216 EXPERIMENT STATION RECORD. 



between the trays." This form of filtration is considered practical only on a 

 small scale, but may be used with advantage in certain horticultural work. 



Report on the sewage irrigation farm of Gennevilliers (BuJ. Mens. Off. 

 Renseig. Agr. [Paris], 8 (1909), No. 2, pp. ISO-lS-'i). — This is a brief report upon 

 the operations of this farm during 1907 and 1908, including detailed statistics 

 of the amounts of sewage water handled during the years 1905 to 1908. 



Agricultural utilization of sewage {Jour. Off. Repub. PrariQ., Jfl {1909), 

 No. J,l, pp. J.',:2.5. L'i2G; ahs. in Rev. Scl. [Paris], 7/7 (1909), I, No. 16, p. 504; 

 Jour. Agr. Prat., n. ser.. 11 {1009). No. 7, pp. 19.',, J9.5).— The official report on 

 the utilization of sewage on the Gennevilliers farm noted above is given, with 

 discussion of the principal facts of agricultural importance brought out in the 

 report. It is indicated that from the standpoint of sewage disposal the results 

 have not been entirely satisfactory, and that in order to secure profitable returns 

 in crop production it is necessary to use the sewage in such large amounts that 

 complete purification is not secured. The use of peat beds according to the 

 Miiutz method has been introduced to secure more perfect purification. 



SOILS— FERTILIZERS. 



Maintenance of soil fertility: Plans and summary tables {Ohio Sta. Circ. 

 92, pp. 32, (Igms. 6). — This circular supplements Bulletin 184 of the station 

 (E. S. II., 20, p. 428) and brings the data of experiments on maintenance of 

 soil fertility begun in 1893 up to the end of the year 1908. The plans and 

 table's are arranged for convenient reference in the field. Among the more 

 important facts brought out by the results of the experiments to date are the 

 following : 



" In the case of the crops grown continuously on the same land there has 

 been a rapid falling off in yield during recent years on tlie unfertilized land, 

 whereas there has been a slight increase in yield on similar land when the 

 same crops liave been grown in rotation with each other and with clover. A 

 given quantity of manure or fertilizer, moreover, has produced a smaller 

 increase on crops grown continuously than on those grown in rotation. 



" In the 5-year rotation of corn, oats, wheat, clover, and timothy the unfer- 

 tilized yield of corn has remained practically stationary throughout the 15 

 years of the test; that of oats has been slightly larger during the last five 

 years than previously, and that of wheat decidedly larger, this gain in wheat 

 yield being due chiefly to greater immunity to insect attack during the latter 

 period. The average increase per acre in all the cereal croi^s has been very 

 much greater during the latter period than formerly, due to the cumulative 

 effect on the fertilizers and manure. 



"As between chemical fertilizers and open-yard manure, the manure has 

 shown the greater increase in effectiveness during the later years of the test. 



" On both the thin land on which this 5-year test is located and on the 

 richer soil used in the 3-year rotation of potatoes, wheat, and clover the great- 

 est total yield and the greatest net gain after deducting the cost of the fer- 

 tilizer, have been produced by comi>lete fertilizers, carrying nitrogen in nitrate 

 of soda, phosphorus in acid i)hosphate, and potassium in muriate of potash. 

 The experiments, however, demonstrate the practicability of replacing the nitro- 

 gen and potassium with stable manure, thus greatly diminishing the cost of 

 fertilizing and increasing the net gain. 



" The experiments with manure forcibly demonstrate the importance of avoid- 

 ing the waste to which manure is subjected while lying in open barnyards and 

 of reenforciug manure with some carrier of phosphorus, to replace the phos- 



