786 11 T H AM S TED EXPERIMENTAL STATION. [DEC, 



producing varieties which would be relatively immune to this 

 pest is being investigated. In the mycological laboratory 

 important work is being done on the killing of fungus spores 

 and on Wart Disease of potatoes. 



Work for the Future. — In the foregoing account reference 

 has been made only to problems of immediate . interest to 

 farmers. At an Experimental Station, however, it is always 

 necessary to look to the future and to conduct investigations 

 which, while of no immediate practical application, show possi- 

 bilities for the future. 



Some of the most interesting work is in connection with the 

 population of micro-organisms inhabiting the soil. The farm- 

 yard manure and the green manure put into the soil are not 

 really agents of fertility, but only raw materials out of which 

 fertility is manufactured. The work is done by myriads of 

 micro-organisms, some useful to the farmer, some not, many 

 of them taking their toll of the valuable plant food in the soil. 

 The nitrates they make are indispensable for the growth of 

 plants, but some of them seem to take up nitrates themselves 

 and thus compete with plants. At Rothamsted enough nitrate 

 was produced on one plot in a single day to produce a 5-qr. 

 crop of wheat, but it had all been removed — presumably taken 

 up by organisms — before the end of the day so that the farm 

 gained no advantage from the process. With fuller knowledge 

 it may be possible to control this population and make it serve 

 the farmer just as horses, sheep and cattle do; but we are a 

 long way from that yet. 



Finally, an attack is being made on a much more difficult 

 problem. The growth of a crop is like the movement of a 

 motor car; it cannot progress without a continuous supply of 

 energy. In the case of the growing crop this energy comes 

 from the sunlight. The plant as we grow it is not a very 

 efficient transformer; a crop of wheat in England utilises only 

 about half of one per cent, of the energy that reaches it. During 

 the last 80 years the growth of plants has been improved, thus 

 increasing their efficiency as utilisers of energy, but we are 

 still far from the 35 per cent, utilisation which the motor 

 engineer has attained. Whether such high utilisation is 

 possible cannot be said, but it is important to try any methods 

 that seem to offer hope of advancement. Careful tests have 

 been made of the effect of high tension electric discharge on 

 crop growth; of the electrical and other treatment of seeds; 

 of the effect of radium ores; of stimulating substances such 



