368 



THE AGRICULTURAL NEWS. 



NOVEMEEE 21, 1914, 



-ative 'crops muler conditions of <lcticient rainfall, 

 reference is made by Mr. Hall to what is now known 

 as dry fanning, and it is explained tKat this consists in 

 nothing more than tiic application of the principles of 

 husbandry worked out by English fanners, which 

 principles were first expounde<l by 'full, an English 

 farmer of the seventeenth century. It is pointed out 

 that there is, however, a new feature introduced into 

 diy farming by the settlers in ai'id districts in North 

 America and Australia, namely the use of a year of 

 bare fallow, in which to accumulate a supply of water 

 for the crop of the next year or two. This is the basis 

 of work in districts that may be described as arid. 



JIuch of the work carried on in the di'ier islands of 

 the West Indies is based on the principles untlerlying 

 .so-called ihy farming, and it i.s the carrying out of these 

 principles, as the outcome of the empirical acijuirement 

 of a sound knowledge of ctinditions governing local 

 circumstances, that produces what is recognized as the 

 good, practical, and successful planter. The object of 

 modem effort, in relation to agricultural educati<jn in 

 its broadest sense, is to bring these principles to recog- 

 nition, and by their further study to deduce from them 

 vet wider and wider generalizations. 



It is interesting to note, as evidence of the fact 

 that the principles of dry farming are extensively used 

 in parts of the West Indies, that the value of mulching 

 with trash and vegetable matter, a practice not referred 

 ■to in Mr. Hall's address, is well recognized; it finds, 

 ■possibly, its best and most systematic application in 

 arable agriculture in the sugar-cane fields of Barbados, 

 but it also finds application in orchard cultivations in 

 many pai'ts of the West Indies, though, perhaps, under 

 circinnstances hardly connected with dry farmiiig. 



As the outcome of various considerations, Mr. Hall 

 puts forward \'ery stiggestive ideas c<jncerning the 

 actual ijuantity of water required by the plant and the 

 crop, leading to the idea that good work remains to 

 be done in the production of varieties of crop plants 

 specially capable of producing large quantities of stored 

 material, such as stai'ch or sugar, with the use of 

 relatively small amounts of water: and in this connex- 

 ion he draws attention to several points requiring 

 investigation, some of which might be well enquired 

 into in tropical countries, if means were found to 

 4-.quip investigators. 



Attention is drawn to the relationship between 

 the quantity of water transpired by the crop, and that 

 lost to the soil by evaporation, and it is explained that 

 under the climatic conditions of Rothamsted in 

 England one half of the annual rainfall finds its way 

 back into the atmosj)here by evaporation fnjm the soilj 



and that the amount evaporated is substantially the 

 same fi'om deep and from shallow soils, being deter- 

 mined by the surface only. \'arious pnjblems await- 

 ing investigation are jiijintid out. .some of which 

 might be capable (jf solution by W^est Indian 

 investigators. 



If loss of water from the soil surface is so impor- 

 tant a matter under the conditions of a temperate 

 climate, it may be suggested that it is of much greater 

 importance under tropical and sub-tri>pical conditioas, 

 and, indeed, that it has a large bearing on agricultural 

 methods in drv districts in these regions. 



In this connexion Mr. Hall raises the question 

 how far evaporation from the bare s<;>il can be checked 

 by suitable screens or hedges that will break the 

 sweep of the wind across the land. 



The persistent sweep of the trade winds over the 

 country makes the effect of wind very obvious: wind- 

 breaks therefore have been a matter of serious consid- 

 eration in many parts of the West Indies, and the exten- 

 sion of their use is constantly advocated. In this connex- 

 ion, however, it would seem that the benefit of mitigat- 

 ing this action of the wind up<3n the plants has had chief 

 consideration, wiml-lireaks having principally been used 

 in connexion with orchanl crops like cacao and limes; 

 the action of the wind upon the soil itself, as affecting 

 the evaporation from the surface, has had little con- 

 sideration. It would now appear desirable to ascertain 

 whether wind-breaks may be usefully applied more 

 extensively than at present in connexion with arable 

 cultivation, as a means of reducing evaporation from 

 soil surfaces. 



As a method of winning for profitable cultivation 

 land suffering from deficient rainfall, reference is natur- 

 ally made to irrigation: but at the outset the note is 

 struck that the history of irrigation-farming is full 

 of disappointments, due to the rise of salts from 

 the subsoil, and the subsequent sterility of the 

 land. But it is pointed out that the conditions 

 are now fully understood, and there is no longer 

 any excuse for the disasters that have overtaken 

 the pioneers of irrigation in almost every coun- 

 try. It is explainied that under almost all cir- 

 cumstances there is a danger of salts accumulat- 

 ing in the surface -soil, and that this can only be 

 obviated by periodic wa.shings out: and also, that there 

 is ever-present danger ot raising the water-table, so 

 that the subsoil becomes water-logged, and no longer 

 permits the free growth of plant roots. It is now well 

 recognized that drainage is an essential accompaniment 

 of irrigation, and that most irrigation troubles havo 

 ari.sen from want of proper appreciation of this. 



