96 OTHER MANURIAL FACTORS 



level of production at these two centres is clearly not due to soil 

 sourness or lack of lime. 



TABLE XLVIII. CHEMICAL ANALYSIS or THE SOILS 

 AT HASSOBTJRY AND FARNHAM 



Hassobury Farnham 



o/ o/ 



/o /o 



Nitirogen 0-180 0-208 



Loss on ignition 7-23 8-23 



Calcium carbonate 0-00 0-45 



Total phosphoric acid ... 0-190 0-118 



Available ... 0-0123 0-0056 



Total potash 0-435 0-644 



Available potash 0-0194 0-0165 



Lime requirement 0-13 0-00 



The Hassobury soil has a lower content of 'total potash' than 

 the other centres, but the Parnham soil is better off in this respect 

 than several of the other centres. At both stations, however, the 

 'available potash' is markedly lower than in any of the other clay 

 soils, and although in both cases the figure is distinctly above Dyer's(7) 

 limit, it seems difficult to come to any other conclusion than that a 

 soil deficiency in available potash is responsible for the poor yields 

 of hay at these two centres. 



At two of the remaining centres, namely Tysea Hill and Martin's 

 Hearne, the curves in Fig. 26 show the operation of a second limiting 

 factor which comes into play after the need for phosphates has been 

 satisfied. 



The soil at both these centres is very similar in composition. It 

 is well supplied with organic matter and nitrogen, and as this store 

 has been considerably added to by the accumulated residues from 

 clover plants, it does not seem probable that there is any deficiency 

 in nitrogen. 



Both soils are sour. They contain no calcium carbonate and have 

 a high lime requirement. Nevertheless the production of nitrates in 

 this soil compares very favourably with that at other centres better 

 supplied with calcium carbonate and where the soil is sweet. (Compare 

 Figs. 21 and 19.) 



At Martin's Hearne and Tysea Hill the plots were cross dressed 

 with lime at the rate of 35 cwts. per acre during the early part of 

 1920, and at Martin's Hearne another plot was marked off and 

 received a dressing of approximately 10 tons of farmyard manure 

 to the acre. The results are recorded in Table XLIX. 



