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Comparative analysis of determination methods for soil reaction and development of conversion functions
No full textMagistritöö
Kalanduse ja rakendusökoloogia õppekavalMulla reaktsioon on oluline indikaator mulla kvaliteedi hindamiseks, ning üks tema tähtsamaid rolle on taimede abistamine toiteelementide omastamisel ja säilitamisel mullas. Liigse happesuse korral on taimede kas pärsitud. Sama on ka liigse aluselisuse korral. Selleks, et taimed saaks optimaalselt kasvada on vajalik määrata mulla happesus, mille määramiseks on mitu erinevat kaudset ja laboratoorset meetodit.
Käesoleva magistritöö eesmärk on võrrelda erinevate põllumuldade pH määramismeetodeid ning töötada välja teisenduse seosed nende kahe meetodi vahel. Töös kasutati 142 põllumulla proovi mis määrati kahes erinevas lahuses, KCl ja CaCl2. Tulemusena pH väärtused varieerusid vastavalt meetodile. KCl oli happelisem keskkond seega tulemused olid väiksemad kui CaCl2 lahuses määratuna. Lisaks tuli kahe määramismeetodite vähe suurem just happelistemate muldade puhul. Neutraal ja aluseliste muldade puhul on meetodite vahe peaaegu, et olematu. Tulevikus võiks suurema valimi kogusega teha mõõtmisi ka teise määramismeetodiga, milleks oleks deioniseeritud vesi.Soil reaction is an important indicator for assessing soil quality, and one of its most significant roles is assisting plants in the uptake and retention of nutrients in the soil. When there is excessive acidity, plant growth is inhibited. The same applies in the case of excessive alkalinity. To ensure optimal plant growth, it is necessary to determine the soil’s acidity, for which there are several indirect and laboratory-based methods.
The aim of this master's thesis is to compare different pH determination methods for agricultural soils and to develop conversion relationships between two of these methods. In this study, 142 agricultural soil samples were analyzed using two different solutions: KCl and CaCl₂. As a result, the pH values varied depending on the method used. KCl provided a more acidic environment, so the results were lower than those measured in the CaCl₂ solution. Additionally, the difference between the two methods was slightly greater for more acidic soils. For neutral and alkaline soils, the difference between the methods was almost negligible. In the future, with a larger sample size, it would be beneficial to also perform measurements using a third method—deionized water
The effect of the chemical pesticide Columbo on wireworms
No full textBakalaureusetöö
Aianduse õppekavalNaksurlased, kes kuuluvad mardikaliste seltsi, on levinud ja tõsised kahjurid maailmas. Nende vastsete tõrjumine on keeruline, sest nad elavad mullas mitu aastat ja tõhusaid insektitsiide nende tõrjeks on vähe. Lõputöö eesmärgiks on selgitada keemilise tõrjevahendi Columbo 0,8 MG mõju mullas elavatele naksuri vastsete liikumisaktiivsusele ja suremusele. Katsed viidi läbi laboritingimustes mullaareenidel, mille keskel oli Columbo 0,8 MG graanulitega ümbritsetud nisuseemned. Kaameraga filmiti 4 tunniga üles traatusside liikumist, käitumist ning hiljem analüüsiti andmeid. Püretroidiga ümbritsetud nisuseemned olid atraktiivsed ja meelitasid naksuri vastseid ligi. Insektitsiid põhjustas traatussidele vingerdamise ja liikumisaktiivsuse suurenemist kokkupuutel. Pärast nelja tundi taastus traatusside vingerdamine, kuid vastsed olid endiselt hüperaktiivsed. Katse lõpuks taastusid kõik katses kasutatud traatussid ja suremust ei täheldatud. Edasi tuleks uurida, missugused on insektitsiidi Columbo 0,8 MG surmavad doosid traatussidele.Click beetles, which belong to the order Coleoptera, are widespread and serious pests worldwide. Controlling their larvae is challenging because they live in the soil for several years, and there are few effective insecticides available. The aim of this thesis is to investigate the effect of the chemical control agent Columbo 0.8 MG on the movement activity and mortality of click beetle larvae living in the soil. The experiments were conducted under laboratory conditions in soil arenas, where wheat seeds surrounded by Columbo 0.8 MG granules were placed in the center. The movement and behavior of the wireworms were recorded with a camera over a period of four hours, and the data were later analyzed. The wheat seeds surrounded by the pyrethroid were attractive and lured the click beetle larvae. Upon contact, the insecticide caused wriggling and increased movement activity in the wireworms. After four hours, the wriggling subsided, but the larvae remained hyperactive. By the end of the experiment, all the wireworms used in the test had recovered, and no mortality was observed. Further research is needed to determine the lethal doses of the insecticide Columbo 0.8 MG for wireworms
Effect of using Pseudomonas fluorescens bacteria, Glomus mosseae fungus and liquid organic fertilizer on soil available nitrogen and phosphorus and some characteristics of fenugreek (Trigonella foenum graecum L.) and choline seed content
No full textReceived: October 24th, 2024 ; Accepted: March 10th, 2025 ; Published: March 31st, 2025 ; Correspondence: [email protected] factorial pot experiment was conducted during the fall season of 2023–2024 in the fields of the College of Agriculture/University of Wasit, according to a randomized complete block design (RCBD) with three factors and three replicates. The first factor is the bacterial inoculum Pseudomonas fluorescens at two levels (addition B1 and without addition B0), the second factor is the fungal fertilizer Glomus mosseae at two levels (addition M1 and without addition M0), and the third factor is the liquid organic fertilizer at two levels as well (addition O1 and without addition O0) added in two batches, thus we have eight treatments with three replicates so that the number of experimental units is 24 experimental units (pots). Available nitrogen and phosphorus in the soil, plant height, number of branches, number of pods, number of seeds per pod, seed content of active substance choline, and biological yield were measured. The triple interaction treatment of the three factors (B1M1O1) gave the best results for the mentioned traits, followed by the dual interaction treatment between bacteria and fungi (B1M1), then the dual interaction treatments between bacteria and liquid organic fertilizer B1O1 and between fungi and liquid organic fertilizer M1O1, then the single treatments B1, M1, and O1, and finally the control treatment without additives (B0M0O0), which gave the lowest results. The mycorrhizal reliability was calculated for each of the plant heights, number of pods, and biological yield and was 22.2, 68.25, and 33.00%, respectively
Rõuge lakes
No full textPhytoplankton biomass, diversity and abundance in samples collected from Rõuge lakes during the period 1933-2003
Ähijärv
No full textPhytoplankton biomass, diversity and abundance in samples collected from Lake Ahijärv during the period 1952-2000
Productive and biochemical responses of Marandu grass under fertilization protocols
No full textReceived: August 25th, 2024 ; Accepted: January 6th, 2025 ; Published: January 20th, 2025 ; Correspondence: [email protected] aim of this study was to evaluate the effects of liming and chemical fertilization protocols, containing different combinations of nitrogen (N), phosphorus (P) and potassium (K), on the photosynthetic pigments, productive characteristics and carbohydrate concentration of Urochloa brizantha cv. Marandu. Five fertilization protocols were evaluated (PK fertilizer combination; NP fertilizer combination; NK fertilizer combination; NPK fertilizer combination; and without fertilizer - control), associated or not with soil correction via liming, in a completely randomized design, with four replicates. The experimental units consisted of plastic pots with a capacity of 12 liters, which were filled with 10 dm³ of sandy clay loam soil. Seeds of Urochloa brizantha cv. Marandu, with 80% cultural value were used. With the corrected soil, the NP protocol provided greater production of dry mass of residue (PMSRE), root volume, leaf area, leaf area index, total sugar content (AST) and starch in the root, compared to the other protocols. Without liming, the NP protocol provided greater production of aerial part dry mass (PMSPA), root volume, leaf aerial volume, leaf aerial index and AST content in leaves, roots and residue. The NPK protocol, with liming, was 73% higher in chlorophyll a content, 50% in carotenoid content, 90% in PMSPA, 78% in leaf area and 76.2% in leaf area index, compared to the soil without correction. The use of NP fertilization with liming is recommended as it provides positive responses on the photosynthetic pigments, productive characteristics and total sugar content of Marandu grass
Peculiarities of soybean growth and development on gray forest soils
No full textReceived: August 2nd, 2024 ; Accepted: October 29th, 2024 ; Published: April 4th, 2025 ; Correspondence: [email protected] scientific and experimental five-year study highlighted the detailed development of technological techniques for growing soybeans under different hydrothermal growing conditions on gray forest soils. The conducted experimental studies established that under the influence of climatic factors, the duration of the growing season of soybean plants changes, and these factors, as a result, affect the field germination, the conservation factor and, as a result, the yield of plants. It has also been proven that during the ontogenesis of the plant, there are natural changes in linear dimensions depending on varietal characteristics, weather conditions and factors that were investigated. On average, over the years of research, the length of the soybean vegetation period ranged from 110 to 118 days, while the longest vegetation period was recorded on the experimental variants, where seeds were inoculated with the BTU Bioinoculant preparation and two foliar feedings were carried out in phase 3 – the third leaf and budding Helprost soybean. Starting from the flowering phase, soybean plants reacted more intensively to the studied factors. On the options where foliar fertilizing was carried out with Helprost soy mineral fertilizer (2.5 L ha-1) against the background of inoculation with BTU Bioinoculant (2 L t-1), the flowering period lasted 28 ± 3.6 days, which is 3 days more compared to with areas where foliar fertilization was not carried out and for 6 days – compared to the control. This is explained by the influence of a number of factors, in particular, hydrothermal, biotic, soil and anthropogenic. During the period of full ripeness, in connection with the action caused by pests and diseases, certain technological techniques and factors that were put to study, the density of plants according to the experimental options was from 488 ± 28.3 to 552 ± 34.5 thousand ha-1
Maardu
No full textPhytoplankton biomass, diversity and abundance in samples collected from Lake Maardu during the period 1953 -1990
Efficiency of seed priming and co-treatment strategies in salt effect mitigation using Nicotiana glauca leaf extract on tomato seedlings (Solanum lycopersicum L.)
No full textReceived: December 18th, 2024 ; Accepted: March 31st, 2025 ; Published: April 3rd, 2025 ; Correspondence: [email protected] Al-Baha region suffers from soil salinity, negatively impacting agriculture. Current study examined aqueous extracts from Nicotiana glauca as plant-based biostimulants to alleviate salinity's effects and reduce chemical fertilizer use. An aqueous extract of N. glauca, applied in ascending doses of 20%, 50%, and 100%, was being used. This biostimulant was applied using two methods: seed priming and co-treatment on the seeds of Solanum lycopersicum L. Results indicated that all tested doses, whether applied through seed priming or co-treatment, enhanced the final germination percentage (FGP) and reduced the mean germination time (MGT) under saline conditions. With priming, the 20% dose was most effective in reducing salt treatment effects on FGP, improving it by 5% compared to untreated salt-stressed seeds. In co-treatment, the 100% dose showed a 4.5% reduction in FGP decline referring to untreated and stressed seeds. For priming treatments, the 20% dose reduced MGT by 22%, while the 50% dose in co-treatment reduced it by 28% compared to untreated and stressed seeds. The priming strategy used in this study did not result in significant enhancements in growth parameters, particularly in the fresh weight (FW) and dry weight (DW) of the epicotyls. As priming, the 20% dose had the most significant mitigation effect on epicotyl FW, DW and chlorophyll (Chl) content by 15%, 10% and 30% referring to untreated and stressed seedlings, respectively. However, all tested biostimulant doses used as co-treatment proved effective in mitigating the negative effects of salt on epicotyl and root FW, DW, and Chl content. Seedlings treated with various strategies and doses showed a smaller increase in malondialdehyde (MDA) and proline (Pro) levels under salinity stress. As stress indicators, both Pro and MDA levels were significantly reduced when a co-treatment strategy was applied. Furthermore, the results indicated that the effectiveness of the N. glauca aqueous extract in alleviating salt stress could be attributed to its content of several phenolics, flavonoids, and tannins, which possess antioxidant properties that enhance the plant's tolerance against salt-induced oxidative stress
Differences in reproductive performance traits of two Platanthera species : [dataset]
No full textThe species Platanthera bifolia and P. chlorantha (Orchidaceae) are both declining in Europe, but P. bifolia has been diminishing relatively more. Loss of habitats and landscape heterogeneity due to agricultural intensification or abandonment of less fertile areas are primary drivers of decreasing orchid populations. We measured reproductive traits (fruit and flower count per plant, fruit weight, seed number and weight, the proportion of seeds with embryos and germination success) to compare the reproductive success of the two species in different habitats across Estonia. P. chlorantha tends to reach its full fruiting capacity in smaller size classes, despite a relatively low base level. Germination success was low for both species but twice as high for P. chlorantha than its congener. We propose that higher proportion of embryos in fruits of P. chlorantha in shade and woodland growing conditions is related to higher availability of diverse pollinators. P. chlorantha, albeit growing on its northern distribution limit in Estonia, seems to be tolerating the abandonment of its habitats more effectively than P. bifolia, at least with respect to reproductive performance traits. M&M. In 2017 and 2018, we studied seven pure P. bifolia populations, seven pure P. chlorantha populations and three mixed populations, comprising a total of 17 populations