tillage forage was the worst method at 19.50 g. This translates to
a 10.9% higher weight for no-tillage mulch than no-tillage forage
at the 268 kg N/ha level. On the average, the dry weight was 38.4%
better at the highest level of applied N of 268 kg N/ha than at the
0 kg N/ha level for all management schemes (Table 3).

 Corn ear leaf N concentration (Table 4 and Figure 3) increased
(on the average) as the amount of N fertilizer increased under all
clover management schemes all the way up to the 268 kg N/ha applied
N fertilizer level. With no applied amount of N fertilizer
conventional-tillage green manure had a ear leaf N concentration of
2.53% while no-tillage forage had a N concentration of 1.64% Thus
at this level conventional-tillage green manure was 35.2% better
than no-tillage forage. In fact the conventional tillage green
manure is only 0.17% N concentration under the 2.70% sufficiency
level6 with no applied inorganic N fertilizer. At the highest
level of applied N fertilizer (268 kg N/ha) conventional tillage
green manure again performed the best with 3.23% N while no tillage
mulch was the worst with 2.99% N although there existed only a 7.4%
difference between the two and both had exceeded the sufficiency
level. On the average, the N concentration was 38.8% better at the
268 kg N/ha level of applied N than at the 0 kg N/ha level for all
management schemes. On the average conventional-tillage green
manure had the highest N concentration, no-tillage mulch was
intermediate, and conventional-tillage forage, no-tillage forage,
and fallow had the lowest average N concentrations at all N levels
(Table 4).

 Rye was the other cover crop used to determine the best
management practice to optimize corn growth. Corn ear leaf area,
dry weight, and N concentration were all uniquely affected by each
management scheme and varying amounts of N fertilizer.

 Corn ear leaf area (Table 5 and Figure 4) increased (on the
average) as the amount of N fertilizer increased under all rye
management schemes up to 201 kg N/ha applied N fertilizer. With no
added N (0 kg N/ha) no-tillage mulch performed the best with a leaf
area of 2201 square cm while fallow performed the worst with 1607
square cm. Thus, with no applied N, no-tillage mulch was 27.0%
better than the fallow. At the highest level of applied N (268 kg
N/ha) no-tillage mulch again was the best at 3161 square cm while
no-tillage forage was the worst at 2777 square cm. At this level,
no-tillage mulch was 12.2% better than no-tillage forage. All leaf
areas were averaged according to N level and management scheme.
These averages represent the leaf areas of 20 subplots (Table 5).
Thus, on the average, the leaf area was 34.9% better at the highest
level of applied N of 268 kg N/ha than at the 0 kg N/ha level for
all management schemes. On the average, the 67 kg N/ha and 134 kg
N/ha levels of N were the same (Table 5).