The Effects of Liming And pH on Litter Decomposition

Plant litter decomposition plays a major role in nutrient cycling and soil formation within an ecosystem. Liming increases the microbial community and alleviates the negative effects of acidification, therefore positively affecting litter decomposition. This research evaluated the effects of liming (three levels = 0, 7.5, and 15 g), simulated acidic rain with varying pH's (three levels = 4.5, 5.0, 5.6), and time (two levels = two and four months) on litter decomposition. Nitrogen, carbon, percent lignin remaining, and percent ash free dry mass remaining was quantified. All main effects had significant effects on nitrogen concentration, however the effect of one main effect (time, lime, and pH) was dependent on the other main effects; making generalizations difficult. Nitrogen content in the leaf litter tended to be higher at the half-liming treatment, after four months, and at a pH of 5.0. Similarly, all main effects had a significant effect on carbon concentrations in the leaf litter, carbon content tended to be higher at half-liming treatment, after two months, at a pH of 4.5. The percent lignin remaining in the litter was mainly influenced by the liming level, however this effect was dependent on time and pH. In general, greater lignin remained at the higher levels of lime. Percent ash free dry mass remaining was determined by the time and liming concentration, but was not affected by the pH. The response of dry mass remaining over time was dependent on the liming treatment. In the half-liming treatment, ash free dry mass was significantly lower after four months. The results from this study show the complexity in determining the effects of liming on properties of leaf litter during decomposition over time and under different acid rain pHs. Managers using liming to treat acidification may need to more closely evaluate the pH of the rainfall in a given area to determine the effects on litter decomposition, and further nutrient cycling.