l8] PLANT ADJUSTMENTS AND APPLICATIONS 1579 



of whether our single-cropping and maintenance for it of open-soil 

 conditions is really sound, involving as it commonly does the 

 destruction of soil structure by deep ploughing ; in weed and 

 disease control, where autecological studies suggest the possible 

 effectiveness of more judicious land management as well as applica- 

 tion of selective herbicides ; in conservation, where vegetative cover 

 is the most effective means of checking erosion ; in water-supply 

 and wildlife management, where the ecological problems are almost 

 endless ; in landscaping, where knowledge of the habitat require- 

 ments of the species concerned is fundamental ; and so on — almost 

 ad infinitum. Indeed we may suggest without serious fear of con- 

 tradiction that it is largely, and perhaps in the long run only, through 

 the enlightened application of effective research in the plant sciences 

 sensii latissimo that Man can continue to keep abreast of population 

 increases and feed and clothe the world's teeming millions. 



It may be claimed with good reason that this is the age for the 

 biological scientist : for whereas the physical sciences have already 

 achieved a high degree of consistency, in the life sciences our know- 

 ledge is often still no more than meagre and our understanding 

 rudimentarv (yet the importance of learning more and more is 

 enormous, as indicated above). And so it is that in plant geography 

 and some of its relatives, our analytical perception is often poor 

 and many fundamental principles doubtless still await discovery. 

 Whether, indeed, with the changing drifts of life, this situation will 

 ever be fully remedied, remains to be seen. But already there is a 

 vast body of knowledge which is being added to all the time, and 

 the present book has as its main object the sifting of this knowledge 

 and introduction to the principles that emerge. 



Additional Re.\ding 



It has been customary to conclude previous chapters with lists of 

 pertinent works or suggestions for further reading. In the present 

 instance any good modern text-book of genetics and plant breeding, such 

 as E. W. Sinnott, L. C. Dunn & T. Dobzhansky's Principles of Genetics, 

 fifth edition (McGraw-Hill, New York etc., pp. xiv + 459, 1958), or 

 M. B. Crane & W. J. C. Lawrence's The Genetics of Garden Plants, fourth 

 edition (Macmillan, London, pp. xvii + 301, 1952), should suffice to give 

 the needful student some background to the cognate facts and principles 

 on which we have (barely) touched. 



The ecological items were dealt with in Chapters X and XI, at the ends 

 of which further reading was suggested. Concerning erosion and its 



