WATER SOILS. 333 



WATER— SOILS. 



The value of silt as a manure, J. W. Leather ( Agl. Ledger, 1897, 

 No. 5, pp. 7). — Notes are given on investigations made in India to 

 ascertain the mannrial value of the silt which is carried on to land by 

 irrigation water. These included experiments in which oats were 

 grown on silted and un silted plats and chemical studies of the fertiliz- 

 ing value of the silt. It was found that the amount of fertilizing mat- 

 ter which the water carried varied widely with the season. From one 

 series of analyses it is estimated that under ordinary conditions in 

 India a crop which, like rice, is grown during the mousoon or kharif 

 period, receives in the irrigation water 154 lbs. of potash, 42 lbs. of 

 phosphoric acid, and 31 lbs. of nitrogen per acre. Under the same 

 conditions the wheat crop, grown during the cold or rabi season, would 

 receive 19.6 lbs. of potash, 5.2 lbs. of phosphoric acid, and 3.8 lbs. of 

 nitrogen; while a crop of sugar cane, occupying the land during the 

 whole year, would receive 54.6 lbs. of potash, 15 lbs. of phosphoric 

 acid, and 10.8 lbs of nitrogen. "The amounts of the plant foods sup- 

 plied in the kharif are probably sufficient for the entire rice crop; but 

 during the rabi they are not sufficient for the wheat, and the deficiency 

 is probably still greater in case of the sugar cane." 



Studies of Oklahoma soils, J. II. Bone (Oklahoma Sta. Bid. 24, 

 pp. 17). — This bulletin is in a measure supplementary to Bulletin No. 5 of 

 the station (E. S. E., 4, p. 710), which gives results of analyses of a large 

 number of Oklahoma soils. It briefly reports and discusses the results 

 of observations and experiments on the texture and specific gravity of 

 Oklahoma soils; the influence of cultivation on weight and porosity; 

 percolation through soils of different character and treated in different 

 ways; and the influence of plowing, rolling, surface cultivation, and 

 freezing on soil moisture. 



The principal results obtained are summarized as follows : 



"(1) The soils examined at the Oklahoma Agricultural Experiment Station prove 

 to he loose textured, with some of the properties of finer soils. They are easily 

 handled. The specific gravity ranges from 2.60 to 2.66. Under field conditions, 

 without water, the weight of the first 12 in. of cultivated soil was 67.5 lhs. per cubic 

 foot, uncultivated 82, alkali 95.1 lhs. 



"(2) The water supply is very important in plant production. Our rainfall is 

 often poorly distributed, and much water is lost by poor methods of soil culture. The 

 water content of the soil at the experiment station during the growing season of 1896 

 ranged from 5 to 26 per cent. 



"(3) Water percolates best into freshly plowed or cultivated soil. Compacting 

 the soil hinders percolation. The plow is the best implement for putting the soil in 

 condition to receive the rainfall. Subsoiled ground receives more moisture during a 

 heavy rain than un subsoiled ground. 



" (4) Cultivation conserves much soil moisture. Soil mulches prevent evaporation. 

 Cultivation sufficient to keep the weeds from growing is very essential, but we should 

 cultivate to conserve moisture. Very frequent cultivation is not so effective as less 

 frequent. 



