1912.] PUBLIC DOCUMENT — No. 31. 65 



during the second year started very poorly, became sickly, and 

 in the course of three months half of them died. This experi- 

 ment was conducted purposely along this line, although we 

 knew we were violating tlie customs of the best growers. 

 ISTeverthelcss, we wished to learn what the result would be. 

 The sickly plants showed no indications of being affected by 

 pathogenic fungi or eel worms, but the roots were abnormal, 

 indicating that the trouble was in the soil. We therefore 

 flooded each bed while the plants were '' in situ " for a period 

 of two hours, washing out the soil very thoroughly. The first 

 water that came through the soil was exceptionally turbid, but 

 that which came through later was very clear. The percolated 

 water was collected at intervals and chemical tests made of it 

 for acidity, etc. These tests gave surprising results, as they 

 showed that the soil was in very abnormal condition for root 

 growth. These soils had been given, the year before, the 

 customary treatment, consisting of a liberal supply of cow 

 manure, both in the solid and liquid form, but this had so 

 filled up the soils with injurious chemical compounds as to 

 prevent root development. Rose growers have found by ex- 

 perience that good results can be obtained only by changing 

 their soils each year, and this experiment verifies the wisdom of 

 the practice.^ On the other hand, lettuce growers seldom if 

 ever change their soil, experience showing that for lettuce the 

 older the soil the better. In the former case cow manure is 

 used, and in the latter, horse manure, mixed with a large per- 

 centage of straw, is used exclusively, the eft'ects on the soil 

 being quite different. 



Carnation soils are treated in the same way as rose soils, the 

 soil being changed each year. Roses and carnations, therefore, 

 require a new soil each year, while most market garden crops 

 are grown year after year in the same soil enriched with horse 

 manure and straw. Repeated applications of horse manure 

 improve such soils, and there is little danger of over manuring ; 

 whereas cow manure has a quite different effect and cannot 

 be used in the same way, as there is danger of root injury and 

 malnutrition. 



' At the present time ro?e growers use Manetti stock for grafting and do not change the soil 

 more than once in two or three years. This stock is said to be more immune to eel worms. 



