814 EXPERIMENT STATION RECORD. 



Experiment Statiou in 1907, Including purification of sewage and water filtra- 

 tion. 



Sewage-grown crops {Agr. Econ., J,! (J 908), ^^os. 467, pp. 289, 290; J,(]8, pp. 

 311, 318). — A general discussion of crops suited to sewage farming. 



SOILS— FERTILIZERS. 



The storage of winter precipitation in soils, J. A. Widtsoe (Utah Sta. Bui. 

 104, pp. 219-316, dgms. .'/). — This bulletin is based upon observations during 

 several years on the variations in the moisture content of the soil, to a depth 

 of 8 ft., on an irrigated farm and on several so-called dry farms. Detailed 

 data are given for physical analyses of the soil and for their moisture content 

 in fall and spring, with fall plowing and spring plowing of the land, with fall 

 and winter irrigation, and with summer fallowing. 



The results em]ihasize the fundamental importance of conserving the natural 

 precipitation and making irrigatiftfi simply supplementary to it. " The natural 

 precipitation over the larger portion of the Great Basin, if properly conserved 

 by summer fallowing, is sufficient to produce crops without irrigation. 



" The amount of moisture found in the soil in the fall depends on the crop 

 grown, the total amount of water applied during the season, the summer pre- 

 cipitation, and, on an irrigated farm, on the date of the last irrigation. On an 

 irrigated farm as high as 95.56 per cent and on nonirrigated farms as high as 

 93.17 per cent of the total winter precipitation were found in the upper 8 ft. 

 of soil. The average of the maximum percentages of the winter i)recipitation 

 found in the upper S ft. for 5 years on an irrigated farm was 82.13; for 3 years 

 on nonirrigated farms, just reclaimed from the desert, was 61.85. 



" The water capacity of soils under field conditions is low, usually not above 

 18 per cent. The drier the soil is in the fall the more of the winter precipita- 

 tion is found in the first 8 ft. of soil." A comparatively small portion of the 

 winter precipitation is lost from the soil by evaporation, but a considerable 

 l)ortion of it passes down through the soil below the eighth foot limit. " In 

 the spring irrigated soils to a depth of 8 ft. are fully saturated and nonirri- 

 gated soils are usually so. . . . In the spring, less than 20 in. of precipitation 

 are usually found in the upper 8 ft. of soil ; that is, not more than the precipita- 

 tion of one and one-half years is stored in the upper 8 ft. of soil. 



" To make farming without irrigation successful, a considerable percentage of 

 soil moisture must be carried over from year to year. Fall plowing tends to 

 conserve the natural precipitation. Fall or winter irrigation is advisable on 

 deep soils with good drainage. It should be practiced in moderation. . . . 

 Summer fallowing conserves the soil moisture; the longer the fallow period, 

 the higher the percentage of soil moisture. The reason why the beneficial 

 effects of summer fallowing and fall plowing are not more evident in the soil 

 moisture content is that the water capacity of most arid soils is small and 

 that during the winter season a large portion of the water moves below the 

 eighth foot limit reached by the soil augers. 



"Lands may be water-logged even when only a small surplus of water is 

 applied at each irrigation. The surplus moves to considerable depths until an 

 impervious soil layer is reached, where the accumulation of water begins." 



Quantity and composition of drainage water and a comparison of temper- 

 ature, evaporation, and rainfall, J. H. Norton (Jour. Amcr. Chcm. Soc, 30 

 (1908), Xo. 1, pp. 1186-1190).— The studies here reported were made in 1906 

 on the drainage basin of Richland Creek, covering an ai-ea of 84,954 acres in 

 ]Madison and Washington counties, Arkansas, of purely agricultural lands on 

 which no fertilizers had ever been used. The rainfall data were secured from 



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