FIELD CROPS. 335 



have averaged 6,817 lbs. per acre, the plats receiving l)onc and potash 6,626 lbs., and 

 tlKip^o roceiving wood ashes, 6. .371 lbs. 



The Woburn Pot-culture Station, J. A. Voelckek (J-w. Ho;/. Af/r. Soc. England, 

 3. ser., 11 (1900), pt. 4, Pl>- 553-604, figs. 17). — This artit v deals with the inception 

 and general arrangement of the Pot-cnltnre Station at Wobnrn, and further discusses 

 in detail the work of the station during 1898 and 1899. The experiments discussed 

 are grouped under two heads, namely, the Hills experiments, consisting of a study 

 of different chemical substances in their relation to plant growtli when applied to the 

 soil, and miscellaneous pot-culture experiments bearing on different agricultural 

 questions. 



The Hills experiments. — These are named for E. H. Hills, who bequeathed a con- 

 siderable sum to the Koyal Agricultural Society of England for the purpose of carry- 

 ing out investigations on the value of "tertiary ash," under which term he included 

 compounds of fluorin, manganese, iodin, bromin, titanium, and lithia. The first 

 year the experiments were made with calcium fluorid, calcium oxid, manganese 

 oxid, sodium iodid, sodium bromid, sodium chlorid, titanium oxid, ferric oxid, 

 lithium chlorid, and calcium chlorid applied at the rate of 5 cwt. per acre. The 

 selected crops — wheat, barley, mustard, jieas, and red clover — were grown in pots. 

 The experiments with wheat showed that sodium iodid applied at the rate of 5 cwt. 

 per acre kills the plant. Sodium bromid seemed to do no harm at first, but later on 

 weakened the plant and reduced the yield. It also seemed to check the growth of 

 the roots and to cause the root stocks to send out fresh roots. Lithium chlorid also 

 had a retarding influence in the beginning, but subsequently the plants grew and 

 matured fairly well. The sodium chlorid pot gave practically the same results as 

 the unmanured pot. Sodium iodid and lithium chlorid retarded germination and 

 lowered the proportion of germinating seed. 



The pots to which sodium iodid had been applied gave off a decided iodin odor, 

 and the soil in them was rendered impervious to water. The effects on barley were 

 much the same as on wheat. Sodium iodid, applied at the rate of 2 cwt. per acre, 

 seemed to have no injurious effects on either wheat or barley. Sodium iodid and 

 lithium chlorid prevented the gi'owth of mustard, lithium chlorid being the more 

 effectual. Sodium bromid at first showed no injurious effects on the mustard plant, 

 but in the end affected it quite seriously. The sodium chlorid and sodium bromid 

 injured peas eventually, although they at first seemed harmless. Sodium iodid and 

 lithium chlorid prevented the pea seed from germinating properly, but when applied 

 at the rate of 2 cwt. per acre, these substances effected a small improvement. The 

 experiments with red clover were the same as with the other crops, with the excep- 

 tion that sodium iodid and lithium chlorid were applied at the rate of 2 cwt. per 

 acre. Results of the experiments with clover for this and the following season were 

 not conclusive, and the statements made regarding the outcome of the test were that 

 lithium chlorid prevented the proper growth of the red clover, while .sodium iodid 

 and sodium l)romid did not this season liave the injurious effects noted with the 

 cereal crops. The second year the plan of the experiments was somewhat changed, 

 tlie investigation being limited to tests with sodium iodid and sodium l)romid applied 

 in different quantities and at different times. It is concluded from the experiments 

 made during the 2 years that sodium iodid and sodium bromid, even at the rate of 

 h cwt. per acre, are injurious to wheat, whether applied at the time of sowing or 

 later on, and that they apparently check ror)t development. Soaking the seed in a 

 1 per cent solution of either .salt exerci.sed a good influence on the wheat plant and 

 increased the yield. The tests with barley gave much the same results, with the 

 exception that the effect of sodium bromid was not so marked, and the re.sults with 

 clover were practically the same as those with barley. The results of a test with 

 mangel-wurzels added to the experiments this year show that .«odium iodid at the 

 rate of 1 cwt. per acre, applied either at the time of sowing or as a top-dressing, was 



