Soil enzyme activities are the direct expression of the soil community to metabolic requirements and available nutrients. While the diversity of soil organisms is important, the capacity of soil microbial communities to maintain functional diversity of those critical soil processes through disturbance, stress or succession could ultimately be more important to ecosystem productivity and stabili...

SUMMARY The impact of a Pseudomonas fluorescens strain, genetically modified for kanamycin resistance and lactose utilisation (the GMM), could be enhanced by soil amendment with lactose and kanamycin. Lactose addition decreased the shoot to root ratio of pea, and both soil amendments increased the populations of total culturable bacteria and the inoculated GMM. Only kanamycin perturbed the bact...

In order to discover the advantages and disadvantages of different fertilization regimes and identify the best management practice of fertilization in greenhouse fields, soil enzyme activities involved in carbon (C) transformations, soil chemical characteristics, and crop yields were monitored after long-term (20-year) fertilization regimes, including no fertilizer (CK), 300 kg N ha-1 and 600 k...

In most ecosystems, the degradation of complex organic material depends on extracellular enzymes produced by microbes. These enzymes can exist in bound or free form within the soil, but the dynamics of these different enzyme pools remain uncertain. To address this uncertainty, I determined rates of enzyme turnover in a volcanic soil with and without added enzymes. I also tested whether or not s...

While multiple experiments have demonstrated that trees exposed to elevated CO₂ can stimulate microbes to release nutrients from soil organic matter, the importance of root- versus mycorrhizal-induced changes in soil processes are presently unknown. We analyzed the contribution of roots and mycorrhizal activities to carbon (C) and nitrogen (N) turnover in a loblolly pine (Pinus taeda) forest ex...

Variability in the activity and composition of soil microbial communities may have important implications for the suite of microbially-derived ecosystem functions upon which agricultural systems rely, particularly organic agriculture. An on-farm approach was used to investigate microbial communities and soil carbon (C) and nitrogen (N) availability on 13 organically-managed fields growing Roma-...

Understanding the effects of external organic and inorganic components on soil fertility and quality is essential for improving low-yielding soils. We conducted a field study over two consecutive rice growing seasons to investigate the effect of applying chemical fertilizer (NPK), NPK plus green manure (NPKG), NPK plus pig manure (NPKM), and NPK plus straw (NPKS) on the soil nutrient status, en...

The present study explored the joint effects of Cu and Se pollution mechanisms on soil enzymes to provide references for the phytoremediation of contaminated areas and agricultural environmental protection. Pot experiments and laboratory analyses were carried out to study the individual and combined influences of Cu and Se on soil enzyme activities. The activities of four soil enzymes (urease, ...

The present investigation was executed with an objective to study the effects of Co stress in Arachis hypogaea L. with special emphasis on antioxidant enzymes activities which are the defense mechanism to any type of abiotic stress. In this we have analysed the effect of cobalt (Co) stress on antioxidant enzyme activities (catalase, peroxidase and polyphenol oxidase) of Arachis hypogaea L. were...

Although elevation of CO2 has been reported to impact soil microbial functions, little information is available on the spatial and temporal variation of this effect. The objective of this study was to determine the microbial response in a northern Colorado shortgrass steppe to a 5-year elevation of atmospheric CO2 as well as the reversibility of the microbial response during a period of several...