Question

Your friend John is having trouble with his compost bin. The material in his compost pile doesn’t seem to be decomposing well. You take a sample of the pile and check for the presence of microorganisms under the microscope. You see that there are indeed microorganisms; however, they don’t appear to be growing very fast. John says that he regularly mixes his compost pile to expose it to oxygen but has noticed the pile feels cold. What is the most likely explanation for this problem?(1 point)

The compost pile was sufficiently moist.

The compost pile contained incorrect amounts of "greens" and "browns".

The compost pile was placed in the sunshine.

The compost pile contained aerobic bacteria.

Answer 1

The compost pile contained incorrect amounts of "greens" and "browns".

Explanation: A cold pile with microbes present usually means microbial activity is limited by C:N imbalance (too much carbon/browns or too little nitrogen/greens). Without enough N, microbes grow slowly and the pile won’t heat up even if moist and aerated.