A phenology-based vegetation index for improving ratoon rice mapping using harmonized Landsat and Sentinel-2 data

Ratoon rice,which refers to a second harvest of rice obtained from the regenerated tillers originating from the stubble of the first harvested crop,plays an important role in both food security and agroecology while requiring minimal agricultural inputs.However,accurately identifying ratoon rice crops is challenging due to the similarity of its spectral features with other rice cropping systems(e.g.,double rice).Moreover,images with a high spatiotemporal resolution are essential since ratoon rice is generally cultivated in fragmented croplands within regions that frequently exhibit cloudy and rainy weather.In this study,taking Qichun County in Hubei Province,China as an example,we developed a new phenology-based ratoon rice vegetation index(PRVI)for the purpose of ratoon rice mapping at a 30 m spatial resolution using a robust time series generated from Harmonized Landsat and Sentinel-2(HLS)images.The PRVI that incorporated the red,near-infrared,and shortwave infrared 1 bands was developed based on the analysis of spectro-phenological separability and feature selection.Based on actual field samples,the performance of the PRVI for ratoon rice mapping was carefully evaluated by comparing it to several vegetation indices,including normalized difference vegetation index(NDVI),enhanced vegetation index(EVI)and land surface water index(LSWI).The results suggested that the PRVI could sufficiently capture the specific characteristics of ratoon rice,leading to a favorable separability between ratoon rice and other land cover types.Furthermore,the PRVI showed the best performance for identifying ratoon rice in the phenological phases characterized by grain filling and harvesting to tillering of the ratoon crop(GHS-TS2),indicating that only several images are required to obtain an accurate ratoon rice map.Finally,the PRVI performed better than NDVI,EVI,LSWI and their combination at the GHS-TS2 stages,with producer's accuracy and user's accuracy of 92.22 and 89.30%,respectively.These results demonstrate that the proposed PRVI based on HLS data can effectively identify ratoon rice in fragmented croplands at crucial phenological stages,which is promising for identifying the earliest timing of ratoon rice planting and can provide a fundamental dataset for crop management activities.

Phenology of different types of vegetation and their response to climate change in the Qilian Mountains,China

The Qilian Mountains(QM)possess a delicate vegetation ecosystem,amplifying the evident response of vegetation phenology to climate change.The relationship between changes in vegetation growth and climate remains complex.To this end,we used MODIS NDVI data to extract the phenological parameters of the vegetation including meadow(MDW),grassland(GSD),and alpine vegetation(ALV))in the QM from 2002 to 2021.Then,we employed path analysis to reveal the direct and indirect impacts of seasonal climate change on vegetation phenology.Additionally,we decomposed the vegetation phenology in a time series using the trigonometric seasonality,Box-Cox transformation,ARMA errors,and Trend Seasonal components model(TBATS).The findings showed a distinct pattern in the vegetation phenology of the QM,characterized by a progressive shift towards an earlier start of the growing season(SOS),a delayed end of the growing season(EOS),and an extended length of the growing season(LOS).The growth cycle of MDW,GSD,and ALV in the QM species is clearly defined.The SOS for MDW and GSD occurred earlier,mainly between late April and August,while the SOS for ALVs occurred between mid-May and mid-August,a one-month delay compared to the other vegetation.The EOS in MDW and GSD were concentrated between late August and April and early September and early January,respectively.Vegetation phenology exhibits distinct responses to seasonal temperature and precipitation patterns.The advancement and delay of SOS were mainly influenced by the direct effect of spring temperatures and precipitation,which affected 19.59%and 22.17%of the study area,respectively.The advancement and delay of EOS were mainly influenced by the direct effect of fall temperatures and precipitation,which affected 30.18%and 21.17%of the area,respectively.On the contrary,the direct effects of temperature and precipitation in summer and winter on vegetation phenology seem less noticeable and were mainly influenced by indirect effects.The indirect effect of winter precipitation is the main factor affecting the advance or delay of SOS,and the area proportions were 16.29%and 23.42%,respectively.The indirect effects of fall temperatures and precipitation were the main factors affecting the delay and advancement of EOS,respectively,with an area share of 15.80%and 21.60%.This study provides valuable insight into the relationship between vegetation phenology and climate change,which can be of great practical value for the ecological protection of the Qinghai-Tibetan Plateau as well as for the development of GSD ecological animal husbandry in the QM alpine pastoral area.

The legacy effects of rubber defoliation period on the refoliation phenology,leaf disease,and latex yield

The leaf phenology of trees has received particular attention for its crucial role in the global water and carbon balances,ecosystem,and species distribution.However,current studies on leaf phenology have mainly focused on temperate trees,while few studies including tropical trees.Little attention has been paid to globally extensive industrial plantations.Rubber plantations are important to both the local and global economies.In this study,we investigated the legacy effects of defoliation phenology on the following year’s leaf flushing,leaf disease,and also latex yield of rubber trees,an economically important tree to local people and the world.Results show that extended duration of defoliation increased the subsequent duration of refoliation and rates of infection by powdery mildew disease,but led to reduced latex yield in March.This legacy effect of rubber defoliation may relate to the carbohydrate reserved in the trees.A longer duration of defoliation would consume more reserved carbohydrates,reducing available reserves for disease defense and latex production.Extended duration of defoliation period was associated with either a lower temperature before the cessation of latex tapping in October-November and/or a higher temperature after the cessation of latex tapping in December-January.Leaf falling signals the end of photosynthetic activities in deciduous trees.Thus,the leaf falling phenology will impact ecological processes involving rubber trees.Our findings indicated that the inclusion of defoliation periods in future rubber trees’ research,will be crucial to furthering our understanding of leaf flushing,powdery mildew disease,and latex yield.

Sensitivity of forest phenology in China varies with proximity to forest edges

Background:Shifts in forest phenological events serve as strong indicators of climate change.However,the sensitivity of phenology events to climate change in relation to forest origins has received limited attention.Moreover,it is unknown whether forest phenology changes with the proximity to forest edge.Methods:This study examined the green-up dates,dormancy dates,time-integrated NDVI(LiNDVI,a measure of vegetation productivity in growing season),and their sensitivities to climatic factors along the gradients of distance(i.e.proximity)to forest edge(0–2 km)in China's natural forests(NF)and planted forests(PF).For the analysis,field-surveyed data were integrated with Moderate Resolution Imaging Spectroradiometer(MODIS)NDVI from 2000 to 2022.Results:Our results reveal that PF had earlier green-up dates,later dormancy dates,and higher LiNDVI than NF.However,green-up sensitivities to temperature were higher at the edges of NF,whereas no such pattern was observed in PF.Conversely,the sensitivity of dormancy dates remains relatively stable from the inner to the edge of both NF and PF,except for a quadratic change in dormancy date sensitivity to precipitation found in NF.Additionally,we found that the green-up sensitivity to temperature increased with decreasing proximity to edge in NF evergreen forests,while it showed the opposite trend in PF evergreen forests.Furthermore,we observed that the precipitation impact on green-up dates shifts from postponing to advancing from the inner to the edge of NF,whereas precipitation dominantly postpones PF's green-up dates regardless of the proximity to edge.The LiNDVI exhibits higher sensitivity to precipitation at the edge areas,a phenomenon observed in NF but not in PF.Conclusions:These results suggest that the responses of forests to climate change vary with the distance to the edge.With increasing edge forests,which results from fragmentation caused by global changes,we anticipate that desynchronized phenological events along the distance to the edge could alter biogeochemical cycles and reshape ecosystem services such as energy flows,pollination duration,and the tourism industry.Therefore,we advocate for further investigations of edge effects to improve ecosystem modelling,enhance forest stability,and promote sustainable tourism.

伊犁河谷植被物候变化特征及其对气候变化的响应

本文基于2001—2021年MODIS NDVI数据和气象数据,利用TIMESAT软件提取伊犁河谷植被物候参数,结合Sen趋势分析、M—K检验和偏相关分析等方法,研究伊犁河谷植被物候变化特征及其对气候(气温、降水)变化的响应。结果表明:伊犁河谷植被生长季始期(Start of the growing season,SOS)、生长季末期(End of the growing season,EOS)、生长季长度(Length of growing season,LOS)主要集中在45~113 d,290~335 d,186~279 d,海拔每上升100 m,SOS约推迟1.9 d,EOS提前1 d,LOS缩短2.9 d。SOS呈提前的像元占79.91%;EOS呈推迟的像元占81.64%;LOS呈延长和缩短的像元占31.89%,26.39%。1000 m以下草原SOS最早且提前天数最多(61.5 d);1000 m以上草原EOS提前天数最多(34.8 d),阔叶林仅提前7.6 d。SOS受2,3月气温及1,2月降水影响,3月气温升高使SOS提前;EOS与8月气温正相关,与9月降水负相关。本研究为伊犁河谷的植被资源保护与生态环境可持续发展提供科学依据。

10个鲜食葡萄品种在贵州贵阳地区引种初报

为筛选出适宜贵阳地区栽培的葡萄品种,并进行规模化推广栽培,从浙江省金华市农业科学研究院引入10个优质葡萄品种进行栽培试验,对各品种的物候期、主要经济性状及抗逆性进行调查分析。结果表明:10个供试品种中,两个晚熟品种表现突出,分别是“甬优1号”和“巨玫瑰”,其中“甬优1号”产量较高、品质较好、抗逆性较强、口感甜,并带有草莓香味;“巨玫瑰”品质较好,抗逆性较强,口感浓甜,并带有玫瑰香味。这两个品种在贵阳地区表现出较强的适应性,适宜在贵阳地区进行设施栽培。

“妃子笑”荔枝高产若干生长发育性状

“妃子笑”荔枝是我国栽培区域最广的荔枝品种,比较研究不同区域“妃子笑”生长发育特性可为树冠、养分管理和成花着果调控及区域适应性发展等参考,为荔枝品种制订高产和克服“大小年”技术方案提供借鉴。2008—2022年,调查统计华南六省(区)北纬18°32′~28°47′的24县(区)39个示范园“妃子笑”物候期;于始花期调查海南、广东、广西和云南省(区)18个果园“妃子笑”结果树枝条、叶片和花穗生长量,并取样分析枝条、叶片、花穗主要养分含量,计算植株不同部位营养需求量。结果表明,主产区“妃子笑”末次秋梢成熟期8月下旬至11月中旬,现“白点”(花穗原基)期11月下旬至翌年2月中旬,盛花期2月上旬至4月上旬,果实成熟期4月下旬至7月底。3次秋梢生长分别约为35.9、39.5和40.2 d,秋梢老熟至现花穗原基(花诱导)约87 d,花穗与花芽分化期约56 d,果实发育期约需63 d。海南等地区“妃子笑”采果后树冠重回缩修剪至1.5 m高,形成矮化树形,而粤西等地修剪至2~3 m高,塑造高大树形。“妃子笑”结果植株采果后秋梢生长1~3次,树冠表面积的平均枝梢数16条/m2,秋梢平均长度37.7 cm,秋梢复叶数17片、叶片数104片。“妃子笑”单株不同部位年生长量,以鲜质量计分别为秋梢枝条16.8 kg,叶片40.2 kg,花穗17.2 kg;以干质量计为秋梢枝条9.50 kg,叶片23.24kg,花穗7.19kg。主要养分含量为秋梢枝条中氮0.76%、磷0.26%、钾0.72%、钙0.54%、镁0.15%;叶片中氮1.79%、磷0.17%、钾0.94%、钙0.77%、镁0.25%;花穗中氮2.20%、磷0.30%、钾1.74%、钙0.32%、镁0.29%。单株50 kg的产量,年度枝叶、花穗和果实生长所需主要元素为氮0.70 kg、磷0.10 kg、钾0.46 kg,秋梢期氮、磷、钾用量分别占比全年用量的71.4%、70.0%、63.0%。从多年产量稳定性看,海南省陵水县、琼海市、海口市,广西北海铁山港区、合浦县,广东省廉江市等地是“妃子笑”适应性表现较好的栽培区。综合而言,随着纬度北移和海拔升高,“妃子笑”物候期延后,果实成熟期持续3个月以上;各地区“妃子笑”物候期相差较大的是末次秋梢成熟期和果实成熟期,差异较小的是花芽诱导期;枝叶养分需求较大,确保秋梢生长量是支撑产量和品质的重要基础。

基于CAMM和CLDAS的黄淮海冬小麦成熟期连阴雨时空特征

利用黄淮海地区2008—2023年的CLDAS数据和同期65个农业气象观测站的冬小麦花期、成熟期观测数据,订正机理性中国农业气象模式(CAMM)中发育模块(RAM)的参数,评估模式对冬小麦成熟期的模拟精度,而后重构格点化的历年成熟期日期,统计成熟期前6天后9天共16天的降水量和雨日数,随后基于连阴雨指标,研究连阴雨的时空分布特征。结果表明:(1)RAM模式对冬小麦成熟期具有较好的模拟能力,各站RMSE平均值为2.28±0.46 d,模拟值与实测值的R2为0.915。(2)黄淮海地区冬小麦成熟期降水量和雨日数均呈南北两端高中间低的空间分布格局,区域平均降水量为8.8~84.6 mm,平均值为31.9 mm,雨日数为1.0~9.1天,平均值为5.4天。(3)2008—2023年连阴雨灾害波动较大,其中2009、2013、2018和2023年较为严重,大致呈4~5年发生一次的周期性规律,且灾情呈加重的趋势。(4)连阴雨灾害在黄淮海地区北部很少发生,河北和山东交界处偶发,灾害高发重发区主要集中在河南省,尤其是郑州以南的驻马店和信阳一带最为严重,发生频率约为5年一遇,持续天数多在9天以上。

蒙古国西部地区植被物候变化特征及其对气候因子的响应

对陆上生态体系而言,植物生理季节性变化是衡量其对气候转变反响的关键度量尺度,尤其对全球气温上升现象极为敏感的高纬度与高海拔地带的植物生理季节性。本研究借助MOD13A1卫星遥感资料,叠加温度与降水数据,剖析2000~2021年间蒙古国西部地区植被生长季始期(Start of growing season,SOS)、生长季长度(Length of growing season,LOS)以及生长季末期(End of growing season,EOS)的时空变化特征和海拔依赖性变化机制。结果如下:(1)蒙古国西部地区的SOS主要集中在第90~125 d,近22 a来SOS呈微弱的提前趋势,提前幅度为0.23 d/a。(2)植被物候与气象要素的关系表明,2月的气温和降水与SOS显著负相关(P<0.05),1月的气温和降水与SOS显著正相关(P<0.05),而EOS主要受8月气温和降水的影响。(3)草甸草原和典型草原SOS主要受降水影响,高山草原、荒漠草原以及针叶林的SOS主要受气温影响,所有植被类型的EOS对温度的响应更大。总的来说,研究区植被物候与气候因子表现出季节性的差异,响应规律复杂。

结合GWRFR和作物物候信息的玉米产量早期预测

及时并准确地估计作物产量,对保障粮食安全、维护世界粮食供应稳定具有重要意义。此前,已有许多研究者使用机器学习方法对作物产量预估进行研究。然而,结合作物的空间分布、使用局部模型进行分析的研究较少;且诸多研究均以年份为时间尺度进行建模,未能精细到作物生长的各个阶段,无法实现作物产量的早期预测。针对以上问题,该研究结合多源遥感数据,利用随机森林(random forest,RF)以及地理加权随机森林(geographically weighted random forest regression,GWRFR)模型对美国县级玉米产量进行建模,探讨全局与局部模型在玉米产量预测方面的性能;并通过将GWRFR模型应用于玉米的各个物候期,获取了玉米产量的最佳提前预测时间。结果表明,GWRFR局部模型的精度(R^(2)=0.87,RMSE=864.21 kg/hm^(2))高于传统的RF全局模型(R^(2)=0.83,RMSE=994.75 kg/hm^(2)),并且能够较好地克服空间数据的非平稳性,即使在全局模型中加入经纬度作为变量,RF模型的预测效果(R^(2)=0.85,RMSE=890.88 kg/hm^(2))仍然低于GWRFR模型。对于玉米产量的预测可以提前至收获前2~3个月,即在乳熟期前后就能得到比较准确的预测结果(R^(2)=0.90,RMSE=748.39 kg/hm^(2))。该研究结果可为大尺度作物产量预估提供一种新的思路,对区域或全球其他作物的产量预测也具有一定的指导意义。

南疆阿拉尔垦区棉花物候期变化的关键气候驱动因子分析

为提高南疆阿拉尔垦区棉田气候变化适应能力,本研究选取1990-2020年南疆阿拉尔垦区棉花物候期及同期地面气象数据,综合运用最小二乘法、相关性分析法、Mann-Kendall非参数突变检验和优势主导分析方法,重点分析南疆阿拉尔垦区棉花物候期动态变化及其关键气候驱动因子。结果表明,1990-2020年南疆阿拉尔垦区棉花播种期、出苗期、吐絮期和停止生长期的提前分别以平均气温升高、气温日较差增大、最低气温升高和最高气温升高影响为主,各影响因子的贡献率分别为52.39%、100.00%、31.35%和100.00%;棉花现蕾期的推迟以降水量的减少影响为主,贡献率达60.55%;开花期的提前与气候变化关系不大。1990-2000年棉花现蕾期和开花期的推迟分别以降水量的减少和气温日较差的减小影响为主,各影响因子的贡献率分别为57.04%和100.00%;1990-2010和2011-2020年棉花吐絮期的阶段性提前分别以平均气温和最低气温的升高影响为主,各影响因子的贡献率分别为30.89%和36.46%。本研究结果可为垦区棉田积极应对与适应气候变化提供理论依据。

基于光周期和温度的物候模型对华北平原刺槐始花期的模拟

光周期和温度是影响木本植物开花的两大关键气象因素。基于我国华北平原1963—2018年57个站点的刺槐始花期实测数据,构建了6种基于气温或光周期驱动的春季物候过程模型(积温模型、光周期模型、光周期-温度顺序模型、温度-光周期顺序模型、光周期-温度平行模型、光周期-温度乘法模型),并进行了参数率定和模型比较优选,以期明确刺槐开花的主导驱动因子以及潜在的光温作用机制。根据内部模拟的赤池信息准则(AIC)判定光周期-温度顺序模型的表现最佳,模拟值与观测值的相关系数(r)为0.86,均方根误差(RMSE)为4.81d,纳什效率系数(NSE)达到0.74,说明刺槐始花期的发生同时受到光周期和温度的作用。同时,在华北平原14个代表性站点上,光周期-温度顺序模型的表现普遍优于均值模型。基于光周期-温度顺序模型的参数率定结果,以下限温度6.5℃和下限日长4.5h来统计刺槐开花的实际有效积温量和实际有效日长累积量的年际变化情况,结果表明56年来刺槐开花的实际有效积温量呈现显著递增趋势,平均每10年增加4.5℃·d(P<0.05),而实际有效日长累积量却呈现极显著递减趋势,平均每10年减少23.9h·d(P<0.01),这说明在气候变暖背景下,刺槐开花的热量需求会更快速完成,引起刺槐开花日期的提前,但自然光周期的年内变化只与地理位置有关,日长累积需求则需要更长的时间完成,因此会在一定程度上抑制春季升温引起的开花日期提前。

Does ash dieback affect the reproductive ecology of Fraxinus excelsior L.?

Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L.and have a major impact on the quantity and quality of pollen and seeds.In this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022.Inflorescences were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern Germany.Not all parameters were examined at every site every year.The average pollen production per tree was estimated at 471.2±647.9 billion pollen grains.In addition,we found that a high number of inflorescences did not equate to high pollen production per inflorescence.Pollen production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced flowers.With regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable pollen.However,a significant difference could only be calculated for trees in the floodplain forest.The percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed orchards.The percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in 2020.Non-viable seeds were usually heavily infested by insects.In general,seed quality was not significantly different between healthy and diseased trees.Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality.Nevertheless,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive performance.Thus,severely diseased trees will transfer their genes to a smaller extent to the next generation.

4种不同果形香花油茶果实生长动态变化分析

【目的】为了更好地指导香花油茶生产。【方法】选取4种不同果形香花油茶无性系68号(橄榄形)、70号(球形)、84号(桔形)、91号(卵形),对香花油茶果实生长发育动态变化进行观测和分析。【结果】1)香花油茶不同无性系果实迅速膨大开始和结束时间均有明显差异。68、70和91号无性系果实体积迅速膨大均始于7月15日,其中70号无性系果实迅速膨大在8月5日结束,期间果实增幅达到8.82 cm^(3),占观测期体积总生长量的50.66%;68和91号无性系在8月25日结束果实迅速膨大,期间体积分别增长了5.47和8.71 cm^(3),分别占观测期体积总生长量的57.07%和51.96%。84号无性系果实体积迅速膨大始于8月5日,并一直持续到10月15日,8月5—25日及8月25日—10月15日期间果实体积增长分别占比34.52%和37.63%。2)果实中籽粒转黑时间与果实结束快速生长期的时间存在相关性,快速生长期结束时间早,籽粒转黑的时间也早。【结论】香花油茶不同无性系果实生长进程存在明显差异,果实迅速膨大关键期主要集中在7月15日—8月25日。

Patterns and drivers of plant sexual systems in the dry-hot valley region of southwestern China

Sexual systems play important roles in angiosperm evolution and exhibit substantial variations among different floras. Thus, studying their evolution in a whole flora is crucial for understanding the formation and maintenance of plant biodiversity and predicting its responses to environmental change. In this study, we determined the patterns of plant sexual systems and their associations with geographic elements and various life-history traits in dry-hot valley region of southwestern China, an extremely vulnerable ecosystem. Of the 3166 angiosperm species recorded in this area, 74.5% were hermaphroditic,13.5% were monoecious and 12% were dioecious, showing a high incidence of diclinous species. Diclinous species were strongly associated with tropical elements, whereas hermaphroditic species were strongly associated with temperate and cosmopolitan elements. We also found that hermaphroditism was strongly associated with showy floral displays, specialist entomophily, dry fruits and herbaceous plants.Dioecy was strongly associated with inconspicuous, pale-colored flowers, generalist entomophily, fleshy fruits, and woody plants, whereas monoecy was strongly associated with inconspicuous, pale-colored flowers, anemophily, dry fruits, and herbaceous plants. In addition, hermaphroditic species with generalist entomophily tended to flower in the dry season, whereas diclinous species with specialist entomophily tended to flower in the rainy season. However, independent of sexual systems, plants that produce dry fruits tended to flower in the rainy season and set fruits in the dry season, but the opposite pattern was found for fleshy fruit-producing plants. Our results suggest that in the dry-hot valleys, plant sexual systems are associated with geographic elements as well as various life-history traits that are sensitive to environmental change.

唐古特瑞香开花物候及繁育系统研究

针对药用植物唐古特瑞香(Daphne tangutica Maxim)野生植株花多果少、坐果率低的问题,以唐古特瑞香野生种群为试验对象,观察其开花物候、花器官形态变化、花粉活力、柱头可授性等特征,并结合花粉-胚珠比(P/O)、杂交指数(OCI)的测定,访花者行为观察,揭示其繁育系统类型及坐果率低的限制因素。结果表明:唐古特瑞香为两性花,顶生或腋生头状花序,花期5—6月,群体开花持续17~22 d,单花序花期8~11 d,单花花期7~9 d;雌蕊先于雄蕊成熟,单花待开时柱头可授性最强,盛开时花粉活力最强;P/O和OCI的判定以及访花者观察显示其以异交为主,部分自交亲和,多数需要如中华蜜蜂(Apis cerana)、三条熊蜂(Bombus trifasciatus)、灰熊蜂(Bombus grahami)等有效传粉者。柱头可授性与花粉活力的最强时期不遇,细长的花冠管需要有效传粉者授粉,盛花期散粉量不高,异交竞争力弱和自交亲和度低,以及有效访花昆虫的数量和种类少等因素可能是造成唐古特瑞香开花量大坐果率低的主要原因。本研究结果为今后规模化、优质化人工繁育唐古特瑞香及祖师麻药材产量提升提供理论依据和实践基础。

9个粉(白)果草莓品种在贵州贵阳栽培比较试验

为筛选出适宜贵州省贵阳地区栽培的粉、白果草莓品种,丰富贵阳地区栽培草莓品种结构,促进贵阳地区草莓产业发展。以9个粉、白果草莓品种为试材,观察物候期,测定植株生长指标及果实品质、产量,比较不同品种在贵阳地区的栽培表现。结果表明:粉玉产量高,硬度最大,可溶性固形物含量高,风味酸甜可口,有香气,口感佳;小白果实成熟期最早,可溶性固形物、可滴定酸含量最高,有香气,风味浓郁酸甜;淡雪果面粉色,果肉浅粉色,可溶性固形物含量、固酸比较高,白粉病病果率低。根据产量、可溶性固形物含量、固酸比、白粉病病果率4个性状的加权得分建立草莓品种筛选标准,筛选出在贵阳地区具有推广前景的草莓品种有粉玉、小白、淡雪。

金银花胡萝卜微管蚜发生规律及防治适期研究

目的:明确金银花胡萝卜微管蚜越冬卵和春季发生蚜型的形态特征和发生规律。方法:2022年2月,在田间观察胡萝卜微管蚜越冬卵分布部位,采集虫卵及各蚜型成虫,室内镜检并描述其形态特征;2022年3—6月,在金银花田按五点取样法选取植株,定期调查各蚜型数量,采用最优分割法划分胡萝卜微管蚜种群动态并分析其与金银花物候的关系。结果:胡萝卜微管蚜虫卵主要分布在金银花植株的芽鳞、树杈和树皮缝等部位。胡萝卜微管蚜春季在金银花上依次发生干母、无翅孤雌蚜和有翅孤雌蚜3个蚜型,其中干母主要发生于3月9日至4月7日,高峰虫量为29.4只/梢;无翅孤雌蚜和有翅孤雌蚜在3月28日至5月27日混合发生,分别于4月19日和5月13日到达高峰,峰值分别为75.5只/梢和105.6只/梢。胡萝卜微管蚜种群动态与金银花物候特征密切相关,在金银花萌芽展叶期,蚜虫种群处于初建期和缓慢增长期,种群数量低,最高虫量为29.4只/梢;金银花抽梢期,蚜虫种群处于快速增长期,数量迅速上升;金银花花蕾期,蚜虫种群处于高峰期,数量达到高峰值,为370.5只/梢;在金银花开花期,蚜虫种群处于衰退期,数量迅速下降,至6月初基本消失。结论:金银花越冬期是防控胡萝卜微管蚜虫卵的关键期,萌芽展叶期是防控该蚜虫春季种群爆发的关键期。

河套灌区农田植被物候和NDVI峰值对气候变化的响应

【目的】研究河套灌区植被物候参数和NDVI峰值时空变化特征及对气候变化的响应。【方法】利用2001—2021年MOD13Q1数据和双logistic四参数模型,识别了河套灌区植被SOS、EOS、LOS、POS、NDVI峰值时空变化特征及对气候变化的响应。【结果】河套灌区植被SOS一般从5月下旬到6月中旬开始,到9月中旬至10月上旬结束,LOS主要介于95~116 d,POS主要介于200~220 d,NDVI峰值主要介于0.5~0.7。植被物候变化趋势主要体现在SOS的推迟、LOS的缩短和NDVI峰值的增加。SOS的推迟导致LOS的缩短。而EOS和POS呈提前和推迟趋势的像元比较接近。河套灌区SOS、EOS、POS与气温均以负敏感为主,与降水量以正敏感为主。NDVI峰值与气温和降水量均呈正敏感。【结论】河套灌区物候参数和NDVI峰值的变化趋势具空间异质性,对不同气候因子的响应也有所差异。

库尔勒香梨芽变材料物候期及坐果特性观测

【目的】观测研究库尔勒香梨芽变材料的物候期及坐果特性,为提升库尔勒香梨品质提供参考依据。【方法】以库尔勒香梨和库尔勒香梨芽变材料为研究对象,设置芽变材料无人工授粉组、普通库尔勒香梨人工授粉组和普通库尔勒香梨无人工授粉组,且3个处理组均不喷施促进萼片脱落的药剂,研究3个处理组的物候期、坐果率及脱萼率。【结果】库尔勒香梨芽变材料与普通库尔勒香梨的物候期高度重合,相差不超过2 d;芽变材料无人工授粉组坐果率与脱萼率>普通库尔勒香梨人工授粉组坐果率与脱萼率>普通库尔勒香梨无人工授粉组坐果率与脱萼率,3个处理组之间均存在极显著差异。【结论】芽变材料与普通库尔勒香梨的物候期基本一致,现有库尔勒香梨种植区的管理方式无需改变即可直接利用该材料进行嫁接;芽变材料的坐果率与脱萼率都显著高于普通库尔勒香梨,在栽培过程中可以有效减少使用化学药剂,降低成本且提高果实品质。