FIELD CROPS, 639 



The much larger amounts of chlonn removed b\' the pine and diest- 

 nut tree.s suggests a reason for the improved quality of the tobacco 

 grown on such lands. Frequently old fields are allowed to lie idle for 

 a time with the idea of reclaiming them for tobacco. Broom sedge 

 {Androjxxjon virginicus) is one of the most common plants on these 

 fields, and later " old field pines" usually come in. The large relative 

 amounts of chloyn taken up by these plants explains the improvement 

 of such lands for tobacco. 



The root system of tobacco at different stages of growth is shown in 

 a number of figures. Frequent and shallow cultivation of tobacco is 

 recommended. 



Wheat experiments, J. D. Towar {2Ilehigan Sta. BuL ISl, j)p. 

 166-109). — These consist of variety and cultural tests and experiments 

 in top-dressing v. plowing under manure. In the variety tests 12 

 different sorts were used. The 3 best sorts in the order of their pro- 

 ductiveness were Gold Coin, Dawson Golden Chaff", and International 

 No. »3. all yielding between 31 and 32 bu. per acre. 



The cultural experiments with wheat involved 5 different methods 

 of preparing the seed bed. The ground was oat stubble. Plat 1 was 

 gang-plowed -l in. deep and followed by 2 harrowings and the grain 

 drill; yield, 23.74 bu. per acre. Plat 2 was plowed 8 in. deep, imme- 

 diately after removing the oat crop, followed promptly l)y the roller 

 and the harrow, and harrowed thereafter at intervals of about 10 days 

 until the wheat was sown; 3"ield, 23.65 bu. per acre. Plat 3 was allowed 

 to lie until the day before the wheat was sown. It was then plowed, 

 rolled, and harrowed twice with a spring-tooth harrow and once with 

 the Acme; 3'ield, 19 bu. per acre. Plat 4 was harrowed twice with a 

 spring-tooth harrow immediately after the removal of the oat crop. 

 Two weeks later the operation was repeated. It was plowed the da}^ 

 before the wheat was sown as in plat 3, but only one harrowing was 

 found necessary; yiekl, 22.93 bu. per acre. Plat 5 was treated the 

 same as plat 3, but had been spring plowed for oats instead of fall 

 plowed, as was the case with plat 3. Yield 16.3 bu. per acre. The 

 largest ^deld was, therefore, from shallow plowing (plat 1), but the 

 author is not convinced that this method of preparation is the best. 

 As a result of this experiment it is concluded that "whatever opera- 

 tions may be performed to conserve the moisture immediately after 

 removing the oat crop will result in an increased yield of the succeeding 

 wheat crop." 



The results obtained in top-dressing and plowing under manure were 

 practically identical. 



Winter wheat, J. Atkinson {lotoa Sta. Bui. 51^ JW- ^Jf-'^O).- — The 

 acreage of winter wheat is being gradually extended in Iowa. The 

 3'ield obtained from winter wheats has been about double that obtained 

 from spring wheats, the average for 10 years with winter wheats being 

 45.1 bu. per acre. 



