Maheviljeluse meetodite mõju porgandi saagile ja kvaliteedile ning umbrohtudele

A Thesis for applying for the degree of Doctor of Philosophy in Agriculture.The thesis covers two organic studies. The first one aimed to estimate organic carrot yield and quality in comparison of conventional production. Comparison of vegetable production systems has often provided inconsistent results as fertilization rates have been higher in conventional production. This thesis deals with two different fertilization regimes: (1) optimal level of nitrogen (N) fertilization in both systems (TP1); (2) below optimal N fertilization only in organic production (TP2). Quality studies consisted of the determination of the content of total sugars (TS), vitamin C, dry matter (DM), N, nitrate (NO3) and pesticide residues in carrots. The second research aimed to study the effect of rolling-crimping technology (RC) on weed density, weed species richness and weed community in organic vegetable no-till cultivation. For the first time in Estonia, RC technology was used and compared with green manure technology (GM). RC technology crushed or crimped the stems of agroecological service crops (ASC) and retained the residues as mulch on the soil surface thereby suppressing weeds during the cultivation period of the cash crop (cabbage). The results showed that significantly higher marketable yield and lower discarded yield in organic management in TP1 was produced. Despite below optimal N fertilization level in TP2, the marketable yield was on the same level and discarded yield was lower in organic treatment compared to these in conventional treatment. These advantages of organic production over conventional can be explained by the influence of compost on the soil properties compared to the synthetic fertilizer. The content of vitamin C was higher in organically produced carrots in TP1. No significant differences in content of TS, vitamin C and DM were found between organic and conventional treatment in TP2. Conventionally produced carrots had a higher N content only in TP2 and a higher content of NO3 than organic carrots in both trials. Pesticide residues were found in conventional carrots of both trials. RC technology reduced weed density and weed species richness but increased the share of perennial weeds compared to GM.Doktoritöö hõlmab kahte maheviljeluse alast uuringut. Esimese uuringu eesmärk oli hinnata maheporgandi saaki ja kvaliteeti võrrelduna tavatootmise tulemustega. Viljelusviiside võrdlemisel köögiviljakasvatuses on saagi ja kvaliteedi kohta saadud sageli vastukäivaid tulemusi, mis on enamasti seotud suuremate väetisenormide kasutamisega tavaviljeluse variantides. Doktoritöö käsitleb kahte erinevat väetamise süsteemi: (1) optimaalsete lämmastiku (N) normide kasutamine mõlemas viljelusviisis (TP1); (2) optimaalsest madalamate N normide kasutamine ainult mahetootmises (TP2). Kvaliteediuuringud sisaldsid porgandite suhkrute (TS), C-vitamiini, kuivaine (DM), N, nitraatide (NO3) ja pestitsiidide jääkide sisalduse määramist. Teise uuringu eesmärk oli kindlaks määrata rullimis-muljumistehnoloogia (RC) mõju umbrohtude tihedusele, umbrohtude liigirikkusele ja umbrohtude liigilisele kooslusele. Minimeeritud harimise rullimis- muljumistehnoloogiat agro-ökoloogiliste kultuuride (ASC) kasvatamisel kasutati Eestis esimest korda ja võrreldi ASC traditsioonilise purustamise ning sellele järgneva muldaviimise tehnoloogiaga (GM). RC tehnoloogia võimaldab ASC kultuuridest muljur-rulli abil moodustada maapinnale tiheda multšikihi, mis takistab umbrohtude tärkamist ja levimist põhikultuuri (kapsas) kasvu perioodil. Tulemused näitasid, et TP1 katseperioodil saadi maheviljeluses usutavalt suurem kaubanduslik saak ja väiksem mittekaubanduslik saak. Vaatamata optimaalsest madalamale N väetamisele mahevariandis TP2 perioodil oli kaubanduslik saak mõlemas viljelusviisis samal tasemel, mittekaubanduslik saak oli aga maheviljeluses madalam võrreldes tavaviljelusega. Saadud tulemust võis tõenäoliselt põhjustada kompost, millel on mulla omadusi parandav mõju ja sellega eelis sünteetiliste väetiste ees. TP1 katseperioodil oli C-vitamiini sisaldus maheporgandis suurem. TP2 katseperoodil puudusid usutavad erinevused suhkrute, C-vitamiini ja kuivaine sisalduses. Tavaporgandis oli suurem N sisaldus ainult perooodil TP2 ja usutavalt suurem NO3 sisaldus võrreldes maheporgandiga mõlemal katseperoodil. Pestitsiidide jääke leiti mõlema katseperioodi tavaporganditest. Rullimis-muljumistehnoloogia vähendas umbrohtude tihedust ja liigirikkust, samas aga suurenes mitmeaastaste umbrohtude osatähtsus umbrohtude koosluses

The impact of the termination technology of agro-ecological service crops on soil properties in open field vegetable production

ArticleThe agro - ecological service crops (ASC) are introduced in the agro - ecosystems to provide or enhance ecological services, thus promoting the whole soil - plant system equilibrium. To avoid competition with the subsequent cash crops, the growth of the interposed ASC is terminated in advance of the cash crop planting. The traditional, most widespread technique to terminate the ASC is incorporation as green manure into the soil by tillage (GM). However, since tillage includes energy and labour consuming and soil dis turbing operations, the use of no/reduced tillage techniques (as the roller crimping technology - RC) has received increasing interest. An international research consortium (SOILVEG) including Estonian Crop Research Institute, was established in 2015 with th e aim to study among others the impact of ASC termination on soil dry bulk density (BD), water content, soil structure and microbiological activity. Data are collected from Estonian tri als in 2016 and 2017 at Jõgeva. The physical properties of 0 – 40 cm soil layers were determined. Higher BD in soil layers (0 – 20 cm) of plots with ASC and RC was determined comparing to the GM and control plots. Bigger water content in same layer of plots with ASC and the RC was determined comparing to the GM plots. The use of the ASC - s helped to arise ratio of agronomically preferred soil particles. Microbial activity was estimated by assessing of enzyme dehydrogenase activity in 0 – 20 cm soil layer. There were no statistically relevant differences in soil dehydrogenase activit y (DHA) be tween the RC and GM treatments

Changes in Polyphenols Contents and Antioxidant Capacities of Organically and Conventionally Cultivated Tomato (Solanum lycopersicum L.) Fruits during Ripening

Polyphenols of fruits and vegetables form an important part of human dietary compounds. Relatively little is known about accumulation of phenolics during fruits ripening process. The goal of this work was to study the changes in antioxidant activity and in content of 30 polyphenols during ripening of tomato fruits. Five organically and conventionally grown tomato cultivars were investigated at three different ripening stages. Phenolic compounds were extracted with methanol and extracts were analyzed by HPLC-DAD-MS/MS. During ripening, four different changing patterns were observed: (1) high level in green fruits with minimal changes; (2) continuous increase with maximum level in red-ripe fruits; (3) decrease; (4) increase and achieving maximum level at half-ripe stage. Similar change patterns were found for organic and conventional fruits. The accumulation patterns of phenolic compounds were similar in standard-type tomatoes but differed in several cases in cherry-type cultivar. Although contents of some polyphenols decreased during ripening, total phenolics and free radical scavenging activity increased in all studied cultivars and in case of both cultivationmodes. The changes in content of phenolic compounds during ripening were greatly influenced by cultivars, but cultivation mode had only minor impact on dynamics in polyphenols contents in tomato fruits.Peer reviewe

Efeito do molibdênio na produção e nos teores foliares de nutrientes do morangueiro

Strawberries (Fragaria x ananassa Duch.) cv. Campinas were cultivated in nutrient solution using five levels of molybdenum (Mo), 0.0010 ppm, 0.010 ppm, 0.10 ppm, 1.0 ppm and control (without applying molybdenum). The experiment was carried out in greenhouse and phytothron at Agronomy School of the Federal University of Rio Grande do Sul, Brazil, to evaluate the changes in the mineral status of the leaves and the quality of the berries. The concentration of Mo in the leaves, at the beginning of fruiting stage, varied from 0.5 ppm to 64 ppm. No visual symptoms of deficiency or toxicity were observed. The total N in the levels was affected significantly by Mo and this can probably be attributed to its toxic effect. However nitrate, P, K, Ca, Mg and leaf area were not affected by the treatments. Total solid solubles, acidity, total solid solubles/acidity and ascorbic acid contents of the berries were not influenced by Mo. Average weight of the berries were affected by treatments and presented a quadratic regression response.Morangueiros (Fragaria x ananassa Duch.) cv. Campinas (IAC 2712) foram cultivados em solução nutritiva e submetidos a cinco níveis de molibdênio (Mo): 1,0 ppm, 0,10 ppm, 0,010 ppm, 0,0010 ppm e testemunha (sem aplicação de Mo). A fase experimental foi conduzida em casa de vegetação e câmara de crescimento, na Faculdade de Agronomia da UFRS para avaliar as alterações no estado nutricional das plantas e na qualidade de seus frutos. A concentração de Mo nas folhas, colhidas de plantas no estádio de início de frutificação, aumentou linearmente, de 0,5 ppm a 64 ppm. Não se verificaram sintomas de deficiência ou toxidez. Os teores foliares de nitrato, P, K; Ca e Mg e a área foliar não foram afetados pelos níveis de Mo; no entanto, os teores de N-total diminuíram linearmente com o aumento da concentração de Mo, o que se atribui a um possível efeito de sua fitotoxidez. Os sólidos solúveis totais (SST), a acidez titulável, a relação SST/acidez e os teores de ácido ascórbico dos morangos não foram afetados pelo Mo. O peso médio de frutos sofreu um efeito quadrático, aumentando até a concentração de 0,10 ppm de Mo na solução

Analysis technique for exceptional points in open quantum systems and QPT analogy for the appearance of irreversibility

We propose an analysis technique for the exceptional points (EPs) occurring in the discrete spectrum of open quantum systems (OQS), using a semi-infinite chain coupled to an endpoint impurity as a prototype. We outline our method to locate the EPs in OQS, further obtaining an eigenvalue expansion in the vicinity of the EPs that gives rise to characteristic exponents. We also report the precise number of EPs occurring in an OQS with a continuum described by a quadratic dispersion curve. In particular, the number of EPs occurring in a bare discrete Hamiltonian of dimension $n_\textrm{D}$ is given by $n_\textrm{D} (n_\textrm{D} - 1)$; if this discrete Hamiltonian is then coupled to continuum (or continua) to form an OQS, the interaction with the continuum generally produces an enlarged discrete solution space that includes a greater number of EPs, specifically $2^{n_\textrm{C}} (n_\textrm{C} + n_\textrm{D}) [2^{n_\textrm{C}} (n_\textrm{C} + n_\textrm{D}) - 1]$, in which $n_\textrm{C}$ is the number of (non-degenerate) continua to which the discrete sector is attached. Finally, we offer a heuristic quantum phase transition analogy for the emergence of the resonance (giving rise to irreversibility via exponential decay) in which the decay width plays the role of the order parameter; the associated critical exponent is then determined by the above eigenvalue expansion.Comment: 16 pages, 7 figure

Predicting the risk of falling – efficacy of a risk assessment tool compared to nurses' judgement: a cluster-randomised controlled trial [ISRCTN37794278]

BACKGROUND: Older people living in nursing homes are at high risk of falling because of their general frailty and multiple pathologies. Prediction of falls might lead to an efficient allocation of preventive measures. Although several tools to assess the risk of falling have been developed, their impact on clinically relevant endpoints has never been investigated. The present study will evaluate the clinical efficacy and consequences of different fall risk assessment strategies. STUDY DESIGN: Cluster-randomised controlled trial with nursing home clusters randomised either to the use of a standard fall risk assessment tool alongside nurses' clinical judgement or to nurses' clinical judgement alone. Standard care of all clusters will be optimised by structured education on best evidence strategies to prevent falls and fall related injuries. 54 nursing home clusters including 1,080 residents will be recruited. Residents must be ≥ 70 years, not bedridden, and living in the nursing home for more than three months. The primary endpoint is the number of participants with at least one fall at 12 months. Secondary outcome measures are the number of falls, clinical consequences including side effects of the two risk assessment strategies. Other measures are fall related injuries, hospital admissions and consultations with a physician, and costs

Roller-Crimping As An Alternative To Incorporation Of Agro-Ecological Service Crops Changes Nitrogen Dynamics In Organic Cabbage Production Under Northern And Western European Conditions

Agro-ecological service crops (ASCs) are used to improve organic vegetable production in terms of weed suppression, nitrogen (N) recycling, or addition of N through symbiotic N2 fixation by legumes. Full incorporation (FI) of ASCs is commonly conducted to terminate ASCs, but alternative termination can be obtained by roller-crimping (RC) in reduced tillage systems. Field experiments were conducted in Estonia, Denmark, and at three locations in Belgium during two growing seasons (autumn 2015-2017) to investigate the effect of ASC termination method (FI and RC) and ASC species (pea, pea/cereal mixtures and cereals), compared with a bare soil control, on soil mineral N content, cabbage yield and N accumulation. Cabbage yield and N accumulation were reduced under RC compared to BS and FI in a majority of cases mainly due to reduced soil mineral N availability, in some cases owing to a later ASC termination time. Furthermore, slower mineralisation of soil organic matter and ASCs at the soil surface contributed to the yield reduction under RC as compared with FI. Cabbage yield could be maintained under RC at standard fertilisation rate following pea ASC in Denmark. The RC system needs further investigation to improve N availability to the succeeding crop before it can be implemented in organic vegetable production

Projective Hilbert space structures at exceptional points

A non-Hermitian complex symmetric 2x2 matrix toy model is used to study projective Hilbert space structures in the vicinity of exceptional points (EPs). The bi-orthogonal eigenvectors of a diagonalizable matrix are Puiseux-expanded in terms of the root vectors at the EP. It is shown that the apparent contradiction between the two incompatible normalization conditions with finite and singular behavior in the EP-limit can be resolved by projectively extending the original Hilbert space. The complementary normalization conditions correspond then to two different affine charts of this enlarged projective Hilbert space. Geometric phase and phase jump behavior are analyzed and the usefulness of the phase rigidity as measure for the distance to EP configurations is demonstrated. Finally, EP-related aspects of PT-symmetrically extended Quantum Mechanics are discussed and a conjecture concerning the quantum brachistochrone problem is formulated.Comment: 20 pages; discussion extended, refs added; bug correcte

Overcoming the fear of lethal injury: Evaluating suicidal behavior in the military through the lens of the Interpersonal–Psychological Theory of Suicide

Suicide rates have been increasing in military personnel since the start of Operation Enduring Freedom and Operation Iraqi Freedom, and it is vital that efforts be made to advance suicide risk assessment techniques and treatment for members of the military who may be experiencing suicidal symptoms. One potential way to advance the understanding of suicide in the military is through the use of the Interpersonal-Psychological Theory of Suicide. This theory proposes that three necessary factors are needed to complete suicide: feelings that one does not belong with other people, feelings that one is a burden on others or society, and an acquired capability to overcome the fear and pain associated with suicide. This review analyzes the various ways that military service may influence suicidal behavior and integrates these findings into an overall framework with relevant practical implications. Findings suggest that although there are many important factors in military suicide, the acquired capability may be the most impacted by military experience because combat exposure and training may cause habituation to fear of painful experiences, including suicide. Future research directions, ways to enhance risk assessment, and treatment implications are also discussed.Psycholog