FIELD CROPS. 331 



test the relative resistance of cork from which tannin hud been extracted as 

 compared with cork soaked with tannin in varions percentages. 



FIELD CROPS. 



A manual of practical farming, J. McLennan {New York, 1910, pp. X+29S. 

 pis. -SS, figs. ^6'). — Soil problems and the production of farm crops and animals 

 are treated in this book with the primary purpose of aiding the practical 

 farmer and student of agriculture. Tables and technical terms have been 

 avoided. 



Dry farming experiments, W. Angus (Jour. Dcpt. Agr. So. Aust., 13 (1910), 

 No. 8, pp. 6.'i2-64o). — Dry farming experiments in disking, plowing at various 

 depths, and subsurface jiacking are reported. 



Deep plowing proved advantageous when the laud was fallowed. The most 

 satisfactory increase followed the use of the subsurface packer immediately 

 after the plow in the process of fallowing both in deep and shallow plowing. 

 No advantage was apparent from the use of the subsurface packer immediately 

 before sowing on fallow land or in fall plowing. 



Dry farming practice in Montana, A. Atkinson and F. S. Cooley (Montana 

 Sta. Circ. -3, pp. 11-3.'/, figs. 7). — This cii'cular discusses the equipment neces- 

 sary for the beginner, the conservation of moisture, tillage operations, dry- 

 land crops, live stock on the farm, and other topics"of general interest to the 

 dry farmer. A brief reading list is appended. 



Water requirements of crops in India, J. W. Leather (Mem. Dept. Agr. 

 India, Clicni. Ser., 1 (1010). No. S, pp. l.i3~lS.'i, pis. 15, charts 23).— The tran- 

 spiration ratios of 10 important field crops as determined by Lawes, Hellriegel, 

 Wollny, and King are presented in parallel columns. The authors have made 

 their own determinations, with a number of field crops, each of which was 

 tested in glazed stoneware jars of soil of capacities varying from 14 to .50 kg, 

 each. Tlie water and fertilizing materials added and the conditions of exposure 

 to sunlight and winds were varied. The water was added by means of unglazed 

 earthenware cylinders, 2 in. in diameter and from G to 10 in. deep and provided 

 with small holes in the lower part. Thus the surface soil remained loose and 

 nearly air-dry, cracking was avoided, and the use of covered jars rendered 

 unnecessary. As control jars showed that the loss of water from the soil under 

 these conditions was very regular and was small by comparison with that tran- 

 spired by a heavy crop, it introduced an error which was immaterial save in 

 the case of small stunted plants. 



The exposure of the jars to the sun had no influence on the ratio, but the 

 addition of nitrate and phos[)hate or rape cake and phosphate reduced the 

 ratio very greatly. A lower ratio was obtained by the use of large jars contain- 

 ing a large mass of earth, this lowering the ratio from 10 to 20 per cent. Other 

 things being equal the better development of the plant was accompanied by a 

 lower ratio. Not only manure but also good tillage and deep soil or any factor 

 which aided in the development of the crop appeared to tend toward an 

 economy of water. In general, crops which mature rapidly have a low ratio 

 and the longer lived ones a high ratio, but this rule is not without conspicuous 

 exceptions. A table presents the ratio of each of the crops experimented with 

 for a harvest of 1,0(X). 2,000, o,(X)0, 4.000, or .5,000 lbs. per acre, and the nmnber 

 of tons per acre or acre inches of water required to produce the.se yields. The 

 average of all ratios obtained for each crop is shown in the following table. 



