646 EXPERIMENT STATION RECORD. 



a quantity equivalent' to about 0.1 in. of rain, and therefore possibly 

 not sufficient to insure the proper effect of the nutrients dissolved in it. 



"The dressings had a retarding influence on the ripening of the crops, especially 

 with one year plants, owing probably to the period of growth being prolonged thereby. 

 The results with the crops during 4 seasons do not prove decisively the existence of 

 any benefit from such dressings. The 2 plats dressed with nitrates and also that 

 which received iron sulphate show a possible excess of 10 to 34 per cent over the 

 undressed plats, but the differences on which this effect depend are uncertain, inas- 

 much as they are not greater than those between the 2 sections of the undressed 

 plats." 



Manurial experiments with strawberries, Duke of Bedford 

 and S. U. Pickering {WoJmrn Ex-jjt. Fruit Farm Rpt. 1900, j)})- 93- 

 97, 251, 252). — As this experiment has been conducted for only S 

 years, it is stated that the results are quoted with considerable reser- 

 vation. The soil used was light in character. There were 6 plats 

 each made up of 288 plants. One plat received no fertilizer, 2 

 received 12 and 30 tons, respectively, of London city manure, and the 

 remaining 3 plats a mixture of mineral fertilizers and nitrate of soda 

 in quantities equivalent to the above amounts of London city manure 

 and applied fractionally. The purpose of the test was to ascertain the 

 respective merits of city manures and commercial fertilizers and the 

 effect of altering the amounts applied. 



On the whole the different dressings have had but little influence on 

 the crops, the excess obtained from the manured plats for the 3 years 

 being on an average but 6 per cent. One year the yield from the fer- 

 tilized plats was 11 per cent less than from the nonfertilized, while in 

 2 other years the increase was 27 and 8 per cent, respectively. The 

 London city manure gave slightly better results on the average than 

 were obtained from the use of commercial fertilizers and slightly 

 higher results, especially the first year, were secured with applications 

 of 30 than with 12 tons. "With artificial manures the indications of 

 the effect of increasing amounts are pretty well balanced in opposite 

 directions in different seasons, the mean result for the B years showing 

 a small but insignificant balance in favor of the smaller dressing." 



Rubber cultivation for Porto Rico, O. F. Cook ( U. S. Dept. Agr.^ 

 Division of Botany Give. 28, j^j?. i-v').— This circular is a part of a 

 report now in preparation on the useful plants and agricultural possi- 

 bilities of Porto Rico. Rubber stands third in importance of the com- 

 mercial products of vegetable origin now imported into the United 

 States, the receipts during 1899 being valued at ^32,500,000. At the 

 present time the largest amounts of i-ul)bor are obtained from the 

 tropics of Africa and South America. The extent of the wild supply 

 is unknown, since large portions of these countries have not 3'et been 

 explored either geographically or botanically. This factor, taken in 

 connection with the possibility that new species will be discovered 



