Lime application lowers the global warming potential of a double rice cropping system

et al. 2021

Carbon Balance Manage

Background Excessive application of chemical fertilizer has resulted in lower nitrogen uptake and utilization efficiency of crops, decreasing soil fertility, increasing greenhouse gas emissions, and worse environmental pollution. Organic material retention is regard as the key to solve these problems. The objective of this study is to conduct an assessment of carbon budget under Astragalus sinicus L. and rice straw retention combined with reduced mineral fertilizer based on the 2-year field experiment in a paddy field in the south of China. The experiment was randomized complete block design including four treatments with triplicates: control CK (winter follow, 120 kg ha−1 N fertilizer for each rice season) and three treatments with Astragalus sinicus L. and rice straw retention named RA, RB, and RC (reduced N fertilizer by 15%, 27.5%, and 40% in each rice season). Results Treatments RA, RB, and RC increased greenhouse gas emissions by 9.30–101.25%, among which CH4 accounted for more than 60%; Carbon input of crops from treatments RA, RB, and RC increased by 2.25–12.10% compared with control CK over the 2 years. Though treatments RA, RB, and RC enhanced CO2 emissions, treatment RB decreased carbon footprint and became carbon sink. Conclusions The results of this study reveal that treatment RB (Astragalus sinicus L. and rice straw retention with reduced N fertilizer by 27.5%) is better in reducing chemical fertilizer amount, increasing crop yield and carbon input, which is more conductive to sustainable development of agriculture.

Section: Resultssupporting

confidence: 94%

Comparison of carbon footprint and net ecosystem carbon budget under organic material retention combined with reduced mineral fertilizer

et al. 2021

Carbon Balance Manage

“…Compared with C footprint of control CK, treatments RA and RC increased by 60.32% and 34.92%, while treatment RB decreased by 17.46%, which maybe attributed to the less N fertilizer application amount, lower C output of CH 4 and N 2 O as well as higher yield of treatments RB (table 3). Our result was consistent with previous studies which reported soil CH 4 was dominate source of C footprint in paddy eld [ [38], [39]]. Compared with control CK, treatments RA, RB and RC enhanced CH 4 emissions mainly resulting from the following reasons: (1) The continuous ood irrigation provided a favorable anaerobic environment for the growth and reproduction of methanogens and methanotrophs (Fig.1) [ [40], [41], [42]]; (2) Mulching and retention of rice straw and Astragalus sinicus L. can maintain soil moisture, provide organic matter for soil and reduce soil redox potential, thus leading to the CH 4 emissions increase [ [43], [44]]; (3) Organic materials retention supplied methanogenic bacteria with adequate substrates [11,[45], [46]], while the decomposition of straw consumed oxygen, enhanced soil anaerobic environment and inhibited the activity of methane oxidizing bacteria, thus promoting CH 4 emissions [ [47]]; (4) The application of mineral fertilizer and the decomposition of organic materials accelerated the rice and its root growth, thus making the secretion and abscission of rice root increase and providing a substrate for related microorganisms, resulting in the rapid increase of CH 4 emissions[ [48]].…”

Section: Footprint Components Of All the Treatmentssupporting

confidence: 94%

Comparison of carbon footprint and net ecosystem carbon budget under organic materials retention combined with reduced mineral fertilizer

et al. 2021

Preprint

Background: Excessive application of chemical fertilizer has resulted in lower nitrogen uptake and utilization efficiency of crops, decreasing soil fertility, increasing greenhouse gas emissions, and worse environment pollution. Organic material retention is regard as the key to solve these problems. he objective of this study is to conduct an assessment of carbon budget under Astragalus sinicus L. and rice straw retention combined with reduced mineral fertilizer based on the two-year field experiment in a paddy field in the south of China. The experiment was randomized complete block design including four treatments with triplicates: control CK (winter follow, 120 kg ha-1 N fertilizer for each rice season) and three treatments with Astragalus sinicus L. and rice straw retention named RA, RB, and RC (reduced N fertilizer by 15%, 27.5%, and 40% in each rice season). Results: Treatments RA, RB, and RC increased greenhouse gases emissions by 9.30%~101.25%, among which CH4 accounted for more than 60%; Carbon input of crops from treatments RA, RB, and RC increased by 2.25%~12.10% compared with control CK over the two years. Though treatments RA, RB, and RC enhanced CO2 emissions, however, treatment RB decreased carbon footprint and became carbon sink.Conclusions: The results of this study reveal that treatment RB (Astragalus sinicus L. and rice straw retention with reduced N fertilizer by 27.5%) is better in reducing chemical fertilizer amount, increasing crop yield and carbon input, which is more conductive to sustainable development of agriculture.

Section: Footprint Components Of All the Treatmentssupporting

confidence: 94%

Comparison of carbon footprint and net ecosystem carbon budget under organic materials retention combined with reduced mineral fertilizer

et al. 2020

Preprint

Background: Excessive application of chemical fertilizer has resulted in lower nitrogen uptake and utilization of crops, decreasing soil fertility, increasing greenhouse gas emissions and worse environment pollution and organic fertilizer materials retention is regard as the key to solve these problems. Whether the retention of Astragalus sinicus L. (Chinese milk vetch) and rice straw would induce lower greenhouse gas emissions and higher carbon sink remains unclear. The objective of this study is to conduct an assessment of carbon budget under Astragalus sinicus L. and rice straw retention combined with reduced mineral fertilizer based on the two years field experiment in a paddy field in southern China. Four treatments were designed: control CK (winter follow, 120 kg ha-1 N fertilizer for each rice season) and three treatments with Astragalus sinicus L. and rice straw retention named RA, RB and RC (reduced N fertilizer 15%, 27.5% and 40% in turn during each rice season).Results: Treatments RA, RB and RC increased GHG emissions by 9.30%~101.25%, among which CH4 accounted for more than 60%; Carbon input of crops from Treatments RA, RB and RC increased by 2.25%~12.10% compared with control CK over the two years. Though treatments RA, RB and RC enhanced CO2 emission, however, treatment RB decreased carbon footprint and became C sink.Conclusions: The results of this study reveal that treatment RB is better in reducing chemical fertilizer amount, increasing crop yield and C balance, which is more conductive to sustainable development of agriculture.