Imperial press and farmer., 1903-03-14
the warm season when growing crops most require the water.
Fertilizing Sits.

reIIlllLluS OllIS'
 Of special interest to the farmer are the fertilizing silts carried by this turbid stream. Analyses made during the year of observation show that the sits varied from a minimum of sixty two parts of sediment in 100000 of water during January to as much as 374 parts during the great annual rise of the river in May and June. During local storm also, on the Arizona watershed, enormous quantities of mud were at one time observed washed into the river, raising the amount of sediment as high as 2O72 parts in 100000, over 2 per cent. by weight of sediment. The total quantity of sediment brought down during the year of observation was found to be sufficient to form fifty-three square miles of dry alluvial soil one foot deep, or to make about 164 square miles of recently-settled submerged mud one foot deep
 By means of such figures it is pos sible to understand the agency ot this river in shutting off with it's deposits that arm of the ocean which after ward became the Salton Basin, and in creating great areas of fertile delta land along it's lower courses.
 The value of these silts to the far mer chiefly consists in the nitrogen they contain which comes in large part with the fertlizing materials swept by storms on the upper water sheds into the stream. Phosphorlc acid and potash are contained in great quantities, also; but, considering nj trogen only, the waters of the Colo rado were found to have fertilizing value of from 53 cents to $3,O9 per acre foot during the year. When it is considered that four acre feet, more or less, is required year for irrlga- tion, in the Southwest, it will be seen that these sediments form no mean contribution to the welfare of the farmer. The southwestern farmer, in deed, is blessed with immunity from the heavy fertilizer bills which are often so great a weight upon those who till the soil in eastern and north ern districts.
 Free From Alkali.
 But most of our irrigating streams are generous literally to fault, for they frequently become charged with alkaline salts to such an extent that the lands irrigated by them are serl- ously injured thereby. Fortunately, however, the Colorado is an exception to this rule At times of low water the river is observed to contain ap- preciable quantities of alkaline salts; but during the great annual rise, when the volume of the river is swelled by the melting snows of Colo rado, Wyoming and Utah the fresh snow water results in a stream of remarkable purity, containing for weeks at a time, during May and June, as low as twenty-five parts of salt in 100000 of water. The fresh ness of the Colorado and the mildness of it's salts are indeed fortunate com pensations of nature, for the districts which will in future be irrigated from this supply are many of them quite alkaline, and will require to be flooded and drained of their noxiOus salts by just such pure water supply as will be available.
 It is safe to say that the irrigable districts adjacent to the Colorado River will, when they are developed and utilized, be among the richest lands in the whole irrigated West The semitropical climate, the diver sity of agricultural products possible l tha ctrOnp markets for agricultura1