392 



NA TURE 



[March 23, 1922 



Some Aspects of 

 'X'HE great importance~of the cotton crop in certain 

 ^ countries has led to special attention being paid 

 to the deterioration in yield and quality that occurs in 

 certain areas and to methods whereby improvements 

 may be effected. 



In Egypt (Bull. Imperial Inst. 19, No. 2) the decline 

 in yield may be attributed chiefly to degeneration of 

 the productive power of the soil, the ravages of 

 insect pests, and to agrarian disturbance. To give 

 satisfactory crops cotton, should be grown only once 

 in a three-year rotation, but this limit has frequently 

 been exceeded, with the natural result that the soil 

 ingredients have been drawn upon unevenly, thus 

 upsetting the balance of fertility. This could have 

 been remedied by the judicious use of fertilisers, 

 but for various reasons this has not been carried out. 

 Even where manures have been used much harm 

 has been done by the introduction of noxious sub- 

 stitutes by unscrupulous dealers. Excessive cotton 

 cultivation has also been encouraged by the practice 

 of leasing land for short three-year periods, the 

 highest rents being paid to landowners who permit 

 the greatest amount of cotton to be cultivated within 

 the period of the lease without insisting on the 

 re-establishment of the fertility of the soil for future 

 tenants. 



Another harmful factor is the prevalence of water- 

 logging. Since the Assuan Reservoir came into use, 

 more water has been available for irrigation, and in 

 addition the water table has risen, so that the drain- 

 age is now imperfect, and the roots of the cotton 

 plant suffer from asphyxiation due to the consequent 

 lack of air supply. The damage is aggravated by 

 harmful salts which are now brought into solution 

 near the soil level, and by surface evaporation remain 

 within the aiea of growth of the cotton roots. 



Until about 191 2 the cotton worm was the most 

 serious insect pest, but was eventually brought under 

 control. Of recent years the pink boll-worm, first 

 discovered near Alexandria in 191 1, has become of 

 paramount importance owing to its rapid spread 

 through nearly all the cotton-growing countries of the 

 world. Its life-history and habits rendered impossible 

 the production of late-maturing cotton, as the late- 

 formed bolls are badly attacked and the lint rendered 

 useless for spinning purposes. Legislative measures 

 are now in force for the uprooting and burning of the 

 cotton plants before the end of the year, and for the 

 treatment of the seed by hot air, whereby the resting 

 worms are destroyed while the germinating" power of 

 the seed is not affected. It is hoped that the attacks 

 of each pest will thus be reduced, and that the yield 

 of cotton will, in consequence, be increased. 



Agrarian disturbances have also caused much 



Cotton Growing. 



trouble, as the cultivators joined in the destruction of 

 the means of transport, whereby difficulties arose in 

 marketing the cotton and also in connection with 

 seed distribution for the next season's crop. 



Deterioration of quality has been considered in the 

 case of Cambodia cotton {Gossypium hirsutum) 

 grown in India ( Agric. Journ. India, vol. 16, part 3). 

 For some years after its introduction in 1907 the 

 quality of its lint was good, but of late years it has 

 been asserted that the lint is shorter, weaker, and 

 much more stained than was the case at first. The 

 weakness and staining are attributed to attacks of 

 the pink boll-worm, and the loss can only be cured 

 by the reduction of the pest. The shortness of 

 staple, however, is due to the fact that the first seed 

 distributed included a mixture of types. The early 

 and more vigorous types, with poorer quality staple, 

 were the better suited to the climate and to the rather 

 haphazard methods of cultivation, and therefore 

 flourished at the expense of the better quality types 

 with longer staple. The line of improvement it is 

 proposed to follow is that of isolation of types by 

 means of single-plant selection and self-fertilisation, 

 followed at a later stage by hybridisation to produce 

 a type combining in itself all the most useful 

 characters. If a more productive type can thus be 

 produced and the loss caused by insect pests be 

 controlled, considerable increase of yield per acre 

 may be secured. 



In this connecdon attention may be directed to an 

 article on the commercial utilisation of cotton stalks 

 (Bull. Imperial Inst. 19, No. i). Enormous quantities 

 of stalks are available after the crop is harvested, 

 and as they afford harbourage for insect pests their 

 destruction is of much importance. Locally the 

 stalks are used as fuel, and in some districts supplies 

 would not be available for other purposes. A fibre 

 resembling that of jute, however, can be obtained from 

 the bark, and possibly the longer fibre might be used 

 as a substitute for the lower grades of Indian jute, and 

 would probably realise rather less than half the price 

 of Bengal jute. 



Preliminary paper-making trials indicate that when 

 treated by the caustic soda process, Indian cotton 

 stalks yield paper pulp of fair qualify which can be 

 bleached to a pale cream tint, and the results are 

 promising enough to deserve further consideration on 

 the spot in India. Distillation experiments have also 

 been carried out both in Egypt and England ; good 

 quality methyl alcohol and acetate of lime have been 

 produced, but the charcoal and tar are of less value. 

 In India the feasibility of distilling cotton stalks 

 successfully would depend upon finding local markets 

 for the products, particularly the charcoal and tar. 



The Geographical Distribution of the Palm Pritchardia. 



'T'HE Bernice Pauahi Bishop Museum of Honolulu 

 -*• has recently issued (Memoirs, vol. 8, No. i) an 

 elaborate monograph of the palm genus Pritchardia 

 by the late Prof. Odoardo Beccari and Prof. Joseph 

 Rock. It is mainly the work of Prof. Beccari, and 

 forms part of a larger monograph which he had 

 prepared for later publication in the. Annals of the 

 Calcutta Botanic Garden. The material for the 

 monograph has been largely supplied by Prof. Rock, 

 who has discovered twenty-one of the thirty-three 

 species described. 



The study of the genus is of special interest from 

 the point of view of geographical distribution. It 

 is one of the most characteristic genera of palms of 

 the Polynesian flora, but has attained its greatest 



NO. 2734, VOL. 109] 



development in the Hawaian Archipelago, where it is 

 the only palm found. It also supplies one of the most 

 interesting problems in the geographical distribution 

 of the family in the existence of a single species in 

 the New World, namely, in Cuba and the Isle of 

 Pines. This may be compared with the presence in 

 South America of a representative of the African 

 genus Raphia and of the solitary representative of the 

 typical American Cocoinese, namely Jubaeopsis, in 

 South Africa. How the fruits of the progenetrix of 

 the Cuban species were enabled to cross the wide 

 space of ocean between the nearest Polynesian islands 

 and the American continent is a mystery. Prof. 

 Beccari suggests the possibility of the transfer of fruits 

 by means of the violent volcanic phenomena which 



