TRESIDENTIAL ADDRESS. 5 J 1 



becoming involved unless one keeps tliem rigidly to one point : but there should 

 be no difficulty in working out a relatively simple scheme for any one locality. 



Intimately bound up with all this is the more economical use of fertilisers 

 generally — not the more restricted use, but the more effective use. To a con- 

 siderable extent the question is one of nitrogen. A'itrates wash out of the soil so 

 readily that it is never safe to assume that any will survive the winter, so that 

 anytJiing left untouched by the standing crop may easily be lost. The Broadbalk 

 results show that more nitrogen is taken up by the crop, and therefore the 

 fertiliser is more economically used when potash and pho.sphates are present in 

 sufficient quantities than when either is lacking. The efficiency of the nitrate 

 is therefore increased by properly balancing the manure. 



Attempts to calculate the best-balanced fertiliser have all failed. Chemists 

 Iiave long since given up the idea that the composition of the crop afforded any 

 clue to its fertiliser requirements, although this idea still persists in places. 

 jSiothing but actual trials can show what the crop needs. A great many trials 

 have been made in the counties during the last twenty years which have added 

 considerably to our knowledge of the action of fertilisers. Unfortunately much 

 of the work lies buried in County Council Reports and Bulletins, some of 

 which seem to Jiave disappeared almost entirely — at any rate we have not 

 succeeded in getting them at Rothamsted, in spite of great efforts to do so. 

 I have recently been through many of these Reports, and have been struck with 

 the value of much of the work. Its main disadvantage is that no uniform 

 scheme was applied all over the country : each county made its own scheme, or 

 did without one if it preferred. It was assumed that soil and climate must 

 profoundly affect the action of fertilisers, and consequently that uniformity 

 would be unnecessary. In Ireland, on the otlier hand, one and the same scheme 

 was adopted everywhere, and the results are of considerable value. 



I hope that our own county authorities will be able to agree on a uniform 

 scheme after the War : this would simplify very considerably the experimental 

 work on the economical use of fertilisers. 



Some of these old experiments served the useful purpose of showing that 

 better returns were got from dung combined with artificials than from dung 

 alone, and the theme, though somewhat hackneyed, is by no means exhausted. 

 Thus, in an experiment by the Leeds University Agricultural Department, 

 20 tons of dung supplemented by artificials gave larger returns than 38 tons of 

 dung without artificials. In the Irish experiments carried out over the eleven 

 years 1901-1911 at 353 centres, additions of superphosphate and of potash to 

 dressings of dung considerably increased the yield, and, of course, the utilisation 

 of nitrogen : — 



No manure .......... 



15 tons farmyard manure per acre ...... 



20 tons farmyard manure per acre ...... 



15 tons farmyard manure per acre + 1 cwt. sulphate of ammonia . 

 15 ton.s farmyard manure per acre + 1 cwt. sulphate of ammonia 



+ 4 cwt. superphosphate ....... 



15 tons farmyard manure per acre -{- ] cwt. sulphate of ammonia 



+ 4 cwt. superphosphate -\- 1 cwt. muriate of potash . . 10 17 



More experiments of this sort are wanted. Generally the experiments have 

 been reported for single crops only. But the farmer works on a different basis ; 

 his unit is the rotation, and therefore the effect should be shown over the 

 rotation. 



Again, it is known in a general way (though there are remarkably few pub- 

 lished experiments on the point, and there ought to be more) that "phosphate.s 

 increase the feeding value of crops, and therefore that a crop intended to be 

 fed to live stock will be improved by dressings of phosphate, even if no increased 

 growth is_ obtained. In many cases the crops are fed on the land to sheep 

 frankly with the idea of benefiting subsequent crops. What is the effect of the 

 phosphate here? IIow are the subsequent crops affected by improving the 

 feeding value to the folded crop ? 



Again, potash and phosphates are known to benefit the clover crop, and 



