March, 1936] Agricultural Research in N. H. 7 



on which all replacements were raised only 1.7 per cent aborted. Those 

 farmers who purchased a bull which had been used for service previous 

 to the time of purchase had more abortion cases than those who purchased 

 a bull before such service, the percentages being 6.3 and 3.4 respectively. 

 Only 2.2 per cent of the cows were slinkers on farms where the bull was 

 raised, although in many cases he was purchased as a calf. Eighty-five 

 farmers used their bulls for servicing neighbors' cows, and 87 per cent did 

 not. The percentage abortion in these cases was 4.7 and 3.7 respectively. 

 (H. C. Grinnell — Purnell Fund.) 



Spray Management Studies 



This past season, 45 apple growers kept records of labor, materials, and 

 equipment used in spraying. Although the season was very favorable for 

 the development of the apple scab fungus, in most instances a commercially 

 clean crop was obtained. The cost records are now in process of analysis. 



A study has been completed of a part of the records having to do with 

 the practice of transporting water or spray mixture to the sprayer by means 

 of a "supply" tank mounted on a truck, thus saving that time usually lost 

 by hauling the sprayer back and forth from orchard to the water supply. 



In the Rockwood orchard, spraying was done with a small machine of 

 six to seven gallons per minute capacity with a 100 gallon tank. Operating 

 in 1934 without the supply tank, 8,700 gallons were applied at an average 

 rate of 79.6 gallons per machine hour or 39.8 gallons per man hour. In 

 1935, using the supply tank, 20,200 gallons were applied at a rate of 129.4 

 gallons per machine hour, or 41.7 gallons per man hour. Allowance must 

 also be made for the fact that in 1935 the spraying was in charge of a more 

 skilled operator than during the previous year. It appears, therefore, that 

 the use of the supply tank did not increase the ef^ciency in man labor, but 

 that by increasing the output of the machine about 62.5 per cent it made it 

 possible to cover the orchard in a considerably shorter time. Timeliness is 

 an exceedingly important factor in disease control. 



In the David Whiting orchard, a machine of 25-30 gallons per minvite 

 capacity and 300 gallon tank is operated. In the early season sprays, filling 

 from waterholes in the orchard, 21,000 gallons were applied at the rate of 

 280 gallons per machine hour or 93.3 gallons per man hour. In the later 

 applications, using the supply tank, 30,635 gallons were applied at the rate 

 of 402.9 gallons per machine hour, or 100.7 gallons per man hour. This 

 indicates a slight increase in labor ef^ciency. Furthermore, late in the sea- 

 son, the waterholes had dried up, and the efficiency without the supply tank 

 would have been lower than in the early part of the season. When the costs 

 of operating truck and sprayer are included, it is found that for the early 

 application in which the machine was filled directly from the waterholes, 

 the application cost per 1,000 gallons was $5.80, whereas for the late sprays, 

 when the supply tank was used, it was $7.00. 



Records in both orchards seem to show that carrying the water or the 

 mixed spray materials to the tank is advantageous chiefly as a means of 

 speeding up operations when quick coverage is needed to protect against 

 disease. From the point of view of economy of operation, providing wells 

 or waterholes in the orchard or constructing a system of supply tanks about 

 the orchard is more desirable. {H. C. Woodvjorth, G. F. Potter, and E. J . 

 Rasmussen — Purnell Fund.) 



