Author
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Unger, Paul |
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Submitted to: Compost Science and Utilization
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/10/1995 Publication Date: N/A Citation: N/A Interpretive Summary: A surface mulch of crop residues reduces soil water evaporation, but residues produced by dryland crops may be inadequate to reduce evaporation effectively. A possible alternative mulch material is waste paper. Two trials, each conducted for 21 days in a laboratory, were used to compare evaporation from soil with paper-pellet or crop-residue mulch to that from bare soil. In Trial I, small (4.8-mm diam.) and large (9.5-mm diam.) waste-paper pellets provided full cover or half that amount (on a weight basis). Large pellets at full cover reduced evaporation more than other treatments during most of the trial. The reduction was greatest on Day 4 when it was 52% of that with bare soil. Both half-cover treatments resulted in similar evaporation. At full cover, evaporation tended to be greater with small than with large pellets. In Trial II, evaporation with small and large pellets at full cover, wheat straw at 0.60 kg m**-2, grain sorghum stover at 1.20 kg m**-2, and bare soil were compared. Except with small pellets after Day 11, evaporation was lower with mulch than with bare soil. Evaporation tended to be greater with small than with large pellets, similar for large pellets and wheat straw, and lower with sorghum than with other treatments on most days. Evaporation was reduced most on Day 1 with sorghum stover when it was 28% of that with bare soil. Use of paper-pellet mulch can reduce evaporation and, thus, increase water conservation. Waste paper use as a mulch on cropland would decrease the amount presently hauled to landfills for disposal. Technology improvements underway should make paper-pellet use on cropland practical. Waste paper use on cropland will require close attention to soil nutrient relations. Technical Abstract: Crop residue mulch reduces evaporation, but residue production by dryland crops may be inadequate to reduce evaporation effectively. An alternative material is waste paper for which disposal on agricultural land is being considered. A laboratory study compared evaporation from soil with paper-pellet or crop-residue mulch in two trials, each conducted for 21 d. In Trial I, small (4.8-mm diam.) and large (9.5-mm diam.) waste-paper pellets provided full cover or half that amount (on a weight basis). Large pellets at full cover reduced evaporation more than other treatments during most of the trial. The reduction was greatest on Day 4 when it was 0.52 of that with bare soil. Both half-cover treatments resulted in similar evaporation. At full cover, evaporation tended to be greater with small than with large pellets. In Trial II, evaporation with small and large pellets at full cover, wheat (Triticum aestivum L.) straw at 0.60 kg m**-2, ,grain sorghum [Sorghum bicolor (L.) Moench] stover at 1.20 kg m**-2, and bare soil were compared. Except with small pellets after Day 11, evaporation was significantly lower with mulch than with bare soil. Evaporation tended to be greater with small than with large pellets, similar for large pellets and wheat straw, and lower with sorghum than with other treatments on most days. Maximum evaporation reduction occurred on Day 1 with sorghum stover when it was 0.28 of that with bare soil. Use of paper-pellet mulch can reduce evaporation and, thus, increase water conservation. Technology improvements underway should make paper-pellet use on cropland practical. Waste paper use on cropland will require close attention to soil nutrient relations. |
