| Abstract |
- Solid municipal waste was applied to Sagehill sand at rates of
0, 100, 200, and 400 tons/acre (0, 67, 133, and 267 tons dry matter).
Sewage sludge (2% solids) was applied at 55 gallons per ton of solid
waste. Hyslop winter wheat was planted as a cover crop in October
1971 and followed by spring-seeded Fawn fescue and Sernac alfalfa.
Ammonium sulfate fertilizer was applied and the plots were irrigated
for two crop seasons.
The solid waste decomposed rapidly, with only plastic, rubber,
and rusted metal remaining on the plots by the end of the first growing
season.
The soil bulk density decreased with the addition of solid waste,
while the organic matter content and moisture retention increased.
Effective wind erosion control was obtained with all solid waste applications.
Alfalfa and fescue yields of 5 to 6 tons/acre were produced
during the first growing season with solid waste treatments of 0, 100,
and 200 tons/acre; yields were reduced when 400 tons solid waste were
applied. The maximum alfalfa and fescue yields were obtained with
the addition of 400 lb N/acre and 1000 lb N/acre, respectively.
Higher nitrogen applications decreased fescue yields due to increased
soil acidity and consequent increased Mn and Zn uptake. Invasion
by weeds decreased yields on plots which received inadequate irrigation
early in the season.
Plant content of N, P, S, Ca, Mg, K, Fe, and Cu was not
affected by the waste treatments. Mn and Zn uptake by wheat, fescue,
and alfalfa increased with waste addition and with nitrogen fertilization.
Zn uptake from the soil with 400 tons solid waste per acre approached
excessive levels (over 200 ppm) during the first season.
B uptake by wheat and fescue reached toxic levels while B uptake by
alfalfa increased only slightly. Mo uptake by alfalfa grown with the
higher waste treatments reached levels potentially hazardous to livestock
during the first growing season, but decreased to normal the
second year. Co and Cr uptake by alfalfa and fescue was affected
very little by the waste additions.
Soil pH decreased slightly with waste application and appreciably
with nitrogen fertilization. Soil Na content exceeded 3 me/ 100g
early in the season in the soils which received 400 tons solid waste per acre, but decreased rapidly as Na was leached with irrigation
water. Levels of extractable soil Fe and Cu increased 50-fold with
the highest waste treatment, while the extractable soil Zn increased
1000-fold. But soil levels of Fe, Cu, and Zn were not excessive
with the lower waste treatments, and decreased to acceptable levels
in all the soils within the first growing season.
Soil B content increased up to 60-fold with the addition of
solid waste. The B remained soluble in the soil and followed water
movement patterns. The hot water extractable B decreased to 0.8
ppm or less within the first season in the soil with the lower waste
treatments, but remained greater than 2 ppm after two years in the
soils which received 400 tons solid waste per acre.
Crop production on Sagehill sand after the incorporation of up
to 200 tons solid waste per acre appeared feasible with a borontolerant
crop such as alfalfa and with irrigation adequate to meet
crop needs. Higher rates of solid waste application decreased yields
and added hazardous amounts of Zn, B, Na, and Mo to the soil.
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