Soil Enzyme Activities and Their Relationship to Total Soil Bacteria, Soil Microbial Biomass and Soil Chemical Characteristics of Organic and Conventional Farming

Soil properties such as physical, chemical, biological, microbiological and biochemical aspects affect on soil quality. Soil microbiological activities directly affect stability of ecosystems and soil fertility. The research aimed to determine soil microbial activities through soil enzyme activities and their relationship to total soil bacteria, soil microbial biomass, and soil chemical characteristics. The research was conducted at Laboratory of Soil Microbiology, Indonesian Soil Research Institute, Bogor from July 2015 to January 2016. Soil samples 0-10 cm depth were taken from organic and conventional farming of some commodities (tomato, carrot, maize, broccoli) from Bogor Regency, while those of rice were taken from Tasikmalaya Regency. Soil dehydrogenase, urease and cellulase activities were determined using some modified methods. The results showed that soil dehydrogenase and cellulase activities in organic farming were higher than those in conventional farming, whereas the soil urease activity in organic farming was lower than that in conventional farming. The total soil bacteria and soil microbial biomass were significantly and positively correlated with soil dehydrogenase, urease, and cellulose activities. Soil dehydrogenase, urease, and cellulose activities were very significantly and positively correlated with all soil characteristics tested, i.e. soil organic C, total N, potential P and K, available P and K, CEC, and pH, except that soil urease activity was very significantly and negatively correlated with soil pH. The results of this research indicated that organic farming is recommended for maintaining soil fertility and plant productivity; however, small use of urea fertilizer is still needed in the farming

Effects of Warming and Nitrogen Addition on Soil Enzyme Activities

Due to the intensification of human activities, global warming and increased atmospheric nitrogen deposition have become important driving factors of global change. In order to understand the effects of long-term warming and nitrogen application on soil physical and chemical properties and enzyme activities, the effects of warming and nitrogen application on grassland soil enzyme activities were measured. The aim was to reveal the response of enzyme activity in an Inner Mongolian desert steppe to long-term warming and nitrogen addition. The results were as follows. In 2018, nitrogen fertilization significantly increased soil dehydrogenase activity, and soil depth significantly affected soil urease, β-Glucosidase, phosphatase and dehydrogenase activities. In 2019, the four soil enzyme activities only showed significant differences at different soil depths, while the effects of warming, nitrogen addition and their interactions on soil enzyme activities were not significant. In general, the enzyme activities of desert grassland soil were not affected by warming, while nitrogen addition had a greater impact on the soil enzyme activities. However, large difference in soil moisture between the two years of the experiment was also a key factor leading to large fluctuations between the two years, which indicated that in the semi-arid desert grassland, the change of soil nutrient characteristics is also affected by water content

Activity of Exoenzymes in Treated Wastewater Irrigated Soils

The reuse of reclaimed wastewater for irrigation of agricultural fields greatly influences the activity of soil microorganisms through the input of organic compounds. Due to the production of exoenzymes by microorganisms for the decomposition of substrates it can be assumed that the irrigation with treated wastewater (TWW) has a strong influence on the soil enzyme pool. In this study the activity of ten exoenzymes, which catalyses processes in C, N and P nutrient cycles, were determined in 3 different soils in 0-10, 10-20, 20-30, 30-50, 50-70 and 70-100 cm soil depth. The soils were used for agriculture and irrigated with reclaimed wastewater reused after a secondary treatment step. Additionally a control after freshwater irrigation was studied. Due to the influence of TWW on the soil biology of these soils, also clear effects on soil exoenzymes in freshwater and TWW irrigated soils could be seen. According to Sinsabaugh et al. (2008) we calculated indices which describe the enzymatic resources for acquisition of organic P and organic N relative to C and therefore give insides into the functional convergence of extracellular enzyme activities in soils and the relative nutrient demand. The distribution pattern of these functional enzyme activities varied between freshwater and TWW irrigated soils and shows therefore a strong influence of the TWW irrigation on the activity of exoenzymes. (Sinsabaugh et al. (2008): Stoichiometry of soil enzyme activity at global scale. Ecology Letters 11 (11), 1252-1264.

Enzyme Activity in Terrestrial Soil in Relation to Exploration of the Martian Surface Third Semiannual Progress Report, 1 Jul. - 31 Dec. 1965

Qualitative and quantitative test for enzyme activities in terrestrial soil adapted to Mars probe telemetry procedure

Enzyme activity in terrestrial soil in relation to exploration of the Martian surface Semiannual progress report, 1 Jul. - 31 Dec. 1967

Enzyme behavior in nonclassical systems, surface pH estimation in soils, and enzymatic activities in stored and geologically preserved soil

Do enzyme activities during decomposition follow predicted patterns? A test of the conceptual model of litter decay.

Surprisingly, there remains a paucity of research examining specific interactions between the relationship between microbial community behavior and plant litter chemistry during decomposition. A more mechanistic understanding of the relationship between these drivers will ultimately help determine the trajectory of litter decomposition and the conditions in which soils serve as either a source or sink for atmospheric C. In order to examine these relationships, a laboratory incubation was established using _Acer saccharum_ litter and a sandy soil (< 1.5% organic matter). Extracellular enzyme activities ([BETA]-glucosidase, N-acetyl glucosaminidase, leucine-amino peptidase, acid phosphatase, phenol oxidase, and peroxidase) were monitored on a consistent basis along with instantaneous rates of carbon dioxide production, microbial biomass (carbon and nitrogen) and phospholipid fatty acid biomarkers (PLFA), and nitrogen and phosphorus availability. Microbial biomass and microbial respiration peaked within the first week of the experiment. This was likely due to the high availability of water soluble substrates early in decay that can be obtained without the production of extracellular enzymes. [BETA]-glucosidase (BG), N-acetyl glucosaminadase (NAG), and acid phosphatase activities increased quickly following the first week and peaked within the first month (at approximately 15% mass loss). Leucine amino peptidase was not detected during the incubation, which may be due to its strong positive correlation with soil pH, while other hydrolytic enzymes tend to track concentrations of soil organic matter. Phenol oxidase and peroxidase activities were not measurable until the second month of the experiment (> 25% mass loss), likely following the depletion of more labile substrates. A second increase in BG activity was observed between Days 83-111, which may be due to an increase in the availability of cellulose that was previously shielded by lignin, since oxidative enzyme activity was first detected on Day 68. We also observed some shifts in microbial PLFAs along with enzyme activities during decomposition. Prior to the increases in enzyme activity we observed a high proportion of PLFA 18:1[omega]7c, which is a bacterial biomarker. As enzyme activities increased, we observed a decrease in this biomarker and an increase in 18:2[omega]6,9c, a fungal biomarker that was correlated with BG and NAG activity. We did not observe any clear relationships between PLFAs and lignolytic enzyme activity, however. Overall, we observed a distinct functional shift in microbial substrate use that may be associated with either changes in composition of the microbial community or community shifts in enzyme production

Enzyme Activity Variability and Comparison in Soils under Medicinal versus Crop Plants of Anguo City, China

Long-term continuous cultivation of different plant species in a similar agroecosystem intensively may result in divergent variability in soil fertility, particularly soil biochemical properties. In this study, an investigation was conducted to clarify the variability of five soil enzyme activities (urease, protease, catalase, polyphenol oxidase and alkaline phosphatase) of croplands under medicinal plants (herbal fields) and food crops (crop fields) in Anguo city, a traditional cultivation base for Chinese medicinal plants in China. The results showed that five soil enzyme activities were similar between herbal and crop fields. However, soil urease and alkaline phosphatase activities of herbal and crop fields decreased significantly with soil depth (0-60 cm), while protease, catalase, polyphenol oxidase activities were similar in all soil layers for two kinds of fields. There were largely variation scenes at linear correlation analysis between soil physicochemical traits and enzymatic activities under medicinal plant versus crop fileds although extensively significant correlations were presented. In conclusion, soil enzyme activities were similar in two type of farmlands, and soil urease and alkaline phosphatase activities decreased with soil depth for both fields. Inconsistent linear correlations between soil physicochemical traits and enzymatic activities under medicinal plant versus crop fields were presented, so soil enzymatic activity variation was subjected to soil physicochemical traits dominated by agronomic managements designed for specific plant species

Dehydrogenase Activity in a Litter Manipulation Experiment in Temperate Forest Soil

Abstract Soil enzyme activities are “sensors” of soil organic matter (SOM) decomposition since they integrate information about microbial status and physico-chemical condition of soils. We measured dehydrogenase enzyme activity in a deciduous temperate oak forest in Hungary under litter manipulation treatments. The Síkfőkút Detritus Input and Removal Treatments (DIRT) Project includes treatments with doubling of leaf litter and woody debris inputs as well as removal of leaf litter and trenching to prevent root inputs. We hypothesized that increased detrital inputs increase labile carbon substrates to soils and would increase enzyme activities particularly that of dehydrogenase, which has been used as an indicator of soil microbial activity. We also hypothesized that enzyme activities would decrease with detritus removal plots and decrease labile carbon inputs to soil. After ten years of treatments, litter removal had a stronger effect on soil dehydrogenase activity than did litter additions. These results showed that in this forest ecosystem the changed litter production affected soil microbial activity: reduced litter production decreased the soil dehydrogenase activity; increased litter production had no significant effect on the enzyme activity.</jats:p

Soil Dehydrogenase Activity: a Comparison Between the Ttc and Int Method. a Review

Soil enzyme activities are very sensitive to both natural and anthropogenic disturbances and show a quick response to the induced change. Soil dehydrogenase enzyme are one of the main components of soil enzymatic activities participating in and assuring the correct sequence of all the biochemical routes in soil biogeochemical cycles. Dehydrogenase activity is measured by two methods using the TTC and INT substrate. Different biotic and abiotic factors such as incubation time and temperature, pre-incubation, soil aeration and moisture content have significant effect on dehydrogenase activity in soil. Dehydrogenase enzyme is often used as a measure of any disruption caused by pesticides, trace elements or management practices to the soil, as well as a direct measure of soil microbial activity. This review describes the role of intracellular enzyme-dehydrogenase in the soil environment, and the most common laboratory procedure used for measure dehydrogenase activity by two methods using the TCC and INT substrate