soil pressed into a firn layer above the seed, improver elavation 
af the seed row with respect to the genersl level of the land, and 
other unfavorable planting conditions canse either delayed or low 
germination and an inferior stand of plants which is reflected in 
the crop ylelds. The adverse effects are manifest in many ways 
and are frequently severe enough to require raplanting. Josses 
also result from faulty transplanting of seedlings and the usa of 
excessive amounts of seed. the estimated $50 million loss is $ 
percent of the total value of seed and seedlings planted. The 
loss may be prevented by selection of the most suitable planter 
or seeder, proper fitting of the seedbed, adjustment of the plant. 
ing unit according to the circumstances, and volanting at the 
proper time. 
Root pruning. A plant suffers from lack of water and nutrition 
when too mich of its root system is severed by tillage tools and 
furrow openers operatad too deaply in the soil or too close to the 
plant. The location on the plant where the tools causs excessive 
pruning depends upon the kind of crop or natura of the root system, 
and the stave of plant growth or extent of root development, Hot 
weather and low soil moisture may apgravate these effects, which 
are reflected in the yield. The estimated loss of $60 million is 
about one-half of 1 perrent of the value of cultivated crops. Un- 
necessary losses can be avoided by taking recommanded precautions 
with regard to tha oneration of these tools. 
Soil compaction. Excessive soil compaction by the wheals of 
tractors and heavy implements reduces air and water in the soil 
and otherwise makes conditions unfavorable for root development. 
The operation of a sprayer or duster a number of times in the sane 
path compacts tha soil so that vields of crops such as potatoes 
and cotton on the rews adjacent to the whesl tracks are reduced a3 
much as 59 percent. With millions of acres of soil susceptible to 
excessive compaction, an estimated crop loss of #100 million from 
this causa seems conservative. Loosaning the soll by the use of 
tillage tools mounted back of tractor whesls, lowering the unite 
area pressure on the soil with wider tires, and the growth of dasp- 
rooted crons are among the corrective measures, 
Weeds 
In his agricultural endeavors man has adjusted himself to live 
with certain snecies of nlants growing’ where thay are not dasired. 
These nlants are called weeds, Too often, and at prohibitive costs, 
weeds have bean taken for grants, Unwanted, non-useful, often 
prolific and versistent, they reduce the efficiency of agricultural 
operations, inereasg labor, add to production costs, and reduce 
yields. 
Weeds compete with crops for water, light, and mineral nutrients. 
For instance, one plant of common yellow mistard requires twice as 
mach nitrogen, twice as much phosphoric acid, four times as much 
Migaies 
