Effect of Length of Soil Sample Storage on Soil Microbiological and Bochemical Properties in Uyo, Nigeria (Published)
In all microbiological and biochemical investigations of soil processes require freshly collected soils from the field. But very often there is some delay between sample collection and experiments or analysis, which require the soil be stored for some period of time. These studies investigate effect of length of soil sample storage at 4oC on soil microbiological and biochemical properties. This experiment was laid out in a completely randomized design (CRD) in triplicates. The experiment was conducted at the Department of Soil Science and Land Resources, Management, University of Uyo, Nigeria, between July 2014 and July 2015. Soil sample was randomly collected from six different points at the old stadium road dumpsite Uyo. The samples were thoroughly mixed to obtain two composite samples. The soil samples were separated into three portions: Soil samples air-dried at room temperature (28o C) for physico-chemical analysis Samples used for microbiological and enzymatic activities the same day of collection to serve as day 0 or control. Soil samples stored in the refrigerator at 4oC for sequential analysis of microbiological and enzymatic activities on the 7, 14,21,28,35 and 42 days after storage. The results revealed significant (P=.05) reduction in bacterial load from 2.45± 0.5 cfu/g soil in Day o of the experiment or control to 1.2±0.06 cfu/g soil in Day 42 which is 48.51% decrease in 0-15cm depth. In 15-30cm depth, bacterial load decreased from 1.76±0.01 cfu/g soil in the control to 1.11± 0.02cfu/g soil, which is 36.97% decrease. Fungal load follows the same trend with significant (P=.05) decrease from 1.75±0.08 cfu/g soil in Day o to 1.042±0.01cfu/g soil in Day 42 of the experiment at (0 -15cm depth which is 40.57% reduction. And in 15 – 30cm depths, a significant (p = .05) decrease was similarly observed from 1.48±0.06 cfu/g soil in Day o to 0.95±0.05 cfu/g soil in Day 42 of the experiment, which is 35.31% reduction. The result also showed that some bacterial genera especially Bacillus which are gram positive persisted up to the end of the experiment. Some fungal genera especially Aspergillus persisted up to the end of the experiment. Enzymes activities similarly suffered significant (P =.05) reduction in this research. Cellulase decreased significantly (P=.05) which is 80% and 98.75% respectively for (0- 15 and 15 – 30cm depths). The same trend was also followed by dehydrogenase. This study showed that long storage of samples before microbiological or biochemical analysis should be discouraged if optimum result is to be achieved.