Effect of defoliation on yield maturity parameters in grapevine (Vitis) cultivar 'Hasanski Sladki'

Bakalaureusetöö aianduse erialalBakalaureusetöö eesmärgiks oli välja selgitada lehtede eemaldamise mõju veiniviinamarja sordi 'Hasanski Sladki' marjamahla kuivaine ja hapete sisaldusele ning küpsusparameetritele. Uurimustöö püstitatud hüpoteesiks oli, et lehtede eemaldamine mõjutab oluliselt ka Eesti tingimustes kasvatatud viinamarjade valmimist ja biokeemilist koostist. Katse viidi läbi avamaa tingimustes Eesti Maaülikooli Rõhu Katsejaamas Tartumaal. Lehtede eemaldamine vähendas orgaaniliste hapete sisaldust, mis varieerus vahemikus 1,3–1,6%. Samas aga ei saavutatud soovitatud vahemikku, mis kirjanduse andmetel on 0,6–0,7%. Lehtede eemaldamine avaldas positiivset mõju mahla kuivaine ja orgaaniliste hapete suhtele. Võrreldes kontrollvariandiga olid eemaldatud lehtedega katsevariantide marjad magusamad. Küpsusindeksit (°Brix × pH²) mõjutas oluliselt lehtede eemaldamine – tulemused jäid vahemikku 146–172. Suurim küpsusindeks oli variandil, mille puhul lehed eemaldati kahelt poolt roheliste viljade faasis. Ent samas ei saavutanud punase veini valmistamiseks soovitatud küpsusindeksit (200) ükski katsevariant. Soovituslik mahla kuivaine sisaldus on 20 °Brix ja katses jäi mahla kuivaine vahemikku 17–20 °Brix. Statistiliselt olulist mõju lehtede eemaldamine ei avaldanud.The purpose of the Bachelor thesis was to identify the effects of defoliation on soluble solids and acid content and yield maturity parameters in grape cultivar ‘Hasanski Sladki’. The hypothesis of this research was that defoliation has a significant effect on fruit maturity and biochemical composition of grapes grown in Estonian climate conditions. The experiment was carried out at the Rõhu Experimental Station of the Estonian University of Life Sciences in open field conditions. Defoliation decreased the content of organic acids, which varied in the range of 1.3…1.6%. The range recommended in the literature (0.6…0.7%) was not reached. Defoliation had a positive effect on the ratio of soluble solids and organic acids. Grapes from defoliated vines were sweeter compared to the control group. The maturity index (°Brix × pH²) was significantly affected by defoliation, the results ranging from 146 to 172. The highest maturity index was seen on the grapevine which had leaves removed from two sides in the early phase of berry development. No treatment reached the maturity index recommended for the production of red wine (200). The soluble solids content in the must was 17…20 °Brix for experimental groups, the recommended value being 20 °Brix. Defoliation had no statistically significant effect on maturity parameters

Time-series MODIS Image-based Retrieval and Distribution Analysis of Total Suspended Matter Concentrations in Lake Taihu (China)

Although there has been considerable effort to use remotely sensed images to provide synoptic maps of total suspended matter (TSM), there are limited studies on universal TSM retrieval models. In this paper, we have developed a TSM retrieval model for Lake Taihu using TSM concentrations measured in situ and a time series of quasi-synchronous MODIS 250 m images from 2005. After simple geometric and atmospheric correction, we found a significant relationship (R = 0.8736, N = 166) between in situ measured TSM concentrations and MODIS band normalization difference of band 3 and band 1. From this, we retrieved TSM concentrations in eight regions of Lake Taihu in 2007 and analyzed the characteristic distribution and variation of TSM. Synoptic maps of model-estimated TSM of 2007 showed clear geographical and seasonal variations. TSM in Central Lake and Southern Lakeshore were consistently higher than in other regions, while TSM in East Taihu was generally the lowest among the regions throughout the year. Furthermore, a wide range of TSM concentrations appeared from winter to summer. TSM in winter could be several times that in summer

Alatskivi Looduskeskuse kujunemine ja rakendamisvõimalused

https://www.ester.ee/record=b5466685*es

Mapping Flood Extent and Frequency from Sentinel-1 Imagery during the Extremely Warm Winter of 2020 in Boreal Floodplains and Forests

The current study presents a methodology for water mapping from Sentinel-1 (S1) data and a flood extent analysis of the three largest floodplains in Estonia. The automatic processing scheme of S1 data was set up for the mapping of open-water flooding (OWF) and flooding under vegetation (FUV). The extremely mild winter of 2019/2020 resulted in several large floods at floodplains that were detected from S1 imagery with a maximal OWF extent up to 5000 ha and maximal FUV extent up to 4500 ha. A significant correlation (r2 > 0.6) between the OWF extent and the closest gauge data was obtained for inland riverbank floodplains. The outcome enabled us to define the water level at which the water exceeds the shoreline and flooding starts. However, for a coastal river delta floodplain, a lower correlation (r2 < 0.34) with gauge data was obtained, and the excess of river coastline could not be related to a certain water level. At inland riverbank floodplains, the extent of FUV was three times larger compared to that of OWF. The correlation between the water level and FUV was <0.51, indicating that the river water level at these test sites can be used as a proxy for forest floods. Relating conventional gauge data to S1 time series data contributes to flood risk mitigation

Maailma walitseja : [romaan]

https://www.ester.ee/record=b1383379*es

Impact of spring and autumn covers on the technological maturity of grapevine (Vitis) yield

Magistritöö Aianduse õppekavalViinamarjade küpsus saagikoristusel määrab veini stiili ning kvaliteedi. Tehnoloogilist küpsust hinnatakse marjamahla kuivaine, orgaaniliste hapete ja pH sisalduse põhjal. Varasem katsetöö Eestis on näidanud, et jaheda suve tingimustes on marjadel probleeme liiga kõrge happesuse ning madala suhkrusisaldusega. Kasvatustehnoloogiliste võtetega on võimalik mõjutada marjade biokeemilist koostist. 2017. aasta suvel uuriti Eesti Maaülikoolis viljatsooni katmist küpsemise faasis, kuid mitmed võtmetähtsusega protsessid leiavad marjas aset arengu algfaasis. Sellest tingituna püstitati hüpotees, et kevad- ja sügiskatetega saab mõjutada viinamarjade küpsemist ja tehnoloogilise küpsuse parameetreid. Uurimistöö eesmärk oli hinnata katete mõju hübriidsortide ‘Zilga’ ja ‘Hasanski Sladki’ marjade tehnoloogilise küpsuse parameetritele: mahla kuivaine, orgaaniliste hapete ja pH sisaldusele. Katse viidi läbi 2018. aastal avamaa tingimustes Eesti Maaülikooli Rõhu katsejaamas Tartu maakonnas. Katsesortideks olid hübriidsordid ‘Hasanski Sladki’ ja ‘Zilga’. Kattematerjalidena kasutati polüetüleenkilet, varjutuskangast ja katteloori. Kevadkatted paigaldati mõlemale sordile perioodiks 16.05–11.06. Sordil ‘Hasanski Sladki’ olid kontrollvariandiks katmata viinapuud, sordil ‘Zilga’ kontrollvariant puudus. Sügiskatteid kasutati ainult sordil ‘Hasasnski Sladki’ ja katteid kasutati viinapuudel, mis olid kevadel katmata. Sügiskatted olid kasutusel perioodil 16.08–19.09. Mahla kuivainesisaldus kevadkatte kasutamisel oli hübriidsordil ‘Hasanski Sladki’ 21 °Brix, katete kasutamine kuivainesisaldust ei mõjutanud. Kevadine katmine mõjutas hübriidsordi ‘Zilga’ mahla kuivainesisaldust, mis jäi vahemikku 14–16 °Brix. Kõige kõrgem tulemus saadi katteloori kasutades. Sügiskatete kasutamisel varieerus sordi ‘Hasanski Sladki’ kuivainesisaldus vahemikus 20–21 °Brix, olles kõrgeim kilekatte kasutamisel. Orgaaniliste hapete sisaldus katsemarjade mahlas varieerus sordil ‘Hasanski Sladki’ vahemikus 0,51–0,63 mg/100g. Madalaim oli happesisaldus kilekatte kasutamisel ning kõrgeim kattelooriga. ‘Zilga’ orgaaniliste hapete sisaldus varieerus vahemikus 0,38–0,54 mg/100g. Kõige kõrgem tulemus saadi varjutuskanga kasutamisel ning madalaim kilekattega. Sügiskatete kasutamisel varieerus sordi ‘Hasanski Sladki’ orgaaniliste hapete sisaldus vahemikus 0,62–0,85 mg/100g, olles kõrgeim linnuvõrguga variandis ning madalaim varjutuskangaga. Mahla pH jäi kevadkatteid kasutades sordil ‘Hasanski Sladki’ vahemikku 3,7–3,9, kõrgeim oli tulemus kilekatte kasutamisel ning madalaim kontrollvariandis. Sort ‘Zilga’ mahla pH varieerus vahemikus 3,1–3,5, kõige kõrgem oli pH kilekatet kasutades ning madalaim varjutuskangaga. Sügiskatteid kasutades jäi ‘Hasanski Sladki’ pH vahemikku 3,6–3,8. Kõige kõrgem oli pH kilekatte kasutamisel, teiste katsevariantide pH oli 3,6. Tööst järeldus, et katete kasutamisega kevadel ja sügisel on võimalik mõjutada marjade tehnoloogilist küpsust. Senised katsed viinapuude katmisega on toimunud erakordselt jaheda (2017) või kuuma (2018) suve tingimustes, mis on oluliselt mõjutanud ka tulemusi. Katete mõju hindamine vajaks täiendavaid uuringuid.The maturity of grapes at harvest determines the style and quality of the wine. Technological maturity is assessed on the basis of dry matter, organic acids and pH of berry juice. Previous testing in Estonia has shown that due to relatively cool summers the acidity in berries remains too high and sugar content too low. However, the biochemical composition of berries can be manipulated by different viticultural techniques. In the summer of 2017, covering of the fruiting zone after verasion was studied at the Estonian University of Life Sciences, but several key processes in berry development take place in earlier stages. Thus, the hypothesis was that spring and autumn covers can affect the ripening process and the technological maturity of grapes. The aim of the study was to evaluate the effect of covers on the technological maturity parameters of hybrid varieties 'Zilga' and 'Hasanski Sladki': the dry matter content, organic acids and pH in juice. The testing was carried out in 2018 under open field conditions at the Rõhu Testing Station of the Estonian University of Life Sciences in Tartu County. Hybrid varieties 'Hasanski Sladki' and 'Zilga' were studied. Plastic cover, shading fabric and polypropylene fabric were used as covering materials. Spring covers were installed on both varieties from 16th of May to 11th on June. The control group of 'Hasanski Sladki' variety consisted of uncovered vines, while there was no control group 'Zilga'. Autumn covers were only applied to 'Hasanski Sladki' vines that were not covered in spring. Autumn covers were in use from 16th of August to 19th of September. The dry matter content of the juice of 'Hasanski Sladki' was unaffected by the use of spring covers, resulting in 21 Brix °.Spring covers did affect the dry matter content of the juice of the hybrid variety 'Zilga', which ranged from 14 to 16 Brix °.The highest result was obtained with using a polypropylene fabric. With autumn covers, the dry matter content of the 'Hasanski Sladki' variety ranged from 20 to 21 Brix °, reaching the highest levels with plastic cover. The content of organic acids in berry juice varied from 0.51 to 0.63mg / 100g in the 'Hasanski Sladki' variety. Acidity was the lowest in berries covered with plastic and highest in berries covered with polypropylene fabric. Organic acid content of 'Zilga' ranged from 0.38 to 0.54 mg / 100g. The highest result was obtained with the use of the shading fabric and the lowest with plastic cover. With the use of autumn covers, the range of organic acids in 'Hasanski Sladki' ranged from 0.62 to 0.85mg / 100g, being the highest with the use of bird netting and the lowest with the shading fabric. With the use of spring covers, the pH levels of the berry juice of 'Hasanski Sladki' ranged from 3.7 to 3.9, reaching their highest with plastic cover and lowest in control group. The pH levels of the variety 'Zilga' ranged from 3.1 to 3.5, reaching their highest with plastic cover and lowest with shading fabric. With the help of autumn covers, the pH levels of 'Hasanski Sladki' ranged from 3.6 to 3.8. The pH levels were the highest when the plastic cover was used, the pH level of the other test variants was 3.6. The study concluded that the use of covers in spring and autumn can influence the technological maturity of grape berries. So far the tests have been made in exceptionally cool (2017) and hot (2018) summer conditions, which have also had a significant impact on the results. The assessment of the impact of covers would require further research