93 



Soda gave the necessary stimulus to make them start again, In 

 such cases Nitrate of Soda may be of value, but they are compara- 

 tively rare. As a rule, it will give an abnormal growth for two or three 

 months, and then, if the soil be poor previously^ there is a tendency 

 for the bush to fall back to its previous position, unless in the mean- 

 time manuring with oilcake has been carried out. There is another 

 reason against its use. It is an extremely soluble salt, and the soil 

 does not retain it in the slightest. A few inches of rain after applica- 

 tion would wash nearly all the application into the drains in a day or 

 two. At any rate, if applied at all, it should be used in very small 

 quantity, say five per cent, of an application containing some more 

 permanently useful manure like oilcake. As an application before 

 collar-pruning, or even heavy-pruning, it is absolutely out of 

 place. 



Nitrate of Potash is very similar in its action. It has the valu- 

 able Potash, instead of the all but useless Soda, but as Potash is 

 not usually required in Assam, this is not usually of very material 

 advantage. 



The third typical Nitrogenous manure is Sulphate of Ammonia, 

 and it contains more nitrogen than any other manure which could 

 be used. I cannot advise it in practically any case in Assam, 

 although it has, in time past, been very extensively advised as a con- 

 stituent of mixtures. It would appear to be objectionable because : 



(l) It causes incidentally the removal of a large amount of 

 other valuable constituents from the soil, the chief being the Lime 

 and the Potash. In order to ascertain to what extent this might go 

 on, I shook two typical Assam tea soils with a one per cent, 

 solution of Sulphate of Ammonia for two days, allowed to settle, and 

 analysed the liquid. There were extracted in the two cases as 

 follows, calculated on the air dry soil : 



Soil No. I, Soil No. II. 



Lime ... -037 per cent. ... '018 percent. 



Potash ... -052 '056 



That is to say, one application of Sulphate of Ammonia might 

 remove more Potash than the tea bush would do in ten years, 

 and a large quantity of Lime, Now the latter is present in very 

 small quantity in Assam soils, and though it could be replaced, yet 

 there are other means of manuring tea which have not this 

 objection, and do not necessitate a further expensive and really 

 unnecessary application. 



