gesamtgebiet der Botanik. 



Herausgegeben unter der Leitung 

 des Präsidenten- des Vice- Präsidenten : des Secretärs: 



Dr. D. H. Scott. Prof. Dr. Wm. Trelease. Dr. J. P. Lotsy. 



und der Redactions-Contmissions- Mitglieder : 



Prof. Dr. Wm. Trelease, Dr. G. Bonaventura, A. D. Cotton, 



Prof. Dr. G. Wehmer und Mag. C. Chrlstensen. 



von zahlreichen Specialredacteuren in den verschiedenen Ländern. 



Dr. J. P. Lotsy, Chefred acteur. 



J^o. 23. 



Abonnement für das halbe Jahr 15 Mark 

 durch alle Buchhandlungen und Postanstalten. 



1918. 



Alle für die Redaction bestimmten Sendungen sind zu richten an: 

 Relaction des Botanischen Centralblattes, Haarlem (Holland), Spaarne 17. 



BuFlison, W. L., Availability of mineral phosphates for 

 plant nutrition. (Journal agr. Research. Washington. VI. 

 p. 485—514. 1916.) 



The subject matter is presented in this paper according to 

 this division: 1. Review of litterature regarding the availability of 

 Phosphate minerals; 2. The availability of phosphorus in Tennessee 

 brown rock phosphate for wheat {Triticiim vulgare), oats {Avena 

 sativa), rye {Seeale cereale), barley (Hordeuni sativum hexastichon), 

 cowpeas ( Vigna catjang) soybeans {Glycine hispida), timothy {Phleuin 

 pratense), red clover {Trifolium pratense) and aUalf si{Medicago sativa); 

 3. A comparative study of the productive powers of six mineral 

 phosphates for farm crops; 4. The influence of fermenting dextrose 

 and crop residues on the availability of phosphorus in finelyground 

 rock phosphate; 5. The influence of the size of particles on the 

 -availability of phosphorus in mineral phosphates. 



The results fofthcoming from the writers experiments, were 

 these : 



Phosphorus in rock phosphate can be assimilated by farm crops 

 in sand cultures under greenhouse conditions, even in the absence 

 of decaying residues. Crop residues, when employed in conjunction 

 with brown rock phosphates were beneficial. 



Tennessee brown rock phosphate, Florida soft rock phos- 

 phate, and Tennessee blue rock phosphate in the heavier appli- 

 cations proved superior to South Carolina land rock phosphate, 

 Utah rock phosphate, and Canadian apatite, for oats, clover, and 

 cowpeas grown in sand. 



The phosphorus in brown rock phosphate and Florida soft 

 Tock phosphate was more soluble in water and in plant-food solu- 



Botan. Centralblatt. Band 137. 1918. 23 



