The Wohum Pot-Culture Experiments, 1914. 317 



Plot 1 (no treatment), 1*2 tons carbonate of lime required 

 per acre. 



There were no great differences observed during growth. 

 If anything, the neutral and excess lime crops had a better 

 colour. The harvest results showed no marked differences, 

 though, from the returns, as compared with those of other plots, 

 it was clear that the land wanted manuring. 



The need for the addition of lime, even to the extent 

 suggested by Dr. Hutchinson, was not clearly brought out. 



Plot 2a (sulphate of ammonia alone), 2*60 tons of car- 

 bonate of lime required per acre. 



This soil came from a plot on Stackyard Field which, for 

 several years past, has never been capable of bearing a crop, 

 no lime having been applied to it, while sulphate of ammonia 

 has been used every year. 



In the untreated pot the crop at first came quite well, but 

 then rapidly fell off and died away just as it does in the field. 



Where the soil was just neutralised, the crop was markedly 

 better, and still better where lime in excess was used, the 

 tillering of the plant being more marked. The harvest results 

 showed an almost entire failure of crop when untreated, but 

 both the neutral and excess lime crops were large, and practi- 

 cally as good as any in the whole series. There was but little 

 difference between them in corn, but the excess lime produced 

 much the most straw. It would appear from these results that 

 it is only lime which the soil requires, and that there is plenty 

 of nitrogen present for plant needs. Also that lime may be 

 safely used in excess. 



Plot 2bb (sulphate of ammonia with 4 tons of lime per 

 acre), *40 ton carbonate of lime required per acre. 



The crops here all grew well, and there were no marked 

 differences. It was clear from the harvest results that this plot 

 has quite sufficient lime in it. 



Plot 5a (sulphate of ammonia and minerals, without lime), 

 1*80 tons carbonate of lime required per acre. 



During the period of growth the neutral and excess lime 

 crops were much in advance of the untreated. This was shown 

 at harvest, when, of the two lime sets, the excess lime one was 

 the better both in corn and straw. It would appear that this 

 soil needs a large amount of lime, and more than is required 

 in the case of plot 2a. 



Plot 5b (sulphate of ammonia with minerals and 4 tons of 

 lime per acre), no carbonate of lime required to neutralise. 



The crops here were all good, the differences being but 

 little marked either during growth or at harvest. It would 

 appear from the results that lime has already been given in 

 sufficiency. 



