시비방법에 따른 감귤원 토양의 미생물 활성과 군집 다양성

Abstract

This study was carried out to evaluate the effect of the long-term different fertilization management on soil microbial activities such as microbial biomass, enzyme activities, phospholipid fatty acid(PLFA) content, bacterial community structures and diversity in volcanic ash citrus orchard soil. Experiment plots composed no-fertilization(Control), Compost, half of recommend application plus Compost(1/2NPK+Compost), recommend application(NPK), recommend application plus Compost(NPK+Compost), 3 times recommend application(3NPK).

Effect of the long-term(13 yrs) different fertilization management on microbial activities and community structures were summarized as follow: 1. Total PLFA content was significantly higher at NPK+Compost than 3NPK in March and May. 2. Distribution of microbial group by using PLFA profiles as biomarkers were high in September and that was in the order of bacteria>fungi>actinomycetes>mycorrhiza. However, Distribution of fungi and mycorrhiza were decreased significantly in control and 3NPK. Biological index such as G-/G+, F/B, cy19:0/18:1ω7c, and Unsat/sat ratios were increased with increasing temperature and those were high in September. 3. Principal component analysis of microbial community by PLFA pattern showed that PLFA profiles in 3NPK and Compost were different other treatments in March. 4. Microbial biomass C and N contents were high 1/2NPK(including NPK) +Compost compared with Compost only and chemical fertilizers(NPK, 3NPK). Thus, metabolic quotients(qCO2) was highest in 3NPK among the other treatments. 5. Soil enzyme activities showed seasonal changes and those that were different significantly between treatments in May. Dehydrogenase activity was two times higher in 1/2NPK+Compost than the Control. β-Glucosidase(NPK and 1/2NPK+Compost), urease(NPK+Compost), and acid phosphatase(Compost) activities were significantly higher than those of 3NPK and Control treatment. 6. Composition change in microbial community structures, microbial biomass, and enzyme activities affected by fertilization effect and environmental factors such as soil temperature and moisture. 7. In conclusion, Microbial activities were low in 3NPK and the Control compared with NPK(1/2NPK)+Com., which showed difference in community structures.

Effect of the long-term(16 yrs) different fertilization management on bacterial group changes, species richness estimators, diversity indices, and community structures in volcanic ash citrus orchard soil were summarized as follow: 1. Rarefaction curves at the 97% sequence similarity showed that distribution range of a clone and the OTUs were high in 1/2NPK+Compost, which were at 5,769-7,982 and 2,181-4,112 in May, respectively. 2. Species richness estimators of Ace, Chao1, and Shannon diversity indices showed higher in 1/2NPK+Compost than other treatments, which were 19,361, 6,428, 10,906, 7.8, respectively. 3. In phylum level, The most abundant bacterial group were Proteobacteria, Acidobacteria, Actinobacteria and those occupied at 58.0-82.9% among the soil-borne bacterial community in citrus orchard soil. 4. In genera level, The dominant bacteria group were Pseudolabrys, Bradyrhizobium, Arthrobacter, which were distributed range at 16.1-32.1%. Bacterial diversity showed seasonal changes and that were more diverse in genera than phylum level. 5. Soil pH showed a positive correlated with Ace, Chao1 richness estimators(p<0.05) and Shannon diversity indices (p<0.01). But exch. Alwas negatively correlated with those (p<0.05). 6. In conclusion, Bacterial community diversity affected by volcanic ash characteristics and pH changes in citrus orchard soil.

Effect of incubation temperature on nitrogen mineralization rate, PLFA content, and enzyme activities during incubation period in volcanic(VBS) and non volcanic ash soil(NVBS) treated with organic materials such as pellet(OFPE) and powder (OFPO)organic fertilizers, pig manure compost(PMC), and food waste compost(FWC) were summarized as follow: 1. Considering on soil pH and C/N ratio, Organic matter decomposition rate was more easily in NVBS than VBS. Nitrogen mineralization rate increased with increasing temperature and that was in the order of OFPO>FWC>OFPE>PMC. OFPO was most highest among the organic matter in both VBS and NVBS. 2. In 75 days, Total PLFA content was higher in NVBS than VBS. That was higher at 270 days in VBS than NVBS. 3. Distribution ratio of microbial group by PLFA profiles were different significantly due to soil characteristics, incubation temperature, and the type of organic matter. 4. Both G-/G+ and F/B ratios were decreased according to the increasing temperature gradually and those reduced more in NVBS than VBS. 5. Principal component analyis using PLFA profiles showed that microbial community structures were composed by soil type at 75 days, but by temperature at 270 days. 6. Urease and β-glucosidase activity were high in NVBS than VBS. Those were decreased gradually during the long-time incubation. Acid phosphatase activity increased according to the increasing temperature and that was higher in organic fertilizers than PMC and FWC. 7. Soil temperature was significantly correlated with acid phosphatase(r=0.728) in both soil. PLFA was significantly correlated with OM at r=0.634(p<0.001) in NVBS. 8. In conclusion, Soil microbial activities showed relative sensitivity and seasonal changes as affected by soil characteristics, temperature, and organic matter type and those were low in VBS.