314 



The Wohurn Pot-Culture Experiments, 1914. 



the soil in increasing amounts until in the highest quantity 

 the lime was double the amount of magnesia present. It was 

 found that lime could be added to this extent without barm, 

 and, indeed, with a beneficial effect. This particular soil had, 

 up to the end of 1913, been alreadj' used for five successive 

 corn crops, the last being wheat in 1913. Although the 

 experiment was practically concluded, and it had been shown 

 that excess of lime did not act in the disadvantageous way in 

 which excess of magnesia did, it was decided to grow in 1914 

 yet another corn crop, namely, barley. 



The soil was turned out from the pots, exposed to the air, 

 broken up, sieved, and replaced in the pots towards the close 

 of February, 1914. Superphosphate at the rate of 3 cwt. per 

 acre and sulphate of ammonia 1 cwt. per acre were added to 

 the top soil, and barley (Chevalier) was sown, 12 seeds per pot, 

 on March 18, 1914. Germination took place well and regularly, 

 and the plants were in due time thinned out to six per pot. 

 No marked differences were shown diiring the period of 

 growth, and the ci'ops were cut on August 20. The results 

 are given in Table III. : — 



Table III. — The addition of Lime to soil rich in Magnesia, 

 1914. Barley (sixth co7isecutive corn crop). 



The results were not so marked as in 1913, when it will be 

 seen (Journal R.A.S.E., 1913, vol. 74, pp. 417-19) that the 

 heaviest dressing of lime gave the largest crop. At the same 

 time, although this was the sixth successive corn-crop, the 

 results now obtained tend in the same direction as those 

 previously recorded. The addition of lime up to 3, 3*5, and 

 4 per cent, respectively gave crops all exceeding the no treatment 

 crop. The produce with the highest amount of lime (4-5 per 

 cent.), though below these, was still as good as the untreated. 



It is therefore clear that addition of lime to a soil rich in 

 magnesia is beneficial, and can be applied without detriment 

 even to an extent where the lime is double the amount of 

 magnesia present in the soil. 



I 



