BUREAU OF PLANT INDUSTRY. 145 



record of ten or more years and 11 others had contiiuions records of 

 five or more years. Over 4,000 permanent phits devoted to crop ro- 

 tations and studies of cultural methods are now coming of record ' 

 each year. Records of such extent and continuity furnish better 

 evidence concerning many fundamental agricultural problems than 

 has ever before been available and enable us to speak with ever- 

 increasing assurance on the questions of adaptation of crops, the 

 response of crops to cultural methods, and the agricultural value 

 and possibilities of each section represented by these stations. 



Use is being made of this information to assist the Geological 

 Survey in classifying lands, as required by recent homestead laws. 

 It is also of timely value in directing useful efforts and in checking 

 unsound schemes for the increase of food supplies to meet the present 

 emergency. 



The horticultural and plant-breeding work at the Northern Great 

 Plains Field Station, Mandan, N. Dak., has continued to develop. 

 Much new material was assembled for test and propagation and a 

 vigorous test of winter hardiness obtained by the unusually severe 

 winter. 



In the spring of 1916, 591,332 trees and cuttings were shipped to 

 639 accepted cooperators under the project for cooperative shelter- 

 belt development in the northern Great Plains. An average of 80 

 per cent of this stock grew. In the spring of 1917, 357,700 trees and 

 cuttings Avere shipped to 639 accepted cooperators : 256 of this num- 

 ber were new cooperators. The other 383 received either additions to 

 or replacements for their 1916 plantings. Four hundred and thirty 

 applications for plantings in 1918 were on file at the time of closing 

 such applications on May 15. This brings the total of possible co- 

 operators for 1918 to 1,257. As not all applicants meet the require- 

 ments of the Department, the actual number will probably be be- 

 tween 1,000 and 1,100. 



STUDIES OF NEW CROP PLANTS AND CROP EXTENSION. 



ESTABLISHING SUPPLIES OF PURE COTTON SEED. 



Constructive steps have been taken to establish supplies of pure 

 seed of the superior varieties of cotton that have been developed by 

 this bureau. For a number of years special care has been exercised 

 to inspect all the fields from which seed for the congressional distri- 

 bution has been obtained, and only seed of known origin and high 

 quality has been distributed. Through effective cooperation with the 

 more interested and appreciative farmers who have received this 

 seed it has been possible to maintain the purity of the stocks and 

 greatly increase the supplies of seed of the superior varieties sent 

 out. In certain sections where community action could be enlisted 

 even greater progress has been made, as it has been possible to devote 

 larger acreages to the production of pure seed. The problem of 

 distributing this seed to the best advantage and of maintaining the 

 purity of the stock is being solved through organization of the seed 

 growers. 



ECONOMIC METHODS OF INCREASING SELECTED COTTON SEED. 



With a view of avoiding the loss usually experienced by cotton 

 breeders in increasing selected cotton seed, more economic methods 



33382°— AGE 1917 10 



