GROUP OF HEAVY SOILS. 
29 
indicate the following amounts of nitrogen, phosphorus, and 
potassium in these soils in pounds per acre, eight inches deep: 
Nitrogen 
Phosphorus 
Potassium 
Average of Lintonia and Knox silt loams... 
Vesper silt* loam 
1,988 
4,566 
5,340 
820 
1,920 
1,440 
(In pounds) 
33,800 
Bates silt loam .. 
35,200 
• 
• 
It will be seen that there is a good deal of variation in the 
amounts of the plant foods found in these different soils. 
Nitrogen and organic matter .—The light colored Lintonia and 
Knox soils have the smallest amounts of these elements. They 
can best be added to the soil by growing and plowing under 
green crops as clovers and alfalfa. Organic matter added to 
these soils helps prevent erosion or washing away of the soil, 
helps prevent drying out by increasing the water holding capac¬ 
ity of the soil, and enlarges the leaf and stem growth of crops 
giving larger straw on the grain crops and improved yields 
of silage and corn. 
Acidity and liming .—Since all of these soils are medium to 
strongly acid and usually show need of lime, difficulty with 
growing clover and alfalfa may be corrected in part by apply¬ 
ing ground limestone. The soil should be tested before this 
application, and this is done without charge by the University 
Soils Department at Madison. The need for lime as shown 
by the crops should also be considered. It should not be ex¬ 
pected that lime will remedy conditions where the soil lacks 
good underdrainage as is often the case on the Vesper silt loam. 
Phosphorus .—The Knox and Lintonia soils are lowest in the 
supply of this element, and although they are and have been 
the best grain soils in the county, if the farm does not produce 
enough manure to revive the soil where grain is becoming poor, 
small applications of phosphate fertilizer to help out the manure 
will be necessary. Even if the supply of manure is liberal the 
additional use of phosphate fertilizer will usually pay. Lodged 
grain or light yield may be laid in part to an unbalanced ration 
of plant food in the soil and addition of lime and small amounts 
of phosphorus fertilizer often help to remedy this condition. 
