Co-benefits and trade-offs in the water–energy nexus of irrigation modernization in China

There are strong interdependencies between water use in agriculture and energy consumption as water saving technologies can require increased pumping and pressurizing. The Chinese Government includes water efficiency improvement and carbon intensity reduction targets in the 12th Five-Year Plan (5YP. 2011–2015), yet the links between energy use and irrigation modernization are not always addressed in policy targets. Here we build an original model of the energy embedded in water pumping for irrigated agriculture and its related processes. The model is based on the physical processes of irrigation schemes and the implication of technological developments, comprising all processes from extraction and conveyance of water to its application in the field. The model uses data from government sources to assess policy targets for deployment of irrigation technologies, which aim to reduce water application and contribute to adaptation of Chinese agriculture to climate change. The consequences of policy targets involve co-beneficial outcomes that achieve water and energy savings, or trade-offs in which reduced water application leads to increasing greenhouse gas (GHG) emissions. We analyze irrigation efficiency and energy use in four significant provinces and nationally, using scenarios based on the targets of the 12th 5YP. At the national scale, we find that expansion of sprinklers and micro-irrigation as outlined in the 5YP would increase GHG emissions from agricultural water use, however, emissions decrease in those provinces with predominant groundwater use and planned expansion of low-pressure pipes. We show that the most costly technologies relate to trade-offs, while co-benefits are generally achieved with less expensive technologies. The investment cost per area of irrigation technology expansion does not greatly affect the outcome in terms of water, but in terms of energy the most expensive technologies are more energy-intensive and produce more emissions. The results show that water supply configuration (proportion of surface to groundwater) largely determines the potential energy savings from reductions in water application. The paper examines the importance of fertigation and highlights briefly some policy implications

Transposable element-initiated enhancer-like elements generate the subgenome-biased spike specificity of polyploid wheat

Transposable elements (TEs) comprise ~85% of the common wheat genome, which are highly diverse among subgenomes, possibly contribute to polyploid plasticity, but the causality is only assumed. Here, by integrating data from gene expression cap analysis and epigenome profiling via hidden Markov model in common wheat, we detect a large proportion of enhancer-like elements (ELEs) derived from TEs producing nascent noncoding transcripts, namely ELE-RNAs, which are well indicative of the regulatory activity of ELEs. Quantifying ELE-RNA transcriptome across typical developmental stages reveals that TE-initiated ELE-RNAs are mainly from RLG_famc7.3 specifically expanded in subgenome A. Acquisition of spike-specific transcription factor binding likely confers spike-specific expression of RLG_famc7.3-initiated ELE-RNAs. Knockdown of RLG_famc7.3-initiated ELE-RNAs resulted in global downregulation of spike-specific genes and abnormal spike development. These findings link TE expansion to regulatory specificity and polyploid developmental plasticity, highlighting the functional impact of TE-driven regulatory innovation on polyploid evolution

Bioenergy versus Soil Improvement: Policy Coherence and Implementation Gaps in Crop Residue-Based Bioenergy Development in China

Promoting crop residue-based bioenergy (CRB) is a strategy for mitigating climate change and ensuring water-energy-food security. Although China has abundant crop residues, CRB is not well developed, and several policy targets are not being reached. These implementation gaps need critical examination as CRB development mainly relies on policy support. This examination provides a framework to assess the feasibility of this policy that covers several cross-cutting issues. By reviewing national policies, this paper analyzes the horizontal coherence of multisectoral CRB policies during the last two decades. Based on 55 semi-structured interviews, conducted with stakeholders, civil servants and experts, we analyzed the vertical coherence among policy implementation to further explore the causes of the limited success of CRB policies. The priority given to the cultivation and livestock sectors (particularly for soil improvement) in crop residue utilization policies and the development of energy policy targets resulted in horizontal policy incoherence. Furthermore, financial limitations were shown to be the most significant obstacle to CRB policy implementation. Successful CRB policy implementation requires a debate about the crop residue utilization for either energy or fertilizer to determine the more sustainable application. Appropriate incentives and increased technological quality of bioenergy projects are also recommended

Functional Characterization of the Maize Phytochrome-Interacting Factors PIF4 and PIF5

Phytochrome-interacting factors (PIFs) play important roles in photomorphogenesis, the shade avoidance response, and other aspects of plant growth and development. PIF family proteins have been well-studied in Arabidopsis thaliana, but little is known about their physiological functions and molecular mechanisms in maize (Zea mays). In this study, we investigated the physiological functions of ZmPIF4 and ZmPIF5, two highly conserved members of the PIF gene family. RT-qPCR and western blot analyses revealed that ZmPIF4 and ZmPIF5 expression and ZmPIF4 and ZmPIF5 levels peak at night and remain low during the day. Overexpression of ZmPIF4 and ZmPIF5 in Arabidopsis partially rescued the reduced hypocotyl elongation and defective response to gravity in pif1 pif3 pif4 pif5 quadruple mutants (pifq). In addition, under high red: far-red light conditions, Arabidopsis lines overexpressing ZmPIF4 exhibited a constitutive shade avoidance response, including early flowering, slender leaves and inflorescences, plant lodging and precocious leaf senescence. Furthermore, ZmPIF4 physically interacted with the Arabidopsis DELLA protein REPRESSOR OF GA1-3 (RGA), indicating a potential interaction between ZmPIF4 and gibberellin signaling pathway on plant growth. Taken together, our results revealed that ZmPIF4 and ZmPIF5 are functionally conserved proteins that may play conserved roles in the response to phytochrome signaling in plants.Highlights:In this study, the functions of ZmPIF4 and ZmPIF5 were characterized by expression in Arabidopsis, revealing conserved roles of PIF family proteins in photomorphogenesis and the shade avoidance response in land plants

Analysis of LULUCF Accounting Rules after 2012

Land use, land-use change and forestry (LULUCF) activities can allow Annex I parties in the Kyoto Protocol to decrease their carbon emission reduction pressure, and comparably expanding more emission space for their domestic industries and energy production. The loopholes resulted from LULUCF activity types and specific accounting methods are always argued among the different parties, particularly including harvested wood products, influences of force majeure, threshold values of the reference level, and gross-net or net-net accounting methods. For estimating uncertainties in accounting loopholes, and to avoid that developed countries take advantage of the accounting loopholes of LULUCF to decrease their emission reduction pressure, the LULUCF data submitted from the main developed countries in Annex I, including EU 27, Canada, Japan, and Russia, were collected. According to the analysis of these data, the loopholes influence the accounting results of LULUCF. The results show that the uncertainty of harvested wood products is excessive. The carbon sink produced by LULUCF activities will increase averagely by at least 30% without force majeure. The threshold values of the reference level of carbon sink should be set to a higher level. The net-net accounting method might be more suitable for LULUCF after 2012. Liu, S., Y. Li, Q. Gao, et al., 2011: Analysis of LULUCF accounting rules after 2012. Adv . Clim . Change Res ., 2 (4), doi: 10.3724/SP.J.1248.2011.00178

Impacts of Temperature Trends and SPEI on Yields of Major Cereal Crops in the Gambia

Variations in the climate constitute a significant threat to the productivity of food crops in the Gambia. A good understanding of the influence of climate variability on crop production is vital for climate resilience and improved food security. This study examined the trends, relationships, and the extent to which growing season temperatures and the SPEI (Standardized Precipitation and Evapotranspiration Index) impacted sorghum, millet, maize, and rice yields in three agro-ecological regions of the Gambia during 1990–2019. Mean temperatures and the SPEI exhibited increasing trends while observed yields showed a decline across all regions. The SPEI had a significant positive relationship with yields, and temperatures were negatively associated with yields. Though yield response to climate variability differs among regions, 20% to 62% of variations in the four crop yields were due to climate trends. The combined effect of the SPEI and temperatures decreased yields from 3.6 kg ha−1 year−1 to 29.4 kg ha−1 year−1, with the most severe decline observed in rice and maize yields in the Sahelian zone. Although uncertainties might arise from not considering related extreme climate events, this study highlights how past climate trends affect cereal yields in the Gambia; thus, any unfavorable change in the local climate could have severe repercussions on the country’s food security. There is a need for concerted efforts to increase investments in adaptation strategies to lessen the effects of the climate for improved crop productivity