WASHINGTON 



2019 



is 14 to 1 as compared with the Yakima 

 valley. 



Prof. Thatcher thinks that "by plowing 

 under each year the leaves which fall 

 from the trees, the nitrogen supply may 

 be prolonged, since the leaves carry more 

 than half the nitrogen taken from the 

 soil. To replace the supply, however, in 

 quantities sufficient to prevent the soil 

 from becoming impoverished, it is neces- 

 sary to plant and plow under leguminous, 

 nitrogen-gathering crops. 



"In lime Yakima soil is stronger than 

 any in the state except Okanogan, Mason 

 and Benton counties. While lime is not 

 of the highest importance as a plant food, 

 it exercises very beneficial effects upon 

 the physical properties of the soil and the 

 ease of tilth and upon the processes 

 which make plant food available. In 

 phosphoric acid, this county has 5,320 

 pounds per acre, which is hardly up to 

 the average of other counties. Of potash 

 there are 8,920 pounds, which is only 

 about one-half or one-third as much as is 

 contained in the soil of nearly all the 

 other east side counties, though gen- 

 erally more than is to be found on the 

 west side. Island county has in places 

 27,040 pounds to the acre and Benton 

 15,340. 



What a Chemical Analysis Shows 



''While a chemical analysis shows the 

 percentage of plant food elements in the 

 soil, it does not show the proportion of 

 this total plant food supply in such form 

 as to indicate what crops are best suited 

 for that particular section. It does not 

 show whether there is a sufficient supply 

 of available plant food for immediate 

 crop needs; nor does it throw much light 

 upon many other questions about which 

 a land owner or prospective purchaser 

 is concerned. The growth of any given 

 crop upon any piece of land depends 

 much more upon elevation, moisture sup- 

 ply, air and moisture drainage, physical 

 conditions of the soil, etc., than it does 

 upon the chemical composition of the 

 soil. 



leaves Hearty Eaters 



"Experiments, however, showing the 



amount of food elements taken from the 

 ground by various crops have been made, 

 and prove interesting readmg A wheat 

 crop, 50 bushels to the acre, takes from 

 the soil 40 pounds of potash, 30 of phos- 

 phoric acid, and 100 of nitrogen. The 

 basaltic loam of Adams county, there- 

 fore, contains enough potash to grow 

 430 crops of such wheat, phosphoric acid 

 enough for 108 such crops and nitrogen 

 enough for only 26. Obviously, there- 

 fore, nitrogen is the limiting factor in 

 wheat production in that soil. 



"Similarly the fine sandy soil of the 

 Yakima valley shows enough potash for 

 QS crops of 600 boxes each of apples, 

 phosphoric acid enough for 160 crops and 

 only nitrogen enough for 12 such crops. 

 On the other hand the same soil, if crop- 

 ped to alfalfa, which draws practically 

 its entire nitrogen supply from the air, 

 would be exhausted of its potash by 52 

 crops of eight tons each of alfalfa hay, 

 while carrying enough phosphoric acid for 

 65 such crops. 



"A whole apple crop of 600 boxes of fruit 

 per acre takes from the soil 134 pounds of 

 potash, 33 of phosphoric acid and 112 of 

 nitrogen. Of this the tree growth re- 

 quires 7 pounds of potash, five of phos- 

 phoric acid and 6 of nitrogen; the leaves, 

 estimated at four tons, 71 pounds of 

 potash, 16 of phosphorus and 59 of nitro- 

 gen, leaving for the apples proper 56 

 pounds of potash, 12 of phosphorus and 

 47 of nitrogen. Potatoes, 300 bushels 

 to the acre, exhaust the soil to the extent 

 of 600 pounds of potash, 22 of phosphoric 

 acid and 80 of nitrogen.'* 



Granvhjle Lowther 



Plant rood in Washington Soils 



In tables 1 and 2 are presented the 

 number of pounds per acre of each of the 

 four important plant-food constituents in 

 the top foot of soil in each of the types 

 of soil more commonly found in the dif- 

 ferent parts of the state, as computed 

 from the results of our analyses of 

 samples representing that type. In nearly 

 every case several samples of the same 

 type from adjacent localities within the 



