Kartul mahe- ja tavaviljeluse süsteemide võrdluskatses aastatel 2008-2012

Kartul on üheks armastatumaiks kultuuriks nii meil kui maalimas. Kartulit on läbi aegade peetud teiseks „leivaks“ ning tänapäeval ei kujutaks meist keegi ette oma toidulauda, kui sealt puuduks toidukartul. Maheviljelus on Eestis aasta-aastalt laienenud on mahekartulikasvatuse pindala siiski iga aastaga vähenenud. Uurimistöö eesmärk oli uurida kuidas erinevad viljelusviisid mõjutavad mugulate saagistruktuuri elemente ning kui suurt mõju avaldab see saagi kvaliteedile

Flavour Characterization Of Jackfruit (Artocarpus Heterophyllus L.) From Five Cultivars And Optimization Of Canning Conditions For Jackfruit Puree

The study concerns flavour characterization of five jackfruit (Artocarpus heterophyllus L.) cultivars and optimization of canned jackfruit puree production. In the first part of this study, twenty three volatile compounds extracted using dichloromethane solvent extraction were tentatively identified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). As ripening progressed, there was an increase in volatile compound formation. Development of new volatile flavour compounds in trace amounts at day 3 after harvest indicated the start of jackfruit ripening. Data obtained showed that the ripening process of jackfruit was at its optimum at day 5 after harvest. Variation of volatile compounds in different portions (top, middle and bottom) of the fruit during ripening was too little to give any significance. The volatile profiles of jackfruit flavour in five cultivars were established using headspace solid phase microextraction (SPME) and gas chromatography-time of flight mass spectrometry (GC-TOFMS). Qualitative and quantitative analyses were carried out using divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber with an extraction time of 10 min. Thirty seven compounds were identified from the five cultivars tested. Characteristic aroma which are in higher concentrations and contributed to jackfruit flavour were found to be ethyl isovalerate, 3-methylbutyl acetate, I -butanol, propyl isovalerate, isobutyl isovalerate, 2-methylbutanol, and butyl isovalerate. The consistent occurrence of these compounds in all cultivars of jackfruit suggested their importance in contributing to the sweet and fruity note of jackfruit. Concentration of the volatile compounds present played an important role in determining the overall flavour of each fruit cultivar. Each cultivar also possessed its own unique compound which distinguished them from one to another

A discrete time relativistic Toda lattice

Four integrable symplectic maps approximating two Hamiltonian flows from the relativistic Toda hierarchy are introduced. They are demostrated to belong to the same hierarchy and to examplify the general scheme for symplectic maps on groups equiped with quadratic Poisson brackets. The initial value problem for the difference equations is solved in terms of a factorization problem in a group. Interpolating Hamiltonian flows are found for all the maps.Comment: 32 pages, LaTe

In crop rotation green manures as winter cover crops enhance ecosystem services of farming

Organic farming systems should be characterized by excellent soil fertility management to keep plant nutrient cycles short and as closed as possible. Therefore, it is extremely important to establish growing systems that have rotations with appropriate crops and intercrops to ensure fertile and biologically active soils, to enhance biodiversity and to provide high quality crop yields. Locally available organic fertilizers include green manures and animal manure. The influence of green manures as intercrops and these combined with composted cattle manure on soil properties, biodiversity indicators and crop yields was studied in a crop rotation experiment in three organic systems at the Estonian University of Life Sciences

Winter cover crops impact on plant nutrients in an organic crop rotation

In crop rotations winter cover crops (WCC) can play a certain role in organic matter and plant nutrient formation. Under Nordic conditions the selection of crops for winter cover crops is quite limited. The aim of the present research was to explain the biomass and nutrients (N, P and K) formation by certain winter cover crops in an organic crop rotation. The effects of WCC on the following main crop yields were monitored

IMPROVING NITROGEN MANAGEMENT IN REDUCED TILLAGE SYSTEMS BY USE OF GREEN MANURES AND APPROPRIATE OFF-FARM INPUTS: REUSLTS OF TILMAN-ORG. TILMAN-ORG SESSION.

Abstract The TILMAN-project aims to develop robust and sustainable arable crop production systems via the introduction of reduced tillage techniques combined with a strategic use of green manures in organic crop rotations, while maintaining and improving soil quality and crop productivity parameters. The adoption of reduced tillage and/or green manures strongly affects nitrogen quantity and availability during the vegetative period and throughout the crop rotation. Specifically, changing soil and water conditions may affect the availability pattern of nitrogen, notably in spring. We present aggregated data of several long- and medium-term European experimental field studies in which green manures including cut-and-carry-fertilizers, and reduced tillage techniques are used in organic cropping systems. By presenting and analyzing field level nitrogen budgets, insight is gained in the nitrogen dynamics of such systems and possible bottlenecks. Moreover, results of model simulations of these trials by the decision support tool Ndicea are shown and analyzed

Teravilja saak ja saagi kvaliteet sõltuvalt viljelussüsteemist

Jätkusuutlikuks maheviljeluseks on oluline arendada viljelussüsteeme, mis tagaksid elurikkuse suurenemise, mullaviljakuse paranemise ja hea ning kvaliteetse saagi. Selles mängib keskset rolli liblikõielisi kultuure sisaldav ja taimetoitainete tasakaalu säilitav kohalikesse oludesse sobiv külvikord. Taimetoitainetega paremaks varustatuseks saab külvikorras kasutada veel vahekultuure, komposte või sõnnikut. Nende lagunemisel muutuvad toitained taimedele kättesaadavaks aeglasemalt ja ühtlasemalt, kindlustades nii külvikorras järgnevate kultuuride stabiilse varustatuse lämmastikuga. Käesoleva uurimuse eesmärk oli selgitada odra ja nisu saagikus ning saagi kvaliteet nende kasvatamisel viieväljases külvikorras kolmes eri maheviljelussüsteemis, mis erinesid talviste vahekultuuride ja sõnniku kasutamise poolest

Lipase-catalyzed acidolysis of palm olein and caprylic acid in a continuous bench-scale packed bed bioreactor

Enzymatic acidolysis of refined, bleached and deodorized (RBD) palm olein with caprylic acid was carried out in a continuous packed bed bioreactor to produce structured lipid (SL) that can confer metabolic benefits when consumed. Lipozyme® IM 60 from Rhizomucor miehei, a 1,3-specific lipase, was used as the biocatalyst in this study. After 24 h of reaction, 30.5% of the total fatty acid content of the modified oil was found to be caprylic acid, indicating its incorporation into the palm olein. The triacylglycerols (TAGs) of palm olein after acidolysis were separated and were characterized by seven clusters of TAG species with equivalent carbon number (ECN), C28, C30, C32, C34, C36, C38 and C40. Caprylic–oleic–caprylic TAGs were predicted in cluster C32, which recorded the highest amount, with 35.3% of the total TAG. Fatty acid composition at the sn-2 position was determined, by pancreatic lipolysis, as C8:0, 9.2%; C12:0, 2.3%; C14:0, 1.8%; C16:0, 21.3%; C18:0, 4.7%; C18:1, 60.7%. Iodine value (IV), slip melting point (SMP) and differential scanning calorimetric (DSC) analyses of SL were also performed. In IV analysis, SL recorded a drop of value from 60.4 to 48.2 while SMP was reduced from 13 to 4.2 °C, in comparison to RBD palm olein. DSC analysis of SL gave a melting profile with two low melting peaks of −15.97 and −11.78 °C and onset temperatures of −18.43 and −14.03 °C, respectively

Talvine vahekultuur mõjutab kartulimugulate hõbekärnaga nakatumist

Kartuli (Solanum tuberosum L.) hõbekärn (Helminthosporium solani Durieu, Mont) on seenhaigus, mis viimastel aastatel on osutunud tootmises äärmiselt problemaatiliseks. Haigustekitaja nakatab valmivaid mugulaid juba mullas, kuid eoste kaudu levib haigus hoidlas jõudsalt edasi, mistõttu peetakse hõbekärna ka säilitushaiguseks. Patogeen tungib mugulasse läbi loomulike avade siis, kui mugulad on saavutanud juba oma suuruse ja massi, kuid toimub veel koore kinnistumine. Seetõttu on vajalik mugulad põllult võimalikult ruttu koristada. Hõbekärna nakatunud mugulate koore pinnale tekivad pruunikashallid laigud. Kui mugulad puutuvad kokku veega ilmneb nakatunud kohal iseloomulik hõbe-metalne läige. Eriti hästi ongi haigust näha just pestud mugulate pinnalt. Nakatunud mugulatel levivad haiguskolded jõudsalt üle terve mugula ning haigus levib edasi tervetele mugulatele, mis omakorda nakatuvad. Kui hõbekärn on katnud kogu mugula pinna, hakkab selle veesisaldus järk-järgult vähenema. Tekivad massikaod, sest nakatunud mugulad tõmbuvad veekao tõttu kokku. Mugulate hõbekärna nakatumist ei ole võimalik maapealse biomassi järgi tuvastada, sest haigus maapealsel osal ei lööbi. Samuti puuduvad andmed, kui pikalt on hõbekärna tekitaja mullas elujõuvõimeline. Hõbekärna tõrjumiseks puuduvad veel praktilised võtted ning ühtlasi puuduvad ka hõbekärna tekitaja suhtes resistentsed sordid Lebeca jt., mis teeb hõbekärnast kartulikasvatuses ühe ohtlikuma haiguse. Seetõttu ongi vaja uurida, millised agronoomilised võtted on võimelised vähendama mugulate hõbekärnaga nakatumist