Alternative Management Systems of Beef Cattle Manure for Reducing Nitrogen Loadings: A Case-Study Approach

Livestock manure is one of the main sources of agricultural nonpoint source pollution and poses a great threat to the environment and human health. Sustainable management of manure via recycling is an effective means to tackle the problem. Based on field interviews in China, multiple case studies were employed to investigate alternative manure management systems. Four conclusions arose. First, compost-based systems, product-based systems, substrate-based systems, and biogas-based systems were identified as four main types of manure management systems, with each possessing its success factors and risk factors. The adoption of a system was driven by various factors. Second, market-oriented operation was the dominant operation mechanism of all the manure management systems. Third, compared to direct application of manure to croplands, all the four manure management systems could reduce nitrogen loadings from livestock farms and lower their environmental effects. Among the systems, biogas-based systems could reduce nitrogen loadings to the greatest extent, followed by product-based systems and substrate-based systems, and then by compost-based systems. Lastly, integrated management of manure with mixed recycling systems is imperative for reducing its environmental effects, which can benefit from the increasing role of third-party entities in manure recycling. Policy implications were also discussed.

Application of anoxic phase in SBR reactor to increase the efficiency of ammonia removal in Vietnamese municipal WWTPs

Process removal nutrients, especially nitrogen – ammonia in municipal wastewater treatment is a challenger of design and operate wastewater treatment plant. Nowadays in Vietnam, technology SBR has been wide applied in biological wastewater treatment but the concentration of nitrogen – ammonia in treated water cannot achieve the discharge standard. For the purpose to reach the Vietnamese Standard A, the modification of SBR has been added the anoxic phase into operated cycle to create the denitrification’s environment and enhance performance of ammonia – nitrogen removal in municipal wastewater treatment at present and in the near future. The results of experiment shows that, the efficiency of N – NH4 removal in reactors sustainable in range 75 – 80% with the nitrogen loadings rate from 0.07 – 0.25 kg N – NH4/kg sludge/d. However, in 3 hours of anoxic phase, the value of specific denitrification rate is 0.10 – 0.15 kg N – NO3/kg sludge/d with the organic loadings rate in range 0.3 – 1.0 kg BOD/kg sludge/d and can reach the maximum is 0.2 kg N – NO3/kg sludge/d when the organic loadings rate increase to 2.0 kg BOD/kg sludge/d.

Integrated approach for managing fertilizer intensification linked environmental issues

Purpose The purpose of this paper is to understand the critical factors associated with growing fertilizer usage culminating in contamination of soil/water in agriculturally intensive regions of Uttar Pradesh, India. The agriculture sector is seen as one of the major contributors in ensuring food security, however adoption of sustainable agriculture to protect water resources from contamination due to fertilizers and pesticides is becoming pressing to achieve long term environmental security. Design/methodology/approach A two staged study aimed at monitoring the soil quality status followed by stakeholder survey has been attempted. Attitude-behavior framework based on the theory of reasoned action has been tried to explain the fertilizer use behavior in the study. The results are analyzed through Analysis of variance. Findings Soil monitoring data showed nitrate and total nitrogen loadings beyond the permissible limit in the identified regions. A questionnaire aimed at determining farmer’s attitude toward fertilizer usage showed a significant influence of factors like net farm income, overall farm yield, extension services, farmer characteristics on one hand and risks associated with changing farming practices, costs of substitutes available, market-based instruments like subsidies and loans on the other. Divergent responses were observed with respect to farmer’s perceived risks from adopting to organic substitutes, linkages of fertilizer application with environmental degradation and the level of adoption of sustainable agricultural practices. Research limitations/implications The study can be scaled up to study the inter-regional differences by benchmarking regional responses. It would be interesting to extend the work to find solutions from the farmers as alternative fertility management strategies. The items used in questionnaire are self-made; hence there is still a possibility of enhancing the robustness of scale by applying advanced statistical techniques. Practical implications Results of the study indicate excessive nitrogen loadings in farm soils which is an indicator of potential future nitrate contaminated zones or vulnerable zones emerging in agricultural intensive regions. Findings reinforce the role of education, knowledge transfer and awareness for long-term agricultural sustainability. The paper highlights the urgency for reorientation of the support system by the government and policymakers. Originality/value The paper attempts to understand the linkage between the agricultural productivity and the environmental implications followed by the reasons culminating in the agri-environmental imbalance. On-site monitoring study followed by assessment of reasons culminating in this scenario has not been attempted earlier and this paper contributes to understanding at dual level. This paper emphasizes on the insights of stakeholder which is instrumental in ensuring agricultural sustainability or otherwise. It takes the position that the farmer’s farm management behavior is strongly influenced by factors like food security and income, keeping environmental quality at second place. It also identifies the barriers for organic farming and other alternative systems as well as explores the economic, social, and philosophical aspects of sustainable agriculture.

Restoration and Purification of Dissolved Organic Nitrogen by Bacteria and Phytoremediation in Shallow Eutrophic Lakes Sediments

Endogenous organic nitrogen loadings in lake sediments have increased with human activity in recent decades. A 6-month field study from two disparate shallow eutrophic lakes could partly reveal these issues by analysing seasonal variations of biodegradation and phytoremediation in the sediment. This paper describes the relationship between oxidation reduction potential, temperature, microbial activity and phytoremediation in nitrogen cycling by calculation degradative index of dissolved organic nitrogen and amino acid decomposition. The index was being positive in winter and negative in summer while closely positive correlated with biodegradation. Our analysis revealed that rather than anoxic condition, biomass is the primary factor to dissolved organic nitrogen distribution and decomposition. Some major amino acids statistics also confirm the above view. The comparisons of organic nitrogen and amino acid in abundance and seasons in situ provides that demonstrated plants cue important for nitrogen removal by their roots adsorption and immobilization. In conclusion, enhanced microbial activity and phytoremediation with the seasons will reduce the endogenous nitrogen loadings by the coupled mineralization and diagenetic process.

Groundwater nitrate concentration evolution under climate change and agricultural adaptation scenarios: Prince Edward Island, Canada

Nitrate (N-NO3) concentration in groundwater, the sole source of potable water in Prince Edward Island (PEI, Canada), currently exceeds the 10 mg L−1 (N-NO3) health threshold for drinking water in 6 % of domestic wells. Increasing climatic and socio-economic pressures on PEI agriculture may further deteriorate groundwater quality. This study assesses how groundwater nitrate concentration could evolve due to the forecasted climate change and its related potential changes in agricultural practices. For this purpose, a tridimensional numerical groundwater flow and mass transport model was developed for the aquifer system of the entire Island (5660 km2). A number of different groundwater flow and mass transport simulations were made to evaluate the potential impact of the projected climate change and agricultural adaptation. According to the simulations for year 2050, N-NO3 concentration would increase due to two main causes: (1) the progressive attainment of steady-state conditions related to present-day nitrogen loadings, and (2) the increase in nitrogen loadings due to changes in agricultural practices provoked by future climatic conditions. The combined effects of equilibration with loadings, climate and agricultural adaptation would lead to a 25 to 32 % increase in N-NO3 concentration over the Island aquifer system. The change in groundwater recharge regime induced by climate change (with current agricultural practices) would only contribute 0 to 6 % of that increase for the various climate scenarios. Moreover, simulated trends in groundwater N-NO3 concentration suggest that an increased number of domestic wells (more than doubling) would exceed the nitrate drinking water criteria. This study underlines the need to develop and apply better agricultural management practices to ensure sustainability of long-term groundwater resources. The simulations also show that observable benefits from positive changes in agricultural practices would be delayed in time due to the slow dynamics of nitrate transport within the aquifer system.