Fig. 1.
Fig. 1.

Schematic diagram of the experimental setup and flux chambers used for studying the effects on the emission of odor and odorants of: moisture content in the straw cover (i.e., rainfall), and age of the straw cover (i.e., microbial development in the cover). Five treatments are shown: Uncovered slurry (U), slurry added dry straw (SD), slurry added straw and moderate moisture content (SM), slurry added straw and high moisture content (SH), and slurry added dry straw with replacement of the aged straw cover by a new straw cover at Week 9 (SDnew). The placement of the chambers in the laboratory was set at random.

 


Fig. 2.
Fig. 2.

Rainfall pattern (mm d−1) and final amount of added water (L chamber−1), assuming no evaporation and water drain, for the moderate moisture (SM) and high moisture (SH) treatments.

 


Fig. 3.
Fig. 3.

Visual evaluation of the slurry surface in flux chambers at the end of the experiment (Week 9) for uncovered slurry (UWeek 9), slurry added dry straw (SDWeek 9), slurry added straw and moderate moisture content (SMWeek 9), and slurry added straw and high moisture content (SHWeek 9).

 


Fig. 4.
Fig. 4.

Evolution of average NH3 concentration measured in the headspace of flux chambers containing uncovered slurry (U), and slurry added straw at different moisture contents (SM, SD, and SH), during the 9 wk storage period. Same letters indicate no differences among treatments at each specific week (P > 0.05). The significances of the differences among weeks are not shown for clearness.

 


Fig. 5.
Fig. 5.

Evolution of average H2S concentration measured in the headspace of flux chambers containing uncovered slurry (U), and slurry added straw at different moisture contents (SM, SD, and SH), during the 9 wk storage period. No significant differences among treatments were found (P > 0.05). Same letters indicate no significant differences over time (P > 0.05) for all four treatments.

 


Fig. 6.
Fig. 6.

Relative concentration of odor, hydrogen sulfide, ammonia, dimethyl sulfide, phenol, p-cresol, skatole, and benzyl alcohol above slurry covered by aged (at different moisture levels) and new straw covers. All values are shown as percent of the concentrations measured above uncovered slurry (UWeek 9)