FIELD CROPS. 



949 



pared in the following table, the yields from American seed being 

 placed at 100 : 



Culture tests with orchard grass. 



Source of seed. 



Location of experiment sta- 

 tion. 



America (United States) 



Europe (Denmark, Germany, Frame, Sn eden) 

 Australia and New Zealand 



— F. W. WOLL. 



Influence of permanent grass culture on the nitrogen content 

 of the soil compared with that of other crops, T. A. Tuxen (Norsk. 

 Landmandsblad, 17 (189S), No. 13, p. 142).— The experiments were con- 

 ducted at the State Agricultural College at Copenhagen to determine 

 the influence of continued grass and barley culture and crop rotations 

 on the nitrogen content of the soil. The plats were divided into 3 

 series; the first was left uu manured, the second received regular appli- 

 cations of complete commercial fertilizers, and the third was regularly 

 manured with barnyard manure. The quantity of nitrogen in the soil 

 was determined after the experiment had been in progress 22 and 30 

 years. The average results are given in the following table: 



Nitrogen per hectare in the upper twenty centimeters of soil on plats under different systems 



of cropping. 



Continuous grass culture . 

 Continuous bailey culture 

 Cropping in rotation 



Plats cropped for 22 years. 



No ferti- 

 lizer. 



4,lt::i 

 3,578 

 4.407 



Commer- 

 cial fer 

 tilizer. 



Kgs. 



5,131 

 3, 6:i9 

 4,582 



Barnyard 

 manure. 



5,842 

 4,596 

 5,493 



Plats cropped for 30 years. 



Xn ferti- 

 lizer. 



Kgs. 

 4,638 



3,470 

 5, 025 



Commer- 

 cial fer- 

 tilizer. 



Kgs. 

 5,010 

 3,403 

 5,185 



Barnyard 

 manure. 



6,793 

 4, 804 

 6,164 



The results show the beneficial effects of grass crops on the nitrogen 

 content of the soil compared with continuous barley culture, and rota- 

 tive cropping. The grass plats which received commercial fertilizers 

 or which were left unmanured gave less favorable results after 30 years 

 of cropping than the plats on which various crops, including beans, 

 were grown in rotation. It is concluded that commercial nitrogenous 

 fertilizers do not increase the nitrogen content of the soil to the same 

 extent as barnyard manure. — F. w. woll. 



Field experiments with fertilizers in 1897 {Ohio Sta. Bui. 94. 

 pp. 291-326, dgms. 2, map 1). — The plan of these experiments, the soils 

 upon which they were conducted, and the results obtained up to the 

 end of 1890 have been described in previous bulletins (E. S. R., 8, p. 

 576; 9, p. 747). In this bulletin the results obtained in 1897 are tab- 

 ulated and discussed and conclusions drawn. 



