Food systems and climate change: impact and adaptation in cropping and livestock

The negative effects of climate change on crop and animal production are evident across the world, slowing agricultural growth rates and declining the production rate. The grain and grass quality are also observed to decline under climate change, as are important concentrations of proteins and most essential nutrients such as zinc and iron. It is fortunate that there are potential adaptation options to reconfigure existing agricultural systems and offset negative impacts of climate change. Observations have demonstrated that trends in global carbon dioxide (CO2) emissions, atmospheric CO2 concentrations, sea-level rise and global temperatures are consistent with the future projections of high emission scenarios. More research focus is therefore needed on more transformative adaptations in order to cope with climate change. Transformative adaptations are significant changes in current systems, for example, changes in the nature, configuration, and location of farms that are under threat. These adaptations can be associated with difficulties if their effectiveness is not assessed and producers and policy makers are not well informed

Estimating the effects of carbon dioxide, temperature and nitrogen on grain protein and grain yield using meta-analysis

As meta-analysis is an effective tool for assisting decision-makers, there has been a recent increase in demand for its use to solve controversies regarding important human life issues. Meta-analysis allows a thematic appraisal of evidence, which can lead to a resolution of suspicions and disagreements. Carbon dioxide, temperature, and nitrogen are considered as the most important factors influencing crop production. These environmental variables significantly affect grain yield and grain protein concentrations, which are key determinants of grain quality. Consequently, they affect human and animal nutrition. A more detailed understanding of how these environmental factors contribute towards the grain protein content is essential for addressing global nutrient security in the changing climate. To our knowledge, there have been no studies conducted to assess the effect of CO2, temperature and nitrogen supply on grain protein and grain yield using meta-analysis. In addition, performance evaluations were mainly conducted in previous studies through traditional statistical measures, and only the combined effect of CO2, temperature and nitrogen on grain protein and grain yield were analysed. Therefore, this study focuses on estimating the effects of CO2, temperature and nitrogen on grain protein and grain yield using meta-analysis. In this work, a new approach based on the dplyr package in R is proposed for organizing and categorizing the research data for meta-analysis. The performances of the proposed methods are evaluated using various measurements, such as the Cochran's Q statistic and its p-value, I2 statistic, and tau-squared. Overall, the aim of this study was to reveal the significance and reliability of a meta-analysis in analysing the effects of carbon dioxide, temperature and nitrogen on the quality of agricultural crops. The results indicated that the protein concentration was decreased by 0.62% and grain yield was increased by 0.52% under elevated carbon dioxide, ambient temperature and low nitrogen. In contrast, protein concentration was reduced by 0.65% and grain yield was increased by 0.78% under the elevated carbon dioxide, ambient temperature and medium nitrogen. We concluded that meta-analysis can be used to study the effects of CO2, temperature and nitrogen on grain protein concentration and grain yield. The outcomes of this project will inform experts and decision-makers about the effects of CO2, temperature and nitrogen on grain quality, and enable the investigation of suitable solution

Effects of elevated carbon dioxide on photosynthesis and carbon partitioning: a perspective on root sugar sensing and hormonal crosstalk

Plant responses to atmospheric carbon dioxide will be of great concern in the future, as carbon dioxide concentrations ([CO2]) are predicted to continue to rise. Elevated [CO2] causes increased photosynthesis in plants, which leads to greater production of carbohydrates and biomass. Which organ the extra carbohydrates are allocated to varies between species, but also within species. These carbohydrates are a major energy source for plant growth, but they also act as signaling molecules and have a range of uses beyond being a source of carbon and energy. Currently, there is a lack of information on how the sugar sensing and signaling pathways of plants are affected by the higher content of carbohydrates produced under elevated [CO2]. Particularly, the sugar signaling pathways of roots are not well understood, along with how they are affected by elevated [CO2]. At elevated [CO2], some plants allocate greater amounts of sugars to roots where they are likely to act on gene regulation and therefore modify nutrient uptake and transport. Glucose and sucrose also promote root growth, an effect similar to what occurs under elevated [CO2]. Sugars also crosstalk with hormones to regulate root growth, but also affect hormone biosynthesis. This review provides an update on the role of sugars as signaling molecules in plant roots and thus explores the currently known functions that may be affected by elevated [CO2]

Elevated atmospheric [CO2] stimulates sugar accumulation and cellulose degradation rates of rice straw

Rice straw can serve as potential material for bioenergy production. However, the quantitative effects of increasing atmospheric carbon dioxide concentration [CO2] on rice straw quality and the resulting consequences for bioenergy utilization are largely unknown. In this study, two rice varieties, WYJ and LY, that have been shown previously to have a weak and strong stimulatory response to rising [CO2], respectively, were grown with and without additional CO2 at China free-air carbon dioxide enrichment (FACE) platform. Qualitative and quantitative measurements in response to [CO2] included straw biomass (including leaf, sheath, and stem), the concentration of nonstructural and structural carbohydrates, the syringyl-to-guaiacyl (S/G) ratio of lignin, glucose and xylose release from structural carbohydrate, total sugar release by enzymatic saccharification, and sugar yield and the ratio of cellulose and hemicellulose degradation. Elevated [CO2] significantly increased straw biomass and nonstructural carbohydrate contents while enhancing the degraded ratio of structural carbohydrates as indicated by the decreased lignin content and increased S/G ratio. Overall, total sugar yield (g m-2) in rice straw significantly increased by 27.1 and 57% for WYJ and LY at elevated [CO2], respectively. These findings, while preliminary, suggest that rice straw quality and potential biofuel utilization may improve as a function of rising [CO2]

Improving rice zinc biofortification success rates through genetic and crop management approaches in a changing environment

Though rice is the predominant source of energy and micronutrients for more than half of the world population, it does not provide enough zinc (Zn) to match human nutritional requirements. Moreover, climate change, particularly rising atmospheric carbon dioxide concentration, reduces the grain Zn concentration. Therefore, rice biofortification has been recognized as a key target to increase the grain Zn concentration to address global Zn malnutrition. Major bottlenecks for Zn biofortification in rice are identified as low Zn uptake, transport and loading into the grain; however, environmental and genetic contributions to grain Zn accumulation in rice have not been fully explored. In this review, we critically analyze the key genetic, physiological and environmental factors that determine Zn uptake, transport and utilization in rice. We also explore the genetic diversity of rice germplasm to develop new genetic tools for Zn biofortification. Lastly, we discuss the strategic use of Zn fertilizer for developing biofortified rice

Arsenic in cooked rice foods: assessing health risks and mitigation options

Human exposure to arsenic (As) through the consumption of rice (Oryza sativa L.) is a worldwide health concern. In this paper, we evaluated the major causes for high inorganic As levels in cooked rice foods, and the potential of post-harvesting and cooking options for decreasing inorganic As content in cooked rice, focusing particularly on As endemic areas. The key factors for high As concentration in cooked rice in As endemic areas are: (1) rice cultivation on As-contaminated paddy soils; (2) use of raw rice grains which exceed 200 μg kg−1 of inorganic As to cook rice; and (3) use of As-contaminated water for cooking rice. In vitro and in vivo methods can provide useful information regarding the bioaccessibility of As in the gastrointestinal tract. Urinary levels of As can also be used as a valid measure of As exposure in humans. Polishing of raw rice grains has been found to be a method to decrease total As content in cooked rice. Sequential washing of raw rice grains and use of an excess volume of water for cooking also decrease As content in cooked rice. The major concern with those methods (i.e. polishing of raw rice, sequential washing of raw rice, and use of excess volume of water for cooking rice) is the decreased nutrient content in the cooked rice. Cooking rice in percolating water has recently gained significant attention as a way to decrease As content in cooked rice. Introducing and promoting rainwater harvesting systems in As endemic areas may be a sustainable way of reducing the use of As-contaminated water for cooking purposes. In conclusion, post-harvesting methods and changes in cooking practices could reduce As content in cooked rice to a greater extent. Research gaps and directions for future studies in relation to different post-harvesting and cooking practices, and rainwater harvesting systems are also discussed in this review

Investigation of ethanol production potential from lignocellulosic material without enzymatic hydrolysis using the ultrasound technique

This research investigates ethanol production from waste lignocellulosic material (sugarcane bagasse). The bagasse was first pretreated using chemicals and ultrasound techniques. These pretreatment techniques were applied separately and combined. The pretreated bagasse was then fermented anaerobically for biofuel production without enzymatic hydrolysis. The results showed higher ethanol production than those reported in the literature. The maximum ethanol production of 820 mg/L was achieved with a combination of ultrasound (60 amplitude level, 127 W) and acid (3% H2SO4 concentration). The combination of two-step pretreatment such as an ultrasound (50 amplitude level, 109 W) with acid (3% H2SO4 concentration) and then an ultrasound with alkaline (23% NaOH concentration) generated 911 mg/L of ethanol

Impacts of elevated atmospheric CO₂ on nutrient content of important food crops.

One of the many ways that climate change may affect human health is by altering the nutrient content of food crops. However, previous attempts to study the effects of increased atmospheric CO2 on crop nutrition have been limited by small sample sizes and/or artificial growing conditions. Here we present data from a meta-analysis of the nutritional contents of the edible portions of 41 cultivars of six major crop species grown using free-air CO2 enrichment (FACE) technology to expose crops to ambient and elevated CO2 concentrations in otherwise normal field cultivation conditions. This data, collected across three continents, represents over ten times more data on the nutrient content of crops grown in FACE experiments than was previously available. We expect it to be deeply useful to future studies, such as efforts to understand the impacts of elevated atmospheric CO2 on crop macro- and micronutrient concentrations, or attempts to alleviate harmful effects of these changes for the billions of people who depend on these crops for essential nutrients

Current and Future Approaches to Mitigate Conflict between Humans and Asian Elephants: The Potential Use of Aversive Geofencing Devices

Conflict between humans and Asian elephants is a major conservation issue. Here we discuss common tools used to manage human-elephant conflict (HEC) in Asia and the potential of animal-borne satellite-linked shock collars or Aversive Geofencing Devices (AGDs) for managing problem elephants. Most current HEC mitigation tools lack the ability to be modified to accommodate needs of elephants and therefore are sometimes unsuccessful. AGDs currently used to manage livestock movement can be adapted to mitigate HEC to overcome this problem. AGDs can constantly monitor animal movements and be programmed to deliver sound warnings followed by electric shock whenever animals attempt to move across virtual boundaries demarcated by managers. Elephants fitted with AGDs are expected to learn to avoid the electric shock by associating it with the warning sound and move away from specified areas. Based on the potential shown by studies conducted using AGDs on other wild species, we suggest that experiments should be conducted with captive elephants to determine the efficacy and welfare impact of AGDs on elephants. Further, assessing public opinion on using AGDs on elephants will also be important. If elephants can learn to avoid virtual boundaries set by AGDs, it could help to significantly reduce HEC incidents