The soil characteristics of a farm or forest habitat may influence speed of decomposition in a manner that is distinct from the influence of litter traits. For example: Nutrient status of the soil directly influences decomposition. If leaf litter is deficient in nitrogen or other nutrients, a soil with high relative levels of nutrients may make up for the deficiency in the litter and speed up the decomposition process.
Sites that are deficient also indirectly influence decomposition by increasing the nutrient resorption efficiency of the trees. As leaves begin to age and die, the plant can retrieve the nutrients prior to ultimate leaf death. This occurs to a greater extent in poor soils, and the result is slower decomposition of the resulting leaf litter.
A phenomenon called “home field advantage” often exerts strong control over litter decomposition traits. The concept is founded in the fact that the decomposer community that is highly efficient at decomposing litter from a particular species tends to increase in population nearby trees of that species. Therefore, if litter from that species falls in these microsites where the species-specific decomposers have increased in population, the decomposition speed is increased.
The weather patterns of a farm or forest site also influence speed of decomposition.
Temperature exerts a strong controlling effect on litter decomposition, with the decomposer microorganisms performing best in moderate temperatures. The temperatures in the Mariana Islands are ideal for growth and performance of these microorganisms.
Rainfall abundance and seasonal distribution also control litter decomposition speed. As with all organisms, the community of microorganisms that decompose litter require abundant but not excessive available water to function.
About 75% of the litter had decomposed by 4 months. The variation among the experimental sites was not substantial, especially in relation to the variation among the species. Litter decomposition in Tinian was slowest and litter decomposition in Saipan was most rapid.
Site characteristics for Tinian farm site.
Site characteristics for South Guam farm site.
|mg/g Zinc|| 49.28
Site characteristics for Rota farm site.
|mg/g Zinc|| 73.89
Site characteristics for North Guam farm site.
Site characteristics for Saipan farm site.
|mg/g Zinc|| 39.49
Results indicate that site-to-site variation of leaf litter decomposition speed is not substantial in the southern portion of the Mariana Islands from Guam to Saipan. The variation in weather patterns is minimal, as most rainfall and cloud cover is controlled by weather patterns that are brought in from the open ocean by trade winds. The small size and relatively limited elevation of the Mariana Islands also exert minimal orographic influence on rainfall patterns. Variation in leaf litter traits exerts much more control over nutrient and carbon turnover than does variation in site traits in the Mariana Islands.