LESSOJS'S ON POTATOES FOK RURAL, SCHOOLS. 15 



tions in connection with potato crops are being carried out and note 

 general conditions of fields, crops, and tillage.) 



Correlatimis. — Correlations in language will be suggested in the 

 matter of written or oral reports on field trips and observations made 

 in the study of the farm practice of the district in rotations. 



Drawing: The construction of the charts suggested under illus- 

 trative material will afi'ord practice in drawing. 



Arithmetic: Problems on yields of potato crops on both rotation 



plan and the continuous cropping plan will be suggested in the study 



of this lesson. 



LESSON VIII. 



Subject. — Soils — kind, preparation, fertilizers, etc. 



Prohlem. — To study kinds of soils suitable for potato growing, 

 their preparation and fertilizing. 



Sources of information. — Farmers' Bulletins 365, 386, and 407; 

 bulletins from State college of agriculture. 



Illustrative matericd. — Collect soil samples from the potato farms 

 of the district; bottle and use in class for comparison. Collect in a 

 like manner the various commercial fertilizers used for potatoes. 

 Clip and mount pictures from farm papers, circulars, etc., showing 

 soil preparation such as plowing, harrowing, applying fertilizers, etc. 



Class exercise. — Characteristics of potato soil: Rich, well culti- 

 vated, one that will conserve moisture and retain soluble fertilizer, a 

 light sandy loam to be preferred to a heavy retentive soil. While 

 excellent crops are frequently grown on heavy clay soils, the lighter 

 soils will usually produce smoother, more even potatoes with bright 

 skin and eyes of medium depth, and usually mature the crop at an 

 earlier date. 



1. Prepartion of the soil: Object of soil preparation — to provide 

 for a rather weak root system, correct faults of local soil and climate, 

 reduce the tillage after planting as much as possible. 



2. Time of plowing — winter or fall plowing more desirable, espe- 

 cially where the soil does not run together and the slope is not steep 

 enough to cause washing. This lessens the spring work and some- 

 times makes earlier planting possible. 



3. Depth of plowing varies with the soil, usually from 8 to 12 

 inches unless subsoil is too near the surface. 



4. Fertilizers: Object of fertilizing — potatoes require a complete 

 fertilizer on most soils. Commercial fertilizers. Rotation. Green 

 manuring. What objections to use of barnyard manure? When 

 should lime be used? Methods of applying fertilizers to the potato 

 crop. 



Practical exercises. — ^Make a study of the types of soil in which 

 potatoes are grown in the district. Which is most common? How 



