RESULTS WITH BARLEY 53 



chosen for manure sowing. Small dressings may be applied 

 later than large dressings. 



BARLEY 



i. Experiments at Rothamsted. The continuous 

 growth of barley by various manures, after the plan already 

 described in the case of the wheat experiments, commenced in 

 Hoos Field, Rothamsted, in 1852, and has proceeded uninter- 

 ruptedly down to the present time. The soil of the field is 

 similar, but somewhat lighter, than that of the adjoining 

 wheat field. 



The manures applied may be taken as the same in 

 quantity and quality as those already mentioned as employed 

 in the wheat field (p. 32), unless the contrary is stated. The 

 cultivation is that usual for barley. The land is ploughed in 

 the autumn, but no manures are applied till the spring. The 

 whole of the manures, including the ammonia salts, are 

 spread on the land in February or March, and are then 

 ploughed in. 



Produce Obtained. For a study of the produce 

 obtained from the various manures we select the results of 

 the same forty years, 1852-91, which have already been made 

 the subject of discussion in the case of wheat. 



The use of manures supplying only the ash constituents of 

 the crop produced but little effect in the wheat field, in the 

 barley field the effect of such manures is seen to be much 

 more considerable. The effect produced by these cinereal man- 

 ures is chiefly due to the superphosphate which they contain. 



The produce on the unmanured plot, and on those plots 

 receiving ash constituents only, is seen in Table XIII (p. 54) 

 to have largely fallen off during the forty years of the experi- 

 ment, a result different from that observed in the wheat field. 

 This different result is largely due to the spring tillage which 

 the land receives in the case of barley, but not in the case 

 of wheat. This spring tillage brings about an active nitrifica- 

 tion of the nitrogenous matter in the soil, and thus at the 

 same time brings about the utilisation and diminution of the 

 soil nitrogen. 



