Intensive organic vegetable production increases soil organic carbon but with a lower carbon conversion efficiency than integrated management

Intensive vegetable production in greenhouses has rapidly expanded in China since the 1990s and increased to 1.3 million ha of farmland by 2016, which is the highest in the world. We conducted an 11‐year greenhouse vegetable production experiment from 2002 to 2013 to observe soil organic carbon (SOC) dynamics under three management systems, i.e., conventional (CON), integrated (ING), and intensive organic (ORG) farming. Soil samples (0–20 and 20–40 cm depth) were collected in 2002 and 2013 and separated into four particle‐size fractions, i.e., coarse sand (> 250 µm), fine sand (250–53 µm), silt (53–2 µm), and clay (< 2 µm). The SOC contents and δ¹³C values of the whole soil and the four particle‐size fractions were analyzed. After 11 years of vegetable farming, ORG and ING significantly increased SOC stocks (0–20 cm) by 4008 ± 36.6 and 2880 ± 365 kg C ha^?1 y^?1, respectively, 8.1‐ and 5.8‐times that of CON (494 ± 42.6 kg C ha^?1 y^?1). The SOC stock increase in ORG at 20–40 cm depth was 245 ± 66.4 kg C ha^?1 y^?1, significantly higher than in ING (66 ± 13.4 kg C ha^?1 y^?1) and CON (109 ± 44.8 kg C ha^?1 y^?1). Analyses of ¹³C revealed a significant increase in newly produced SOC in both soil layers in ORG. However, the carbon conversion efficiency (CE: increased organic carbon in soil divided by organic carbon input) was lower in ORG (14.4%–21.7%) than in ING (18.2%–27.4%). Among the four particle‐sizes in the 0–20 cm layer, the silt fraction exhibited the largest proportion of increase in SOC content (57.8% and 55.4% of the SOC increase in ORG and ING, respectively). A similar trend was detected in the 20–40 cm soil layer. Over all, intensive organic (ORG) vegetable production increases soil organic carbon but with a lower carbon conversion efficiency than integrated (ING) management.     

CMS-D2恢复基因对陆地棉主要性状的影响

选用1对同质异核的哈克尼西棉细胞质雄性不育恢复基因近等基因系——保持系和恢复系为试验材料，分别在黄河流域棉区（河南安阳）和长江流域棉区（江西九江）2个生态点种植，对棉花苗期生长、全生育期主茎功能叶片光合生理指标、花药发育状况、产量及其构成因素以及纤维品质性状进行比较分析。结果表明：（1）恢复基因对棉花苗期生长、花药发育以及全生育期净光合速率无显著影响；（2）恢复基因对黄河流域棉区棉花产量性状具有显著的正效应，对长江流域棉花产量无显著影响；（3）恢复基因可以显著增加棉花纤维长度。本研究对棉花胞质不育恢复系的选育和改良具有一定的指导意义。     

磷供应水平对盆花月季'仙境'生长和品质的影响

以盆花月季'仙境'为试材,采用根部浇灌方式,设置0(P0)、10 (P10)、20(P20)、30(P30)g·柱-14个磷供应水平,研究了磷水平对盆花月季'仙境'根系生长、不同器官氮磷养分吸收、叶片SPAD值以及开花品质(花朵数量、花径、花朵干质量等)的影响,以期为月季养分管理提供参考依据.结果 表明:磷不同供应水平明显改变了'仙境'的根系形态,P20和P30处理较P0和P10处理,总根长增加了81％～111％,总根表面积扩大了133％～196％,细根总长度增加了95％～119％.植株不同器官(新生叶片、新生枝条和根系)生物量和氮、磷养分积累量表现出与根系生长类似的趋势.与P0和P10处理相比,P20和P30处理单株花朵数量增加128％～206％,叶片SPAD值增加16％～21％.与对照P0相比,P10、P20和P30花径分别增加12％、19％和24％.植株总根长与总氮和总磷吸收量表现出显著的正相关关系.综上所述,盆花月季'仙境'对不同磷供应水平表现出高度的根形态可塑性,适宜的磷供应水平促进根系生长和养分吸收,提高开花数量和品质.     

冀西北地区不同生态系统枯落物的水文效应

[目的]揭示不同植被生态系统枯落物水文效应的差异,为张家口地区生态空间格局优化提供支撑。[方法]基于样地调查和统计分析方法,分别对冀西北地区张家口市森林、农田和草地3种生态系统的枯落物在生长季末期持水能力及其与生物量之间的关系进行分析。[结果]①森林生态系统枯落物的最大持水量(30.7t/hm~2)、有效拦蓄量(22.97t/hm~2)、有效拦蓄率(187.49%)和吸水速率(5.84g/h)4个指标均优于其他两类生态系统。②草地枯落物的各项水文指标均值皆高于农田,最大持水率甚至高于森林生态系统。③枯落物生物量与其最大持水量和有效拦蓄量呈显著正相关关系,而枯落物占生态系统总生物量的比例随总生物量增加呈幂数下降。[结论]如果造林营林方式正确,森林生态系统能够提升区域水源涵养水平,同时草地的水源涵养能力不容忽视,市域内大范围的耕地向草地扩展,将直接影响区域的水源涵养能力。以生物量表征的生态系统固碳能力与枯落物蓄水所反映的水源涵养能力之间的响应关系在生态系统不同尺度下具有不同的表现,在对区域生态空间格局进行优化时,需明确特定环境下不同生态系统类型枯落物的水源涵养能力及其变化对其他生态服务功能的影响,从而实现各生态系统平衡发展。     

Effect of dietary chitosan oligosaccharide complex with Ce (IV) on growth,immunity and disease resistance against Vibrio splendidus of sea cucumber,Apostichopus japonicas

An 8‐week feeding trial was conducted to investigate the effects of dietary chitosan oligosaccharide complex with cerium (Ce IV) (COS‐Ce) on growth performance, nonspecific immunity and disease resistance of sea cucumber, Apostichopus japonicas. Five isonitrogenous (18.6%) and isolipidic (1.1%) practical diets were formulated with graded level of COS‐Ce (0, 150, 300, 600 and 1200 mg kg^?1 dry feed), which were named as COS‐Ce/0, COS‐Ce/150, COS‐Ce/300, COS‐Ce/600, COS‐Ce/1200 respectively. Each diet was allocated to four replicates of sea cucumbers (Initial weight: 6.72 ± 0.02 g). Sea cucumbers were fed to apparent satiation once daily (19:00 hours) for 56 days. During the experiment, water temperature was kept at 16 ± 0.5°C, pH 7.8–8.2, dissolved oxygen beyond 5 mg L^?1, ammonia nitrogen below 0.5 mg L^?1 and salinity from 30‰ to 31‰. Results showed that the specific growth rate of sea cucumbers was significantly higher in COS‐Ce/600 than that in other four treatments. Activities of phagocytosis, respiratory burst, acid phosphatase and alkaline phosphatase in COS‐Ce/600 were significantly higher than that in COS‐Ce/0 (P < 0.05) respectively. On the contrary, cumulative mortality was the lowest in COS‐Ce/600 following 14 days exposure to Vibrio splendidus (P < 0.05). In conclusion, these results confirmed that dietary COS‐Ce had beneficial effects on growth performance, nonspecific immunity and disease resistance of sea cucumber.     

密度与环境因子对蒙古黄芪育苗影响研究

为了明确育苗时密度与环境因子对蒙古黄芪生长特征影响,本试验以蒙古黄芪为研究对象,通过单因素田间随机区组试验,测定蒙古黄芪株高、茎粗、根粗和根长4个指标。结果表明,密度对蒙古黄芪影响最大,其次是湿度,最后是光照和电导率。密度与蒙古黄芪株高、茎粗、根粗呈现负相关性,与根长呈正相关性(P<0.05),密度为400株/m ²时,株高、茎粗及根粗最大,密度为1000株/m ²时根长最大。     

h指数及其衍生指标评估兽用疫苗领域单篇专利的适用性探索

随着禽流感、非洲猪瘟等疾病的出现,兽用疫苗的开发研制成为了动物防疫体系建设的重要一环,同时兽用疫苗领域国际竞争日益激烈,直接影响到我国相关企业的生存和发展,因此国家必须加强对兽用疫苗领域专利质量和专利保护的重视.本文以计量学中的h指数及其衍生指标为对象,研究其与传统专利价值评估指标的关系,通过相关性分析来筛选评估兽用疫苗领域高价值专利的指标.结果表明:h指数、g指数和hg指数这三个指标,与传统专利价值评估指标相关性强,且计算简便,相对于传统指标,能够快速准确地对兽用疫苗领域专利价值进行预估.     

Nutrient addition and disturbance effects on the community composition and assembly in a desert steppe北大核心CSCD

The effects of short-term nutrient additions (NPKμ, 10 g·m- 2) and disturbances on the species diversity, functional traits, soil properties, and community assembly mechanisms of the herbaceous community in the Urat desert steppe were examined. A mixed linear model, principal component analysis, and null model methods were utilized and both disturbance and interaction treatments were found to significantly reduce species richness and β diversity. Short-term nutrient additions significantly reduced soil pH but increased soil electrical conductivity. Six functional traits of the dominant species (i.e. Stipa glareosa, Peganum harmala, Salsola collina, Corispermum mongolicum) and six community-weighted mean significant changes under the disturbance and nutrient addition treatments were identified. The disturbance and nutrient additions promoted the transformation of the dominant species in the community from conservative strategies to acquisitive strategies. The results of the two null models revealed that community assembly under the control tended to be a stochastic process, while the disturbance and interaction treatments tended to be deterministic processes, and that of the nutrient addition treatments tended to be weaker deterministic processes. Plant communities in the desert steppe responded and adapted to the nutrient additions and disturbances through changes in the dominant species and their crucial functional traits. © 2023 Chinese Academy of Sciences. All rights reserved.