Effects of reduced plant height on breeding requirements and ...

correfation between diastatic power and alpha-anylase levels
as dld Hayter and Riggs (I9?3),
Response to_Nitroeen Fertilization
The use <strong>of</strong> nitrogenous fertilizers for increased cereal
production has been carried out unknowingly sinee man changed
from nomadic to village agriculture and began to grow crops
repetitively on the same land. fhe return <strong>of</strong> manure, bones,
ashes and crop residue to the soil constituted the use <strong>of</strong>
fertítizer. Slack (1pf0) indicated that prinítive fertilization
<strong>of</strong> the soil began as early as 900 B.C. the value <strong>of</strong>
legumes being gro'wn before eereal-s was noted before the
birth <strong>of</strong> Christ.
fhe "fertilizer industry" began ín the 1800's lvith the
use <strong>of</strong> potassium-nitrate mined primarÍIy in Chile (Slack,
I97o), It was used as a nítrogen source around the world
until the productíon <strong>of</strong> fertilizers, as we know it today,
began after ltlorld tr¡ar ïI. Nitrogen was, and still is, the
primary element required and utilized as fertilizer.
The effect <strong>of</strong> nitrogen ferti.lizer on grain yields is
clearly demonstrated by corn yield data from North Carol-ina.
Corn yields there moved progressively from 1BOO-2000 trg, /na.
i,n 1945 to 3600-JB0o xg,/ha. in l-968, accompanied by a
progressive increase in the application <strong>of</strong> nitrogen fertilizer
<strong>of</strong> 24 :Kg,/:na, in L945 to 84 kg./na. in t96B (cummings
and Gleason, ]-97l-). Â simitar relationship has developed
in the other eereals as well.
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