Effect of Fertilization on Soil Microorganisms in Kampong Cham Province, Cambodia

Abstract

Fertilizers are one of the most important nutrient inputs into soil for supplying nutrients that were absorbed by plants. Application of organic and inorganic fertilizers has given an effect to soil properties directly or indirectly. Recently, organic fertilizers application such as compost, cow manure or green manure were introduced to local farmers in Kampong Cham Province, Cambodia. However, improper agricultural practices incorporating with raw materials or immature compost have a direct impact on plant health and crop productivity with resulting in contamination of soils with pathogenic microbes. Therefore, the objective of this study was to investigate the survival of pathogenic microbes with organic and inorganic fertilization in Kampong Cham Province, Cambodia. Twenty samples of soils where collected from farmlands where organic and inorganic fertilizers were applied in Samraong and Baray Communes. Also, 5 samples of compost and cow manure were collected in the same areas. From these samples of soil, compost and cow manure, the biological properties such as pathogenic bacteria Escherichia coli and fungi were analyzed. The experiment results indicated that there was a certain contamination of E. coli in these samples of soil, compost and cow manure. Also, the degrees of contamination were divided into 4 categories as very low, low, medium and high, respectively. In addition, the results of pathogenic bacteria E. coli in samples of soil were summarized in hazard map. However, the correlation between microbes such as pathogenic bacteria E. coli or fungi and fertilization was not observed statistically, while organic and inorganic fertilizers has been applied to the soil. It was considered that the sources of E. coli are not only from organic fertilizer applied in this area, but also transported from upstream, as there are many range lands for breeding cows in the upstream of both Samraong and Baray Communes.