Scientific Agriculture. 



152 



[August, 1909. 



sine ) Professor Bottomley devised special 

 prestations, which he hoped would be 

 useful nob only with legumes, but wich 

 plants of other orders as well), The 

 experiments made are reported upon on 

 page 151 of this issue. It will be seen 

 that while inoculation had no influence 

 on the returns obtained with cowpeas 

 at Antigua, the crop yields of woolly 

 pyrol showed, in the case of one estate 

 at least, considerable increase as the 

 result of treatment. The results at 

 Grenada also show one or two points of 

 interest. Inoculation of sugar-cane at 

 Antigua and Barbados had no effect 

 whatever. 



There are undoubtedly certain condi- 

 tions under which inoculation of the 

 soil with nitrogen-fixing bacteria may 

 prove to be of very considerable value, 

 but on the majority of cultivated lands, 

 which have already borne leguminous 

 crops, inoculation is likely to prove 

 beneficial only if the bacteria intro- 

 duced belong to a more vigorous race of 

 nitrogen-gatherers than those normally 

 present in the soil, or are specifically 

 adapted to the peculiar crop to be 

 grown. In this connexion it may be men- 

 tioned that it has not yet been fully 

 decided whether nitrogen-fixation is 

 carried on by more than one species of 

 soil bacteria, or whether the bacteria 

 which are associated with the various 

 leguminous crops all belong to the 

 species Pseudomonas radicicola. Points 

 of similarity and slight points of differ- 

 ence are observed in organisms from 

 different plants, and it would appear 

 that if all are of the same species, there 

 are a number of varieties of this species 

 in existence. Evidence has been brought 

 forward in support of the belief, held 

 by many investigators, that the 

 bacteria, when grown continuosly in 

 association with one kind of leguminous 

 crop only, become in time so modified 

 as to be capable of giving the best re- 

 sults with that crop alone. At any 

 rate, a greater degree of success has in 

 many cases been obtained when each 

 species of legume is directly infected 

 with bacteria from nodules taken from 

 other plants of tne same species. 



The most notable instances of success 

 in soil inoculation that have so far been 

 recorded have naturally been obtained 

 on lands which have not previously 

 borne a leguminous crop, more especially 

 on virgin soil newly broken up, or on 

 heath or bog land lately reclaimed. 

 The presence of suitable quantities of 

 lime and mineral manures are necessary 

 for success, and must be provided, if 

 normally deficient in the soil. In East 

 Prussia very large ai'eas of barren sandy 

 heath land have been reclaimed and 



made valuable for agricultural purposes 

 by working on this principle. Dressings 

 of basic slag and kainit were applied to 

 the soil, and after preliminary inocula- 

 tion, crops of lupins have been repeatedly 

 grown, and ploughed in. As a result, 

 the nitrogen content of the first 8 inches 

 of land has been raised from 0027 to 

 0'177 per cent, in the course of twenty- 

 five years, while it has also become 

 proportionately richer in the mineral 

 constituents of fertility. 



SPRAYING FOR WEED 

 DESTRUCTION. 



(Prom the Agricultural News, Vol. VIII., 

 No, 178, February 20, 1909.) 



Spraying with various chemicals has 

 in many cases been found to be the best 

 means of destroying certain pestilent 

 weeds. This method of destruction is 

 especially worthy of adoption when the 

 weed in question occurs over extensive 

 areas, is of vigorous growth, and re- 

 produces itself readily by vegetative 

 means. Cheapness of the chemical em- 

 ployed is an essential factor in the eco- 

 nomic success of the method. 



In England and other European coun- 

 tries, spraying with a solution of copper 

 sulphate is frequently adopted for the 

 destruction of ' charlock,' a pestilent 

 and vigorous weed which occurs largely 

 in fields of wheat, oats, and barley, at 

 an early stage of the development of 

 these crops, and tends to choke "out their 

 growth. This method, which was first 

 adopted about ten years ago, has proved 

 both successful and economical. The 

 ' charlock,' which possesses broad, rough 

 leaves, and is allied to the mustard plant 

 (Brassica alba), is destroyed, while the 

 growing corn suffers little or no injury. 



Another example of the application of 

 spraying methods to weed destruction 

 comes from the Malay States. In that 

 country large areas of land are covered 

 with what is known as 'lalang' grass 

 (Imperataarundinacea). This is a creep- 

 ing weed, with underground stems, 

 which rapidly propagates itself by vege- 

 tative means as well as by seed, and 

 quickly covers the ground with its thick, 

 coarse growth. Slow-growing crops are 

 checked out, and cattle refuse to eat 

 the dry, coarse lalang. Digging out 

 the weed proved to be a costly and 

 unsatisfactory method, but experiment 

 has lately shown that the lalang can 

 be got rid of by spraying with a solu- 

 tion of arsenite of soda. The leaves 

 are all killed within a comparatively 

 short time, and are either turned into 

 the ground, or allowed to rot on the 



