Scientific Agriculture. 



m 



[May 1908. 



diately by mixing with the moist seed a 

 small quantity of dry, sifted earth. 

 Planting should follow as soon as practi- 

 cable, using the same methods as for 

 untreated seed. 



It is sometimes desirable to treat the 

 soil direct instead of ti-eating the seed. 

 The solution is then mixed with enough 

 dry soil (preferably from the field to be 

 inoculated) so that it will just moisten 

 the soil. This treated soil is again mixed 

 thoroughly with a larger quantity of 

 soil — say, half a wagonload for an acre. 

 The inoculated soil is then distributed 

 evenly over the prepared ground and 

 should be harrowed in at once to avoid 

 exposure to sunlight. 



In special cases the amount of culture 

 supplied is largely increased, and this is 

 to be used immediately instead of 

 waiting twenty-four hours for develop- 

 ment. If the quantity of seed to be 

 treated does not exceed 12 to 15 pouuds, 

 the user has simply to open the bottle 

 at once and pour the contents upon the 

 seed. If more liquid is needed to moisten 

 a larger quantity of seed, water up to one 

 gallon niciy be added, reckoning one 

 quart to a bushel of seed. 



Applications for Cultures. 



As cultivated soils in any one place 

 are usually well supplied with nodule- 

 forming organisms adapted to inoculate 

 the legumes that have been grown suc- 

 cessfully for many years in that region, 

 very little benefit will be obtained from 

 further inoculation. To guard against 

 useless experiments and to make those 

 carried out of value for future guidance, 

 the applicant for inoculating mateiial is 

 required to fill out a blank form which 

 asks for information in regard to the 

 legume to be treated, date of planting, 

 soil conditions, etc. 



On the reverse of the application form 

 a circular letter gives briefly the plan 

 of the distribution. Atteution is called 

 to the fact that the bacteria are benefi- 

 cial only in connection with legumes, 

 such as the various clovers (including 

 alfalfa), vetches, peas, and beans, and 

 are not applicable to other farm or 

 garden crops. 



Report op Results. 



It is expected that each one who 

 secures a culture for inoculating legumes 

 will follow the directions carefully and 

 report the results, whether a success 

 or a failure, to the Bureau of Plant 

 Industry. Blanks for this purpose are 

 furnished at the proper time. The main 

 facts desired for this report are quantity 

 of seed (or area) planted and date of 



planting ; whether the culture was 

 applied to the seed or soil; how the land 

 was fertilized ; whether it was new laud, 

 an old field, or garden soil ; the kind of 

 crop previously grown ; and whether 

 the culture when applied was clear, 

 faintly clouded, milky or frothy. 



As to results, the roots should be ex* 

 amined to determine whether the nodules 

 are present or absent, apd should be 

 compared, if possible ■, with plants grown 

 on ground not inoculated. In making 

 this examination care should be taken 

 in digging the plants not to detach the 

 small root hairs. Plants simply pulled 

 from the ground will usually be stripped 

 of nodules along with the broken-off 

 rootlets. Even with careful digging in 

 compact soil it is necessary to examine 

 the clumps of soil about the roots as well 

 as the roots themselves. Any unusual 

 conditions which appear to have affected 

 the results of the experiment should be 

 mentioned especially, together with 

 information as to the geueral appear- 

 ance and yield of the inoculated crop 

 compared with the uninoculated portion 

 or with previous experience with the 

 same legume. 



The Effect of Soil Conditions upon 

 Legume Bacteria. 

 In the investigation of the results of 

 inocculation the wide range of soils for 

 which cultures have been furnished has 

 brought out the complexity of the sub- 

 ject and developed many special prob- 

 lems. The constitution or character of 

 the soil itself has been found to have 

 an effect upon the growth of nodules 

 bacteria, as well as upon the formation 

 of nodules.* Some soils have a chemical 

 composition distinctly unfavourable to 

 the development of the introduced 

 bacteria ; other soils are so compact or 

 reteutive of moisture a* to exclude air, 

 and thus be unfavorable to the growth 

 of the bacteria and to nodule formation. 



A study was made of the reports 

 received from experimenters who used 

 cultures for inoculating legumes to cor- 

 relate, if possible type and condition of 

 soil, treatment, legume species, etc., for 

 those showing favourable results and 

 those showing unfa vourable results. Two 

 representative and widely grown legume 

 crops were studied in this way— alfalfa 

 and red clover. The ouly selection made 

 in the reports chosen for this study was 

 in taking all those received during the 

 two calendar months of November aud 

 December, 1905. These were classified 

 (as illustrated in the reports quoted on 



* For a discussion of this, see Bulletin 100, Part 

 VIII., of the Bureau of Plant Industry, U, S- 

 Department of Agricultnre. 



