220 EXPERIMENT STATION RECORD. [Vol.38 



The relative value of single fertilizer ingredients, for the farm and virgin 

 soils, respectively, based on the growth of sweet clover, was, nitrogen 25.1 and 

 200, phosphoric acid 73.1 and 275, and potash 57.1 and 135. 



" Based on the growth of sweet clover, phosphoric acid and limestone is con- 

 clusively the most economic treatment for building up these DeKalb soils. Phos- 

 phoric acid gave an increased growth in each case and its absence depressed the 

 yield without exception. Nitrogen proved to he unnecessary for the production 

 of red clover on DeKalb soil." 



Thirty-five years' results with fertilizers {Pennsylvania Sta. Bui. 147 

 {1911), pp. 11-20, fig. 1). — The principal conclusions and recommendations from 

 these experiments are summarized, the work having been noted in detail else- 

 where (E. S. R., 37, p. 62G). 



Progress of green manuring in Mysore, A. K. Yegnanaeayana Iyer {Mysore 

 Agr. Calendar, IDll, pp. IJf, 15). — The green manuring of paddy lands and of 

 sugar-cane plantations with leaves of the honge tree {Pongamia glabra) and 

 with green-manure crops grov/n on the fields is briefly discussed. Crops used 

 in the latter instance included sunn hemp, cowpeas, green gram, black gram, 

 horsegram, Crotalaria striata, and daincha. 



Previous studies in green manuring in Mysore have been noted (E. S. R., 27, 

 p. 21). 



[The relative value of oil cakes available in Mysore and the results of 

 oil-cake manuring on sugar cane], H. V. Krishnayya, A. K. Yegnanarayana 

 Iyer, and D. G. Rajiachandea Rao {Mysore Agr. Calendar, Wit, pp. 18-23). — 

 The nitrogen content of the oil cake of safflower, peanut, white castor, black 

 castor, neem {Melia azadlrachta) , honge {Pongamia glabra), and cotton seed 

 is reported as determined by the ftlysore Department of Agriculture. The 

 analyses ranged from 3 to 8 per cent, with safflower cake showing the highest 

 percentage. Greatly increased yields from the application of even small 

 amounts of oil cake to sugar cane are brietly noted. 



Cyanamid as a source of nitrogen {Pennsylvania Sta. Bui. IJ^I {1911), pp. 

 23-25). — Commercial cyanamid was compared with nitrate of soda and dried 

 blood from 1912-1914, inclusive, for potatoes, oats, and wheat, and from 1913- 

 1916 with nitrate of soda as a top-dressing for timothy. 



The only significant differences were secured with potatoes, where increases 

 over no nitrogen were obtained amounting to 32.8 bu. for nitrate of soda, 

 101.3 bu. for dried blood, and 56.7 bu. for cyanamid. With nitrogen as nitrate 

 of soda used as a top-dressing for timothy, an average yield was obtained of 

 4,910 lbs. of field-cured hay per acre, and with cyanamid 4,618 lbs. 



Availability of potash, fertilizer residue in the soil {Pennsylvania Sta. But. 

 HI {1911), pp. 3S-J,0, fig. 1).—A study of the availability of potash fertilizer 

 residues in the soil is briefly noted, indicating that potash-treated land car- 

 ries about twice as much potash removable by weak solvents as untreated land. 

 Analyses of five crops, each grown in a different year upon treated and un- 

 treated land, show that the crops grown on treated soil removed 105.08 lbs. of 

 potash in their grain and stalky parts, while those from the untreated plats 

 removed 73.81 lbs. of potash to the acre yield. These results led to the fol- 

 lowing conclusions: "Clays and loams that have been well fertilized with 

 potash until quite recently still hold in their surface layers considerable fer- 

 tilizer potash in condition to feed the crops for several years. Hence for most 

 field crops inability to supply fertilizer potash at this time does not threaten 

 a great reduction in yields froiii lands of such history." 



Belative value of limestone of different degrees of fineness {Pennsylvania 

 Sta. Bui 1J,1 {1911), pp. 22, 23, fig. /).— Experimental data are presented on 

 the relative value of limestone of different degrees of fineness, based upon its 



