Carbon sequestration and saving potential associated with changes to the management of agricultural soils in England

Abstract. The potential for soil organic carbon sequestration, energy savings and the reduction of the emission of greenhouse gases were investigated for a range of changes in the management of tilled land and managed grassland. These parameters were modelled on a regional basis, according to local soils and crop rotations in England, and avoided the use of soil related indices. The largest carbon sequestration and saving contribution possible comes from an increase in the proportion of permanent woodland, such that a 10% change in land use could amount to 9 Mt C yr⁻¹ in the initial years (arable and grassland). Changes in arable management could make a significant contribution to an abatement strategy if carried out in concert with greater use of permanent conservation field margins, increased returns of crop residues and reduced tillage systems, contributing 1.3 Mt C yr⁻¹ in the initial years. It should be noted, however, that true soil carbon sequestration would be only a minor component of this (125 kt C yr⁻¹), the main part being savings on CO₂ emissions from reduced energy use, and lower N₂O emissions from reduced use of inorganic nitrogen fertilizer.     

Maintaining Genetic Resources of Peach Palm (<Emphasis Type="Italic">Bactris gasipaes</Emphasis> Kunth): The Role of Seed Migration and Swidden-fallow Management in Northeastern Peru

Knowledge of the effects of farmer practices on population genetic parameters of peach palm (Bactris gasipaes Kunth) is relevant to the improvement and conservation of the palm’s genetic resources. Microsatellite markers were used to assess genetic diversity and population structure of peach palm in swidden-fallow agroforestry systems in northeastern Peru. The study covered eight communities, comprising two study areas 160 km apart – one occupied by indigenous Amerindians and the other by mixed race campesinos. Simultaneous analysis of an ex situ peach palm germplasm collection provided a means to compare population genetic parameters. Farmers who were surveyed on seed selection practices for peach palm reported that an average of only four palms (4.3 for campesino and 1.5 for indigenous populations) were used to provide seed for the establishment of the forest gardens sampled. As expected, inbreeding coefficients observed within communities were relatively high (f = 0.105 − 0.210), however, observed heterozygosities within communities were also high (0.625–0.741). A metapopulation approach was used to describe migration within and among regions, implying a hierarchical structure of gene flow which maintains relatively high levels of genetic diversity. Seed migration was found to occur over longer distances (≤600 km) and at a higher frequency (46% of palms sampled) in the indigenous study area, and a proportionally greater number of alleles was found (49 vs. 43 over three loci) with twice as many private alleles occurring only in the indigenous populations. The farmers’ practice of preserving remnant palms through successive swidden generations may have contributed to the maintenance of alleles by reducing the severity of founder effects. Although the campesino study area exhibited a significant (20% of the variation; p < 0.01) isolation-by-distance relationship across 35 km distance, in general, both study populations had relatively limited genetic structure (θ = 0.012–0.03), which is believed to have resulted from the exchange of seeds over long distances and periods of time.     

密闭式无糖组培室环境控制系统设计与控制性能

报道了一种密闭式植物无糖组培室,以及一套应用于该组培室的综合环境控制系统(包括环境因子检测与控制子系统和洁净控制子系统)中的环境因子检测与控制子系统。环境因子检测与控制子系统中,温度控制采用触点控制方式,相对湿度和CO2浓度控制采用比例控制方式。测试结果表明:在温度可将室温控制在设定值±0.1￣0.5℃范围内;在控制值30%和35%时内,系统可将相对湿度控制在控制值±5%的范围内;在控制值为800和1200mL.L-1时,CO2浓度可被控制在控制值±50mL.L-1范围内。     

Preliminary evaluation of pineapple mixed-cropping systems for protecting reclaimed gulleys in the tropics: An experiment in Southeast Nigeria

This paper reports on research into the effectiveness of pineapple monocropping or intercropping systems (with cowpeas or egusi-melon) for reestablishing vegetative cover to check soil erosion on a reclaimed gulley in the tropical rainforest of southeastern Nigeria. High-density pineapple planting, intercropped with egusi-melon, was found to promote rapid vegetative cover, checked soil loss, improved soil structural stability and produced a high crop yield. Soil loss was moderate in pineapple plots intercropped with cowpeas and least in pineapple plots intercropped with egusi-melon. Increasing pineapple density enhanced the field establishment of cowpea and egusi-melon respectively.     

BUILDING CLIMATE-RESILIENT FOOD SYSTEMS IN EAST AND SOUTHEAST ASIA: VULNERABILITIES,RESPONSES AND FINANCING

Food system resilience to climate change is uniquely imperative for bringing Sustainable Development Goals within reach and leaving no one behind. Food systems in East and Southeast Asia are interacting with planetary boundaries and are adversely affected by extreme weather-related events. A practical question for East and Southeast Asian stakeholders is how to foster climateresilient food systems in the face of lingering food system vulnerabilities and policy gaps. This paper reviews food syste...     

智能化纳米释药系统用于细菌感染治疗的研究进展

细菌耐药性的相关研究已成为多学科交叉研究的热点,纳米技术因其独特的物化性质在药物递送系统(drug delivery systems,DDSs)的应用中具有可以改善药物的药代动力学和药效学特性,为应对全球细菌抗生素耐药性问题提供了一种新的策略。作为药物载体,理想的纳米粒子必须具有较高的载药量,将药物运送到特定的病理部位和(或)靶细胞,同时不发生药物泄漏,并且在作用部位迅速释放药物。为此,人们积极寻求各种"智能"纳米释药系统,这种纳米释药系统可以对内部或外部刺激(如pH、氧化还原、温度、磁和光等)进行响应,从而实现对药物的可控释放。本文围绕pH、温度、光照以及酶和其他内源或外源因子刺激响应的智能化抗菌药物递送系统领域的最新研究进展进行了评述。     

Mitigating nitrous oxide emissions from agricultural soils by precision management

Nitrous oxide (N₂O) emissions make up a significant part of agricultural greenhouse gas emissions. There is an urgent need to identify new approaches to the mitigation of these emissions with emerging technology. In this short review four approaches to precision managements of agricultural systems are described based on examples of work being undertaken in the UK and New Zealand. They offer the opportunity for N₂O mitigation without any reduction in productivity. These approaches depend upon new sensor technology, modeling and spatial information with which to make management decisions and interventions that can both improve agricultural productivity and environmental protection.     

Response of industrial hemp to Salsola kali subsp. tragus densities under organic and conventional fertilisation

A 2-year field study was conducted to determine the effects of different nutrition systems and Salsola kali subsp. tragus densities on industrial hemp yield and its components. Experiments were conducted as a split plot in a randomised complete block design with three replicates. Factors were fertilisation (poultry manure, vermicompost and nitrogen fertiliser) as the main plot and weed density (0, 5, 10, 15 and 20 plants/m²) as the subplot. Results indicated that the maximum number of racemes per plant, seeds per raceme, 1000-seed weight, biomass, grain yield and harvest index (HI) of industrial hemp were obtained using vermicompost and were reduced with nitrogen fertiliser application. All measured properties in hemp plants decreased due to increasing S. kali subsp. tragus density, especially at 15 and 20 plants/m². The most significant reduction in hemp grain yield and its components was observed by increasing weed density with the application of nitrogen fertiliser. The application of vermicompost at high weed densities resulted in greater hemp grain yield and its components compared with nitrogen fertiliser. It is recommended to apply organic fertilisers, especially vermicompost at high S. kali subsp. tragus densities.     

不同耕作方式和工作深度对玉米生产的影响

为了比较不同耕作方式和工作深度对玉米生产的影响,在华南农业大学农场进行了两组对比试验,试验土壤为沙壤土和粘壤土,试验作物为玉米。第一组试验中安排了５种耕作方式,分别为犁耕加圆盘耙（ＭＢ＋ＤＨ）,凿形耕（ＣＨ）,圆盘耙两次（ＤＨ２）,旋耕（ＲＴ）和不耕（ＮＴ）,第二组试验中安排了２种耕作方式,犁耕加圆盘耙（ＮＤＬ）和犁耕、圆盘耙加深松（ＮＬ）。试验结果表明,不同的耕作方式和工作深度对土壤容重、土壤耕     

不同架式‘爱神玫瑰’葡萄果实成熟期间单萜积累及相关基因的表达

【目的】探讨不同架式对葡萄果实成熟期间单萜类化合物合成的影响,进一步从基因表达水平揭示基因转录与单萜积累的关系,以期为生产中架式选择及葡萄果实香味品质的提高提供一定的理论依据。【方法】以T型和V型架式栽培的‘爱神玫瑰’葡萄果实为试材,于果实成熟初期（花后30 d）开始取样,直至果实完全成熟。连续两年常规方法测定果实样品可溶性固形物及可滴定酸含量,利用顶空固相微萃取结合气相色谱与质谱联用技术（SPEME-GC-MS）测定果实中单萜类组分和含量的变化,采用实时荧光定量PCR技术分析单萜合成途径中关键基因脱氧木酮糖磷酸合酶基因（DXS1和DXS3）、脱氧木酮糖磷酸还原异构酶基因（DXR）、异戊烯基焦磷酸还原酶基因（HDR）、里那醇合成酶基因（Liner syn）和萜品醇合成酶基因（Terp syn）的表达变化。【结果】随着果实成熟,可溶性固形物含量逐渐升高,而可滴定酸含量逐渐降低。成熟期的T型架葡萄果实可溶性固形物含量显著高于V型架,可滴定酸含量没有显著差异。2016年和2017年两种架式果实样品中分别检测到27和28种单萜类化合物。检测结果表明不同架式主要萜烯类化合物组分不尽相同,随着果实成熟,主要萜烯类成分也发生变化。成熟时,T型架果实中主要单萜类化合物有里那醇、柠檬烯、α-萜品醇、β-cis-罗勒烯和香叶醇;V型架主要有里那醇、α-萜品醇、柠檬烯、橙花醚和β-cis-罗勒烯等,其中以里那醇含量最高。2016年成熟期T型架果实单萜总量达到108.18 μg?L ^-1,是V型架最高含量的1.9倍。而2017年成熟期T型架果实单萜总量达到403.24 μg?L ^-1,是V型架最高含量的1.5倍;大多数单萜类化合物含量在成熟时表现为T型架显著高于V型架。在整个果实成熟期间,两种架式葡萄果实单萜类化合物积累表现为两种变化模式,包括里那醇、香叶醇、橙花醇及萜品醇等在内的大部分化合物遵循第一种模式,即在果实成熟时含量达到最高。但是不同架式表现又略微不同,(E,Z)-别罗勒烯、β-cis-罗勒烯、柠檬烯和α-萜品醇等化合物在T型架果实中表现为先下降,花后57 d急剧升高,成熟后期（花后76 d）又下降的趋势。而在V型架果实中这些化合物含量随着果实成熟逐渐上升,花后48 d达到积累高峰,之后又逐渐下降至最低含量。另外,果实成熟期间单萜合成途径基因（DXS1、DXS3、DXR、DHR、Liner syn 和Terp syn）表达量随着果实成熟呈上升趋势。不同架式葡萄果实成熟期间单萜总量积累规律与DXS3、HDR、Liner syn和Terp syn表达规律相似。成熟期T型架果实中各个基因表达量明显高于V型架,与单萜类化合物积累模式相一致。【结论】T型架式栽培更有利于果实单萜类物质的积累,T型架式单萜类化合物的高效积累与其代谢途径多个关键酶基因高效表达密切相关。