WATER SOILS. 931 



of the humidity of the soil no definite conclusions can be drawn. — 

 P. FIREMAN. 



A study of methods of cultivation, J. H. Shepperd and J. A. 

 Jeffery {North Dakota Sta. Bui. 29, pp. 185-206). — An account is 

 given of one year's experiments on 52 quarter-acre and 8 fifth-acre 

 plats at the station to test the relative merits of deep and shallow and 

 fall and spring plowing, subsoiling to different depths, subsurface pack 

 rag, harrowing after plowing, disking, and the ordinary and Campbell 

 methods of cultivation. 



The Campbell method of cultivation is described as follows: 



"(1) Plow deeply — 7 or 8 in. — preceding the plow with a disk harrow to mellow 

 the surface about to be turned under. 



"(2) Follow the plow within a few hours with the Campbell subsurface packer. 

 This machine consists essentially of a series of cast-iron wheels placed abreast upon 

 an iron axle, so that their rims, which are about an inch thick at the base, narrow- 

 ing to a sharp angle at the extreme circumference, are about 5 in. apart. The Avhole 

 machine, when run over the soil, is heavily loaded. The object of the subsurface 

 packer is, first, to further pulverize the soil, and second, to bring the newly turned 

 soil, which is held up to a greater or less extent by the stubble, iuto contact with 

 the bottom of the furrow. This packing of the furrow slice upon the bottom of the 

 furrow renews the capillary relation between the newly turned soil and that below, 

 a tiling desirable in a dry fall, and also opens a way downward for rain, should 

 there be any. It is well known that water does not percolate so readily into a soil 

 that is dry and filled with air spaces as it does into one that is already moist, and, 

 while mellow, is not filled with large openings. 



"(3) Follow the subsurface packer with a li<;ht peg tooth harrow and harrow the 

 land at intervals thereafter until the crop is sown. This is to keep a shallow mulch 

 over the surface of the ground to retard the evaporation of the moisture into the air. 



"(4) Put in all crops so that they may be cultivated. Grains are sown in drills 16 

 to 24 in. apart. 



"(5) Cultivate shallow and often, The Campbell grain drill can be converted 

 into a spring- tooth cultivator, which cultivates the same number of rows that the 

 drill sows. Mr. Campbell's theory is (a) that by this cultivation the loss of moist- 

 ure into the air is lessened, and (h) that a fewer number of plants with all the moist- 

 ure the\ may need will produce a greater yield than more plants with an insufficient 

 supply of moisture." 



Moisture determinations were made by King's method 1 in samples of 

 soil from most of the plats May 24 and August 19 and 20, and from a 

 few of them June 6, and the results with data for cost of production 

 and yields are given in tables. 



"In drawing conclusions as to the relative merits of the methods employed in 

 these experiments, it must be remembered that- the present year has been one of very 

 unusual conditions, and that future results, under conditions usually prevailing, 

 may be very different from those recorded in this bulletin. Bearing these facts in 

 mind, observe: 



"(1) On ground fall-plowed with ordinary plow, (a) the largest average yield 

 w;ts from ground subsoiled 8 in. below a G-in. furrow, (b) This yield was practically 

 equaled by the average yield from plats packed by Campbell's subsurface packer 

 and cropped in the ordinary way. (c) The highest yields from single plats were 

 from plats subsoiled 8 in. below the bottom of a 6-in. furrow. These were followed 



1 Wisconsin Sta. Rpt. 1890, p. 160 (E. S. R., 2, p. 445). 



