Global warming potential and energy dynamics of conservation tillage practices for different rabi crops in the Indo-Gangetic Plains

Cleaner tillage and irrigation options for food-water-energy-carbon synergism in wheat-maize cropping systems

The conventional wheat-maize systems in the North China Plain are energy and water intensive with high carbon emissions. It is imperative to find cleaner production technologies for sustainable food-water-energy-carbon synergism. Here, a three-year field experiment was performed to explore the effects of two tillage modes and four irrigation regimes during wheat season on crop yield, economic profile, water use efficiency, energy utilization, and carbon footprint in typical wheat-maize cropping systems in the North China Plain. Pre-sowing irrigation resulted in the lowest crop yield and benefit profile. Pre-sowing + anthesis irrigation decreased economic benefit and water use efficiency with higher carbon footprint. Pre-sowing + jointing + anthesis irrigation led to the greatest energy consumption and greenhouse gas emissions. However, pre-sowing + jointing irrigation increased yield by 2.3-8.7%, economic benefit by 4.0-11.1%, water use efficiency by 7.4-10.9%, and net energy by 6.5-12.0% but reduced carbon footprint by 9.8-14.3% compared to pre-sowing + anthesis irrigation and pre-sowing + jointing + anthesis irrigation. The corresponding metrics in rotary tillage improved by 9.6%, 13.9%, 7.0%, and 14.2%, respectively, relative to subsoiling, whereas carbon footprint decreased by 12.4-17.2%. Besides, rotary tillage coupled with additional jointing irrigation obtained the highest value based on a Z-score method, which was recommended as a cleaner management practice to improve benefit return and water use efficiency with lower energy consumption and carbon footprint. This work provides valuable insights into food-water-energy-carbon nexus for ensuring food security and achieving environmental sustainability in the wheat-maize cropping systems.

Carbon trade-off and energy budgeting under conventional and conservation tillage in a rice-wheat double cropping system

Amid rising energy crises and greenhouse gas (GHG) emissions, designing energy efficient, GHG mitigation and profitable conservation farming strategies are pertinent for global food security. Therefore, we tested a hypothesis that no-till with residue retaining could improve energy productivity (EP) and energy use efficiency (EUE) while mitigating the carbon footprint (CF), water footprint (WF) and GHG emissions in rice-wheat double cropping system. We studied two tillage viz., conventional and conservation, with/without residue retaining, resulting as CT0 (puddled-transplanted rice, conventional wheat -residue), CTR (puddled-transplanted rice, conventional wheat + residue), NT0 (direct seeded rice, zero-till wheat -residue), and NTR (direct seeded rice, zero-till wheat + residue). The overall results showed that the NTR/NT0 had 34% less energy consumption and 1.2-time higher EP as compared to CTR/CT0. In addition, NTR increased 19.8% EUE than that of CT0. The grain yield ranged from 8.7 to 9.3 and 7.8-8.5 Mg ha-1 under CT and NT system, respectively. In NTR, CF and WF were 56.6% and 17.9% lower than that of CT0, respectively. The net GHG emissions were the highest (7261.4 kg CO2 ha-1 yr-1) under CT0 and lowest (4580.9 kg CO2 ha-1 yr-1) under NTR. Notably, the carbon sequestration under NTR could mitigate half of the system's CO2-eq emissions. The study results suggest that NTR could be a viable option to offset carbon emissions and water footprint by promoting soil organic carbon sequestration, and enhancing energy productivity and energy use efficiency in the South Asian Indo-Gangetic Plains.

Anaerobic digestion as a sustainable technology for efficiently utilizing biomass in the context of carbon neutrality and circular economy

Carbon emissions and associated global warming have become a threat to the world, the major contributor being the extensive use of fossil fuels and uncontrolled generation of solid wastes. Energy generation from renewable energy sources is considered an alternative to achieving carbon neutrality. Anaerobic digestion (AD) is a sustainable technology that has been endorsed as a low-carbon technology complimenting both waste management and renewable energy sectors. The AD technology recovers the volatile matter from waste biomass as much as possible to produce biogas, thus reducing carbon emission as compared to open dumping or burning. However, there is a need of compilation of information on how each subsystem in AD contributes to the overall carbon neutrality of the entire system and chances of achieving a circular economy along with it. Therefore, this article aims to clarify the associated internal and external factors that determine the low carbon characteristic of anaerobic digestion technology. From this review, the potential of AD system for energy-atmosphere-agriculture nexus has been explored. Carbon emission mapping of the potential entities involved in AD were identified and perspective to life cycle assessment and future research direction has been pointed out. Climate change impact and acidification potential are the two entities that can influence the overall environmental sustainability of an AD system. It was recognized that each stage of AD system starting from substrate supply chain, biogas production, upgradation, utilization, and digestate application had a remarkable effect on the overall carbon emission potential based on its design, operation, and maintenance. Selection of suitable substrates and co-digesting them together for improved biogas production rate with high methane content and proper digestate post-processing and storage can vastly reduce the carbon emission potential of the AD technology. Further, a case scenario of India was assessed considering the utilization of major surplus biomass available through AD. Re-routing the three major substrates such as agricultural crop residues, animal wastes and organic fraction of municipal solid wastes through AD can reduce at least 3.5-3.8 kg CO2-eq per capita of annual carbon emission load in India. Furthermore, the pathways in which the policy and legislations over establishment of AD technology and how to explore linkages between achieving circular economy and low carbon economy for Indian scenario has been highlighted.

Threshold effects of green technology application on sustainable grain production: Evidence from China

Sustainable production is considered as an important approach to solve the dilemma of food insecurity. Green technologies have made contributions to improving food production and reducing environmental pollution. Studying the effects of green technologies on sustainable food production has great significance. The paper started with the influence mechanism of green technology application on the green total factor productivity of grain (GTFPG). With the GTFPG, green technology efficiency change of grain (GECG) and green technical progress change of grain (GTCG) measured, threshold models were constructed to explore the nonlinear impacts of various green technologies on GTFPG and the influence paths. Results indicated that the differences of GTFPG among provinces in China were decreased mainly due to the changes of GTCG, while the regional differences of GECG remained small. The impacts of green technologies had threshold effects that depended on the ecological effects of green technologies in different application stages, and were significantly different in the major and non-major grain producing areas. Meanwhile, significant differences existed in the influence paths of green technologies. In the major grain producing areas, green technologies were more likely to improve GTFPG through the GTCG path; while in the non-major grain producing areas, the GECG path and the GTCG path were both important to improve GTFPG. The differences of green technologies' threshold effects and influence paths in the major and non-major grain producing areas were caused by regional technology preference, resource endowment and technology compatibility. This study emphasizes that the development of green technologies should fully consider the resource endowment and economic development of different regions, as well as the applicability and adoption rate of green technologies.

Future global concurrent droughts and their effects on maize yield

Droughts are one of the most devastating natural disasters. Droughts can co-exist in different forms (e.g. meteorological, hydrological, and agricultural) as concurrent droughts. Such concurrent droughts can have far reaching implications for crop yield and global food security. The present study aims to assess global concurrent drought traits and their effects on maize yield under climate change. The standardized indices of precipitation, runoff, and soil moisture incorporated as multivariate standardized drought index (MSDI) using copula functions are used to quantify the concurrent droughts. The ensemble data of several General Circulation Models (GCMs) considering the high emission scenario of Coupled Model Intercomparison Project phase 6 (CMIP6) are utilized. Applying run theory on a time series (1950-2100) of MSDI values, the duration, severity, areal coverage, and average areal intensity of concurrent droughts are computed. The temporal evolution of drought duration and severity are compared among historical (1950-2014), near future (2021-2060), and far future (2061-2100) timeframes. The results indicate that the most vulnerable regions in the late 21st century are Central America, the Mediterranean, Southern Africa, and the Amazon basin. The indices and spatial extent of the individual droughts are used as predictor variables to predict the country-level crop index of the top seven producers of maize. The historical dynamics between maize yield and different drought forms are projected using XGBoost (Extreme Gradient Boosting) algorithms. The future temporal changes in drought-crop yield dynamics are tracked using probabilities of various drought forms under yield-loss conditions. The conditional concurrent drought probabilities are as high as 84 %, 64 %, and 37 % in France, Mexico, and Brazil, revealing that concurrent drought affects the maize yield tremendously in the far future. This approach of applying statistical and soft-computing techniques could aid in drought mitigation under changing climatic conditions.

Energy, economic, and environmental assessment of coriander seed production using material flow cost accounting and life cycle assessment

The agricultural sector in the world is facing social expectations to improve energy efficiency and reduce environmental impacts, and at the same producing enough food and fiber for the growing world population. The purpose of the present research is to determine the economic, energy consumption, and environmental impacts in coriander seed production using material flow cost accounting approach along with life cycle assessment. The positive output and negative energy were 25,485 and 6742 MJ ha^-1, respectively. Energy efficiency, net energy gain, specific energy, and energy productivity indicators were calculated as 0.6, - 11,944 MJ ha^-1, 17.4 MJ kg^-1, and 0.06 kg MJ^-1, respectively. The average production cost was calculated as 588 $ ha^-1 whereas gross income was 1267 $ ha^-1. The value of negative products in coriander production was estimated as 239 $ ha^-1. Seed shedding at harvest and water loss due to inefficient irrigation system were found to be the major negative products (economic and energy) in the system that can enhance the system productivity upon improvement. The values of benefit costs ratio and economic productivity were 1.74 and 3 kg $^-1, respectively. The acidification potential (102.5 kg SO₂ eq ha^-1), global warming potential (897.3 kg CO₂ eq ha^-1), photochemical oxidation potential (0.13 kg C₂H₄ eq ha^-1), and eutrophication potential (40.3 kg PO₄^-3 eq ha^-1) indicators were evaluated. The hotspots in point of economic (labor and seed shedding), energy use (nitrogen fertilizer and machinery) and energy loss (seed shedding), and environment (diesel fuel consumption) were determined which can be used to optimize coriander production through decreasing the material and energy consumption in the field. The results showed that MFCA combined with LCA is a powerful tool in identifying hotspots in crop production systems and can be used in developing more sustainable systems as well as in developing sustainability models.

Effects of no-tillage on greenhouse gas emissions in maize fields in a semi-humid temperate climate region

Agricultural tillage practices have a significant impact on the generation and consumption of greenhouse gases (GHGs), the primary causes of global warming. Two tillage systems, conventional tillage (CT) and no-tillage (NT), were compared to evaluate their effects on GHG emissions in this study. Averaged from 2018 to 2020, significant decreases of CO₂ and N₂O emissions by 7.4% and 51.1% were observed in NT as compared to those of CT. NT was also found to inhibit the soil CH₄ uptake. In this study, soil was a source of CO₂ and N₂O but a sink for CH₄. The effect of soil temperature on the fluxes of CO₂ was more pronounced than that of soil moisture. However, soil temperature and soil moisture had a weak correlation with CH₄ and N₂O flux variations. As compared to CT, NT did not affect maize yields but significantly reduced global warming potential (GWP) by 8.07%. For yield-scaled GWP, no significant difference was observed in NT (9.63) and CT (10.71). Taken together, NT was an environment-friendly tillage practice to mitigate GHG emissions in the soil under the tested conditions.

Optimized tillage improves yield and energy efficiency while reducing carbon footprint in winter wheat-summer maize rotation systems

Conventional tillage consumes a lot of energy and produces a lot of greenhouse gases (GHGs), with quite limited contribution to food production. Optimizing tillage practices is an important measure to save energy, protect the environment and increase productivity. Based on this concept, a field experiment of two years duration (2019-2021) was performed to assess the impacts of various tillage techniques on grain yield, energy balance, carbon footprint (CF), and economic benefits of a winter wheat-summer maize rotation system in the Loess Plateau of China. The treatments included conventional tillage (CT), no-tillage (NT), ridge cultivation with no-tillage (RNT), and occasional tillage (OT). This study is the first to evaluates the economic and environmental benefits of OT and RNT in dry farming. The total annual average greenhouse gas emissions calculated through the life cycle assessment are 2869.2-3407.6 kg CO₂-eq·ha^-1, and the energy consumption and output are 28.2-37.7 GJ ha^-1 and 575.2-659.0 GJ ha^-1, respectively. The net ecosystem economic benefit is 26,206.6-34,787.4 CNY ha^-1. Compared with CT, annual crop yields of RNT, OT and NT have increased by 13.5%, 15.4% and 4.0%, respectively, energy utilization efficiency has increased by 47.8%, 31.2% and 35.3%, and carbon footprint has been reduced by 79.3%, 46.2% and 73.2%, economic efficiency has increased by 32.7%, 29.8% and 19.6%, respectively. Despite reducing energy consumption and carbon footprint, NT has no significant impact on annual crop yields. Optimizing tillage practices (RNT and OT) can achieve higher economic and environmental benefits. The Z-score shows that RNT in dryland agroecosystems can be used as a promising tillage practice to boost crop productivity, energy efficiency and economic efficiency, reduce CF, and achieve sustainability. RNT can be selected as the recommended agricultural management measure suitable for areas with similar climatic patterns in the Loess Plateau.

Exploring the Role of Contiguous Farmland Cultivation and Adoption of No-Tillage Technology in Improving Transferees’ Income Structure: Evidence from China

Seasonal alternations of extreme weather such as continuous drought and rare rainstorms significantly influence farmers’ adoption of agricultural technologies. Compared with traditional tillage, no-tillage technology has more advantages to cope with extreme weather. It is hypothesized that the cultivation of contiguous farmland is still minimal in spite of the transference of farmland on a large scale in China, which ultimately halts the adoption of no-tillage technology and influences the income of households. The current study used 793 farmland transferees’ data from Shaanxi, Gansu, and Ningxia provinces of China to explore this phenomenon empirically. By employing the endogenous switching regression model, the study revealed that contiguous farmland significantly promotes the adoption of no-tillage technology and positively influences households’ agricultural and non-agricultural income. Meanwhile, the moderating effect of the stability of farmland rental contracts is explored. Further, it was also found that education level, organizational participation, relationship networks, and information acquisition channels influence the income of transferees who opt for no-tillage technology. The study further revealed that if a transferee who opts for no-tillage technology switches to traditional technology, their agricultural and non-agricultural income will decrease by 0.2893 and 1.6979 ten thousand yuan (RMB), respectively. In contrast, if a transferee who opts for traditional technology then switches to adopt no-tillage technology, their agricultural and non-agricultural income will increase by 0.1919 and 1.3044 ten thousand yuan (RMB), respectively. Conclusively, the current study’s empirical findings offer policymakers possible guidelines to devise strategies and encourage transferees to opt for no-tillage applications to increase their families’ income.