434 GENETICS IN RELATION TO AGRICULTURE 



Climatic: 



1. Character of season as to rainfall, temperature, etc. (These data are usually 

 available in the Weather Bureau records.) 



Edaphic: 



2. Character of soil. 



3. Preparation of soil. 



4. Fertilizers. 



5. Cultivations. 



6. Irrigations. 

 Experimental: 



7. Size and shape of plots. 



8. Error due to marginal effect. 



FIQ. 181. Increase plots harvested and ready to thresh. The plots in this field averaged 

 60 bu. to the acre. (After. Montgomery.) 



9. Method of obtaining yields. 



10. Percentage of moisture at time of weighing. 

 Biological: 



11. Variety of plant, including purity and trueness to type. 



12. Source of seed. 



13. Viability of seed. 



14. Preceding crop or crops. 



15. Date of seeding or planting. 



16. Rate of seeding or planting. 



17. Method of seeding or planting. 



18. Date of appearance above ground. 



19. Percentage of stand. 



20. Uniformity of stand. 



21. Uniformity of growth. 



22. Percentage of weeds. 



23. Date of blooming or heading. 



24. Date of maturity. 



