y 
EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE. 79 
TABLE XLV.—Average yields of corn, oats, wheat, clover, cowpeas, and oat hay 
in an 8-year experiment at Hurdland, Mo. (1907-1914). 
Corn, | Oats, | Wheat,| Clover, Cow- | Oat 
Fertilizer. Application per acre. peas, | Hay, 
8 crops.| 6 crops.| 6 crops.| 3 crops. T crop. | 1 crop. 
Y ¥ Bushels.|Bushels.|Bushels.|Pounds,|Pounds.|Pounds. 
Pesume ES SEES eae gate pra M5 5 a eC 29.3 27.9 14.4 | 2,500 | 3,850 3, 850 
Oa He SEU ODO CODOCEOES Tae obe coos BAOLE AROSE se ‘ 
Pigs woe Roden \ 29.3] 31.2] 181) 3,213] 7,150| 4,150 
TEPER ON ETS) et ene aera es Li ay Ue cso a nO Ue OT 
Bonemmealaw. .e kl) ss 150) Pounds sks wiee Bey 34,1 35, 2 18.0 | 3,775 | 5,850 4,650 
AIO 5 pS ee ee ee De GO rere te NS aN 
Legume Sie ear aa Seyret 
OU® WIM sao osGubecabood]s 150 POUNGS eee secscee es 
aed Sip eG Taare eaten RC RED | 37.8 34. 3 17.1] 4,116} 6,100 4,050 
Potassium cholride....... SO POU See ere ese o eee 
INORERCAtIMCTIE AR Ss ale oe Mees sc Rae Cn eae 33.1 26.9 13.7 | 2,741 | 4,200 2, 200 
(Mamntirenet seca ts San: Shon She one ae ae ALG eS On leaala coe S4lul 3.525 | a aea25 
1D) OF Ses e nee SELOMSS aa cee eee e \ 40. 4 32.0 17.2] 3,241 | 5,450 3, 700 
Rock phosphate.......... 1,000 pounds 3 ...........-.- 
Manure cere eo alae. SiCONS SF 2 a eae oc ee teu 
Rock phosphate.......... 1,000 pounds 3............. etn, 35.7 18.5] 3,300 | 4,150 3, 500 
GED UIT Chaya teen ieee eet aR Ma Sa UE A OAS ees 
1 Applications made every two years. 
jopledonemaiec er tol sae 
In the Hurdland experiment the addition of phosphate rock to 
manure seemed to have little effect, except in the case of cowpeas and 
oat hay, where the yields were considerably greater than on the plots 
recelving manure alone. Bone meal also seemed to be more effective 
on these same crops, but as in the case of the other experiments the 
data are such that no rigid conclusion can be drawn from a compari- 
son of the results as to the relative value of the two forms of phos- 
phoric acid. 
The fourth experiment, similar in most respects to the three just 
described, 1s being conducted near Laclede, Linn County, Mo. The 
last published report! gives the results obtained after eight years’ 
work in a four-year rotation of corn, oats, wheat, and clover (sub- 
stituting cowpeas when the latter crop failed). 
The field is located on gently rolling prairie land. The soil is the 
typical Shelby loam, which consists of a dark-brown loam to fine 
sandy loam, changing at a depth of about 10 inches to a light-brown 
or grayish-brown loam. The subsoil below 18 inches is a light-brown 
stiff sandy clay. According to the analysis the phosphoric acid and 
nitrogen content of this soil was rather low. The field was laid out 
in four tracts, each tract being subdivided into eight plots, as in the 
case of the three experiments just described. The fertilizer applica- 
tions were the same as in the Hurdland experiment. 
The results of eight years’ work on the Laclede field are given in 
Table XLVI. 
e 1Mo. Agr. Expt. Sta., Bul. No. 128, pp. 388-394 (1915). 
