30 



CIRCULAR KO. 129, BUREAU OF PLANT INDUSTRY. 



while others are vegetables of some kind. The fertilizers used are nitrate of soda, 

 potash, phosphoric acid, lime, blood meal, tankage, and stable manure. Chemical 

 tests were made before the fertilizers were applied, to determine the condition of 

 the virgin soil, and Avill be repeated at intervals of two years to determine the rate 

 and nature of any changes which may occur. 



F G. 3._View in field used for experiments in soil building. Three crops of winter vetcli have been 

 plowed under on this field, and the soil has been markedly improved. 



A fourth experiment, which seeks to determine the value of different leguminous 

 plants as cover crops and nitrogen accumulators for the local orchard soils, has been 

 in progress since 1910. This test includes 10 different crops, as follows: Sainfoin, or 

 esparsette {Onohrychis saliva), red clover, mammoth red clover, crimson clover, sweet 

 clover, alfalfa, Canada field peas, cowpeas, hairy vetch ( Vicia villosa), and spring 

 vetch ( V. saliva). In addition to the work being done with these legumes at the 



Fig. 4.— Peanuts and milo, following a winter cover crop of vetch, grown between the rows of young 



orchard trees. 



experiment farm, cooperative experiments with some of the more promising crops are 

 in progress with farmers on the Umatilla and Inland irrigatit)n projects, to determine 

 the value of the crops on the different types of soil. 



Some very encoiiraging results have been derived from these ex- 

 periments. Hairy vetcli sown in August or September makes a 



ICir. 1201 



