BULLETIX 372, U. S. DEPARTMENT OF AGRICULTUEE. 



CULTIVATION AND FERTILIZERS. 



The plants should be set in the field in rows 3 feet apart and about 

 18 inches to 2 feet apart in the row. This wOl permit the use of horse 

 cultivation as soon as the plants have become established in the field. 

 The usual cultivation should be given until the plants are large 

 enough to shade the ground and thus prevent the growth of weeds 

 which might injm'e the crop at harvest time. 



In 1912 a series of fertilizer experiments was carried out on 36 

 plats. It was found that although certain special methods of treat- 

 ment had a marked effect on the percentage of yield of oil and of 

 thymol in the oil, the greatest yield was obtained by promoting the 

 growth of the plant and thus securing the largest possible yield of 

 herb per acre. 



Acid phosphate gave more herb and a higher percentage of oil 

 than did bone black, and calculated on the yield of thymol per acre 

 the ratio was as 2 to 1 in favor of the acid phosphate. Nitrate of 

 soda did not give as satisfactory results as sulphate of ammonia. 

 The use of an organic source of nitrogen in the complete formula did 

 not give as good results as when aU the nitrogen was appHed in the 

 fonn of sulphate of ammonia. There was a slight difference m favor 

 of the application of the potash in the form of sulphate. The best 

 results were obtained by the use of a complete fertilizer having the 

 following analysis: Nitrogen, 4 per cent; phosphoric acid, 6 per cent; 

 potash, 10 per cent. With this fertilizer made from sulphate of 

 ammonia, acid phosphate, and sulphate of potash, 600 pounds per 

 acre should be sufficient to produce a good crop, and less could be 

 used on land having a fair degree of fertility. 



It has been found advisable to make the application of fertilizer 

 after the plants have become established in the field, but care should 

 be taken to prevent injury to the leaves by the fertilizer. 



The average composition of a number of samples of horsemint 

 made both before and after distillation is shown in Table I, the results 

 bemg calculated on the basis of dry material. 



Table I. — Composition of horsemint before and after distillation. 



Time of analysis. Ash. 



1 



Nitrogen, 

 as am- 

 monia. 



Phos- 

 phoric 

 acid , as 



P2O5. 



Potash, 

 as K2O. 



Before distillation 



Per cent. 

 7.73 



8.17 



Per cent. 

 1.46 

 1.33 



Per cent. 

 0.58 



.54 



Per cent. 

 2.38 



After distillation 



2.12 







Takmg as a basis the average composition of the herb before 

 distillation and allowing 25 per cent as the average quantity of dry 

 matter, the quantity found in a large number of determinations, it 



