14 



Yields of hay were not affected greatly by the harvesting system, although 

 production responses from the two-cut are greatest when an application of 

 phosphate fertilizer accompanies this practice. Low rates of nitrogen appli- 

 cation, when combined with the two-cut system, give approximately the same 

 production per acre as the single -cut with comparable applications of nitrogen. 



The highest percentage of crude protein was obtained under the two-cut sys - 

 tem when no nitrogen was used. Applications of nitrogen reduce the crude pro- 

 tein content under the two-cut harvest system below that of the unfertilized meadow. 



More extensive research by Willhite and Rouse has sho"wn that the pro- 

 duction increases reported in table 3 cannot be maintained in all years or 

 under all conditions. Length of growing season and average temperature 

 during the growing season influence the results obtained under the two-cut 

 system. These experiments were made where the frost-free period averaged 

 52 days with an average July temperature of 61, 5°. At an experimental area 

 in the South Park of Colorado, the two-cut system produced less hay than 

 the single system. This experimental area averaged 38 frost-free days per 

 season during the experiments. The two-cut system produced 22. 3 percent, 

 or 0. 47 ton per acre, less hay than the single-cut system at this location 

 (table 4). 



Table 4. - Influence of elevation and growing season on hay production, 

 Colorado experimental areas, specified periods, 1950-56 



Season 



' Eleva- 

 tion 



Frost- 

 free 

 days 1/ 



Production per acre 



Differ- ' 

 ence [ 



After- 

 math 2/ 



and 

 area 



Two-cut • 

 harvest 



Single -cut 

 harvest 





Feet 



Number 



Tons 



Tons 



Tons 



Percent 



South Park 















1955-56---: 



9, 250 



38 



1. 64 



2. 11 



-0.47 



22. 3 



Blackstock 















1950-55--- 



: 7, 694 



52 



2. 69 



2. 56 



. 13 



38. 9 



Hayden 

 1955-56--- 



: 6, 337 



85 



3. 56 



2. 90 



. 66 



48. 



1/ During the period of the experiments. 



2/ Usable growth after harvest of hay under the two-cut system. 



Willhite, F. M. and Rouse, H. K. Colorado Mountain Meadow Annual 

 Reports, 1951 and 1956. Fort Collins, U.S. Agricultural Research Service, 

 Soil and Water Conservation Branch. (Mimeographed. ) 



