78 EXPERIMENT STATION. [Jan. 



coiistitiients than do the normal sweet-pea soils. Even the 

 normal soils show a very liberal amount of water soluble plant 

 food. 



The normal soils showed the presence of .46 per cent, of total 

 nitrogen, and the affected soils .GG per cent., mostly in organic 

 form. The appearance of the soils indicated that a large 

 amount of horse manure had been iised in their preparation. 



Soils to be used for sw^ect-pea culture should not have an 

 excessive amount of available nitrogen present, as it produces 

 a large watery growth of stem and leaf which results in 

 weakening the })lant and is unfavorable to blooming. The soils 

 examined were noticeably acid, a condition undesirable for this 

 crop. 



Discussion" and Suggestions. 



The results of our observation on all of the above greenhouse 

 soils suggest that there is a serious fault in the construction of 

 the beds and benches in many cases. Good drainage should 

 always be provided, and, in fact, is more important in the 

 greenhouse than in the open. The soil in the former case is 

 made much more fertile and does not have the benefit of oc- 

 casional heavy rains to cause leaching, as in the case of the out- 

 of-door soil. In the field there is always a free movement of 

 soil water after each heavy rain, and analyses show the drain- 

 age water to contain an appreciable amount of the various 

 mineral constituents. In fact, large quantities of soluble resid- 

 ual salines are thus removed from the soil each year. 



A sufficient amount of all the elements of plant food in suit- 

 able and available forms should, of course, be supplied, and 

 a certain excess is even essential in order that the crop may 

 make a quick growth and be ready for the early market. Too 

 great an excess of horse manure should be avoided, however, 

 and chemical plant food should be used with the same care and 

 judgment that would be used when applying them to crops 

 grown in the open field. If 500 pounds of high-grade sulfate 

 of potash are considered the maximum amount to be applied 

 per acre (4,840 square yards), then 1.6 ounces would be the 

 maximum amount to ap]-)ly per square yard in the greenhouse. 

 In other words, a calculation can easily be made for the appli- 

 cation of all fertilizing materials in the greenhouse, and if this 



