Introduction
Cotton is the most produced natural fibre in the world, with an annual output of 23 million t of lint in the period 2000–2013. Africa produced in average 6% of that output, and despite ...being a relatively minor contributor to global cotton supply chains, it has been estimated that a large percentage of the continent’s population depends on cotton cultivation for their livelihood. Most published cotton LCAs focused on the main global producers (India, China, USA), a few consider African cotton, and none to date Malian cotton. This work presents an LCA of the Malian cotton sector, consisting of an agricultural phase and ginning operations, in contrast with other African and global cotton LCAs.
Material and methods
The goal of the study is to assess the absolute and relative environmental impacts of Malian cotton, per agricultural production system type, including the processing of seed cotton in ginning plants to produce cotton fibre bales (cradle to processing plant gate). Inventories were built for the two initial phases in the production cycle of cotton fibre, namely, the agricultural phase and the ginning phase. The main agricultural production system types were identified, according to distinctive differences in yields and technical processes―such as phytosanitary strategies―as well as the main processes performed in ginning plants. Operational data, representing the period 2002–2010, were provided by the Malian Company for the Development of Textiles (CMDT). It included yields and input and their uncertainty data. Direct field emissions of the agricultural phase were estimated following the AGRIBALYSE methodology, adapted when necessary to tropical conditions (e.g. a modified version of the Indigo-N model set was used to estimate N losses). Impact assessment was based on the European-sanctioned ILCD 2011 Midpoint+ v1.0.9, May 2016 method. Sensitivity was explored with scenarios and uncertainty data was propagated with Monte Carlo.
Results and discussion
The agricultural phase of cotton production in Mali differs from that of the largest producing countries, in that it is non-irrigated and non-mechanised and that non-Bt varieties are used. Instead, Malian cotton is rainfed―thus produced during the rainy season, from April/May to October/November―in rotation with maize or sorghum, manual work is prevalent up to the harvest, ploughs are towed by animals, and local varieties are grown (mainly STAM 59A and NTA 90-5). Malian yields were in the order of 400 kg lint/ha in the period 2001–2018, corresponding to ~ 1 t seed cotton/ha. The dominant production system, conventional agriculture, was sub-classified into three sub-types based on the phytosanitary strategy followed: calendar (81%), threshold control (15%) and targeted (4%). An average conventional system type was also constructed, as a production-weighted average of calendar, targeted and threshold. An existing marginal production of organic (0.5‰) cotton was also modelled. Organic cotton products (seed cotton, lint and cottonseed) feature lower impacts than conventional both per t and per ha (except for the toxicity, climate change and eutrophication impact categories), despite comparatively lower yields, due to lower input intensity. A single score–based contribution analysis confirms that, for conventional cotton, pesticide application is the main contributor to impacts, followed by mineral fertilisers. For organic cotton, the main drivers of impacts are natural pesticides and organic fertilisation. The overwhelming contribution of pesticides is largely due to the provision of organophosphorus compounds, specifically the insecticide profenofos. Moreover, the ginning phase contributed very little to the overall impacts (up to 3%). When data uncertainty is considered, the impacts per t of lint are always lower for organic cotton.
Conclusions
Impacts were generally larger for conventional than from organic cotton. The main hotspots are related to pesticide use, and therefore, efforts should focus on that factor, despite pesticide inputs being already relatively lower than elsewhere. Climate change indicators for Malian cotton products were compared with literature values, having similar orders of magnitude. Malian cotton production features lower yields than the main global producers do, which is mainly due to low soil fertility and, to a lesser extent, to its dependence on rainwater. A shift towards organic cotton would be desirable only if the yield gap can be overcome.
•Abiotic stresses, including; temperature fluctuations, salinity, water logging, and others, reduce the endotoxin protein content of transgenic cotton crops making the crop less resistant to ...pests.•Gene silencing, post-transcriptional changes, and protein degradation are some crucial reasons discussed in the article as important research-demanding areas of the crop.•Under harsh environmental conditions, the overall nitrogen metabolism of plants is disturbed, leading to inefficient field performance of Bt Cotton.•Decreased Cry1Ac insecticidal protein content in the plant also impacts the peculiar feeding behaviors of insect larvae and gives useful insights about the abiotic stress influences on the crop.•Combined abiotic stresses are also discussed in correlation to unstable environmental stress to explain the crop performance better.•A detailed systematic meta-analysis substantiates the different abiotic stresses and relevant research done in the recent decade.
Bt cotton is a genetically modified crop that combats cotton pests (bollworm) by its insecticidal properties induced by insertion of endotoxin Cry1Ac gene from soil dwelling bacterium Bacillus thuringiensis. Bt cotton has been a big agricultural hit product of biotechnology for past 2 decades. Many countries have been successfully cultivating Bt crops on commercial scales. Transgenic Bt crops have favorably increased crop yields and solved global crisis of food shortage. Bt cotton crop shows variable insect resistance levels under the influence of multiple environmental abiotic stresses like high temperature, soil salinity, water logging and water deficiency, nitrogen deficiency, and humidity. These factors have been observed to degrade endotoxin protein content of transgenic crop and ultimately reduce its insecticidal efficacy. Under harsh environmental conditions, plant undergoes disturbed nitrogen metabolism and physiological mechanism distress. This review has discussed some of the major stress factors of Bt cotton and the underlying mechanisms of its unstable insecticidal efficacy under individual and combined stresses. Gene silencing, post transcriptional changes, protein degradation are some crucial reasons discussed in this review, but nitrogen metabolism is the most important research needed area of this domain. A detailed meta-analysis table has been drawn as a summary of various vital researches done in order to investigate the stress impacts. A deep research approach is needed to further elaborate the metabolic and physiological changes that take place in transgenic cotton crop under harsh stress states. Due to insufficient evidences and lack of solution strategies against this problem, there is a need of further research data to address this unstable protection of Bt crops against insects in order to enhance the ability and performance of the cotton crop worldwide.
The flame resistance of cotton fabric was greatly enhanced by a novel reactive flame retardant with serrated structure, ammonium salt of 1,3-diaminopropane tetra-(methylenephosphonic acid) (ADDTMPA), ...and the softness of cotton fabric was retained very well. The results showed that cotton fabric modified by 30% ADDTMPA had a LOI value of 41.5%, which remained well after 40 laundering cycles with a LOI value of 26.3%. The treated cotton fabric was not ignited in vertical flammability tests, and the results of cone calorimetry proved that the heat release rates and total heat release of treated cotton fabric decreased substantially. TG analysis showed that the treated cotton fabric had the lower initial decomposition temperature and more residues than control cotton fabric during combustion. TG-IR analysis showed that the treated cotton fabric released much less flammable volatile species than control cotton fabric. FTIR analysis indicated that the flame retardant was reactive in condensed phase and the flame retardant was grafted on cellulose by P–O–C bonds. EDX results showed that a large amount of phosphorus was introduced into the cotton fabric. SEM showed that the modification had little effect on the surface of cotton fibers, and a large amount of residue was maintained after combustion. The treatment by ADDTMPA could produce highly effective flame-retardant and soft cotton fabric.
Graphical abstract
A novel phosphorus-based, halogen-free and formaldehyde-free flame retardant with serrated structure and reactive groups was synthesized to prepare highly efficient flame-retardant and soft cotton fabric by chemical grafting.
Upland cotton (Gossypium hirsutum) is the most important natural fiber crop in the world. The overall genetic diversity among cultivated species of cotton and the genetic changes that occurred during ...their improvement are poorly understood. Here we report a comprehensive genomic assessment of modern improved upland cotton based on the genome-wide resequencing of 318 landraces and modern improved cultivars or lines. We detected more associated loci for lint yield than for fiber quality, which suggests that lint yield has stronger selection signatures than other traits. We found that two ethylene-pathway-related genes were associated with increased lint yield in improved cultivars. We evaluated the population frequency of each elite allele in historically released cultivar groups and found that 54.8% of the elite genome-wide association study (GWAS) alleles detected were transferred from three founder landraces: Deltapine 15, Stoneville 2B and Uganda Mian. Our results provide a genomic basis for improving cotton cultivars and for further evolutionary analysis of polyploid crops.
Summary
Functional genomics has transformed from futuristic concept to well‐established scientific discipline during the last decade. Cotton functional genomics promise to enhance the understanding ...of fundamental plant biology to systematically exploit genetic resources for the improvement of cotton fibre quality and yield, as well as utilization of genetic information for germplasm improvement. However, determining the cotton gene functions is a much more challenging task, which has not progressed at a rapid pace. This article presents a comprehensive overview of the recent tools and resources available with the major advances in cotton functional genomics to develop elite cotton genotypes. This effort ultimately helps to filter a subset of genes that can be used to assemble a final list of candidate genes that could be employed in future novel cotton breeding programme. We argue that next stage of cotton functional genomics requires the draft genomes refinement, re‐sequencing broad diversity panels with the development of high‐throughput functional genomics tools and integrating multidisciplinary approaches in upcoming cotton improvement programmes.
The number of cotton (Gossypium sp.) ovule epidermal cells differentiating into fiber initials is an important factor affecting cotton yield and fiber quality. Despite extensive efforts in ...determining the molecular mechanisms regulating fiber initial differentiation, only a few genes responsible for fiber initial differentiation have been discovered. To identify putative genes directly involved in the fiber initiation process, we used a cotton ovule culture technique that controls the timing of fiber initial differentiation by exogenous phytohormone application in combination with comparative expression analyses between wild type and three fiberless mutants. The addition of exogenous auxin and gibberellins to pre-anthesis wild type ovules that did not have visible fiber initials increased the expression of genes affecting auxin, ethylene, ABA and jasmonic acid signaling pathways within 1 h after treatment. Most transcripts expressed differentially by the phytohormone treatment in vitro were also differentially expressed in the ovules of wild type and fiberless mutants that were grown in planta. In addition to MYB25-like, a gene that was previously shown to be associated with the differentiation of fiber initials, several other differentially expressed genes, including auxin/indole-3-acetic acid (AUX/IAA) involved in auxin signaling, ACC oxidase involved in ethylene biosynthesis, and abscisic acid (ABA) 8'-hydroxylase an enzyme that controls the rate of ABA catabolism, were co-regulated in the pre-anthesis ovules of both wild type and fiberless mutants. These results support the hypothesis that phytohormonal signaling networks regulate the temporal expression of genes responsible for differentiation of cotton fiber initials in vitro and in planta.
In her incisive analysis of the shaping of California's agricultural work force, Devra Weber shows how the cultural background of Mexican and, later, Anglo-American workers, combined with the ...structure of capitalist cotton production and New Deal politics, forging a new form of labor relations. She pays particular attention to Mexican field workers and their organized struggles, including the famous strikes of 1933.
Weber's perceptive examination of the relationships between economic structure, human agency, and the state, as well as her discussions of the crucial role of women in both Mexican and Anglo working-class life, make her book a valuable contribution to labor, agriculture, Chicano, Mexican, and California history.
Display omitted
•Cotton gin trash catalyst is effective in the dehydration of fructose to HMF.•Cotton gin trash catalyst consists of 3 aromatic layers, –COOH and –SO3H groups.•The reusability of ...cotton gin trash derived catalyst is >5 times.•Fructose was transformed via a carbaldehyde intermediate prior to dehydration.•Adsorption mechanism of catalyst goes by liquid film and intra-particle diffusions.
Biomass-derived carbon catalysts have been extensively studied for the dehydration of sugars to platform chemical 5-hydroxymethyl furfural (HMF), which can be used to produce valuable chemicals and fuels. However, only limited studies have been conducted to determine their carbon molecular structures and how these influence the conversion process. Here, we prepare a chlorosulfonated carbon catalyst derived from cotton gin trash (CGT) at 400 °C for the dehydration of fructose to produce 5-hydroxymethyl furfural (HMF) in the ionic liquid, 1-butyl-3-methyl-imidazolium chloride (BMIMCl). The highly efficient chlorosulfonated carbon catalyst consisting of 3 aromatic layers of furanic, phenolic rings and aliphatic–aromatic carbon structures with –COOH, phenolic OH, -SO3-, and -SO3H functional groups were found to have a similar performance as the commercial catalyst, Amberlyst-15. The carbon material was reused 5 times without loss of catalytic activity. The formation of the sugar intermediate, 3,4-dihydroxy-5-hydroxymethyl-tetrahydrofuran-2-carbaldehyde may be related to –COOH and phenolic OH groups forming hydrogen bonds with fructose, and the adsorption of fructose onto the graphitized sp2 internal carbon regions where interactions with the defects in the carbon material occur.
PDF
