FIELD CROPS. 



41 



Moiniurc in soil of polaio j^lats. 



"Onthisdato tlie irrigated soil was markedly more moist than the other 2, l)ut 

 there was not much difference between the unirrigated and mulched soils. It will 

 be seen that the irrigated soils contain the least amount of soluble salts and the 

 mulched most, except in the bottom foot." 



Comparisons were made of hill culture with irrigation with hill and 

 level culture without irrigation. As between hill and level culture 

 without irrigation, there was relatively little ditierence in the yield, 

 the latter giving 9.1 bu. of largo tubers per acre more than the for- 

 mer, but more of the potatoes being greened in level culture. In the 

 case of the irrigated potatoes there was an increased 3neld of 111 bu. 

 of large tu))ers per acre over the hilled potatoes not irrigated and 108 

 bu. per acre over those receiving level culture without irrigation. 



Seven days after the last irrigation determinations were again made 

 of the amount of moisture in the soil of each plat, this time of the 

 amount in and between the rows respectively. The irrigated plat con- 

 tained about per cent more water in the surface foot of soil under the 

 hills and S per cent more between the rows. The second foot of soil 

 contained about 2 per cent more water than the unirrigated plats. 

 With this increase in amount of soil Avater is associated an increased 

 yield of about 100 bu. of merchantable potatoes to the acre. "This 

 relation makes it very clear that the right amount of water at the 

 right time is a very important factor in determining the 3deld. The 

 amount of water which was added to the soil this year to secure this 

 increase in yield was only al)out 2 acre-inches, divided ))etween 2 irri- 

 gations." 



Continued effects of fertilizing the soil, W. C. Latta {Ind'iana 

 Sfd. jRj)t. 1899, pp. Jfi-fJO). — Corn has l^een grown continuously since 

 1880 on plats fertilized with either horse manure, gas lime, or ammo- 

 niated phosphate to study the residual effects of these manures. The 

 yields of grain and stover on the different plats are given for 10 years 

 for the gas lime and phosphate plats, and for 16 3'ears for the horse- 

 manure plats. 



The results show the effects of the lime and ammoniated phosphate 

 on grain yield to be slight and transient. The aggregate increase of 

 corn due to the residual effects of the horse manure has amounted to 

 131.8 l)u. of grain and 0,212 l])s. of stover, estimated to be worth $.55.11. 



