Edible Products. 



546 



[December, 1908. 



potatoes will be small and the yield 

 unsatisfactory on soils that do not 

 contain sufficient organic matter to 

 produce a fair growth of vine. 



Use op Stable Manure. 



The use of stable manure as a fertilizer 

 for sweet potatoes is recommended on 

 lands that are deficient in organic 

 matter. Heavy applications of fresh 

 manure to sweet potatoes shortly be- 

 fore planting the land will stimulate not 

 only the growth of weeds but also of 

 the vines at the expense of the roots. 

 Well-rotted stable manure may be used 

 at the rate of 10 to 15 cart-loads to 

 the acre, spread broadcast or beneath 

 the ridges and harrowed into the soil, 

 but it is always well to apply thw 

 manure with the crop grown the pre- 

 vious season. By this method the man- 

 ure will become thoroughly incorporated 

 with the soil and become somewhat 

 reduced before the sweet potatoes are 

 planted upon the land. 



Stable manure will be found most 

 beneficial on worn-out soils, but on the 

 more fertile soils its use should be 

 restric ted and the method of application 

 carefully studied. In some sections 

 where the organic matter in the soil is 

 insufficient all kinds of vegetable mat- 

 ter, including manure, pine needles, 

 corn fodder, straw, and stubble are 

 turned into the land to bring up the 

 fertility. The sweet potatoe vines will 

 go a little way toward keeping up the 

 organic matter in the soil, but have a 

 souring tendency and should be ac- 

 companied with a moderate application 

 of lime or plaster. 



Leguminous plants grown as cover 

 crops or in the rotation will serve to 

 keep up the organic matter in the soil 

 the same as stable manure. Sweet 

 potatoe growers are coming to realize 

 the value of crimson clover for use in 

 the rotation in which sweet potatoes 

 are grown. If the land is planted to 

 corn, crimson clover may be sown in 

 the alleys at the same time the corn 

 receives its final cultivation. This will 

 provide a covering for the land during the 

 winter, and as the crimson clover starts 

 into growth quite early in the spring a 

 heavy crop is produced by the time it is 

 necessary to plough the land for sweet 

 potatoes. In order to secure the best 

 results the crimson clover should be 

 turned under not later than the ap- 

 pearance of the first blooms; if allowed 

 to remain longer the stems become 

 tough and do not decay quickly enough 

 to be of benefit to the sweet potato crop 

 which follows. 



Use of Commercial Fertilizers. 



The sweet potatoe is one of the few 

 of our crops that thrive equally as well 

 (or better) upon commercial fertilizers 

 as upon stable manure. A fertilizer for 

 use in the majority of sweet potato 

 lands should contain 3 to 6 per cent, of 

 nitrogen, 6 or 7 per cent, of phosphoric 

 acid, and 8 to 10 per cent, of potash. 

 Every grower should make a study of 

 the requirements of this soil and apply 

 the fertilizer that will give the best 

 results. Many growers purchase the 

 ingredients and mix their own special 

 fertilizers, or use a standard fertilizer 

 as a base and increase the percentage 

 of certain elements by adding high- 

 grade elementary ingredients. Some 

 soils require that certain elements 

 should be in a more available form than 

 others ; in the case of nitrogen it is 

 often desirable to have a portion of that 

 contained in the fertilizer quickly avail- 

 able and the remainder more slowly 

 in order to feed the plants throughout 

 the season. 



A mixture adapted to the growing of 

 sweet potatoes on most soils may be 

 made by combining the following : — 



200 pounds of high-grade sulphate 

 of ammonia, 25 per cent. pure. 



200 pounds of dried blood, or 300 

 pounds of fish scrap. 



1,200 pounds of acid phosphate, 11 

 per cent pure. 

 400 pounds of high-grade muriate 

 of potash, 50 per cent. pure. 



This mixture contains approximately 

 4 25 percent, of nitrogen, 6'6 per cent- of 

 phosphroic acid, and 10 per cent, of 

 potash. Nitrogen in two forms is pre- 

 sent, the dried blood being quickly avail- 

 able and the sulphate of ammonia more 

 slowly, becoming available later in the 

 season when ,the potatoes are forming. 



Experience has demonstrated the ne- 

 cessity of having an abundance of 

 potash in the fertilizers used for sweet 

 potatoes. In experiments with fertili- 

 zers for this crop an increased yield of 

 from 40 to 60 per cent, has been noted 

 on plots where a liberal application of 

 potash had been made in comparison 

 with plots to which no fertilizer was 

 applied. In most cases the highest 

 yield is secured where a complete, or 

 balanced, fertilizer is used. 



Quantity and Time of Applying 



Commercial Fertilizers. 

 The quantity of fertilizer that may be 

 profitably applied will be governed en- 

 tirely by local conditions. Many growers 



