jyii Contents 



Manganese in Relation to Sterility 132 



The Occurrence of Manganese in Pasture Grass and 



Hay IN THE Netherlands 133 



Supplementary Research on Copper, Cobalt, Molybde- 

 num AND Selenium 0''^ collahoration with J. de Wael) . 136 



Discussion of Results 136 



Summary 138 



References 140 



Discussion 140 



Author Index 142 



Plates 145 



LIST OF ILLUSTRATIONS 



Textfigure 1 .— Demineralised water system flow-sheet .... 12 



Textfigure 2.— Automatic sand washing equipment 17 



Textfigure 3.— Influence of increasing quantities of potassium and 



calcium hydrate on the manganese content of oat straw .... 29 

 Textfigure 4.— Effect of increasing amounts of copper and nitrogen 



on wheat grown in a copper-deficient soil 44 



Textfigure 5.— EflFect of copper on the production of acetic acid by 



Acetohacter aceti 45 



Textfigure 6.— Diagram showing some possible functions of copper 



and manganese in the iron metabolism of plants 57 



Textfigure 7.— Manganese content of foliage of Phaseolus vulgans 



grown on plots with various amounts of limestone (1946) ... 65 

 Textfigure 8.— Manganese content of foliage of Phaseolus vulgaris 



grown on plots with various amounts of limestone (1947) ... 66 

 Textfigure 9.— Manganese content of foliage of healthy and affected 



beans grown on the same field 68 



Textfigure 10.— Manganese content of foliage of a number of crops 



grown on the same plot (1946) 69 



Textfigure 1 1 .—Manganese content of foliage of three crops grown 



on the same plot (1944) 70 



Textfigure 12.— Manganese content of foliage of Phaseolus vulgaris 



and exchangeable manganese in the soil (1946) 71 



Textfigure 13.— Manganese content of foliage of Phaseolus vulgaris 



and exchangeable manganese in the soil (1947) 72 



Textfigure 14.— Exchangeable manganese in the soil of the same 



plots at different times 73 



Textfigure 15.— Increases in yield with different copper fertilizers 93 

 Textfigure 16.— Recolte et concentration de I'aliment . . . . 110 

 Textfigure 17.— Courbe des r^coltes en fonction de la concentration 



en Mg Ill 



Textfigure 18.— Variation du coefficient d'action du Mg avec la 

 concentration en NH^ 112 



