Planting under plastic-film mulches is widely used in spring maize production in arid-cold regions for water conservation and warming the soil.To ameliorate the associated issues such as plastic-film residues and addi...Planting under plastic-film mulches is widely used in spring maize production in arid-cold regions for water conservation and warming the soil.To ameliorate the associated issues such as plastic-film residues and additional labor during the“seedling release”in spring maize production,we have developed a plastic-film-side seeding(PSS)technology with the supporting machinery.In the semi-arid regions of Northwest China,a 7-year trial demonstrated that PSS increased plant number per hectare by 6547 and maize yield by 1686 kg ha–1compared with the traditional method of seeding under plastic-film mulch(PM).Two-year experiments were conducted in two semi-arid regions to further understand the effects of PSS on three important aspects of production:(i)the moisture and temperature of soil,(ii)maize development,yield output,and water use efficiency(WUE),and(iii)the revenue and plastic-film residuals in comparison with that of flat planting(CK)and PM.Continuous monitoring of the soil status demonstrated that,compared with CK,the PSS treatment significantly increased the temperature and moisture of the 0–20 cm soil in the seeding row at the early stage of maize development,and it also promoted grain yield(at 884–1089 kg ha^(–1))and WUE,achieving a similar effect as the PM treatment.Economically,the labor inputs of PSS were equal to CK,whereas the PM cost an additional 960 CNY ha–1in labor for releasing the seedlings from below the film.Overall,the PSS system increased profits by 5.83%(547 CNY ha^(–1)yr^(–1))and 8.16%(748 CNY ha^(–1)yr^(–1))compared with CK and PM,respectively.Environmentally,PSS achieved a residual film recovery rate of nearly 100%and eliminated 96 to 130 kg ha^(–1)of residual plastic-film in PM in 3–5 years of maize production.Collectively,these results show that PSS is an eco-friendly technique for improving yield stability and incomes for the sustainable production of maize in semi-arid regions.展开更多
There are two main theories, the 'temperature-raising' theory and the 'precipitation-based regulation' theory, which guide the optimum sowing time of the plastic-film corn. The former was applied in th...There are two main theories, the 'temperature-raising' theory and the 'precipitation-based regulation' theory, which guide the optimum sowing time of the plastic-film corn. The former was applied in the humid or semi-humid ecotope and on irrigated or half-shaded land in the arid and semi-arid ecotopes, while the latter was suitable for the dry-farming land in the semi-arid ecotope. The results of experiments and investigations for many years showed that the corn output was increased by 69.2% when the former theory was applied to guide the optimum sowing time for plastic-film corn in the semi-humid ecotope, and by 60. 0% when the latter theory was applied in the semi-arid ecotope. In the semi-arid ecotope, however, the output was increased only by 15.7% when the former theory was applied, and even dropped by 14.4% when the latter theory was applied.展开更多
塑料-金属聚合物复合集流体(metallized plastic current collector,MPCC)通过减厚、减重可大幅提高电池的能量密度,且因聚合物自身绝缘、受热收缩、熔融等特性可提高电池的安全性,因此吸引了产业界研究者的诸多关注。了解聚合物基底和M...塑料-金属聚合物复合集流体(metallized plastic current collector,MPCC)通过减厚、减重可大幅提高电池的能量密度,且因聚合物自身绝缘、受热收缩、熔融等特性可提高电池的安全性,因此吸引了产业界研究者的诸多关注。了解聚合物基底和MPCC的特性及制备方法有利于高质量MPCC的研发,同时可促进高能量密度、高安全电池的发展,因此本文着重介绍了常用和亟待开发的聚合物的特性,阐明了目前市场生产的高质量PET、PP基复合集流体虽已应用于锂离子电池,但面临着各种挑战,例如PET的溶胀溶解反应,PP与金属层间的低黏结性等,并提出了相应的改进措施。此外,本文总结了聚合物表面沉积金属层的多种方法(磁控溅射、蒸镀、化学沉积和电镀等)的原理、优缺点和设备改良策略、注意事项,以期提高聚合物表面金属层的均匀性、一致性和导电率。最后,为提高MPCC在电池中的应用可行性,明确了MPCC未来研发的重点攻关问题,例如提高金属-聚合物界面黏结性,进一步提高电池安全性和导电率,并阐述了将来的发展趋势:功能化和精细化MPCC在电池中的应用。展开更多
为研究我国废旧地膜回收利用模式经验、面临问题与优化路径,本研究选取甘肃、山东两大代表省份开展实地调研,并比较了不同再利用方式的经济和生态效益。结果显示:山东一方面通过花生种植制度创新,成功实现地膜减量,另一方面基于行政层...为研究我国废旧地膜回收利用模式经验、面临问题与优化路径,本研究选取甘肃、山东两大代表省份开展实地调研,并比较了不同再利用方式的经济和生态效益。结果显示:山东一方面通过花生种植制度创新,成功实现地膜减量,另一方面基于行政层级架构回收网络体系,及创新“秸-膜”协同回收模式,大幅降低废旧地膜捡拾含杂率;甘肃通过全链条多主体协同回收利用模式、企业“多功能”集成一体化回收处理模式等创新,实现县域废旧地膜回收全覆盖。此外,1 t废旧地膜(指废旧地膜与秸秆、根系、泥土等的混合物,经分离清理后含杂率为20%~30%,下同)再生造粒的经济效益为20~120元·t^(-1),碳排放量为8.68 kg CO_(2e)·t^(-1),焚烧发电的经济效益为129~194元·t^(-1),碳排放量为1.83 kg CO_(2e)·t^(-1)。当前,进一步提升回收利用效率面临着地膜使用不科学、机械设备作业场景较单一、资源配置不科学、财政持续支持困难、废旧地膜再利用产业内生“造血”能力弱等一系列障碍。研究表明,源头减量替代与回收体系建设是我国废旧地膜回收的主要路径,焚烧发电和再生造粒是再利用的主要路径,且焚烧发电的经济和减碳效益均优于再生造粒,解决现有问题,需因地制宜地制定覆膜技术规程,强化地膜生产、销售标准化管控,加强回收、捡拾、处置等机械设备创新,全域统筹配置各项资源,调动各级财政与社会资本长效支持,加快生态产品价值转化市场机制建设等。展开更多
基金supported by the earmarked fund for China Agriculture Research System(CARS-02-16 and CARS-02-75)the National Key Research and Development Program of China(2016YFD0300301)。
文摘Planting under plastic-film mulches is widely used in spring maize production in arid-cold regions for water conservation and warming the soil.To ameliorate the associated issues such as plastic-film residues and additional labor during the“seedling release”in spring maize production,we have developed a plastic-film-side seeding(PSS)technology with the supporting machinery.In the semi-arid regions of Northwest China,a 7-year trial demonstrated that PSS increased plant number per hectare by 6547 and maize yield by 1686 kg ha–1compared with the traditional method of seeding under plastic-film mulch(PM).Two-year experiments were conducted in two semi-arid regions to further understand the effects of PSS on three important aspects of production:(i)the moisture and temperature of soil,(ii)maize development,yield output,and water use efficiency(WUE),and(iii)the revenue and plastic-film residuals in comparison with that of flat planting(CK)and PM.Continuous monitoring of the soil status demonstrated that,compared with CK,the PSS treatment significantly increased the temperature and moisture of the 0–20 cm soil in the seeding row at the early stage of maize development,and it also promoted grain yield(at 884–1089 kg ha^(–1))and WUE,achieving a similar effect as the PM treatment.Economically,the labor inputs of PSS were equal to CK,whereas the PM cost an additional 960 CNY ha–1in labor for releasing the seedlings from below the film.Overall,the PSS system increased profits by 5.83%(547 CNY ha^(–1)yr^(–1))and 8.16%(748 CNY ha^(–1)yr^(–1))compared with CK and PM,respectively.Environmentally,PSS achieved a residual film recovery rate of nearly 100%and eliminated 96 to 130 kg ha^(–1)of residual plastic-film in PM in 3–5 years of maize production.Collectively,these results show that PSS is an eco-friendly technique for improving yield stability and incomes for the sustainable production of maize in semi-arid regions.
文摘There are two main theories, the 'temperature-raising' theory and the 'precipitation-based regulation' theory, which guide the optimum sowing time of the plastic-film corn. The former was applied in the humid or semi-humid ecotope and on irrigated or half-shaded land in the arid and semi-arid ecotopes, while the latter was suitable for the dry-farming land in the semi-arid ecotope. The results of experiments and investigations for many years showed that the corn output was increased by 69.2% when the former theory was applied to guide the optimum sowing time for plastic-film corn in the semi-humid ecotope, and by 60. 0% when the latter theory was applied in the semi-arid ecotope. In the semi-arid ecotope, however, the output was increased only by 15.7% when the former theory was applied, and even dropped by 14.4% when the latter theory was applied.
文摘塑料-金属聚合物复合集流体(metallized plastic current collector,MPCC)通过减厚、减重可大幅提高电池的能量密度,且因聚合物自身绝缘、受热收缩、熔融等特性可提高电池的安全性,因此吸引了产业界研究者的诸多关注。了解聚合物基底和MPCC的特性及制备方法有利于高质量MPCC的研发,同时可促进高能量密度、高安全电池的发展,因此本文着重介绍了常用和亟待开发的聚合物的特性,阐明了目前市场生产的高质量PET、PP基复合集流体虽已应用于锂离子电池,但面临着各种挑战,例如PET的溶胀溶解反应,PP与金属层间的低黏结性等,并提出了相应的改进措施。此外,本文总结了聚合物表面沉积金属层的多种方法(磁控溅射、蒸镀、化学沉积和电镀等)的原理、优缺点和设备改良策略、注意事项,以期提高聚合物表面金属层的均匀性、一致性和导电率。最后,为提高MPCC在电池中的应用可行性,明确了MPCC未来研发的重点攻关问题,例如提高金属-聚合物界面黏结性,进一步提高电池安全性和导电率,并阐述了将来的发展趋势:功能化和精细化MPCC在电池中的应用。
文摘为研究我国废旧地膜回收利用模式经验、面临问题与优化路径,本研究选取甘肃、山东两大代表省份开展实地调研,并比较了不同再利用方式的经济和生态效益。结果显示:山东一方面通过花生种植制度创新,成功实现地膜减量,另一方面基于行政层级架构回收网络体系,及创新“秸-膜”协同回收模式,大幅降低废旧地膜捡拾含杂率;甘肃通过全链条多主体协同回收利用模式、企业“多功能”集成一体化回收处理模式等创新,实现县域废旧地膜回收全覆盖。此外,1 t废旧地膜(指废旧地膜与秸秆、根系、泥土等的混合物,经分离清理后含杂率为20%~30%,下同)再生造粒的经济效益为20~120元·t^(-1),碳排放量为8.68 kg CO_(2e)·t^(-1),焚烧发电的经济效益为129~194元·t^(-1),碳排放量为1.83 kg CO_(2e)·t^(-1)。当前,进一步提升回收利用效率面临着地膜使用不科学、机械设备作业场景较单一、资源配置不科学、财政持续支持困难、废旧地膜再利用产业内生“造血”能力弱等一系列障碍。研究表明,源头减量替代与回收体系建设是我国废旧地膜回收的主要路径,焚烧发电和再生造粒是再利用的主要路径,且焚烧发电的经济和减碳效益均优于再生造粒,解决现有问题,需因地制宜地制定覆膜技术规程,强化地膜生产、销售标准化管控,加强回收、捡拾、处置等机械设备创新,全域统筹配置各项资源,调动各级财政与社会资本长效支持,加快生态产品价值转化市场机制建设等。
