606 



BuLIvETiN 84 



is again abundant. It has been observed on the Prescott Dry-Farm 

 that ahnost every crop which remained thrifty until the beginning 

 of summer rains in July, yielded profitable returns. 



When work is well timed, a harrow satisfactorily maintains a 

 mulch and destroys weeds on summer fallowed land. In one ex- 

 periment a small area of summer fallowed land was divided into 

 three portions, the first of which was harrowed when weeds were 

 first showing; the second, six days later; and the third portion 

 twehe days after harrowing the first. On the first plot fully 95 

 per cent of the weeds were killed, while on the second portion not 

 to exceed 60 per cent, and on the third portion less than 25 per cent 

 were destroyed. 



The imixjrtance of timely operations on dry-farms is not always 

 fully realized. Cultivations delayed for even a day, especially dur- 

 ing times of high temperatures and strong winds, may very se- 

 riously hinder crop production. Planting should be done at times 

 ^\']K■n the utmost advantage can be taken of precipitation imme- 

 diately after it falls. Delayed plowing often causes failure, when 

 timely tillage would have sufficed to insure a profitable yield. 



The influence of leguminous cover crops on the humus and 

 nitrogen content of the soil is shown in Table LXV. While the 

 data are meagre the value of cover crops is clearly indicated. 



Yields are t)ften reduced because of too thick seeding on drv- 



lAKLE LXV. IXl'LUJCXCr; of LIvr,i:MI.\()US COVER CROPS ox HUMUS AND 

 XITROOEX, PRESCOTT DRY-FARM ORCHARD 



