Carbon footprint and net carbon gain of major long-term cropping systems under no-tillage. (1st April 2022)

• Record Type: Journal Article
• Authors: Bansal, S.; Yin, X.; Schneider, L.; Sykes, V.; Jagadamma, S.; Lee, J.
• Is Part Of: Journal of environmental management. Volume 307(2022)
• Publication Date: 2022-04-01
• Subjects: Crop rotation -- Bio-cover -- Carbon input -- Carbon output -- Sustainability index; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.114505
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Due to increased contribution from agriculture sector to total greenhouse gas emissions, there is need to study the ability of no-tilled diverse cropping systems including crop sequences and bio-covers to mitigate C equivalent emissions. Thus, C-footprint was calculated for a long-term experiment at the University of Tennessee's Research and Education Center in Milan with six-crop sequences: continuous cotton ( Gossypium hirsutum L.), cotton-corn ( Zea mays L.), continuous corn, corn-soybean ( Glycine max L.), continuous soybean, and soybean-cotton interacted with four bio-covers: poultry litter, hairy vetch ( Vicia villosa ), winter wheat ( Triticum aestivum ), and fallow control with three replicates in a strip-plot design. During the experiment duration (2002–2017), field inputs (fertilizers, pesticides, and machinery used for planting, chemical applications, and harvesting) and outputs (crop yield, aboveground, and belowground residue) were assessed for each crop sequence/bio-cover combination to calculate total C equivalence of inputs and outputs, net C gain, C footprint per kg yield, sustainability index, and nitrous oxide emissions. For continuous corn, C-based input emissions were significantly higher by 0.28–0.62 Mg CO2 eq. ha −1 yr −1 than all other sequences, however, a greater net C gain (5.4 Mg C eq. ha −1 yr −1 ) was also observed due to increased crop yield, aboveground and belowground residues. Poultry litter application resulted in lower C-footprint (1.59–2.09 kg CO2 eq. kg −1 yield) than hairy vetch, wheat, and fallow under all crop sequences. Hairy vetch also lowered C-footprint per kg yield (∼2–14%) when compared with wheat under continuous systems of corn, soybean, and cotton, and cotton-corn rotation. Poultry litter application increased sustainability index (23–45) of all cropping sequences compared with other bio-covers. Hairy vetch improved sustainability index of corn including cropping sequences as compared with wheat and fallow. Inclusion of soybean and cotton with corn significantly decreased nitrous oxide emissions by 20–25%. The major factor contributing towards C-based input emissions was N fertilizer with 68% contribution to total emissions on average. It is concluded that application of poultry litter can reduce per yield C-footprint and enhance production system sustainability compared with hairy vetch, wheat, and fallow for monocultures or rotations of corn, soybean, cotton. Additionally, hairy vetch can outperform wheat in reducing the per yield C-footprint for continuous corn/soybean/cotton, and cotton-corn rotation. Especially for corn production systems, hairy vetch can enhance sustainability index compared with wheat and fallow. In order to increase per hectare net C gain, reduce per yield C-footprint and enhance sustainability index simultaneously, integration of continuous corn or corn-soybean/cotton rotation with bio-cover poultry litter or hairy vetch may perform better than the monocultures of soybean or cotton integrated with bio-cover wheat or fallow control in the Mid-south USA. Highlights: N fertilizer accounted for 68% of the total CO2 equivalent emissions. Poultry litter reduced C-footprint than bio-covers hairy vetch, wheat, and fallow. Corn when rotated with soybean/cotton reduced nitrous-oxide emissions by 20–25%. Continuous corn had highest net C gain compared with corn/soybean/cotton sequences. Continuous soybean/cotton or rotation had lowest C-equivalent emissions than corn.