Soils — FERTIL1ZEBS. • 647 



200 lbs. per acre each of sodium nitrate, potassium sulphate, and acid phosphate. 

 The smaller applications of lime i 1,000 lbs. per acre) gave a slightly larger increase 

 than applications of 2,000 lbs. per acre. The lime produced aearly twice as much 

 gain when used with a complete fertilizer as when used alone 



"Barnyard manure has given a considerable increase, but from the economical 

 standpoint is not equal to cowpeas and lime, and, furthermore, its use is restricted 

 for want of supply." 



To tesl the residual effects of the various treatments a number of the baskets were 

 replanted without further addition of fertilizing materials. The mosl striking feature 

 of the results was "the marked reduction in the growth of the second crop, which is 

 frequently less than half what it was in the firsl instance. The relative growth as 

 affected by the treatments ia essentially the same in both crops, hut there has been 

 a marked reduction regardless of the treatment. In only two out of eighl Instances 

 has the residual effect been sufficient to exceed or equal the original irrowth on the 

 untreated soil." 



It is stated that the results obtained in these experiment- "seem to be thorough ly 

 in accord with the observations that have been made in the Held and with the experi- 

 ence of the planters in Darlington ( lounty." 



Liming: soils (J////. Rpts. r»l. Agr. Del, n. ser., 8-4 (1908-4), pp. 123-128).— A 

 general discussion of this subject, based largely on the work of the Rhode [sland Sta- 

 tion, as summarized in Farmers' bulletin 77 of this Department. Attention is called 

 to the advantages of the method somewhat recently introduced of applying finely 

 ground, freshly burned lime before it has been slaked to the soil by means of a grain 

 drill. 



On the action of the water-soluble mineral constituents of plant residues 

 on the soil, S. Kkawkow (Jour. Landw., 53 (1905), No. • •'. /</<. ?79-288). — Analyses 

 of water extracts of fine-ground oak leaves before and after passing through a marly 

 soil showed that sulphuric acid, potash, magnesia, and phosphoric acid were freely 

 dissolved from the leaves, the lime and silica in only small amounts, iron oxid in 

 moderate amounts. 



The soil absorbed from the leaf extract large amounts of the potash (58 per cent), 

 phosphoric acid (69 per cent), magnesia (38 per cent), and organic substances. The 

 latter, however, were removed by repeated washing. Silica, manganese oxid, soda, 

 and iron oxid were not absorbed by the soil. Considerable amounts of lime and 

 sulphuric acid were removed from the soil by the leaf extract, due to exchange of 

 bases and the action of organic acids. 



Soil inoculation. — Tubercle-forming- bacteria of legumes, L. L. Lewis, J. F. 

 Nicholson, et al. (Oklahoma Sta. Bid. 68, pp. 80, figs. 8). — The investigations here 

 recorded included a series of pot experiments with sterilized soil to study (] ) effect of 

 cultivation and composition of media on the activity of the germ from the alfalfa 

 plant; (2) nature of the organisms from the cowpea and the soy bean, and of a com- 

 mercial culture; (3) cross inoculation, or the inoculation of one plant with cultures 

 ohtained from another; (4) normal distribution of the tubercle-forming bacteria of the 

 legumes in the United States; (5) ability of the tubercle-forming bacteria to increase 

 the nitrogen content of culture media in which they are grown; ( t> ) methods of send- 

 ing out cultures; (7) cultural characters of the tubercle-forming bacteria of the 

 legumes. 



Methods of determining nitrogen in the cultures and the results ohtained in a series 

 of analyses are also given, as well as the cultural characteristics of the tubercle- 

 forming bacterium (Pseudomowix radicicola) of legumes. The results obtained are 

 believed to justify the following conclusions: 



"(1) Soil inoculation with cultures of the tubercle-forming bacteria is practicable 

 only when other conditions are favorable for plant growth. 



20408— No. 7—06 3 



