重度盐渍化湿地土壤酶活性对生物炭添加及浅翻处理的响应

The effects of biochar adding and ploughing on heavily salinized soil were studied in the coastal wetland of the Yellow River Delta.The changes of soil physio-chemical parameters and soil enzyme activities were analyzed under different treatments,and the improvement effects of ploughing and biochar addition on severely salinized soil were discussed.Compared with the control group,the ploughing treatment increased the soil surface conductivity,but did not significantly change the soil bulk density,water content and total carbon content.However,the high amount of biochar adding treatment significantly reduced the soil bulk density,and increased total carbon and organic matter content.The activity of sucrase did not significantly changed by ploughing treatment,but after adding the medium or high amount of biochar,the activity of sucrose increased significantly.In conclusion,biochar addition could increase soil enzymes in a short time,which could be helpful for soil improvement of heavily degraded saline wetland.</p

Effect of Biochar Addition and Ploughing on Soil Enzyme Activities in Heavily Degraded Saline Wetland

The effects of biochar adding and ploughing on heavily salinized soil were studied in the coastal wetland of the Yellow River Delta. The changes of soil physio-chemical parameters and soil enzyme activities were analyzed under different treatments, and the improvement effects of ploughing and biochar addition on severely salinized soil were discussed. Compared with the control group, the ploughing treatment increased the soil surface conductivity, but did not significantly change the soil bulk density, water content and total carbon content. However, the high amount of biochar adding treatment significantly reduced the soil bulk density, and increased total carbon and organic matter content. The activity of sucrase did not significantly changed by ploughing treatment, but after adding the medium or high amount of biochar, the activity of sucrose increased significantly. In conclusion, biochar addition could increase soil enzymes in a short time, which could be helpful for soil improvement of heavily degraded saline wetland

Study on the differences of root spatial distribution characteristics of Phragmites australis in two different water-salt habitats in the Yellow River Delta

In order to study the growth differences of Phragmites australis, especially the differences of root ecological characteristics, between the tidal and fresh water habitats of the Yellow River Delta, two typical habitats of P. australis in tidal and fresh water habitats were chosen, and the electrical conductivity (EC) and pH of different soil layers were measured; the height, density, biomass of stem, leaf, main and fibrous root and ion content in different soil layers of P. australis were also analyzed. The results showed that the EC of surface soil (0-10 cm) was higher than that of the lower soil in both habitats and the minimum EC was tested in 20-30 cm soil layer. However, with the increase of soil depth deeper than 20-30 cm, the EC value increased and the pH decreased. The mean density and height of P. australis were (20.805.93) stem·m~(-2) and (35.7016.01) cm in tidal area, (309.60 39.15) stem·m~(-2) and (91.48 13.09) cm in fresh water habitat, separately. In terms of biomass allocation, the proportion of the main root, fibrous root, stem and leaf of P. australis in tidal and fresh water habitats were 79.70%, 11.88%, 6.79%, 1.64% and 66.77%, 8.76%, 18.54%, 5.92%, respectively. The main and fibrous root biomass of P. australis in fresh water habitat was mainly concentrated in 0-30 cm and 0-10 cm(68.1838.99) g·m~(-2) soil layer, respectively. And the main root biomass of P. australis in tidal water area was mainly concentrated in 20-3 0cm (146.57109.94) g·m~(-2) soil layer. After analyzing the ion content of roots in two habitats, we found the average content of Na~+ and K~+ in the main root of P. australis from tidal water habitat were (6.381.56) mg·g~(-1) and (1.080.17) mg·g~(-1) respectively, and the distribution of Na~+ and Cl- had a significantly positive correction (P<0.01). The average contents of these two ions in the main root of P. australis in fresh water habitat were (2.820.56) mg·g~(-1) and (3.931.10) mg·g~(-1) respectively. The results show that P. australis can adjust the height, density and biomass allocation of different organs and the distribution of ions to adapt to the different salt-water environment, which is the typical adaptation mechanism of P. australis in high-salt areas

Stable isotope analysis of water use sources of Phragmatis australis in heterogeneous water-salt habitats in the Yellow River Delta

To clarify the effects of the historical diversion of Yellow River on the hydrological use sources of vegetation in the Yellow River estuary,we used stable isotope tracing techniques to monitor hydrogen and oxygen isotope abundances of rainwater,surface water,soil water in different soil layers,and Phragmatis australis in different water-salt habitats,including the intertidal Yellow River course (TC),the new area on the current banks of the Yellow River (NC),and the abandoned Yellow River course in 1996 (OC) during the growing season.We analyzed water sources of P.australis in different habitats using the Bayesian mixed model.The results showed that there were significant differences in soil salinity and water potential among the three habitats.The value of salinity followed an order of TC>OC>NC.There were significant differences in salinity between the surface soil (0-10 cm) and the sub-surface soil in the OC habitat,but no differences in salinity among different soil layers in other two habitats.Water potential was greater in the NC than the other two habitats.Water use strategy of P.australis varied with habitats in different seasons.During the wet season (July-September),P.australis in the TC mainly used groundwater (25%),surface tidal water (25%) and soil water at 0-20 cm layer (23%).P.australis in the NC mainly used groundwater (26%),Yellow River water (25%),and topsoil water (24%).P.australis in the OC mainly used surface soil water (50%),as well as groundwater (27%).Increased rainfall enhanced soil water and surface runoff,dilution of soil surface salts,and water table,facilitating the water uptake of P.australis.In the dry season (May-June),P.australis in the TC mainly used deep soil water (more than 50%).The use of groundwater(24%),Yellow River water (23%) and soil water by P.australis in the NC was relatively evenly distributed across all layers.P.australis in the OC mainly used water from the 20-40 cm soil layer (86%),which was related to water source type and soil water retention capacity.In summary,water use strategies of P.australis are different in the water-salt heterogeneous habitats formed by the historical diversion of the Yellow River,which is also the physiological and ecological mechanism underlying the adaptation of P.australis to diversified water-salt environments