JO 1''eb., jyio.] 2\sts ■K/t/i Cidtiircs oj Root-tubLrcU Bacteria. 



1. If .111 old field is cliisc ,it: hand in which the same Icf^uminous crop 

 has succeeded, iiiocul.ile the new sdil with 130-300 lbs. (if soil ])er acre 

 from the old one. s|ire;iding broadcast .nid h.irrow iny in with llie seed, 

 or. prior to di-illing il the drill is used. 



2. On ,1 sm.dl senile soil nia\ In; inoculated li\ planluij^ with li\in^ 

 legumes ol the same kind. lians])l anted with as complete ,1 root s\stem 

 as possible. 



3. On a larger scale, il plants are pi-(.H:urable, the njot tubercles m.iv 

 be- strip|>e(l oil, pounded to a ihin ])asle with water, which is then mixed 

 with the se<'(!s before plantin^i;. 'i'lu- addition of a little milk aids the 

 therms to adhere to the seeds, which should be dried and planted at once. 



j[. Xitragin or nit ro cultui'e max he used in the same w,i\ for the 

 inoculation of Ji<' seed. alwa_\s pro\ide<l that the cultures are good ones, 

 and suitable for tlie particular crop. J'his is th<' most ex]>ensive and iea.st 

 -ure method of infecting a sterile soil. To inoculate tlv soil directb 

 with bacteria from cultures or from tin,' tubercles is both wasteful and 

 costl)', no appreciable effects being produced unless relatixcK large i|u.iii- 

 tities are used. Hence, there is no iieeid for a largt; outla\ for cultures, 

 even when there is iki e-ther means of obtaining thi- required root tubercle 

 bacteria, liut an\ farm<'r desirous ol maintaining tlu' humus ,ind nitrog<ii 

 content of his land b\ the growth of leguminous crops which he has not 

 been able to establish b\ other uhmun, will incur no great risk b\ e.\ 

 perimeiiting in the directions indicated, a.nd il he car<'S to ex|)<'nd a few 

 shillings in <'Xp<'rimenting with a bottle of (ailture no gri.-al harm will be 

 ■done. As matters stand ,it presi-nt, howexcr. and in view oj all th<' lact.s, 

 it is im])OSsible to adxise an\ /</.',i;(' expenditure on laillnres |or use u\\ an 

 extended scale. In an\ case, ewii if llu; cailtni-'s lulliljed all that is 

 <:laimed loi' them, the larnier would i)robabl\ alwaxs lind il moic prf.- 

 litable to use them on small jjlots on which the required legumes are 

 grown, then infecting large fields b_\ s|)rea(ling the soil from the plots in 

 the b illow ing \<'ar or \ ears. 



l'"inall\, it is doubtful whether an\ well-drained land on which stock 

 ha\c been gra/id. or to which farmyard manure nas lieen added, is ever 

 totall\ dex'oid of the root-tulxTcle bacteria which the Lcguniinosu- need 

 to enable them to form the root-tubercles, b\ wlK>se aid thev ran assimilate 

 free nitrogen. There can be no doubt that the bacteria from the tubercle.« 

 of one member of the pea famih- ma\ infect others though possibb not 

 all of the members of fhe same lamib. but so far as is known, oiilv 

 memlK^rs of that famil\- ([mms, beans, \-etches, clo\er, lucerne, medick, 

 sainfoin, trefoil, kc.) aif enabled b\ bacteria to directb assimilate th(- 

 free nitrogen of the air. Hence, to adxcrtise bacterial ciiltiu'es as of 

 direct benefit to cereals is not justifiable, and e\'en their use for legumin- 

 < us crops is' hardly beyond the experimental stage, and is not to Ik- arlvis^xl 

 until e\cry other method of establishing a leguminous crop on sterile soil has 

 failed, inchiding manuring and culti\;ilion. for fertile soils on which 

 legumes have prexiouslv grown, the cultuxes are quite u.seh^ss. 



According to K. B. I"' red (Virginia Station Re])ort, T908, p]). 132 131) 

 root-nodule bacteria are able to assimilate [yrr nitrr>gen even when not 

 gr()wing within the r<^iots of a leguminous plant. 'I'luw can onb do this, 

 however, when the culture medium eoiitains carbo hv drates. so that in the 

 soil their nitrogen-fixing activity when free is slight or negligible. Actual 

 tests have .shown that, in the absence of leguminous jilants, the net result 

 of the activitv rif micro-organisms in well-aerated and culti\'alerl soils is 

 to produce a loss, rather than a gain, <S nitrogen, and this loss is especiallv 

 marked after the addition of oriranic nilro'renons manures to the soil. 



