254 



EXPERIMENTS ON THE CULTURE OF TURXIPS. 



carried off a large quantity of nitric acid and also a little potash, 

 but of phosphoric acid it apparently had carried off none. 



When it is considered that the drain in question was discharg- 

 ing water at the rate of many thousand gallons a day, containing 

 a considerable quantity of nitric acid, it will at once be evident 

 that a large quantity of this valuable article was being washed 

 away in the drains. A little potash had also got into the drains, 

 but the quantity seems to have been very small, and as the first 

 sample of water (which was entirely bottom or spring water) 

 showed a faint trace of it, it is questionable whether much or 

 even any of the potash salts applied to the soil had been carried 

 away, — as the soil and subsoil in their natural composition 

 contain about '25 per cent, of potash. A very trifling percentage 

 of this quantity, however, is in a soluble condition. 



Agriculturists generally appear to think that such abnormally 

 wet seasons as 1879 favour the action of insoluble more than 

 soluble phosphates, and that the results of experiments with 

 these articles in such seasons are not reliable ; but, while the 

 popular belief is that a portion of the soluble phosphates are 

 washed into the drains by excessive rains, and that these rains 

 favour the decomposition of ground phosphates by assisting the 

 action of the solvents present in the soil, this season's inquiries 

 seem to point entirely in the opposite direction. There does not 

 appear to be any phosphoric acid carried off in the drains, although 

 it may have been washed into the subsoil, and the results of this 

 year's experiments with insoluble versus soluble phosphates, 

 comparatively speaking, show that this hot dry season has been 

 more favourable for the action of ground than of soluble phos- 

 phates. Comparing the present results with those obtained in 

 1879, we find that the excessive wet season, instead of materially 

 assisting in the decomposition of ground phosphates, had the oppo- 

 site effect. In 1879 the no-manure plot of the Sandyford experi- 

 ments weighed 143 cwt. of roots, and the average this year was 

 180 cwts — nearly 2 tons per acre of an increase. The average 

 increase per acre over the no-manure plot in both years, with 

 the various applications, was as follows : — 



