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3.2.2.2 Aspect-Mulch Interactions <br />.; a. 4:1 Slopes (Appendix B-1 through B-6) <br />Early spring moisture was generally greater (15-25X) at all <br />depths on south aspects than the north aspects (15-17X). <br />Exceptions were the relatively high (25X) Scm soil moisture <br />under the north aspect control; this reading was matched by <br />- the south aspect control. Soil moisture levels declined at <br />.depth (50~) more slowly under north than south aspects. Rear <br />_ surface moisture (5-25 cm) declined in a steep curve for all <br />treatments, regardless of aspect or mulch treatment. <br />b.. 2:1 Slopes (Appendix B-7 through B-12) <br />Early spring moisture was generally greater (15-2D°,() on the <br />north plots as compared to the south (5-15X)• An exception <br />vas the south aspect control, which showed higher soil mois- <br />ture at all depths than either mulch treaUaeat on the same <br />- aspect, and moisture levels equal to any of the north aspect <br />~. treatments. Controls on both aspects retained deep (50®) <br />moisture longer than nay of the mulch treatments. <br />'~ 3.2.3 Discussion and Summary <br />The observed soil moisture curves show a pattern very similar to <br />that of 1978: adequate early spring moisture followed by summer <br />drought. A consistent rapid decline in soil moisture levels over time <br />i. is apparent at shallow (Scm-25 cm) depths regardless of mulch, slope, and <br />_ aspect. This observation suggests that the growing season is very brief <br />on these plots (mid April - early June), and that mulching, slope, and <br />aspect factors do not significantly extend or shorten the growing <br />season. <br />Aa important factor that enters into the 1979 analysis that vas <br />' probably less important in 1978 is water consumption by planted species <br />and needs. Primary conclusions from the analysis of vegetation <br />(Section 3.5) were that pleat density and production were much greater <br />on north than south aspects, regardless of slope, and mulches appeared <br />to provide beneficial effects oa north aspects,. and less benefits on <br />south aspects. Since early spring moisture levels were not greatly <br />different regardless of aspect, it is hypothesized that a significant <br />amount of the available soil moisture on north aspects was consumed by <br />16 <br />