22 EXPERIMENTS IN BLUEBERRY CULTURE. 



in the limewater had been deposited in the upper laj'ers of the soil. 

 The following laboratory experiment confirmed this. A small quan- 

 tity of the acid peaty soil used in growing blueberries was placed 

 in a o-lass vessel and moistened. Then dilute limewater reddened by 

 the addition of phenolphthalein, a substance giving a delicate color 

 test for alkalies such as lime, was stirred into the soil and the mixture 

 poured into an ordinary paper filter. The water came through the 

 filter without a trace of red color, showed none after boiling, to drive 

 off any possible carbonic acid, and when tested with ammonia and 

 ammonium oxalate showed not a trace of lime. The precipitation 

 of the lime had been complete and practically instantaneous. Only 

 ten seconds had elapsed between the time when the limewater was 

 added to the soil and the time when the liquid entirely free from lime 

 began to drop through the filter. 



In order to ascertain whether a large part of the lime in the lime- 

 water used on the plants may not have passed through the pots by 

 running down the partially open channel along the label, some lime- 

 water was poured upon the surface of one of the pots. The excess 

 water that soon began to drip through tlie bottom of the pot was 

 tested for lime. It was found that while the limewater poured into 

 the pot contained 0.1014 per cent of lime, the water that came 

 through contained only 0.004(3 per cent. In other w:ords a pot of soil 

 that for over seven months had been used essentially as a limewater 

 filter still continued to extract over 95 per cent of the lime contained 

 in the limewater that was passed through it, notwithstanding the 

 fact that there was a partially open channel down one side of the 

 pot. It is believed that had the soil been evenly compacted in the 

 pot no lime whatever would have been able to pass through, bu.t that 

 all would have been precipitated in the uppermost layers. 



While the experiment has no important bearing on the subject of 

 blueberry culture it is of very great significance in its bearing on the 

 method of applying lime to acid soils in ordinary agricultural prac- 

 tice. A surface application of lime would have no appreciable effect 

 in neutralizing the acidity of a soil unless the soil was so sandy or 

 gravelly or otherwise open that the rain water containing the dis- 

 solved lime could run down through it practically without obstruc- 

 tion. A surface dressing of lime would have little effect in neutraliz- 

 ing the acidity of an old meadow or pasture. To secure full action 

 of the lime, as now generally recognized in the best agricultural 

 practice, requires its intimate mixing with the soil, such as can be 

 accomplished by thorough harrowing, especially after joutting the 

 lime beneath the surface Avith a drill. A full discussion of the phys- 

 ical reasons for the deposition of the lime in the upper layers of the 

 soil, when not worked into it mechanically, is given in Bulletin 52 of 

 the Bureau of Soils, published in 1008. 



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