1919] EDITORIAL. 103 



series of problems, such as the depredations of birds and insects 

 which had been harbored by the hedge rows, the coming in of weeds, 



and the liability to loss of the elements of stored-up fertility. Wire- 

 worms began to appear in numbers which caused apprehension, and 



provision was made for studying their life history, morphology, and 

 control, especially by means of sterilization — an old subject at Roth- 

 amsted in soil investigation. A further set of difficulties arose out 

 of the weed flora, and with characteristic thoroughness the observa- 

 tions on the viability of weed seeds in grassland were extended to 

 other fields which had been in grass for 30, 60, and up to "200 years. 

 It is interesting to note that soil from fields 30 years old gave a 

 copious weed flora, that from fields 60 years old showed less, while 

 none developed in the soil of fields which had been in grass for 200 

 years. 



An important feature of this problem of plowed up grassland was 

 the rate at which the stored-up fertility was utilized or became dis- 

 sipated. This fertility was found to be liberated by exposure to the 

 air, the decomposition of the organic matter proceeding more rapidly 

 than the crops were able to take up the nitrogen compounds set free. 

 The result was waste, the nature and cause of which was studied from 

 both the chemical and bacteriological sides. 



So long as the land lies in grass the soil contains considerable car- 

 bonic acid and a reduced percentage of oxygen, so that conditions are 

 not particularly favorable for aerobic organisms ; but as soon as it is 

 plowed up the conditions become more favorable. The nitrogen 

 compounds are broken clown in the first instance to ammonia, but 

 the evidence is that the process is not a simple bacteriosis as formerly 

 believed. The loss of nitrogen is thought to be parti} 7 due to a definite 

 evolution of gaseous nitrogen which occurs neither in entire absence 

 of air nor in complete access of it, but only under intermediate con- 

 ditions of aeration. This indicates that it is due neither to a 

 simple oxidation nor to a simple reduction, but to some more complex 

 action. The application of the findings to the soil problem under 

 consideration is not simple and will require further investigation. 



Another line of study centered on the handling of barnyard manure. 

 on which the above findings have a direct bearing. These studies re- 

 lated especially to the nature of the loss and how it arises. This was 

 an appropriate war time problem in view of the need of conserving 

 all sources of fertilizing material, and some important progress was 

 made upon it. Attention was not confined to nitrogen but was di- 

 rected to other constituents, notably the cellulose furnished by straw. 

 Experiments showed that when this straw was applied unchanged to 

 the soil, it might in large measure neutralize the effect of other com- 

 ponents of the manure. But straw mixed with soil, chalk, and certain 

 organisms living free in the soil resulted in a decomposition of the 



