FIELD CROP PRODUCTION 



CHAPTER I 



INTRODUCTORY VIEW 



All the plants that grow on the earth are called, col- 

 lectively, the plant kingdom. The plant kingdom is made 

 up of innumerable forms of vegetation, ranging in size 

 from the tiny one-celled plant, so small that it cannot be 

 seen with the unaided eye, to the giant trees of the forest. 

 Between these two extremes are to be found myriads of 

 intermediate forms, the algae that grow in ponds and 

 streams, the mosses and lichens that grow on the trees 

 and rocks, the ferns of the woods, the grasses and grains of 

 the fields, the wonderful shrubs and plants with which we 

 beautify our yards and gardens, and numerous other 

 similar and related forms. Plants differ not only in their 

 size, structure and habitat, but also in the kinds of food 

 that they are able to use and in their usefulness to man. 

 Some forms of vegetation are able to secure their food 

 from the inanimate world in the form of chemical elements 

 or compounds in the soil and in the atmosphere, and by 

 certain life processes are able to convert them into forms 

 useful in building up their own structures. Other forms 

 are not able to do this, but must derive a part of their 

 food from compounds that have already been incorporated 

 in the bodies of other plants or animals. To the former 

 class belong most of our cultivated plants, while in the 



