LESSONS OIT POTATOES FOE RUEAJL SCHOOLS. 13 



various parts of its structure noted. What distinguishes the potato 

 from the other members of the nightshade family? A study of the 

 characteristics of the various types of potatoes should be made with 

 a view of aiding the student to identify the different groups. 



Correlations. — Drawings of a tuber, showing parts, and of sections 

 showing structure should be made. In studying the entire plant 

 the student may sketch the plant or make a copy from a chart. 



Language: Look up the nightshade family of plants in a good 

 reference book, and bring to class a written report on same. Make 

 a written or oral report on the differences between the potato and 

 tomato or other members of that family. Write an account of the 

 usefulness of the nightshade family. 



LESSON VII. 



Siilyject. — Place of potatoes in the rotation. 



Prohlem. — To study the place of potatoes in a rotation in order 

 that the greatest yields may be made and soil fertility maintained. 



Sources of information. — Farmers' Bulletin 365 ; a good reference 

 text ; bulletins from the State college of agriculture. 



Illustrative material. — Comparative charts showing yields of po- 

 tatoes grown in a rotation and those grown continuously on the same 

 field; field diagram showing suggested 3-year, 4-year, and 5-year 

 rotations; diagram of crop rotation with potatoes actually being 

 carried out in the district. All these will make helpful illustrative 

 material. v^ 



Class exercise. — Discuss with the class the following topics show- 

 ing the advantage of growing potatoes in a rotation with other 

 crops : 



1. Plant diseases often become rapidly worse in the continuous 

 cropping system, which has often been the case with potatoes. The 

 class may be shown how modem scientific methods of care of seed 

 selection, disinfection, spraying, and other details of culture some- 

 what reduce this danger. 



2. In the business management of the farm rotation reduces the 

 danger of excessive losses in seasons of low prices or of poor yields 

 and arranges the work of the farmer through the season to better 

 advantage. 



3. Weeds are more easily controlled under a system of rotation. 

 The high value of the potato crop pays for thorough tillage and care 

 which cleans the soil of weeds for the rest of the rotation. 



4. Insect pests are kept down more easily under rotation. 



5. The high cash value of the potato justifies considerable expendi- 

 ture for fertilizers, and justifies the use of more of the time of 

 the rotation in producing organic matter to be returned later to the 



