CHAPTER V. 



CULTIVATION OF MIXED CROPS- 



In cultivating mixed crops we must first of all thoroughly under- 

 stand what conditions are necessary to ensure a permanent mix- 

 ture, for otherwise a crop raised originally as a mixed crop and 

 intended to remain such, may eventually sooner or later become 

 of itself transformed into a pure one. When these conditions have 

 once been thoroughly understood, we must next know how to create 

 and treat a mixed forest in any given case. We will now discup 3 

 these questions from a general standpoint, and conclude the Chap- 

 ter with an enquiry into the characteristics of a good auxiliary 

 species. 



SECTION I. 

 Conditions necessary for a mixture of species. 



In a general manner it may be said that the possibility of obtain- 

 ing and maintaining a mixed growth depends 



1. On the suitability of the soil for the more or less prosperous 

 growth of more than one species. Many large stretches of late rite in 

 Burmah practically exclude the existence of other species with the 

 eng, save in specially favourable localities. In the Central Pro- 

 vinces certain ferruginuous soils can bear nothing but Boswellia 

 serrata. Terminalia tomentosa occupies almost by itself patches of 

 stiff, wet soils in the immediate vicinity of sal and teak forest. And 

 so on. It is not enough if two or more species can simply grow in 

 a given soil, nor is at all necessary that the soil should at every 

 point be equally suited to all the associated species; what is want- 

 ed is that their vegetation on it should be vigorous enough to enable 

 them to survive in the struggle for existence with little or no ex- 

 traneous aid on the part of the forester. 



The infringement of this, the first, condition, must necessarily re- 

 sult in the originally mixed crop becoming ultimately pure, with 

 the consequence that the forest growth must, with advancing age, 

 become increasingly more open than if no mixture had been origi- 



