416 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



CROP TECHNOLOGY. 



During the past year many interesting and important nematode 

 problems have come to light. The serious potato losses occurring in 

 Nevada have required considerable attention. As a result of coop- 

 erative action, publications have been issued and active measures 

 undertaken to cope more adequately with the causal parasite. A 

 second and more thorough reconnaissance in California and Nevada 

 has fully corroborated the opinions formed earlier as to the present 

 distribution of the beet-root nematode. 



Study of the nematode fauna of Arlington Farm has made ma- 

 terial progress. Many new and interesting forms, both free-living 

 and parasitic, have been discovered. 



Soil examinations have been made in various parts of the country 

 to ascertain more definitely the intensity and nature of the nematode 

 population of the soil. New parasitic nematodes, which attack both 

 underground and aerial parts of various plants, and striking facts of 

 life history and of nematode anatomy have been discovered. 



Other portions of the work that have hitherto been carried on in 

 the technologic projects have received as much attention as funds 

 have allowed. 



PAPER-PLANT INVESTIGATIONS. 



In the search for fibers that may serve as substitutes for wood in 

 the manufacture of paper, special attention has been given to a con- 

 tinuation of the studies of cornstalks, of broom-corn stalks, and of 

 rice straw. 



Field work. — The numerous lots of materials collected or grown 

 for use in the laboratory and mill experiments included three car- 

 loads of carefully harvested cornstalks for food-extract production 

 on a large scale and a ton of papyrus tops imported from Palestine. 



As a result of the work accomplished, the conclusion has been 

 reached that materials better suited for special purposes must be 

 found rather than something cheaper than those now in use. In 

 line with this conclusion, more emphasis will be placed in the future 

 on the production of crops especially for paper making. 



Laboratory experiments. — Among the digestions made in the 

 laboratory at Washington have been those of sugar-cane pith (a by- 

 product of the diffusion process of making sugar), vetiver grass (a 

 plant which yields a soap-scenting material), Nolina texana (a yucca 

 and sotol relative), flax straw, castor-bean stalks, palmetto leaves, 

 hop vines, and papyrus. An attempt is now being made to work out 

 methods of cooking specially suited to each material. Preliminary 

 tests that promise well have been made to determine the suitability of 

 hemp pulp, produced by the soda process directly from retted stalks. 

 Hand-made sheets are prepared from all pulps. A specially con- 

 structed pulp screen has been devised which greatly facilitates the 

 work. In all laboratory digestions determinations are made of 

 optimum steam pressure, per cent of cooking reagents, and yields of 

 fiber. 



Paper-mill tests. — During the year 54 cooks of soda pulp have 

 been made. Rice straw is a promising material, but the problem of 



