SOILS FERTILIZERS. 419 



analyzed was in regard to nitrogen. Tlie soils of tlie nortliern part of the area 

 were found to be fairly well supplied with lime, while many of those of the 

 southern part were deficient. Comparatively few of the soils examined are 

 classed as deficient in phosphoric acid or potash. 



Out of the 45 soil samples analyzed for alkali only 9 samples, 7 of which were 

 Karroo soils, contained sodium carbonate, which occurred in very small amounts 

 and only in the surface soil. Sodium chlorid composed the bulk of the alkali 

 salts. 



Pakihi lands: Note on their treatment, B. C. Aston {Jour. Agr. [yeio 

 Zcal.l, 7 {19 IS), No. 3, pp. 295-300, figs. .^).— The results of field and pot tests 

 Indicate that the chief need of these lands, which have been described previ- 

 ously (E. S. R., 23, p. 621) is for lime and phosphorus, and that they may be 

 profitably reclaimed where cheap ground limestone or quicklime and phosphate 

 are available. 



The storag'e and use of soil moisture, W. W. Burr {Nebraska 8ta. Research 

 Bui. 5 {191Jt), pp. 88, figs. 20).— The results of field studies of soil moisture 

 accumulation and con.servatiou conducted for (5 years on fairly uniform fine 

 sandy loam soil at the North Platte substation ai"e reported. 



Under field conditions the maximum capacity for water of the soil in ques- 

 tion was found to be from IG to 18 per cent of its dry weight, of which above 

 7 to 8 per cent is available for plant use. The more important findings are sum- 

 marized as follows : 



Summer tillage is the most effective means of storing water in the soil, the 

 annual storage by this means varying from 10 to 33 per cent of the seasonal 

 rainfall, according to the amount and distribution of the rainfall, the effective- 

 ness of the tillage, and the presence or absence of a growing crop. Plowing 

 seems better than disking for accumulating water in the soil, although disking 

 small grain stubble to kill weeds and stir the surface is generally effective. 

 Artificial mulches of straw or hay are more effective than soil mulches in ab- 

 sorbing and retaining rain water, and a 3-in. mulch is more effective than a 

 shallower one. Corn, oats, spring wheat, and barley use water from the first 

 4 or 5 ft. of soil, winter wheat at a depth of 6 or 7 ft., and alfalfa and grasses 

 when well established at much greater depths. Under normally favorable con- 

 ditions growing vegetation is a greater factor than surface evaporation in re- 

 moving water from soil, and weeds are frequently the most effective agents in 

 removing available water from soils and in preventing the storage of water 

 for the use of other plants. Capillary movement is feeble in soils that are dried 

 to any considerable extent below the saturation point, so that in the main the 

 plant roots to obtain water extend themselves into the soil where available water 

 is present rather than depend upon capillarity. 



In order to store water in these soils it is necesary that the soil surface 

 should be in condition to catch rains, and kept loose and rough by cultivation 

 to reduce evaporation and prevent blowing. Weeds should be suppressed, as 

 far as possible, before and after seeding. Crops which will withstand con- 

 siderable drought or escape drought by maturing early should be chosen. 



The storage and use of soil moisture, W. W. Burr {Nebraska Sta. Bui. 140 

 {19H), pp. 20). — A popular edition of the above. 



Mineral acid soils, O. Loew {Landw. Jahrb., 46 {JBUi). No. 1, pp. 161-164). — 

 The author reviews his own and other studies on mineral acid soils of several 

 tropical countries, particularly Porto Rico (E. S. R.. 29, p. S15), with special 

 reference to the determination and correction of the acidity and the relation of 

 acidity to the biological activities of the soil. Such soils are thought to owe 

 their acidity chiefly to acid clay constituents. 



