CONTENTS 



Page 



INTRODUCTION 1 



HISTORICAL 4-63 



Effect of Weeds on Yield and Quality of Produce 4 



Effect of Weeds on Soil Moisture 12 



Composition of Weeds, Com, Millet smd Oowpeas 16 

 Effect of Weeds on Fertilizing constituents 



of the Soil • 19 

 Effect of "Weeds" Growing in Com on the Total 



Salts and NO3 Content of the Soil 27 



Transpiration 30 

 The Relation of franspiration to Plant Pood 



Transferred to the Plant 34 



Capillarity 36 

 Influence of Texture of Soil upon Moisture 



Content and its Relation to Yield of Com 41 

 Diffusion of Soil Nutrients 44 

 Drought Limit *9 

 Interruption of Water hy Plants 52 

 Effect of Weeds on Ligjit, Warmpth, and Protect- 

 ion from Air Currents 53 

 Effect of Weeds in Producing a Toxic Substance 55 



