Elevational patterns of warming effects on plant community and topsoil properties: focus on subalpine meadows ecosystem

Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.

Effects of planting patterns on yield, quality, and defoliation in machine-harvested cotton

The aim of this study was to elucidate the effects of different machine-harvested cotton-planting patterns on defoliation,yield,and fiber quality in cotton and to provide support for improving the quality of machine-harvested cotton.In the 2015 and 2016 growing seasons,the Xinluzao 45(XLZ45)and Xinluzao 62(XLZ62)cultivars,which are primarily cultivated in northern Xinjiang,were used as study materials.Conventional wide-narrow row(WNR),wide and ultra-narrow row(UNR),wide-row spacing with high density(HWR),and wide-row spacing with low density(LWR)planting patterns were used to assess the effects of planting patterns on defoliation,yield,and fiber quality.Compared with WNR,the seed cotton yields were significantly decreased by 2.06–5.48%for UNR and by 2.50–6.99%for LWR,respectively.The main cause of reduced yield was a reduction in bolls per unit area.The variation in HWR yield was–1.07–1.07%with reduced bolls per unit area and increased boll weight,thus demonstrating stable production.In terms of fiber quality indicators,the planting patterns only showed significant effects on the micronaire value,with wide-row spacing patterns showing an increase in the micronaire values.The defoliation and boll-opening results showed that the number of leaves and dried leaves in HWR was the lowest among the four planting patterns.Prior to the application of defoliating agent and before machine-harvesting,the numbers of leaves per individual plant in HWR were decreased by 14.45 and 25.00%on average,respectively,compared with WNR,while the number of leaves per unit area was decreased by 27.44 and 36.21%on average,respectively.The rates of boll-opening and defoliation in HWR were the highest.Specifically,the boll-opening rate before defoliation and machine-harvesting in HWR was 44.54 and 5.94%higher on average than in WNR,while the defoliation rate prior to machine-harvesting was 3.45%higher on average than in WNR.The numbers of ineffective defoliated leaves and leaf trash in HWR were the lowest,decreased by 33.40 and 32.43%,respectively,compared with WNR.In conclusion,the HWR planting pattern is associated with a high and stable yield,does not affect fiber quality,promotes early maturation,and can effectively decrease the amount of leaf trash in machine-picked seed cotton,and thus its use is able to improve the quality of machine-harvested cotton.

Effects of rainfall patterns on annual plants in Horqin Sandy Land, Inner Mongolia of China

Growth of annual plants in arid environments depends largely on rainfall pulses. An increased understanding of the effects of different rainfall patterns on plant growth is critical to predicting the potential responses of plants to the changes in rainfall regimes, such as rainfall intensity and duration, and length of dry intervals. In this study, we investigated the effects of different rainfall patterns（e.g. small rainfall event with high frequency and large rainfall event with low frequency） on biomass, growth characteristics and vertical distribution of root biomass of annual plants in Horqin Sandy Land, Inner Mongolia of China during the growing season（from May to August） of 2014. Our results showed that the rainfall patterns, independent of total rainfall amount, exerted strong effects on biomass, characteristics of plant growth and vertical distribution of root biomass. Under a constant amount of total rainfall, the aboveground biomass（AGB）, belowground biomass（BGB）, plant cover, plant height, and plant individual and species number increased with an increase in rainfall intensity. Changes in rainfall patterns also altered the percentage contribution of species biomass to the total AGB, and the percentage of BGB at different soil layers to the total BGB. Consequently, our results indicated that increased rainfall intensity in future may increase biomass significantly, and also affect the growth characteristics of annual plants.

Vertical patterns in plant diversity and their relations with environmental factors on the southern slope of the Tianshan Mountains(middle section)in Xinjiang(China)

The investigation of distribution patterns of species diversity is significant for successful biodiversity conservation. The spatial patterns of vegetation and different life-forms species diversity along an elevation gradient in the middle section of the southern slope of the Tianshan Mountains in Xinjiang, China were explored, using the detrended canonical correspondence analysis(DCCA) and the generalized additive model(GAM) methods based on a field survey of 53 sampling plots. In this work 158 species of seed plants were recorded, including 141 herbaceous, 14 shrub, and 2 tree species, in which the woody plants are very limited. 53 sampling plots were classified into 9 major plant communities. The results indicate that the herb communities were the most sensitive to changes in elevation gradient. The diversity indices of the community as a whole presented bimodal patterns. The peak values for the species diversities were found in the transition region between mountain steppe desert and mountain desert steppe(2,200–2,300m), and in the alpine grassland region(2,900–3,100m), while maximum species diversities were in the areas of intermediate environmental gradient. The main environmental factors on the distribution patterns in plant diversity were the elevation, soil water, total nitrogen, available nitrogen, organic matter, and total salt. The response tendency of the four diversity indices for the whole community to the soil environment was the same as that of the herb layers.

Landscape pattern and its effect on ecosystem functions in Seoul Metropolitan area:Urban ecology on distribution of the naturalized plant species

During land transformation process in the human history, naturalized plants were introduced to several land use patterns by the different ways of plant itself. Including some naturalized plants that had been contribute to land restoration, many naturalized plants have been invaded to original habitat or landscape for native plants. Once the plants were colonized, they extend their area and population size. Urban developed areas often give an important role of source habitat for naturalized plants and expanding their population size. In recent, this situation is appearing as one of environmental problems about the urban landscape management controlling the naturalized plants that invaded in the developed area and conserving the native vegetation. This paper is focusing on relationships between distribution of habitat of naturalized plants and landscape patch in urban area in Seoul. Gangdong-Gu, one of the administrative areas in Seoul was selected for this study. We examined the recent land use change using LANDSAT TM data and spreading of the representative naturalized plants (Robinia pseudoacacia and Eupatorium rugosum) by Seoul Biotope Mapping Project and field survey in 1999. As a result, these two species were often occurred in the same habitat and distributed in forest edge disturbed by man. Their distribution patterns were related to landscape indices (patch size and shape) in the forest edge.

Leaf Photosynthetic Characteristics of High-Yield Soybean[Glycine max(L.)Merr.]Under Different Planting Densities,Different Fertilization Rates,and Single/Mixed Planting Patterns

Understanding the photosynthetic characteristics of high-yield soybean[Glycine max(L.)Merr]cultivar(HYC)would aid research aiming at investigating the soybean high yield formation mechanism and optimization of cultivation system.To assess the photosynthesis of HYC,a pot experiment was conducted to quantify the differences in photosynthetic characteristics between HYC and common-yield soybean cultivar(CC)under different planting densities,fertilization rates,and single/mixed planting patterns.The leaf greenness(Lg),net photosynthetic rate(Ph),stomatal conductance(St)and transpiration rate(Tr)were significantly higher in HYC than CC mainly in seed-filling stages.HYC was more tolerant to dense and mixed planting because the decreases of Ph and St under high planting density and those of Ph,St,and Tr under mixed planting were lower in HYC than CC.The Lg and Ph in HYC were more superior to those in CC at high fertilization rate.Thus,the HYC has a superior performance in photosynthetic characteristics under the varied cultivation practices,which may contribute to the greater seed yield in HYC than CC.

Improving Soil Fertility with Different Planting Patterns in Rocky Desertification Areas

[Objectives]This study was conducted to investigate the effect of different planting patterns on soil improvement in rocky desertification areas.[Methods]The one-way ANOVA analysis method was used to statistically analyze the soil physical and chemical properties,enzyme activity,microbial quantity,CEC,ECEC,and aggregate content distribution with different planting patterns.[Results]The walnut+sesame+mung bean planting pattern showed the highest soil available phosphorus,available potassium,porosity,non-capillary porosity,and contents of free living nitrogen-fixing bacteria,organophosphate-dissolving bacteria,bacteria,fungi and actinomycetes,at 63.2 mg/kg,178.8 mg/kg,22.85%,6.89%,10.0×10^6 bacteria/g,18.0×10^6 bacteria/g,21.0×10^5 CFU/g,5.7×10^3 CFU/g and 7.9×10^5 CFU/g,respectively,and it reduced soil bulk density(the same as treatment F and treatment E)compared with other planting patterns.The walnut+American chicory+sweet potato planting pattern had the highest alkali-hydrolyzale nitrogen,organic matter,CEC,ECEC,water-air ratio and moisture content,which were 227.9 mg/kg,46.30 g/kg,36.38 cmol/kg,24.00 cmol/kg,8.13,and 32.89%,respectively,and it reduced soil bulk density,increased capillary porosity,acid phosphatase,and contents of bacteria and actinomycetes compared with single cropping of walnut.[Conclusions]Interplanting crops under walnut forests is an effective measure to improve the ecological environment of rocky desertification farmland.

Construction of Spatial Pattern of Garden Plant Landscape in Urban Waterfront

The spatial pattern of urban waterfront landscape is an important factor affecting the quality of urban culture and improving the recognition of the city.As the core material of urban landscape design,garden plants play a very important role in the construction of spatial pattern of urban waterfront landscape.The spatial pattern of garden plant landscape can be divided into three types:two-dimensional,vertical and special.The two-dimensional spatial pattern focuses on the construction of"meaning and form".The vertical spatial pattern focuses on the construction of"image".The special spatial pattern of garden plants focuses on the construction of"artistic conception".The three types are used to create a spatial pattern of urban waterfront landscape with rich spatial and temporal changes and artistic connotation.

An Analysis of the Correlation between the Changes in Sa-tellite DNA Methylation Patterns and Plant Cell Responses to the Stress

The differences in satellite DNA methylation pattern of corn seedlings with various spontaneous chromosome aberration yields and changes in methylation pattern of these DNA sequences under different exposure modes of acute UV-C and chronic gamma-irradiations have been investigated. The obtained experimental data and the conducted correlation analysis demonstrated the significant correlation between the satellite DNA methylation pattern varieties and chromosome aberration yields under various stress exposure modes. The role of satellite DNA methylation pattern variability and its changing in key responses to stress such as mobile elements’ activation, cell’s passage of checkpoints, and homological repair was discussed.

武夷山不同种植模式下茶园土壤理化性质和酶活性的季节变化特征

土壤酶活性是表征土壤肥力水平和养分转化的重要指标,揭示种植模式和季节变化对茶园土壤酶活性影响,阐明影响茶园土壤酶活性变化的主要环境因子,为合理评估有机茶种植的土壤生态效应提供理论依据。结合野外调查和室内分析方法,以武夷山茶区3种类型样地,即林地(FD)、常规茶园(CT)和有机茶园(OT)为研究对象,测定了参与土壤碳、氮和磷循环的6种酶活性,研究不同种植模式下土壤酶活性的季节变化规律及影响因子。结果显示,与林地土壤相比,常规种植模式茶园土壤铵态氮、全磷、有效磷和有效钾含量显著增加,土壤全钾和pH显著降低;相比常规茶园,有机茶园土壤有机质和全氮含量显著增加,土壤全磷、有效磷、全钾和速效钾含量显著降低,土壤pH有所增加,土壤养分比例更为协调。种植模式和季节及其交互作用对土壤脲酶和过氧化氢酶活性影响显著。与林地土壤相比,常规茶园土壤脲酶、多酚氧化酶、过氧化氢酶和酸性磷酸酶活性下降了12.05%~63.55%,有机茶园土壤脲酶显著提高了324.95%,种植模式并未改变土壤硝酸还原酶活性。总体而言,夏秋季节(5月和8月)土壤脲酶、多酚氧化酶、蔗糖酶和酸性磷酸酶活性明显高于冬春季节(11月和2月),土壤硝酸还原酶和过氧化氢酶活性在春季最高。置换多元方差分析结果显示,种植模式对土壤整体理化性质的影响远大于季节变化。冗余分析结果显示,土壤环境因子解释了土壤酶活性变异的77.03%,土壤有机质、全氮、铵态氮、全磷、有效磷、全钾、有效钾和pH对土壤酶活性有显著或极显著的影响。综上所述,林地转变为茶园对土壤理化性质和酶活性产生显著影响,常规种植导致茶园土壤速效磷钾积累,土壤酶活性降低,有机种植提高了土壤酶活性,增强了土壤碳氮养分供应能力,具有良好的生态环境效应。

黑龙江省种植模式区划研究

合理构建黑龙江省种植模式区划,对优化耕作制度、促进农业高质量发展、推进黑土地保护具有重要意义。基于地学信息图谱识别种植模式类型,选取作物生育期平均气温、作物生育期平均湿润指数、地貌类型、种植模式4项指标构建区划指标体系,以县级地域单元为区划的基本单元,采用聚类分析、叠置法两种定量区划方法,拟定黑龙江省种植模式区划方案。结果表明,黑龙江省种植模式可分为玉米连作、水稻连作、大豆连作、米豆轮作、混合模式五种类型,面积占比分别为27.91%、23.11%、10.40%、21.50%、17.08%,空间分异特征显著。黑龙江省县级地域单元种植模式结构多样,可分为14种类型。其中,以种植模式结构单一型为主,种植模式结构单一型与种植模式结构混合型占比分别为69.84%、30.16%。黑龙江省划分为8个种植模式区,各区种植模式因水热条件、地貌条件差异表现出地域分异规律,文章针对各区存在问题提出相应对策建议。

不同作物种植模式下坡耕地产流产沙的模拟研究

产流产沙是坡耕地水土流失的主要形式,为探讨不同种植模式对坡耕地产流产沙的影响,采用室内人工模拟降雨试验方法,在同一坡度、3种雨强下对坡耕地7种种植模式进行模拟试验。结果表明:1)不同种植模式下坡面产流量随雨强增大而增大,初始产流时间随雨强增大而缩短。坡面产流量趋势为先逐渐增大,之后(10 min左右)逐渐趋于稳定。C单种模式减流效果最差;A-B-C套种模式减流效果最好;低矮作物单种及参与的套种模式能更好促进降雨入渗。2)不同种植模式下坡面产沙量与雨强呈正相关,低矮作物参与的种植模式径流含沙量变化幅度较小,中、高单种或套种模式径流含沙量变化复杂。小、中雨强下,A-B-C套种模式减沙效果最好;大雨强下,A-B套种模式减沙效果最好。低矮作物参与的种植模式减沙效果优于中、高作物单种其套种模式。3)不同种植模式下产流量和雨强均呈极显著正相关。B、C单种模式与A-B-C套种模式产沙量与雨强有相关关系,其余模式与雨强的相关性不显著。综上,低矮作物单种及低矮作物参与的套种模式能有效减流、保土,因此坡耕地在进行农作物种植时应考虑增加低矮作物参与种植,避免造成大量水土流失。

安徽稻油两熟制不同种植方式下气候资源配置和演变

安徽沿江地区稻-油复种模式下茬口衔接紧密、光温资源紧张,季节间气候资源配置备受关注。移栽和直播是补充和调配气候资源的有效种植方式,而稻油两熟制中不同种植方式下不同作物生长季气候资源配置、演变特征以及对未来气候变化的适应性尚不清晰。本研究以安徽沿江地区27个气象站1992—2022年的气温、日照时数、总辐射和降水等气象资料为基础,分析了不同种植方式下稻-油复种季节间气候资源配置与演变特征以及光温生产潜力。结果表明,近30年稻-油复种模式下季节间总辐射量、日照时数和光合生产潜力均呈下降趋势,气温、降水量和光温生产潜力呈上升趋势。水稻季移栽和直播方式下总辐射量倾向率分别为-27.9 MJ·m^(-2)·(10a)^(-1)和-28.8MJ·m^(-2)·(10a)^(-1),油菜季分别为-40.5 MJ·m^(-2)·(10a)^(-1)和-26.6 MJ·m^(-2)·(10a)^(-1)。水稻季移栽和直播方式下平均日最高气温倾向率分别为0.30℃·(10a)^(-1)(P<0.05)和0.24℃·(10a)^(-1),最高达32.70℃(2022年,青阳)。油菜季移栽和直播方式下平均气温倾向率分别为0.36℃·(10a)^(-1)(P<0.01)和0.39℃·(10a)^(-1)(P<0.01),移栽方式下平均气温较直播方式高0.96~1.43℃。稻油两熟制两季均面临光资源持续下降和气温不断上升等问题,采用移栽方式可通过延长作物生育期优化光、温资源配置,提高光温生产潜力。同时,适当推迟移栽期将有利于应对油菜苗期和水稻花期的高温。直播方式下宜采用高光效品种和构建光资源高效利用作物群体。

不同种植方式大米中碳氮同位素比率与矿质元素特征及加工影响

为探究不同种植方式大米稳定同位素特征指标与矿质元素差异,该研究利用元素分析-同位素质谱仪和电感耦合等离子体质谱仪分析,研究有机、绿色和常规种植方式下糙米与精米δ^(13)C、δ^(15)N与11种矿质元素变化。结果表明,精米δ^(13)C、δ^(15)N分布分别为-27.7‰~-26.9‰和3.7‰~4.9‰,糙米δ^(13)C、δ^(15)N分布分别为-27.8‰~-26.9‰和3.4‰~4.7‰。精米δ^(13)C在有机和绿色栽培下差异显著,δ^(15)N在绿色与常规栽培下差异显著,Na、Mg、K、Mo元素存在显著性差异;糙米δ^(13)C和δ^(15)N在各栽培条件下均无显著差异,K、Mn元素存在显著性差异。糙米加工成精米后,有机大米中矿质元素减少42%,绿色大米矿质元素损失40%,常规大米矿质元素下降54%。精米比糙米可以更好地反映稳定同位素特征,常规栽培下糙米矿质元素含量最高,绿色栽培下精米矿质元素含量最高。不同种植方式和加工制备影响大米中δ^(13)C、δ^(15)N、矿质元素含量,该研究为科学评价大米中矿质元素含量和指导消费提供科学依据。

弃土坡面不同建植恢复方式的减流减沙效应

[目的]生产建设项目弃土场进行植被恢复后能够有效防治水土流失。探讨弃土场不同植被恢复方式的减流减沙效果,可以为弃土场后续治理与监管提供理论依据。[方法]选取皖西大别山区生产建设项目弃土,通过人工模拟降雨试验获得不同建植方式(撒播、条播、穴播)和植被恢复阶段(生长期、成熟期、枯萎期)的弃土坡面产流产沙特征,并利用累积距平等方法分析其规律和差异。[结果]相对裸坡,植被恢复可有效延缓初始产流时间,撒播种植的效果最为明显。不同建植方式均起到一定的减流减沙效应,坡面累积产流产沙量呈现出:撒播<条播<穴播<裸坡以及生长期<成熟期<枯萎期的规律;坡面产沙与产流过程存在差异性,减流效应弱于减沙效应。[结论]建植方式减流减沙效益表现为撒播优于条播,穴播最差。生长期减流减沙效益优于成熟期,枯萎期最差。撒播方式在生长期内呈现出最佳的减流减沙效益,减流率和减沙率分别达到49.6%,95.5%。

不同混交模式下幼龄桉树混交林的生长和水土流失特征研究

设计尾巨桉×红椿和大花序桉×闽楠的垂直、水平、块状三种混交方式的试验林,以研究不同混交模式下桉树混交林的生长和水土流失规律。结果表明:1年生尾巨桉、红椿、大花序桉和闽楠分别在水平、块状、块状和水平混交模式下的树高增长率最大,依次为1560.00%、863.33%、457.50%和6.67%,因此水平混交模式和块状混交模式的林分树高生长效果较好。在尾巨桉×红椿和大花序桉×闽楠两种林分中的月均地表径流以块状混交模式最少,分别是107.72 L和215.24 L,月均土壤流失以块状混交模式较少,分别是4.95 kg和7.25 kg,因此块状混交模式对水土保持的效果较优于垂直混交模式和水平混交模式。综合考虑,采用块状混交模式效果最好。

不同种植模式和品种对棉花光合物质生产及产量的影响

【目的】研究不同种植模式与品种对棉花光合物质生产及产量的影响。【方法】试验于2022年在新疆阿克苏地区沙雅县海楼镇进行,选择2种不同株型结构的棉花品种源棉11号、新陆中80号、新陆中84号和J206-5,选用2种种植模式:76 cm等行距(1膜3行)和(66+10)cm宽窄行(1膜6行),设置田间试验分析不同种植模式及品种对棉花生育进程、植株形态、叶面积指数、净光合速率、干物质积累和产量的影响。【结果】不同棉花品种在1膜3行处理下较1膜6行处理生育期缩短4~6 d,株高、始果枝高度、果枝夹角和平均果枝长度受种植模式影响较大。盛铃前期之前,不同株型棉花品种在1膜3行处理下的叶面积指数较高。但随着生育期推移,株型松散型的源棉11号、J206-5和株型紧凑的新陆中80号、新陆中84号分别在1膜3行处理、1膜6行处理下叶面积指数下降幅度较小,在棉花生育后期能维持较高的叶面积指数。盛花期前,不同株型棉花品种的净光合速率均表现为1膜3行处理高于1膜6行处理,但在盛花期至吐絮阶段,株型松散型的源棉11号、J206-5和株型紧凑的新陆中80号、新陆中84号净光合速率分别在1膜3行处理、1膜6行处理下达到最大值且下降缓慢,延长了光合作用持续时间,有利于棉花后期产量形成。株型松散型的源棉11号、J206-5在1膜3行处理下较1膜6行处理皮棉产量增加15.45%~17.23%,株型紧凑的新陆中80号、新陆中84号在1膜6行处理下皮棉产量较1膜3行处理增产9.23%~12.00%。【结论】不同株型棉花品种应选择适宜的种植模式,才能进一步发挥其增产潜力。株型松散的棉花品种适宜在76 cm等行距下种植,株型紧凑的棉花品种适宜在(66+10)cm模式下种植。

不同种植模式对麦后复播棉花产量的影响

为缓解喀什粮棉争地矛盾,探索麦后复播棉花种植模式,开辟粮棉双丰新途径。通过设置不同种植密度及保留果枝台数二因素试验,分析不同处理对棉花花铃数、单铃质量、产量、品质的影响。研究表明:高密度A_(2)平均产量较常规密度A_(1)平均产量增加15.58%;常规密度A_(1)模式,保留不同果枝台数,产量差异不显著,高密度A_(2)模式,保留7台果枝,产量最高达2207.55 kg·hm^(-2);2种不同种植密度单铃质量均随着保留果枝台数增加而增加;高密度A_(2)(32.8965万株·hm^(-2))5行种植模式,有利于提高光和效率增加产量;麦后复播棉棉纤维成熟度不够。在喀什麦后复播棉花尚不成熟的情况下,较高的有效积温生态区、合理安排种植密度、选择麦棉两早品种、抢时播种、保留7台果枝,是提高麦后复播棉花的产量有效措施。