Importance of biochar as a key amendment to convert rice paddy into carbon negative.

Biochar being made up of recalcitrant carbon (C) compounds is considered a negative emission technology (NET) due to its indirect removal of atmospheric carbon dioxide (CO). However, there is no clear report about how biochar remains a NET when organic amendment application in rice paddy results in a huge emission of greenhouse gases (GHG) particularly, methane (CH). To evaluate the net impact of biochar application on the net global warming potential (GWP) in rice paddy, no organic amendment (control), fresh manure, compost, and biochar treatments were selected during the whole investigation period.

Critical evaluation of biochar utilization effect on mitigating global warming in whole rice cropping boundary.

Biochar and compost were accepted as a stable organic amendment to increase soil C stock as well as to decrease greenhouse gas (GHG) emissions in rice paddy soils. However, in most studies, their effect on GHG flux was evaluated only within the cropping boundary without considering industrial processes. To compare the net effect of these organic amendment utilizations on global warming within the whole rice cropping system boundary from industrial process to cropping, fresh, compost, and biochar manures were applied at a rate of 12 Mg ha (dry weight) in a rice paddy, and total GHG fluxes were evaluated.

Biochar as soil amendment: Syngas recycling system is essential to create positive carbon credit.

Biochar utilization is accepted as the most cost-effective practice to mitigate global warming via increase in soil C stock. However, its utilization effect on greenhouse gas (GHG) fluxes was evaluated only within land application without considering industrial processes. To evaluate the net effect of biochar utilization on global warming within whole system boundary, swine manure-saw dust mixture was pyrolyzed under four different temperatures, and GHG fluxes were characterized under with/without syngas recycling systems.

Uncertainty of methane emissions coming from the physical volume of plant biomass inside the closed chamber was negligible during cropping period.

In rice paddy, the closed chamber method is broadly used to estimate methane (CH4) emission rate. Since rice plants can significantly affect CH4 production, oxidation and emission, rice plantation inside the chamber is standardized in IPCC guidelines. Methane emission rate is calculated using the increased concentration inside the headspace.

A new approach to suppress methane emissions from rice cropping systems using ethephon.

Rice is the main staple food for more than half of the world's population. Yet, rice cultivation is subjected to criticism because of its important role in methane (CH) emissions. Although several agronomic practices such as controlled irrigation and conservation tillage have been widely adopted to mitigate CH emissions from rice cultivation, the benefits gained by these practices are highly dependent on site-specific soil and climate conditions, and often offset by yield reduction.

Effect of plastic film mulching on maize productivity and nitrogen use efficiency under organic farming in South Korea.

Winter cover crop cultivation and its biomass recycling as green manure (GM) were accepted as an ideal nutrient management practice in temperate organic farming fields. Since its biomass growth was boosted with air temperature rising from late Spring to early Summer, this stage overlapped with cash crops' seeding or transplanting. Thus, organic farmers were suffering from low crop productivity, due to delayed mineralization of incorporated biomass.

Silicate Fertilizer Amendment Alters Fungal Communities and Accelerates Soil Organic Matter Decomposition.

Soil microorganisms play a crucial role in organic matter decomposition and nutrient cycling in cropping systems. Compared to bacteria, fungal community composition and the role of fungi in organic matter decomposition and nutrient cycling in agro-systems are, however, elusive. Silicon (Si) fertilization is essential to improve agronomic performance of rice.

Different response of plastic film mulching on greenhouse gas intensity (GHGI) between chemical and organic fertilization in maize upland soil.

Since plastic film mulching (PFM) can deplete soil organic carbon (SOC) stock but increase greenhouse gas (GHG) emissions, PFM utilization is still debating. To determine the influence of PFM on global warming, PFM and no-mulching treatments were installed under chemical and organic fertilizations. In organic fertilization, cover crop was cultivated during the fallow season, and its biomass was incorporated as green manure.

Source partitioning and emission factor of nitrous oxide during warm and cold cropping seasons from an upland soil in South Korea.

Nitrous oxide (NO) is a major greenhouse gas (GHG) with high global warming potential. A majority of the NO flux comes from agricultural sources, mainly due to nitrogen (N) fertilization. The soil NO flux, induced by N fertilization, mainly originated from two different sources, i.