It is known that the compost plays an affective role in enhancing soil fertility,
consequently, plant growth and crops yield, so it is very important to the farmers to get compost has a
good quality and distinguished properties. Therefore this study was carried out to investigate the effect
of the amount of the oxygen (air) required to convert one Kg of lettuce, tomatoes, potatoes and turnip
plant straw into compost. It was found that there is a relationship between the amount of oxygen and
the weight of organic matter which refers to using the amount of O2 as an indicator to the good quality
of manufactured compost. In this study, carbon ratio and hydrogen ratio in straw of lettuce, tomato,
potato and turnip vegetables and the amount of oxygen (air) required to convert one kilogram of straw
into compost was measured. The most important results were that the greater the amount of oxygen
used in the fermentation of raw materials, the greater the amount of organic matter, consequently
increasing the quality of compost. The amount of oxygen used in the fermentation of raw materials
was high for the potato fodder (6.20 kg) and the amount of organic matter (813 g) while the amount of
oxygen required was less in the leaves of the Lettuce plant (4.69 kg) and organic matter (670 g).
Therefore, it is important to pay attention to the amount of oxygen required to obtain good compost by
knowing the amount of air that is needed to oxidize the organic waste, which is consists all mostly
from the hydrocarbon chain (carbon and hydrogen).