BUREAU OF PLANT INDUSTEY. 319 



Relation of nutrition to the composition of the plant. — Ex- 

 periments are in progress to determine the factors controlling the 

 production of the important constituents of crop plants, with special 

 reference to the influence of the various elements of plant food on 

 nutrition and composition. During the past year particular attention 

 has been given to the quantitative production of oil in such plants as 

 cotton and soy beans. These plants offer many advantages for investi- 

 gating the relation of the factors of nutrition to the amount of oil 

 produced, and very satisfactory progress has been made on these 

 problems. There is much need for information on this important 

 subject and it is believed that the results of the investigations now in 

 progress will aid in a better understanding of the underlying prin- 

 ciples involved. 



Functions of the secondary elements of plant food. — The 

 aim of this study is to acquire more definite information regarding the 

 role of some of the mineral elements which are commonly regarded as 

 of little practical importance, but which may perform very important 

 functions in influencing the nutrition of the plant. The practical 

 question involved is as to the relative value of the so-called high-grade 

 and low-grade mineral fertilizer salts for feeding crop plants. A 

 series of field tests are being conducted to determine in a practical 

 way whether the secondary constituents of the low-grade fertilizers 

 play any important part in the nutrition of the plant, either direct or 

 in the maintenance of a physiological balance with the most valued 

 elements of food supplied. 



Most favorable nutrition ratios for crop plants. — Although 

 a knowledge of the optimum nutrition ratios for different crop plants 

 is of fundamental importance to practical agriculture, little exact 

 information on the subject is to be had, mainly for the reason that no 

 satisfactory methods have been available for determining these ratios. 

 The work under this head for the present, therefore, has to do pri- 

 marily with the development of methods whereby the various disturb- 

 ing factors of environment may be controlled, so as to make it pos- 

 sible to determine the relative quantities of the important elements 

 of plant food actually required to produce definite crop yields, not 

 only with respect to gross yields, but also with reference to the more 

 valuable crop constituents. It is hoped that a series of experiments 

 now in progress will demonstrate the efficiency of a proposed method 

 of procedure for acquiring reliable data on this subject. 



DRY-LAND AGRICULTURE INVESTIGATIONS. 



The investigations in dry-land agriculture in the Great Plains area, 

 under the direction of Prof. E. C. Chilcott, Agriculturist, have pro- 

 gressed along the lines outlined in previous reports. 



The season's results. — The season of 1910 has been a particularly 

 favorable one for obtaining results from the various rotations and 

 methods of cultivation. The seasonal precipitation has been normal 

 or loss than normal at all stations; and at some, notably Amarillo 

 and Dalhart, Tex., Williston and Edgeley, N. Dak., and Bellefourche, 

 S. Dak., the drought has been severe. The results of the various 



