354 Report of the Horticultural Department of THBi 



fiutlier iucrease of but 2.87 points; the 15 per ct. application 

 gave an increase of but 0.38 point over the 10 per ct. and the 

 20 per ct. gave an increase of but 1.25 points over the 15 per ct. 

 application. 



In the next crop from the same soil the 5 per ct. application 

 was followed by a very large increase in yield over that where 

 commercial fertilizers were used alone; the 10 per ct. and 15 per 

 ct. applications showed but little increase over the 5 per ct., 

 while with the 20 per ct. application the yield actually dropped 

 below that obtained with the 5 per ct. 



In the following season the 5 per ct. application again showed 

 a very large increase in yield over that where commercial ferti- 

 lizers alone were used; the 10 per ct. application resulted in but 

 slightly greater yield than that secured with the 5 per ct. appli- 

 cation, the 15 per ct. showed a falling off in yield while with 20 

 per ct. it dropped still lower, being even less than the yield with 

 the 5 per ct. application. 



Similar cumulative effects of repeated applications of manure 

 also appeared when loose lettuce was grown on the clay loam. 

 Where the higher percentages of manure were used the later 

 crops of lettuce showed an actual loss in yield. 



On sandy loam the first crop of head lettuce showed an in- 

 creased yield from the 5 per ct. and 10 per ct. applications of 

 manure but higher percentages of manure showed a falling off 

 in yield. With the next crop of lettuce the use of the higher 

 percentages of manure was followed by successive increases in 

 yield except that the yield with the 15 per ct. fell below that 

 with the 10 per ct. application but the following season the 

 highest yield was reached with the 10 per ct. application and the 

 yields with the higher percentages of manure dropped below 

 that of the 5 per ct. application. Results similar in kind if not 

 in degree were obtained with the loose lettuce on sandy loam. 



The data secured by the series of tests with nitrate of soda, 

 sulphate of ammonia and the combination of dried blood and 

 nitrate of soda confirm the testimony of the dried blood series 

 on this point. They support the general conclusions that with 

 soils similar to those used in these investigations: 



