HINTS ON SOILS AND FERTILIZERS 15 
Most of us are familiar with the old adage, “A 
chain is no stronger than its weakest link.” 
Likewise, a soil is no more productive than its 
scarcest element. We may apply a great quan¬ 
tity of phosphorus and potash to our corn land, 
but if the land needs nitrogen to feed to the 
corn, then we will get about as large a corn 
crop as if we had not put on any phosphorus 
or potash. It would be the nitrogen that would 
be the determining factor in this case. 
Often a farmer wonders why his clover does 
not grow normally as it should. He may even 
add a complete fertilizer of nitrogen, phos¬ 
phorus and potash, and still not be able to note 
any material gain in the yield. The trouble 
may lie entirely in the amount of calcium, or 
lime, in the soil. The soil may be not only 
deficient in lime for feeding purposes of the 
plant, but the land might be so acid, due to 
lack of lime, or calcium, that the bacteria that 
are so essential for clover to grow have left 
the soil, and consequently the clover is unable 
to thrive, simply due to a lack of this soil 
neutralizer. 
Thus we see that the soil yields up to the 
plant the mineral elements demanded by the 
plant in the process of growing. It also fur¬ 
nishes nitrogen in a form that is soluble in 
water. The water in the soil supplies the hy¬ 
drogen and part of the oxygen used by the 
plant. In fact, water is simply a chemical com¬ 
bination of hydrogen and oxygen, containing 
two parts of the former, and one part of the 
oxygen. By means of its leaves, the plant takes 
in carbon and oxygen in another chemical com- 
