TOFG-all

Soil Biology & Ecology

Unit 2.3 | Part 2 – 101
Instructor’s Demonstration 1 Outline

Demonstration 1: Organic Matter Decomposition

in Litter Bags

for the instructor

OVERVIEW

To demonstrate the capacity of

different soils to decompose organic

matter, this exercise requires you

to bury cellulose disks (Whatman

filter paper) in a variety of locations.

This should be done at least two

weeks prior to the class to allow

decomposition to proceed before the

disks are retrieved on the day of the

class. To accelerate decomposition,

filter paper disks can be dipped in

a bucket of water with some fish

emulsion added just before burial.

MATERIALS NEEDED

Ê UÊ 7…>̓>˜ÊwÌiÀÊ«>«iÀÊ`ˆÃVÃ

Ê UÊ *>Ã̈VʓiÅÊL>}Æ

Ê UÊ >}ÃÊ̜ʓ>ÀŽÊLÕÀˆ>ÊÈÌiÃ

Ê UÊ >ÌÊŜÛi

Ê UÊ ˆÌÌiÀÊ    >}Ê>Ì>Ê-…iiÌÊ­ÃiiÊ
««i˜`ˆÝÊÓ®

Ê UÊ *i˜VˆÃÊ

†Ê œÀÊ«>Ã̈VʓiÅÊL>}Ã]ÊޜÕʓ>ÞÊÕÃiÊ«œ˜`Ê>˜`Ê«œœÊ˜iÌ̈˜}Ê

obtained from a local feed and seed supply. It is a 3/8-inch

polypropylene mesh. Cut the mesh into 6-inch x 12-inch

pieces, fold in half, then fold the edges over and staple

the edges shut. Other sources are the mesh bags that

bulbs are sold in, garlic or onion bags, or the mesh bags

that imported rice noodles are packed in. The smaller the

“iÅÊÈâi]Ê̅iÊÓ>iÀÊ̅iʜÀ}>˜ˆÃ“ÃÊ̅>ÌÊ܈ÊLiÊiÝVÕ`i`Ê

from the bag. This feature can be exploited by comparing

decomposition rates of organic matter buried in bags of

`ˆvviÀi˜ÌʓiÅÊÈâiðÊ"À}>˜ˆVʓ>ÌÌiÀʈ˜ÊL>}ÃÊ܈̅ÊÛiÀÞÊw˜iÊ

mesh will be decomposed primarily by microflora and

microfauna. Organic matter in larger mesh bags will also

be decomposed by larger fauna.

PREPARATION

Ê £°Ê*>ViʏˆÌÌiÀÊL>}Ãʈ˜Ê܈Ê>Ìʏi>ÃÌÊÌܜÊÜiiŽÃÊ«ÀˆœÀÊ̜ÊV>ÃðÊ

*>ViÊ̅i“ÊÛiÀ̈V>Þʈ˜Ê܈Ê>˜`Ê>Ê>ÌÊ̅iÊÃ>“iÊ`i«Ì…°Ê

œÀÊ>Ê£äÊV“Ê`ˆÃV]ÊäÊ̜ʣäÊV“ʈÃÊ>ÊVœ˜Ûi˜ˆi˜ÌÊ`i«Ì…°Ê

Ê Ó°Ê>}Êi>V…ÊÈÌi]Ê>˜`ʓ>ŽiÊ>ʘœÌiʜvÊ̅iÊLÕÀˆ>ÊœV>̈œ˜Ã°Ê

A minimum of 3 bags should be placed in each

…>LˆÌ>Ì°Ê*œÃÈLiʅ>LˆÌ>ÌÃʈ˜VÕ`iÊÀ>ˆÃi`Ê}>À`i˜ÊLi`Ã]Ê

VՏ̈Û>Ìi`Êwi`Ã]Êv>œÜÊwi`Ã]ʜÀV…>À`Ã]ÊVœ“«œÃÌÊ«ˆiÃ]Ê

vermicompost bins, weedy borders, and on the soil

ÃÕÀv>ViÊ­˜œÌÊLÕÀˆi`®°