Nitrogen (N) in the agricultural production system influences many aspects of agroecosystems and several critical ecosystem services widely depend on the N availability in the soil. Cumulative changes in regional ecosystem services may lead to global environmental changes. Thus, the soil N status in agriculture is of critical importance to strategize its most efficient use. Nitrogen is also one of the most susceptible macronutrients to environmental loss, such as ammonia volatilization (NH3), nitrous oxide (N2O) emissions, nitrate leaching (NO3), etc. Any form of N losses from agricultural systems can be major limitations for crop production, soil sustainability, and environmental safeguard. There is a need to focus on mitigation strategies to minimize global N pollution and implement agricultural management practices that encourage regenerative and sustainable agriculture. In this review, we identified the avenues of N loss into the environment caused by current agronomic practices and discussed the potential practices that can be adapted to prevent this N loss in production agriculture. This review also explored the N status in agriculture during the COVID-19 pandemic and the existing knowledge gaps and questions that need to be addressed.

Nitrogen losses and potential mitigation strategies for a sustainable agroecosystem

Controlled release fertilizer: A review on developments, applications and potential in agriculture.

Abstract The use of nitrogen fertilizers in agriculture produces significant quantities of nitrogenous gases including ammonia, nitric oxide, and nitrous oxide. Through better farmland management practices, the emission of nitrogenous gases can be reduced while realizing clean water environment and climate-smart agriculture. In this article, we first provided an overview of the international movements on reducing nitrogenous gas emissions from farmlands. Then, we summarized the effect of agricultural management practices on nitrogen use efficiency for various crops, and evaluated their effect on nitrogenous gas emissions. The results indicated the importance of implementing site-specific sustainable management practices to enhance nitrogen use efficiency, and thus mitigate nitrogenous gas emissions. We also addressed the impact of agricultural activities on cropland nitrogen cycles, and highlighted the need to perform systematic trade-off evaluations with a well-defined scope to maximize environmental benefits and maintain ecosystem services. Lastly, we proposed three priority directions by moving toward a low-emission agriculture. 

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Addressing nitrogenous gases from croplands toward low-emission agriculture

Modern intensive agriculture worldwide is generating increasing environmental pressure, which prevents its sustainable development. A number of agricultural sustainability assessment approaches and methodological frameworks have been developed by research worldwide to assess the environmental costs and impacts of resources used in agricultural production. A joint use of Life Cycle Assessment (LCA, to assess a process' performance and environmental impacts) and Emergy Accounting (EMA, to estimate environmental support to resource generation and provision) is proposed in this study. The goal is not only to ascertain the environmental ‘cost’ of production of selected chemical resources used in agricultural processes, but also to develop a reliable calculation procedure capable to integrate the two approaches (LCA and EMA), while considering their different allocation algebra and space-time scales of application. Specifically, the UEVs of glyphosate and urea, which are respectively the most used herbicide and nitrogen fertilizer used in worldwide agriculture, are calculated, yielding values of 2.47E+13 sej/kg and 7.07E+12 sej/kg, respectively. In order to do so, UEVs of intermediate process chemicals such as ammonia, acetic anhydride, chlorine gas, formaldehyde, phosphorous chloride, and sodium hydroxide have also been calculated or updated, thus providing at the same time a procedure and a set of values potentially useful for future studies. The LCA impacts of agro-chemicals in China are compared to worldwide averages from the Ecoinvent database, and the UEVs for several chemicals are also compared to previous estimates from published emergy literature.

Environmental cost and impacts of chemicals used in agriculture: An integration of emergy and Life Cycle Assessment

Promoting coordinative development of phosphogypsum resources reuse through a novel integrated approach: A case study from China

Impact of fertilization schemes with different ratios of urea to controlled release nitrogen fertilizer on environmental sustainability, nitrogen use efficiency and economic benefit of rice production: A study case from Southwest China

Yanfeng Lyu

Papers

Impact of fertilization schemes with different ratios of urea to controlled release nitrogen fertilizer on environmental sustainability, nitrogen use efficiency and economic benefit of rice production: A study case from Southwest China

Environmental cost and impacts of chemicals used in agriculture: An integration of emergy and Life Cycle Assessment