BUREAU OF PLANT INDUSTRY. 55 



atmospheric nitrogen, in the hope of finding a way of accelerating 

 the beneficial action of species that do not require a symbiotic rela- 

 tion with the roots of higher plants. Nonleguminous plants will also 

 be studied to find if possible some having root tubercles that will 

 fix larger quantities of nitrogen or which are adapted to soil and 

 climatic conditions unfavorable to leguminous plants. Other soil 

 organisms which may aid or hinder the fixation of nitrogen are also 

 receiving attention. It is hoped that by means of these studies 

 the cost of nitrogen will be appreciably cheapened, and that a com- 

 prehensive knowledge will be gained in regard to sources of obtain- 

 ing it, etc. A special fu«nd will also be required for this important 

 branch of our work. 



PLANT NUTRITION. 



For several years special attention has been given to plant nutrition 

 in relation to the health of plants and their productiveness. It is not 

 necessary to summarize the work already done along this line, but it 

 may be said that during the past year we have completed preliminary 

 investigations on the relation of lime and magnesia to plant growth 

 and called attention to the fact that liming of soils is of much greater 

 importance than has been heretofore realized. A report on this sub- 

 ject is now in press. A special investigation has also been carried on 

 in regard to the relation of -alkalis to plant growth, and observations of 

 great practical importance have been made, especially in reference to 

 the action of gypsum in diminishing the injurious action of magnesium 

 and other salts which occur in alkali soils. It has been found that 

 plants may support over one hundred and twenty-five times as much 

 magnesium with a supply of gypsum as they can without it. A report 

 of the work on the relation of alkali to plant growth has been prepared 

 in connection with the Bureau of Soils, which is cooperating in this 

 phase of the work, and is now going through the press. Another 

 important phase of the work is the securing of alkali-resistant crops, 

 and already we have obtained some valuable strains of alfalfa which 

 will grow in soils having a higher percentage of alkali than any on 

 which this crop has hitherto thrived. This will be discussed further 

 under " Plant breeding," and will receive special attention during the 

 current year. 



PLANT BREEDING. 



There is a constantly increasing interest in the subject of plant 

 breeding, partially as a result of the work undertaken by the Depart- 

 ment, and now many of the experiment stations and some private 

 individuals and firms are engaging more actively in work of this 

 nature. The results which have been obtained in our work in this 

 line are in many cases far-reaching and of almost incalculable value. 

 Owing to the fact that the obtaining of valuable variations requires 

 considerable skill and is precarious and costly, private individuals 

 are generally deterred from undertaking such work, hence it is very 

 desirable that it should be pushed under the direction of the Govern- 

 ment, particularly in cases where the work must be carried through 

 a number of years to obtain definite results. The plants to which we 

 have been giving special attention from the standpoint of breeding 

 are those of the greatest agricultural value, but the limited amount 

 of money at our disposal has greatly restricted the work under way 

 and has prevented our taking up to any extent the improvement of 



