Effect of Composts Combined with Chemical N Fertilizer on Nitrogen Uptake by Italian Ryegrass and N Transformation in Soil

Combining compost with sufficient chemical N fertilizer (CF) in agricultural lands is a popular practice to reduce the amount of inorganic nitrogen and accumulation of non-nutrient constituents in soils. A pot culture experiment was conducted to study the effects of 130 mg N of either solids waste compost (Scomp) or biosolids waste compost (Bcomp) complemented with 130 mg (CF, 1N) and 260 mg·N·pot-1 (CF, 2N) as 15N labeled (NH4)2SO4 (13.172 atom %) on growth and N uptake by Italian ryegrass. A separate soil incubation without plants was set up by only blends of Scomp and CF. The results from pot culture experiment show that total plant biomass and N uptake from Bcomp were significantly higher than Scomp alone. Scomp combined with CF improved yield and N uptake over those of Scomp alone. For Scomp + 1N treatment, plant nitrogen uptake derived from compost and CF accounted for 29% and 56% of added N from Scomp and CF, respectively. The incubation study indicates that 16.08 - 29.62 mg·N·kg-1·soil·day-1 from inorganic-N were immobilized into organic pools, while only 0.40 - 0.66 mg·N·kg-1·soil·day-1 from organic-N were mineralized to inorganic pools. Because a part of additional N could be tied up in organic form, combining solids compost with chemical N fertilizer therefore need to consider the effective use of compost-N.

Develop an Air Emission Inventory for Potential Point Sources in Northern Key Economic Zone and Simulate Its Impacts on Air Quality in Hanoi City,Vietnam

The Northern Key Economic region of Vietnam is a dynamic economic center that is an important economic locomotive of the North and the whole of Vietnam.In this area,large industrial parks are concentrated,attracting many large FDI projects.Key industries:cement production,cars-motorcycles,electronics,...Economic development entails environmental problems.The industrial sector has been identified as the number one driving force driving the growth of Hanoi city and neighboring provinces.Therefore,industrial development is one of the main causes of environmental pollution.In addition,the growth rate of industry in neighboring provinces significantly affects the air quality in Hanoi city.Some factories in Vinh Phuc,Hung Yen,Bac Ninh and Hai Duong provinces have large sources of gas emissions,potentially affecting air quality around Hanoi city.Monitoring results show that air pollution in Hanoi city is mainly caused by dust pollution,especially PM2.5 superfine dust.This is a very harmful dust to health;it is necessary to determine the cause and control solution.Therefore,the objectives of this study are:(1)inventory of potential emissions sources for industrial activities in the northern key economic region around Hanoi;(2)Simulate air spread by AERMOD model to get an overall picture of the industrial impact of surrounding provinces in Hanoi city;(3)Propose solutions to manage air quality for the city in the coming time.Simulation results for pollutants with the highest concentration of NOx for 1 hour,24 hours and the average of the year is 7.94;1.02;0.222(μg/m3);of CO for 1 hour and 8 hours are 27.616;8.89(μg/m3);of SO2 for 1 hour,24 hours and the average of the year is 4.005;0.288;0.038(μg/m3);of PM2.5 for 1 hour,24 hours and the average of the year is 0.32;0.023;0.003(μg/m3);of PM10 in 1 hour,24 hours and year average are 1.03;0.074;0.098(μg/m3).