EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE.- 53 
there was a cumulative effect. When the phosphates were used in 
connection with the “basal mixture,” however, their effect seemed 
more marked. A comparison of the phosphate-basal-mixture plots 
shows that the bone meal and floats gave on the whole higher yields 
than either dissolved bone black or acid phosphate, but these differ- 
Bences are negligible when compared with the differences in yield | 
between the various “ basal-mixture” plots. 
A fertilizer experiment with sugar cane begun at Audubon in 
1890, was continued for 10 years, and in 1900 the averages of the 
results obtained during that period were published. There were, 
however, during this period only eight crops of cane harvested. 
' The land selected for this experiment was part of Audubon Park 
and had not been under cultivation for years. It had grown the 
native deep-rooted grasses which had sometimes been cropped for 
hay, but more frequently allowed to decompose on the fields. The 
soil, therefore, was rich in organic matter and might be considered 
at the outset almost new. No description is given of the soil type. 
The land was tile-drained. The fertilizers were applied only in 
those years in which cane was grown and raw rock phosphate was 
not introduced into the experiment until 1891. The acidulated phos- 
phates were applied at the rate of 250 pounds per acre when used 
alone, but when used in conjunction with potash and nitrogen car- 
riers they were applied at two rates, namely, 250 pounds and 500 
pounds per acre. The less soluble phosphates, bone, basic slag, and 
South Carolina “ floats” were applied at the rate of 500 pounds per 
acre throughout. 
The results are given in Table XXVIII. 
TABLE XXVIII.—Hight-year average results obtained at Audubon Park, La., in 
the growing of sugar cane (1890-1900). 
Average yield per acre. 
Fertilizer and annual application per acre. 2 
: Sucrose in 
Cane. juice. 
Tons. | Per cent. 
DSsolvedrponerblackss 200 POUNGS. 225. 5.52 oa to eB ie eae Sais 29. 88 TA, 
Dissolved bone black, 250 and 500 pounds; basal mixture,? 330 pounds. ........... 429.52 410. 64 
ISSSO WCUTCHMOS SEO coy obere lS) ee See ees ee ee eee eee 28. 19 10. 84 
Meidennospuntes spUspOUnGS@s 9), 3755.02 0f 28 Se oS Ist Sis . LS ss ete A ee 26. 12 11.55 
Acid phosphate, 250 and 500 pounds; basal mixture,? 330 pounds...............- 429.55 411.04 
iGelonumingreper: semeeiaw see ANS PES OL eee Pepe es AS LEE 25. 10 11. 59 
ROMER AC Ken SOUR DOUNOS Re seria. Se seein Sen aa ols Me ne Sew caaesecesehcctnenmeaes 27. 26 AES 7, 
Bone black, 500 pounds; basal mixture,? 330 pounds.............---------------- 27. 59 11.35 
Siew ine BOD eon. eee et pe eet e Gee Soe aem as Meena ane Seana 27.68 11. 62 
Slag meal, 500 pounds; basal mixture, ? 330 pounds............-.--- Diep Mice Ss ee 30. 44 11. 82 
fee asc MMM PRLIN sso U MP OUMC Sees hos Scio seiocisc as Jacek aakee Saco cies cat Betas cecieenis 28. 45 11.70 
Sawin Carolima tl atsso00 pounds. 223222250. eke. Ra. ib 58522 tks 26. 76 12. 04 
South Carolina ficats, 500 pounds; basal mixture, ? 330 pounds..........-..---- 29.19 11. 67 
MM OnEN IZ Oey ae ee it nS eee Looe cc aS ohicmee es ccd sas te ae e ger eens 25. 38 12. 29 
TEVEIES TONER IG AAD ONO ee Ie | Sea I Oe ee ee aa ees ea 26. 73 12. 26 
Bone meal, 500 pounds; sulphate of potash, 100 pounds........-.-...----.------- 26. 03 12. 34 
Bone meal, 500 pounds; basal mixture,’ 330 pounds.-..-..........---------------- 27.44 11. 96 
1La. Agr. Expt. Sta., Bul. No. 59 (new series) (1900). 
2 Fertilizer applications made only in years cane was grown (8 years). : 
3 Basal mixture=230 pounds ammonium sulphate and 100 pounds potassium sulphate. 
4 Average of two plots. ; 
