Residue Placement Effects on Decomposition, Evaporation, and Soil Moisture Distribution1
- Paul W. Unger and
- J. J. Parker2
In a greenhouse study, wheat (Triticum aestivum L.)residue placement affected residue decomposition, evaporation, soil moisture distribution, pH, and nitrate-N content. Residues mixed with or covered by soil decomposed at similar rates, but surface residues did not decompose measurably. Surface and covered residue treatments, compared with the mixed residue treatments, reduced evaporation 57.4 and 18.9%, respectively. When approximately 60% of plant available moisture remained in the soil, moisture contents decreased with soil depth below the residue layer for surface and covered residue treatment. For the mixed residue treatment, soil moisture content initially increased with depth, then decreased. Soil pH remained relatively high for mixed and covered residue treatments, but decreased for the surface residue treatment.
No differences in decomposition, evaporation, or soil moisture distribution were noted due to rate of N or sulfur application. Soil pH was lowered by the high N application rate and was significantly correlated with soil nitrate-N content. Applied sulfur did not affect pH.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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