Vol. XVI. No. 409. 



THE AQRICULTUKAL NEWS. 



405 



workers on the plantation, such as those engaged 

 in ploughing, tie working of weeding machines, and 

 the care ot live itock. 



Cotton groving gives rise to a demand tor 

 skilled workers )f the labourer class, who can be 

 entrusted with tie work of planting and caring for 

 the crop, and the control of the pests and diseases to 

 which the crop is liable: and this in perhaps a 

 greater degree thai is seen in the sugar industry. 



Where orchad work is engaged in, such as 

 the growing of '.acao or of limes, there arises 

 a demand for skiiad labourers: for in these indus- 

 tries there is muci work in connexion with plant- 

 ing the trees and pruning them, and in handl- 

 ing the crop, tha has to be done b}- labourers 

 working more or les alone, as distinguished from the 

 working in large gaigs which characterizes the work 

 of some industries. Here the worth of training is soon 

 felt, and a good wirkman is valued, and should be 

 remunerated accordiigly. 



From this, perh.ps, it follows that the training of 

 pupils in Botanic G;rdens and Experiment Stations 

 will find most favourin cacao and lime-growing coun- 

 tries, though it is pnbable that the effort to diversify 

 industries, which is low evident, will lead to an early 

 extension to sugar aid cotton-growing regions of this 

 means of training: wiile this will probabi}- be hastened 

 by the increasing ue of implements and motors in 

 agricultural work, aid the necessity these will create 

 for skilled workers. 



In all communites there is a demand for gardeners, 

 though this demand lay be quite small in some of them. 

 The FJotanic Gardeis and Experiment Stations afford 

 excellent training gi-und in which the limited numbers 

 of skilled workers of ihis class may be readily produced, 

 without the necessit' for setting up any elaborate train- 

 ing institution. 



On surveying the whole question of agricltural 

 instruction, it shoild be recognized that there already 

 exist in these clonics valuable means for giving 

 instruction. What is needed on the part of those 

 directing affairs iS that they shall carefully study 

 the facilities this existing, and endeavour to use 

 them to the fulest extent, and out of them to 

 lievelop further aid better means of education. The 

 means are withii reach, and in many cases involve 

 but little expeise in procuring their utilization. 

 .Such a course b more likely to be attended with 

 success than eforts at the present time to create 

 entirely new orianizations for teaching purposes. 



POTASH FROM KELP. 



Until the beginning of the war the supjjly of potash as- 

 a fertilizer wa.s almost a monopoly of Germany's. In 1915 

 Germany prohibited the exportation of all potash salts. 

 This action stimulated the attempt of American manufac- 

 turers to produce potash, and resulted in the erection of large 

 plants in Southern Cilifornia for the extraction of this 

 material from kelp. Along the PdciKc coast of North 

 America a'-e found beds of giant kelp of several species. 

 These huge sea plants sometimes grow into a length of 

 100 feet, containing a surprising amount of potash salts. 

 According to an article in the YearborA- of the United States 

 Department of Agriculture, 1916, dried kelp of the most 

 important species will yield from 2.5 to 30 per cent, of 

 potassium chloride. These species of kelp appear to be one 

 of the most hopeful sources of an adequate supply of potash 

 for fertilizing purposes. Eight large factories are operating 

 with an aggregate daily capacity for dealing with 2 500 tons 

 of raw kelp, yielding approximately 10 per cent, of dried 

 kelp. The reaping of the kelp is however not without difB- 

 culties The beds are located close in shore, almost all of 

 them within the 3-mile limit. The kelp is harvested by 

 cutting the upright stems from 3 to 6 feet below the surface, 

 which secures not only that portion but also the much 

 larger portion which floats on the surface of the water. 

 The plants are non-fibrous, and of a gelatinous nature, 

 which makes it almost impossible to extract the water they 

 contain, which has to be removed by pressure. 



Several methods hive been suggested for treating these 

 kelps with a view to their utilization for fertilizer purposes. 

 The simplest is to dry and grind the material, and market the 

 product for direct application to the soil. The dried, ground 

 kelp contains 25 per cent, potassium chloride, 2 per cent, 

 nitrogen, and organic matter of value for improving the 

 condition of the soil by the form ition of humus 



Another process is to burn the dried kelp, and market 

 the ash for its potash content. By this process, however, 

 the value of the nitrogen is volatilized and lost, and a small 

 part of the potash content is similarly destroyed. 



Another process, which seems most likely to succeed- 

 eventually, is to distil the dried kelp in retorts constructed 

 en the general principle of the by-product coke oven. This 

 results in a charged residue containing all the potash salts, 

 which may be recovered by leaching and evaprration. 

 In the process of distillation the nitrogen is driven off and 

 recovered in the form of ammonia. Combustible gas is 



evolved in considerable quantities, and is available for use as 

 f uelin the retorts and under the evaporating vats, and charcoal 

 and tarry products are recovered which may be sold or used as 

 fuel. Iodine and some other by-produc's may also be 

 recovered. 



If the kelp grew on the eastern sea-board, close to the 

 regions of large fertilizer demands, the first method of 

 treatment would probably be the most economical and 

 satisfactory. The kelp, however, occurs on the western 

 sea-board, and the heavy freight ch irges on the transportation 

 of the dried kelp, three-fourlhs of which consist practically 

 of valuele.3S matter, would prove too heavy an item to 

 permit of successful competition with importations of pota=h 

 salts from mines in other countrie.s. Investigafion« ar,- 

 new being made with the hope of transplanting the l^iciri.; 

 kelp to the .'Atlantic coast, and successfully eroivms it tluTi- 

 If this should be accomplished, and the pi mts est.ibli.slict 

 in extensive beds, dried ground kelp would nndoubleJIy 

 become a widely used fertilizer on eastern f uuis. 



