NOTES AND ABSTRACTS. 



259 



7. In the majority of cases surface irrigation gave the largest yields 

 of dry matter, sub -irrigation nearly as much, and standing water the 

 smallest yields. 



8. Approximately the same number of pounds of water are 

 required to produce a pound of dry matter under conditions of sub- 

 irrigation and standing water, a somewhat larger number is required 

 under conditions of surface irrigation. 



9. Probably the number of pounds of water actually transpired for 

 the production of a pound of dry matter is the same under the various 

 methods of irrigation. 



10. Sub-irrigation is most satisfactorily on loam soils. 



11. The evaporation of water from bare soils increased with the 

 increased saturation of the soil. The increase in the lots was usually 

 much larger than the increase in saturation. Heavy irrigations 

 should, therefore, be followed by immediate, careful, and thorough 

 cultivation. 



12. Increasing the saturation of soils increased in a somewhat 

 larger ratio the yields of dry matter. 



13. Approximately the same number of pounds of water are 

 required under various conditions of soil saturation for the production 

 of one pound of dry matter. 



14. The amount of water actually transpired for each pound of 

 dry matter appears to be somewhat lower under conditions of high 

 saturation. 



15. On fertile soils heavy applications of water are not likely to be 

 so wasteful as on infertile soils. 



16. The yield of dry matter was much larger on soils that had 

 rested during the three preceding years than on soils that had been 

 cropped during the same period. 



17. The number of pounds of water required for one pound of dry 

 matter was much smaller on the soils that 'had been bare than on those 

 that had been cropped during the preceding three years. 



18. Fertile soils will produce crops with a smaller amount of water 

 than will unfertile soils. 



19. The additions of fertilizers to infertile soils enables crops to 

 produce dry matter at a lower water cost, 



20. Soils vary greatly in their relationship to plants and water. 



21. The seasons have a strong effect upon the yield of dry matter 

 and upon the amount of water required for the production of one pound 

 of dry matter. 



22. The number of pounds of water required for the production of 

 a pound of dry matter varies greatly with the crop, the soil, the season, 

 Ithe method of irrigation, and the cultivation. In general, however, the 

 {amount of water required for the production of dry matter is very 

 imuch higher in an arid region than in regions of abundant rainfall. 

 fThe conservation of moisture is therefore of greater importance in the 

 [west than in the east of N. America. 



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