2002-07-08_GENERAL DOCUMENTS - M2002004 ‎(4)‎

• Permit No: M2002004
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Date: 7/8/2002
• Doc Name: ATTACHMENT, PART 3
• From: HABITAT MGMT
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• Media Type: D
• Archive: No

: -•
E dr ag .6 Tor i -...
D46t.Y # el g I ^ � SPO ' ' 2.3
0.49 12 , l i , T8.'PIs SPO . 3.7
avg 8.8: . llil f f T '•.
avg
16.bTST;`'e, - - 1.1
Z9iSPO:` #. - 4.1
x SPO 7,0
HALVORSON ET AL.: TOPSOIL THICKNESS REQUIREMENTS FOR RECLAMATION OF NONSODIC MINED -LAND 421
Table 2. Crop yields from trench plots averaged
:. over fertility treatments.
:. Spoil texturei =
.r • . . Loamy sand £. ? i ; i s's
Topsoil - t /? Silty'? TV
thick - .. - sub .,+ sub- Clay clay-
- ness soil _ *
HSD (0.05)
at Wbeat,1979 „ltl�sr'
• 0.23 0.74 1.02'=:-: `- 21.0C-;:f : 0.90 tr: 0.94 TSTt' -. 0.13
=
0.48 ;1.08- ,s 1.18,14. - 3.14.4019.,28. }.17, SPO _ - NS
0.69 , 1.29 1.29 ‘ 1.20. 1.03 1,19 TS'rx SPO, NS
kf avg:: 1:0 ai .lf
u (s Yf
0.22k j.3 0.38;
.0.46 •:-; 0.3711 .0.43
0.69, ,Yt 0 6b
- i
avg0.3 -- 0.46
0.23 11.3
0.46 15.51
0.69 20 .-
avg; 15.8
Rd'
0.23 1.68
0.46? 2:44J
0.69
avg . 2.
0.23 d 0.87-
0.46 1.008;
avg' 1.12
NS
0.08
NS
4. 0.38
0.50
X.SPOc, 0.95
0.11
0,13
jt.SPO , 0.20
zr ,h
11 TST - - - 0.26
SPCY .�'; ` - 0.67
-TST x SPO'-- NS
and subsoil treat-
,
elds in 19.83 $Trenches:filled with loamy
sand spoil showed.mar ticrease ini Meld with in-
creasing thicknesses ofiopsoiliNields vere`sometimes
twice as high on 0.69 ai 'as they were° inn 0.23 m of
topsoil. The silt . loam topsoil impreved yields on these
plots because the loamy sand_spoil was more drought
prone. Therefore; as 'the loPsoil 'thickness increased
the ability of the soil profile; to continuously supply
the growing crop ,withiwater, throughout, the growing
`'`season also increased This conclusion is consistent
with data reported from other' experiments on re-
claimed land in North Dakota (Doll et al., 1984).
When subsoil was put back over loamy sand, yields
from plots with 0.23 . m of topsoil were considerably
m
higher than fro those without subsoil (Table 2). The
addition of >0.23 m of topsoil over replaced subsoil,
significantly increased yields only for corn silage in
1983. Yields from plots with 0.69 m of topsoil were
consistently higher on loamy sand spoil with subsoil
than without subsoil; however, these differences were
Table 3. Yields from the high fertility treatments of the
noncompacted trenches, which were irrigated
in 1982 and 1983.
Loamy sand
Topsoil
thick- -sub- +sub
nesr soil soil
Spoil texture
Silty
Clay clay
loam loam Avg HSD (0.05)
Mg ha
Wheat, 1982
0.23 1.51 2.02 2.18 2.08 1.95 TSTt NS
0.46 1.73 2.27 2.15 2.15 2.08 SPO NS
0.69 1.76 2.40 2.22 2.22 2.15 TST x SPO NS
avg 1.67 2.23 2.18 2.15
Silage, 1983
0.23 25.5 41.2 37.4 37.9 35.5 TST 2.3
0.46 30.4 42.3 41.6 43.2 39.4 SPO 6.9
0.69 34.4 41.0 42.8 38.9 - 39.3 TST x SPO - NS
avg 30.1 1 41.5 40.6 - 40.0 -
Corn grain, 1983
0.23 5,13 _ 7.12 7.27 - 7.26 6.70 TST NS
0.46 - 5.60 7.96 , 6.51 7.39 6.87 SPO 0.82
0.69 - 7.12 7.66 ` 7.70 6.92 7.35 TST x SPO NS
avg 5.95 ' 7.58 7.16 7.19
t TST = topsoil thickness treatments, SPO = spoil and subsoil treat=
manta • - -
usually not significant based on HSD (0.05) compar-
isons. This suggests that yields obtained on reclaimed
land with 0.69 m of topsoil put back over loamy sand
spoil are close to the maximum obtainable under ex-
isting climatic - and management conditions. There-
_- fore, placement of subsoil over loamy sand spoil is
unlikely to result in significantly greater yields than
replacement of 0.69 m of topsoil alone.
Yields from trenches filled with clay loam spoil also
increased with increasing thickness of topsoil (Table
2). However, based on HSD (0.05) comparisons, these
yield increases were significant only for silage and corn
grain in 1981. Yields obtained from these trenches
filled with clay loam spoil were very similar to those
obtained from loamy sand filled trenches with re-
placed subsoil.
Except for silage yields in 1981, topsoil thickness
did not significantly affect yields on trenches filled with
silty clay loam spoil, although yields were often less
on 0.69 m than on 0.46 m of topsoil. The silty clay
loam filled trenches were slightly concave in the mid-
dle on plots with 0.46 m of topsoil. The run -on water
that collected on these plots was probably enough to
improve yields above those on 0.69 m of topsoil (Wol-
lenhaupt and Richardson, 1982.)
Yields on trenches filled with loamy sand plus sub-
soil, clay loam, or silty clay loam tended to increase
with increasing topsoil thickness at least up to 0.46 m
of replaced topsoil, but these increases were rarely sig-
nificant. Placement of 0.5 to 0.7 m of topsoil over
these materials should be sufficient to produce maxi-
mum yields under the climatic conditions of the site.
Yields of wheat in 1982 were increased about 50%
by the addition of 76 mm of water (Table 3). Yields
of corn silage were more than doubled and corn grain
yields were more than tripled in 1983 on plots irri-
gated with 152 mm of water compared to nonirrigated
plots. Irrigated wheat yields in 1982 were not signifi-