Changes In Soil Enzyme Activities Research Articles

Landward changes of soil enzyme activities in a tidal flat wetland of the Yangtze River Estuary and correlations with physico-chemical factors

The landward changes of soil enzyme activities and physico-chemical properties of the surface sediment in Chongming Dongtan of the Yangtze River Estuary, were studied. Along the elevation gradient or succession series, the contents of total phosphorus ( TP), total nitrogen ( TN) and organic matter ( OM) in the sediment increased, but the average grain size ( AGS) of the sediment and the content of the dissolved inorganic phosphorus ( DIP) decreased. The activity of alkaline phosphatase increased gradually along the elevation gradient, and was positively correlated with the values of TP, TN and OM ( P<0.05), but negatively to AGS and DIP ( P<0.05). It was correlated with a mechanism of substrate inductivity and product inhibition. Catalase activity had the similar trend of gradual increase along the elevation gradient, enhancing the fertility of the soil and the oxidative process of OM in the sediment. Along the succession series, from the tidal flat to the bulrush ( Scirpus mariqueter) zone, and then to the reed ( Phragmites australis) zone, the activity of sucrase only changed insignificantly, but there was a higher activity in the bulrush zone than in other zones. The activity of proteinase decreased from the tidal flat to the reed zone, and the activity was negatively correlated with OM and TN ( P<0.05), but positively with DIP ( P<0.05). Through the succession zones a decrease in the number of diatoms resulted in a decline in the concentration of protein, which influenced the proteinase activity, suggesting that the proteinase in the sediment was produced by diatoms.

Changes of soil enzyme activities in different restoration ages of spruce forests on the eastern Qinghai-Tibet Plateau

Six soil enzymes (invertase, acid phosphatase, proteinase, catalase, peroxidase and polyphenoloxidase ) were chosen for investigation under different spruce forests with restoration ages of 4,10,16 years and an old-growth spruce forest over 400 years old in the eastern Qinghai-Tibet Plateau, China. Results showed that the activities of invertase, phosphatase, proteinase, catalase and peroxidase decreased in newly restored forests except for pholyphenoloxidase. With the development of forests after restoration, the activities of invertase, acid phosphadase, proteinase increased gradually. Our study also indicated that the soil enzyme activities were associated with surface soils and decreased with depths. This result suggested that in the earlier restoration stage the application of organic fertilizer may be more effective by surface addition to soils than deep addition.

Changes in soil enzyme activity, fertility, aggregation and C sequestration mediated by conservation tillage practices and water regime in a maize field

We examined the medium-term (3 year) effects of no-tillage, reduced tillage (subsoil-bedding and shred-bedding) and water regime on the soil profile distribution of organic matter and physical and microbiological soil quality indicators in a maize field under subtropical conditions. Soil carbon sequestration was evaluated as well. Residue on the soil surface was about 17–21-fold increased in the no-tillage plots over the mouldboard plough plots, with intermediate increases in the reduced tillage plots. In the surface 0–5 cm, organic matter decreased with increasing tillage and was increased by irrigation. The no-tilled soil had increased values of water-soluble C, dehydrogenase, urease and acid phosphatase activities, aggregate stability and glomalin compared to tilled soils, especially in the shallowest (0–5 cm) layer. The water regime had no effect on soil structural stability or total microbial activity.

Changes in soil enzyme activities following additions of cyanobacterial biomass and exopolysaccharide

The aim of this research was to establish changes in the overall activity of extracellular enzymes: β-glucosidase, phosphomonoesterase, arylsulphatase, protease and urease and the intracellular enzyme dehydrogenase produced by the addition of Tolypothrix tenuis and Microchaete tenera (Cyanobacteria) exopolysaccharide (EPS) and biomass to a silty clay loam soil. Both biomass and EPS of M. tenera significantly ( p<0.05) increased β-glucosidase activity by 0.1 and 29.3%, respectively. Both cyanobacteria species significantly ( p<0.05) increased urease activity by 15±1%. Cyanobacterial biomass and EPS from T. tenuis and M. tenera produced significant increases in protease (76–90%, 101–136%), phosphomonoesterase (19–27%, 13–22%), arylsulphatase (148–167%, 406–174%) and dehydrogenase activity (16–32%, 43–30%).

Changes of Soil Enzyme Activities By Simulated Acid and Nitrogen Deposition

Effects of acid and nitrogen depositions on soil microbial activities were studied in a laboratory-based experiment. Five treatments were added to forest soil for five weeks, and soil enzyme activities were determined along with chemical properties. There was little change in pH and nitrogen availability. Dehydrogenase, phosphatase and arylsulphatase activities were decreased by all the acidic treatments compared to the control, while urease activity was increased by the pH 4 treatment. at the same pH treatment, different nitric acid contents induced different urease activities. the results suggest that acid deposition would inhibit microbial activities and that more study is needed to elucidate the impact on nitrogen cycling in forests.