632 EXPERIMENT STATION KECORD. 



" Since rather low and fairly uniform soil temperatures seem to be essential 

 to the production of high-class seeil tubers, the use of a mulch of straw or 

 other coarse material about the plant suggested itself. This method has been 

 under test at the station for eight j'ears, and during that time 22 separate 

 tests have been conducted, all with the Early Ohio variety. In evei'y test 

 a uniform stock of tubers was divided into two lots, one grown by ordinary 

 cultivation and the other one mulched. The seed tubers produced on the two 

 plats were kept under identical conditions over winter. The next spring 

 both were planted in the same way on adjoining plats of as uniform soil as 

 could be had, and both were given the same cultivation throughout the summer. 

 Differences in yield the second year of tbe test are, therefore, attributable 

 to the difrorent methods of culture by which the seed tubers were produced In 

 the first year of the test. Tests wei'e also made of the effect of different num- 

 bers of years of mulching and cultivation. 



" In ten comparisons of seed tubers grown one year under a mulch with seed 

 tubers of the same stock grown one year by ordinary cultivation, for each 

 100 lbs. of tubers produced from mulched seed the cultivated .seed produced 02, 

 68, 70, TO, 7G, 80, 82, 83, 88, and 93 lbs., respectively, or an average of 

 77 lbs. The other 12 tests compared from two to eight years of mulching with 

 the same number of years of cultivation. The results from all the 22 tests 

 are that for each 100 lbs. of marketable tubers grown from mulched seed the 

 average yields of marketable tubers from cultivated seeds were: Cultivated 

 1 year (10 tests). 77 lbs.; 2 years (4 tests), 68 lbs.; 3 years (1 test). 74 lb.s. ; 

 4 years (1 test), 68 lbs.; 5 years (1 test), 66 lbs.; 6 years (2 tests), 61 lbs.; 

 7 years (2 tests), 49 lbs. ; 8 years (1 test), 54 lbs. 



" Continued cultivation in southeastern Nebraska results, then, in a pro- 

 nounced though somewhat gradual deterioration of potato stocks. One year of 

 mulching, however, restores the normal vigor of the stock, as is indicated by 

 two tests as follows: Mulched 6 and 7 years, 100 lbs.; mulched fi and years 

 and cultivated 1 year, 82 lbs. ; cultivated 6 and 7 years, 67 lb.s. ; cultivated 5 

 and 6 years and mulched 1 year, 100 lbs. 



" Comparisons of home-grown mulched stocks of Early Ohio potatoes with 

 northern-grown stocks of the same variety have been made in five of the eight 

 years. For each 100 lbs. produced on the average by mulched seed tubers, the 

 northern-grown seed tubers yielded an average of 98 lbs. 



" Northern-grown seed tubers ordinarily retail for about 25 per cent more 

 than home-grown tubers. The estimated cost of producing seed tubers by 

 mulching is $10 to $12 an acre more than the cost of producing them by 

 cultivation, but a mulched seed plat will ordinarily yield about 25 per cent 

 more soeil tubers an acre than will a cultivatetl seed plat. The cost i>er bushel 

 is, therefore, not greatly different for the two methods. The grower can pro- 

 duce high-class seed tubers at home by mulching at a cost somewhat less than 

 he can buy northern-grown seed of equal quality. 



" It is recommended to mulch a few rows of potatoes along one side of the 

 field to furnish seed for the next year's crop. The mulch should be about 

 4 hi. deep after settling and may consist of hay. straw, stable litter, or other 

 coarse material free from grain and noxious weed seeds. It is best applied 

 before the plants come up and must be spread by the time the new tubers 

 begin to develop. To insure that the plants are strong enough to push up 

 through the mulch and to produce as large a yield as possible for a given 

 amount of mulching, large seed pieces from 4 to 6 oz. should be planted. The 

 depth of planting should be the same as in the rest of the field, about 4 in." 



The use of Paris green and Bordeaux on the farm, J. W. Ince (Xorth Da- 

 kota .S7a. Spec. Bill., 3 {1915), No. U,, pp. 239, 2^0).— This article briefly de- 



