Variation in Calcium Content of Ginger Germplasm Inoculated with Bio-Agent, Trichoderma viride against Root-Knot Nematode, Meloidogyne incognita

The study was aimed to control nematodes in ginger crop in a sustainable way through inoculation of bio-agent, Trichoderma viride. The outcome of our research revealed that Trichoderma viride alone (T2) was the most effective treatment among all. This bio-agent has lowered the root-knot nematode populations by suppressing the disease intensity and responsible for enhancement of plant growth, increases the availability of nutrients to host plant. Meloidogyne incognita alone (T1) infected rhizomes resulted in highest reduction of calcium content amounting 2.26 and 2.43 mg/100g dry weight whereas maximum content was recorded in Trichoderma viride alone (T2) inoculated rhizomes as 2.84 and 3.08 mg 100g-1 dry weight in suravi and suprabha over control (T7) respectively. Trichoderma viride inoculated 15 days prior to Meloidogyne incognita (TV→MI) was found to be most efficient one among all combined treatments. Susceptibility towards nematode induced more nutrient deposition in rhizomes of ginger crop due to poor translocation process through xylem.

Phosphorus supply affects long-term carbon accumulation in mid-latitude ombrotrophic peatlands

Ombrotrophic peatlands are a globally important carbon store and depend on atmospheric nutrient deposition to balance ecosystem productivity and microbial decomposition. Human activities have increased atmospheric nutrient fluxes, but the impacts of variability in phosphorus supply on carbon sequestration in ombrotrophic peatlands are unclear. Here, we synthesise phosphorus, nitrogen and carbon stoichiometric data in the surface and deeper layers of mid-latitude Sphagnum-dominated peatlands across Europe, North America and Chile. We find that long-term elevated phosphorus deposition and accumulation strongly correlate with increased organic matter decomposition and lower carbon accumulation in the catotelm. This contrasts with literature that finds short-term increases in phosphorus supply stimulates rapid carbon accumulation, suggesting phosphorus deposition imposes a threshold effect on net ecosystem productivity and carbon burial. We suggest phosphorus supply is an important, but overlooked, factor governing long-term carbon storage in ombrotrophic peatlands, raising the prospect that post-industrial phosphorus deposition may degrade this carbon sink.

Floods and Their Impact on the Environment

Resources like air and water are present in the Ecosystem for the benefit of biological life, but a slight disturbance in them results in catastrophic calamities; the flood is one of them. Floods are wrecking threats not only to the life of the individuals but also result in long-term destructions to the economy, environment, and the psychological state of the affected individuals. A slight disturbance in a geographical area's climatic conditions and natural cycles like heavy rainfall and extra precipitation result in floods. Other human activities like over urbanization, deforestation to make residential societies, poor drainage systems, poor number of dams and banks are also the reasons behind such drastic calamities. There are many types of floods, but urban floods are more destructive as they affect highly populated areas, and there are more chances of mortalities in such situations. Floods have broad impacts not only socially and economically but also on the environment. Floods affect the agricultural sector by causing over-saturation, infertility, and soil erosion, damaging the crop fields, especially the winter crops. Flood contaminates the groundwater and makes it impure and improper for drinking purposes. Floods contaminate groundwater with pathogenic microbes and result in water-borne diseases, which have detrimental effects on health. The freshwater's aquatic life is also affected by the disturbance of the natural hydrology of the water. According to some reports, Floods have some positive Impacts on aquatic life as it results in nutrient deposition and favorable habitat for most species. Floods also leave after-effects on the microinvertebrates like small insects, which are primary role players in the Ecosystem's food chain. So, the floods are a curse for some and a blessing for others.

Changing atmospheric acidity as a modulator of nutrient deposition and ocean biogeochemistry

Anthropogenic emissions to the atmosphere have increased the flux of nutrients, especially nitrogen, to the ocean, but they have also altered the acidity of aerosol, cloud water, and precipitation over much of the marine atmosphere. For nitrogen, acidity-driven changes in chemical speciation result in altered partitioning between the gas and particulate phases that subsequently affect long-range transport. Other important nutrients, notably iron and phosphorus, are affected, because their soluble fractions increase upon exposure to acidic environments during atmospheric transport. These changes affect the magnitude, distribution, and deposition mode of individual nutrients supplied to the ocean, the extent to which nutrient deposition interacts with the sea surface microlayer during its passage into bulk seawater, and the relative abundances of soluble nutrients in atmospheric deposition. Atmospheric acidity change therefore affects ecosystem composition, in addition to overall marine productivity, and these effects will continue to evolve with changing anthropogenic emissions in the future.

Soil erosion impacts on nutrient deposition in a typical karst watershed

<p>Soil erosion has a significant influence on nutrient redistribution and deposition. However, the effect of soil erosion on nutrient deposition remains unclear in karst areas such as southwest China, which represents an ecologically fragile zone experiencing severe soil erosion. The objective of this study was to investigate the characteristics of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) deposition in a karst watershed of southwest China over the past 60 years and evaluate the relationship between soil erosion and nutrient deposition. The peak-cluster depressions in southwest China are typical for the geomorphological type, which is an ideal place to determine the sediment chronology, and the estimation of sediment and nutrient deposition rates. Three soil profiles were excavated in a typical karst depression. The characteristics of <sup>137</sup>Cs, <sup>210</sup>Pb<sub>ex</sub>, particle size distribution, and nutrients at different soil depths were investigated to evaluate the effect of soil erosion on nutrient deposition. Results showed that there was a significant negative correlation between nutrient concentrations and clay content (<em>P</em><0.001). Generally, compared with<sup> 137</sup>Cs, <sup>210</sup>Pb<sub>ex</sub> had a higher correlation with SOC and TN. In an undisturbed sediment profile, Pb/Cs can reflect nutrient dynamics better than a single nuclide. The nutrient deposition rates increased before 1953, reached its maximum in 1954-1956, and then dropped rapidly from 1957 to 2015. The sediment deposition rates were negatively correlated with nutrient concentrations (<em>P</em><0.01), but had a positive influence on nutrient deposition rates (<em>P</em><0.01). This implies that the temporal variation in nutrient deposition rates over the past 60 years was dominated by soil erosion rather than nutrient concentrations. This study provides a new insight to explore the historical nutrient deposition rates in a peak-cluster karst depression, and may help effectively control soil erosion and sustainable development of agro-ecosystems.</p>