Lithuanian Research Research Articles

Plum Cultivar Evaluation on Myrobalan Rootstock in Lithuania

Abstract Twenty plum cultivars on Myrobalan (Prunus cerasifera Ehrh.) seedling rootstock were tested in 2012–2017 at the Institute of Horticulture of the Lithuanian Research Centre for Agriculture and Forestry. Plum trees were spaced at 4.5 × 2.5 m and trained as spindles. Orchard floor management included frequent mowing of grass in the alleyways with herbicide strips along tree rows. ‘Duke of Edinburgh’, ‘Kijevas Vēlā’, ‘Dąbrowicka Prune’, ‘Čačanska Najbolje’, ‘and ‘Štaro Vengrinė’ cultivars were the most vigorous plum trees at the end of 6th year. Their trunk diameter achieved 92–96 mm. ‘Valor’, ‘Queen Victoria’, ‘Herman’, ‘Čačanska Najbolje’, ‘Favorita del Sultano’, ‘Ave’, and ‘Jubileum’ cultivars had the lowest trunk diameter — 72–78 mm. The highest cumulative yield of four fruiting years was recorded for ‘Kometa’ and ‘Violeta’ cultivars, respectively, 43.0 and 46.5 kg/tree. ‘Favorita del Sultano’, ‘Rausvė’, and ‘Kijevas Vēlā’ produced the largest fruits — 52–60 g. The smallest fruit occurred on ‘Dąbrowicka Prune’ and ‘Herman’ cultivars, respectively, 22 and 25 g. ‘Dąbrowicka Prune’ had the highest soluble solids content (SSC) — 19.5%. The least SSC was recorded in ‘Kometa’, ‘Violeta’ and ‘Herman’ fruits — 10.6–11.8%. ‘Renklod Rannij Doneckij’, ‘Čačanska Najbolje’, and ‘Valor’ cultivars had the highest fruit flesh firmness.

Konferencijos „Lietuvos magistrantu informatikos ir IT tyrimai“ darbai

Konferencija „Lietuvos magistrantų informatikos ir IT tyrimai“ skirta pristatyti magistrų baigiamųjų darbų tyrimus informatikos ir IT srityse. Šio renginio tikslas – pakelti magistrantų įgūdžius, supažindinti su kitų magistrantų atliekamais tyrimais, paskatinti domėtis moksline veikla. Konferencijoje savo pranešimus skaitys magistrantai iš Kauno technologijos universiteto, Vilniaus universiteto, Vytauto Didžiojo universiteto.
 Konferencija vyks Lietuvos mokslų akademijoje (LMA). Tai įstaiga, jungianti žymiausius Lietuvos ir savo veikla su Lietuva susijusius mokslininkus. Ji yra nepriklausoma Seimo, Vyriausybės ir jai pavaldžių institucijų ekspertė ir patarėja mokslo bei studijų, kultūros, socialinės raidos, ūkio, gamtosaugos, sveikatos apsaugos, technologijų bei kitais klausimais. LMA įgyvendina šalies mokslui ir eksperimentinei plėtrai reikšmingus ES struktūrinių fondų projektus, rengia šalies bei tarptautines mokslines konferencijas, užsienio mokslininkų seminarus, mokslininkų susitikimus, akademinius skaitymus, parodas. Tikime, kad dalyvavimas šioje LMA vyksiančioje konferencijoje paskatins magistrantus tęsti mokslinę veiklą ir pabaigus magistro studijas.
 Šiuose konferencijos darbuose spausdinami magistrantų pranešimų santraukos ir straipsniai. Tai dažniausiai pirmosios mokslinės publikacijos, bet tikimės, kad ateityje virs į straipsnius prestižiniuose mokslo žurnaluose. To norėtume palinkėti konferencijos dalyviams.

Risk factors for mycotoxin contamination of buckwheat grain and its products

The United Nation’s Food and Agriculture Organisation have indicated that higher contamination of agricultural produce with mycotoxins is associated with the alterations in the weather conditions. The aim of the current study was to quantify mycotoxin contamination on buckwheat grain at early and complete ripening stages and to estimate the effects of the weather conditions on mycotoxin occurrence as well as to consider natural measures that could potentially reduce mycotoxin contamination in buckwheat products. Mycotoxins deoxynivalenol (DON), T-2 toxin (T-2), zearalenone (ZEA), aflatoxin B1 (AFB1), ochratoxin A (OTA) were analysed in fully ripe buckwheat grain in 2013 and at early ripening stages in 2014 and 2015. The field trials of buckwheat were set up at the Perloja Experimental Station, Lithuanian Research Centre for Agriculture and Forestry. The least concentrations of the investigated mycotoxins in buckwheat grain were found in 2013. Particularly high concentrations of AFB1 (up to ~72 μg/kg) were identified in buckwheat grain at early ripening stages in 2014 and 2015. It is likely that buckwheat grain were contaminated with AFB1 under favourable weather conditions, which were uncharacteristic of Lithuania’s climate in 2014 and 2015: hot weather and drought prevailed during the buckwheat flowering and ripening stages. However, such meteorological conditions were less favourable for the synthesis of DON, T-2, ZEA and OTA mycotoxins in buckwheat grain. The high AFB1 contents found in grain question the quality of buckwheat products. Hulls were 10-fold more contaminated with AFB1 than grain, which suggests that they serve as a protective shield against buckwheat groat, bran and flour contamination with this mycotoxin. Phenolic compounds were found to decrease the risk of mycotoxin occurrence in grain: with increasing concentrations of rutin, quercetin and total phenolics content in hulls and grain samples, the contents of trichothecene mycotoxins were significantly (P<0.05) lower.

Towards apple bearing stability in strictly alternating orchard

Investigation of the effect of rootstock on apple bearing stability was performed at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2014-2016. Apple cultivars ‘Auksis’ and ‘Ligol’ on M.26 semi-dwarf rootstock; M.9, B.396 and P 67 dwarf rootstocks; and P 22 super-dwarf rootstock were included in the trial. The orchard was planted in spring 2005. Fruit thinning was not performed up to 2014, in order to maintain the apparent effect of the rootstock. During this period the alternate bearing index (ABI) of ‘Ligol’ varied from 0.58 on B.396 rootstock up to 0.80 on M.9; and ABI of ‘Auksis’ varied from 0.70 on B.396 rootstock up to 0.78 on P 67. Starting from 2014 blossom thinning was initiated in order to stabilize tree bearing. Three crop levels were established expecting apple yield from 20 to 54 t ha(-1). More intensive accumulation of phytohormones at lower crop load levels was recorded. At the same time more intensive flowering inhibiting phytohormones along increasing crop load was established for both cultivars on all rootstocks. Positive effect of crop load adjustment was less obvious in the first year after the treatment but more expressed in the second year. Return bloom depended both on crop load in previous year and on rootstock. Experiment revealed differences between rootstock impact on apple bearing stability. Stable average yield of ‘Auksis’ is possible to maintain at 30 t ha(-1) level with all tested rootstocks. Stable average yield of ‘Ligol’ is possible to maintain at 35 t ha(-1) level on M.9 and B.396 rootstocks, but at more than 50 t ha(-1) level on P 67 rootstock only.

Changes in Physical Fitness among High Grade Schoolgirls

Research background and hypothesis. During the last five years Lithuanian long-term research related to the peculiarities of changes in physical fitness among 10-12 th -grade schoolgirls has not been found. Other research in Lithuania showed negative tendencies of physical fitness changes of Lithuanian schoolchildren and prevailing sedentary lifestyle.Research aim was to determine peculiarities of change results in physical fitness among Kaunas schoolgirls (10–12 th grades).Research methods. The present research included 10 th -grade schoolgirls (n = 244) of Kaunas city who were at school during the research and were able to perform the necessary Eurofit tests: 10 × 5 m Shuttle run, Standing Broad Jump, Sit ups in 30 seconds, 20 m endurance Shuttle run.Research results. Changes in results of Eurofit tests performed from 10 th grade autumn to 12 th grade spring were different. Results of girls (10–12 th -grade) in 10 × 5 m shuttle run test did not change (p > 0.05). Results of standing broad jump improved significantly in Grade 11 (p < 0.05). Results in 20 m endurance shuttle run test improved in Grade 12 (p < 0.05). Results in Sit ups in 30 seconds test improved in spring. Significant differences were found between 10 and 12 th -grade schoolgirls spring Sit ups in 30 seconds test results, and 10 and 11 th -grade autumn results.Discussion and conclusions. Comparison of physical fitness of 10 and 12 th -grade girls showed that it improved only in 20 m endurance shuttle run, in the 11 th grade explosive strength of schoolgirls significantly improved.Keywords: changes in physical fitness, Eurofit tests, physical characteristics.

A model study on the effect of water and cold stress on maize development under nemoral climate

Farmers in northern latitudes face significant risks because of low temperatures and water shortage when attempting to benefit from climate warming by expanding maize for grain. The study was aimed to investigate maize development and suitability of two models to simulate maize growth in a cool climate.Field experiments were conducted at the Lithuanian Research Centre for Agriculture and Forestry on sandy loam soil. Management was performed to guarantee optimum growth. The AquaCrop and AgroC models were calibrated and validated using the data sets from 2015 (cool/dry season) and 2016 (warm/wet), respectively.Both models provided adequate results in terms of simulating total above-ground biomass, grain yield, canopy cover, and soil water content. Grain yield losses due to abiotic stress (low temperature and water shortage) simulated with AquaCrop were 3.41 t ha−1 in cool/dry and 2.02 t ha−1 in warm/wet seasons and for AgroC 4.32 and 2.84 t ha−1, respectively.Maize grain yield above 9 t ha−1 (dry weight) was obtained under favourable temperature and rainfall regime in nemoral climate. Low air temperature, is the main factor defining yield losses, while the water stress, which occurs occasionally, is of secondary importance.

Fungal disease resistance of perspective sugar beet varieties and their yield potential

The research was conducted on 11 sugar beet varieties, grown at the Rumokai Experimental Station of the Lithuanian Research Center for Agriculture and Forestry, in 2016 and 2017. The experiments were carried out on two backgrounds: the crops were not sprayed and sprayed with fungicide epoxiconazole 125 g l–1. During the study years, rust (causative agent Uromyces beticola), powdery mildew (causative agent Erysiphe betae Vaňha Weltzien) and leaf spot disease (causative agent Cercospora beticola Sacc.) were the most prevalent in sugar beet. Rust, the intensity of which was 9.66–61.79%, caused most damage to sugar beet. The intensity of powdery mildew was 12.71–55.98% and that of leaf spot disease was 7.47–54.23%. Of the investigated varieties of sugar beet, the most sensitive to leaf spot disease were ‘Merens’, ‘Balear’, ‘Davinci’, ‘Kashmir’ and ‘Pottok’, the most resistant were ‘Berton’, ‘Selma KWS’ and ‘Wellington’. ‘Merens’ and ‘Texel’ were the most sensitive to rust. This disease was least damaging to the ‘Minta’, ‘Berton’ and ‘Strauss’ varieties. Powdery mildew was most harmful to leaves of the ‘Merens’, ‘Balear’ and ‘Minta’ varieties of sugar beet. The most resistant to powdery mildew was ‘Texel’. According to the average two-year data, the most productive was the ‘Pottok’ variety, whose root yield was 90.46– 93.85 t ha–1. The ‘Straus’ variety had the highest sugar content. Epoxiconazole increased the sugar beet yield from 0.44 to 6.53 t ha–1 in 2016 and from 0.07 to 11.63 t ha–1 in 2017.

The influence of climate conditions and fertilizer rates calculated by different methods on spring wheat crop

In 2011–2015, at the Rumokai Experiment Station of the Lithuanian Research Centre for Agriculture and Forestry research was carried out with spring wheat on Bathihypogleyi-Calc(ar)ic Luvisol (LVk-gld-w) with predominant silt loam ant clay loam. The main aim was to determine the influence of climate conditions and fertilizer rates calculated by different methods on spring wheat. Five years of research have shown that using the Fertilization Program “Derlius” of the Agrochemical Laboratory at the Lithuanian Research Centre for Agriculture and Forestry, during spring wheat fertilization the nitrogen fertilizers were less consumed by 15.8%, phosphorus by 81.9% and potassium by 41.1% compared with fertilization for obtaining the planned 5 t ha–1 spring wheat grain yield. Also, the studies have shown that climatic conditions in the eastern part of the Baltic Sea greatly affect the yield of spring wheat. The yield of wheat grain and straw, and the number of productive stems correlated with the amount of precipitation and the sum of active temperatures in spring wheat BBCH 21–37 growth stages. A negative correlation was established in the growth stages BBCH 61–89 between higher rainfall and spring wheat yields. The average data from the five years of research showed that the sum of active temperatures during wheat growth increased nitrogen, phosphorus and potassium in the straw, and phosphorus and potassium concentrations in the grain.

How the Lithuanian research and studies center got started

The Lithuanian Research and Studies Center, established in the 1980s, is the only scholarly institution in the U.S. Lithuanian diaspora. Its appearance was due to the presence of an ever increasing trove of Lithuanian heritage items that needed to be preserved and publicized, an ever more assertive scholarly potential among Lithuanian-Americans, some consequences of the Soviet occupation, and an unfavorable evaluation of Lithuanian-Jewish relations during World War II. In 1982 a group of Lithuanian scholars led by Professors Jonas Račkauskas and Thomas Remeikis founded this institution housed in the Lithuanian Youth Center in Chicago for the purpose of safeguarding Lithuanian material of interest to scholars, making it available to researchers, and encouraging them to study it. Prior to 1990 the Lithuanian Research and Studies Center was still in the process of getting organized and building its financial base, although the years from 1998 to 1990 which saw Lithuania being reborn and regaining independence also witnessed increased scholarly activities at the Chicago-based Lithuanian Research and Studies Center. From 1990 onwards it entered a new phase.

Areal-typological complexity of Lithuanian dialects

This article deals with one of the most promising stages in Lithuanian dialectology discussed in the article “Seven stages of Lithuanian dialectology” published in the 2016 issue of the scientific electronic journal “Lietuvių kalba” (‘The Lithuanian Language’) (see Kardelis 2016). I referred to this stage as typological; however, now I think that the best term for this stage is the term areal-typological complexity (arealtypologische Komplexität) which originates from works by Alfred Lameli (2013). The concept of complexity is not associated with the attempt to classify dialects according to different “distinctive features” but rather with an idea, clearly supported by empirical facts that diatopical variation in language is highly complex. A closer look at the context of Lithuanian dialectology research reveals that the concept of complexity is still not discussed thoroughly; while specific studies are practically non-existent. The most general methodological principle which should be applied in carrying out an areal-typological study of the complexity of Lithuanian dialects could be referred to as the principle of offside. This means that studies of Lithuanian dialectology should offside from the conventionally applied research tradition and from: a) the aim to classify dialects typologically; b) all classifications of Lithuanian dialects published up to date; c) distinctive features described in the contemporary classification (as well as earlier classifications); d) the goal to specify the boundaries of dialects and subdialects. The second general theoretical criterion is related to the approach to the linguistic system. Here I rely on the concept of a diasystem introduced into the field of dialectology by Uriel Weinreich (1954; 1974). The whole area of the Lithuanian language together with its diatopical variants may be interpreted as a diasystem of Lithuanian which consists of separate systems. The most suitable, convenient and universal criteria for the analysis of empirical data established by the long-standing theory and practice of research into phonology are the following: 1) the quality of the elements of a vocalism system; 2) the quantity of the elements of a vocalism system; 3) the interrelationship between the quality and quantity of a vocalism system. Since here we are dealing with the Lithuanian language which features a complex prosodic system, we must introduce an additional criterion, i.e. 4) stress. Empirical data for the present study were collected from modern, phonological “grammars of dialects”. This article does not encompass the whole diasystem of the Lithuanian language since it only tackles the area covered by the Aukštaičiai dialect. The main phonological qualities according to which the basic vocalism model of the diasystem of the Aukštaičiai dialect can be described are the following: 1) the system of long vowels in the stressed position; 2) the shift in the level of rise of low vowels; 3) the system of short vowels in the stressed position; 4) automatic qualitative shifts; 5) vowel reduction (three degrees). The basic vocalism model described in accordance with the above criteria rather clearly indicates that the great differentiation of Lithuanian dialects postulated in the works on Lithuanian dialectology only has a phonetic and not a phonological basis and it can only be based on the differences of phonetic features. A phonological approach to the diasystem of the Aukštaičiai dialect of Lithuanian does not reveal any radical or extreme differentiation. In addition, the model also shows another significant regularity. The more features are taken into account, the lower the occurrence of individual, less significant dialectal elements distinguished on the basis of one feature (in comparison to the classification by A. Girdenis and Z. Zinkevičius). This approach thus allows solving the complexity of the puzzle of Lithuanian dialects (or, rather the complexity of the diasystem of the Aukštaičiai dialect of Lithuanian) which is summarised in Figure 10. As the matrix in Figure 9 illustrates, the diasystem of the Aukštaičiai dialect of Lithuanian so far consists of three zones represented in the matrix by three different colours.

Dynamic capabilities and their impact on research organizations’ R&D and innovation performance

PurposeThe purpose of this paper is to reveal and justify influential factors of dynamic capabilities on research organizations’ R&D and innovation performance.Design/methodology/approachAdoption of seminal D. Teece’s (1997) concept of dynamic capabilities and operationalized matrix of key performance indicators in the area of R&D and innovation allowed the construction of the strategic management model for research organizations, consequently tested by methods of statistical analysis.FindingsThe empirical findings reveal that there exists positive influence of the dynamic capabilities on research organizations’ R&D and innovation performance. Explicitly, sensing, seizing and re-configuring dimensions of dynamic capabilities have positive impact on R&D and innovation results; consequently, the peculiarities of their inter-dependencies are identified.Research limitations/implicationsDelivered research is based on the investigation of Lithuanian research organizations’ dynamic capabilities and their impact on their R&D and innovation performance. Therefore, further research could be extended to foreign countries.Practical implicationsThe model on management of research organization’s dynamic capabilities with the aim for better R&D and innovation performance is conceptualized and specified hereinafter. In the course of the research, constructed toolkit to eventually measure research organization’s R&D and innovation performance or use it as the set of key performance indicators in the benchmarking exercise is suggested.Originality/valueThe paper is one of the first to suggest novel application of dynamic capabilities’ view within the domain of research organizations.

LMPA

The Association of Lithuanian Serials was formed in 2010 with 6 members. Recently it is an umbrella organisation for approximately 120 Lithuanian research journals published by 20 members.

Lower nitrogen nutrition determines higher phenolic content of organic apples Juozas Lanauskas1, Darius Kviklys1, Mindaugas Liaudanskas2, Valdimaras

Phenolic content of apples from an integrated and organic apple tree orchard was analysed at the Institute of Horticulture of Lithuanian Research Centre for Agriculture and Forestry in 2012–2013. Apples of ‘Lodel’ and ‘Aldas’ cultivars on rootstock B.396 in 8–9<sup>th</sup> leaf were tested. Nitrogen and potassium fertilizers were applied annually at the rates of 50 kg/ha N and 66.4 kg/ha K in an integrated fruit orchard. A mixture of perennial grasses with 25% of white clover was sown in interrows in the second year after tree establishment in the organic production system. Every two years sward in alternate interrows was tilled for natural organic matter mineralization. Fertilizers were not used in the organic apple orchard. Organic apples of both cultivars had a higher content of procyanidins B1 and B2, phloridzin, chlorogenic acid, (+)-catechin, and (–)-epicatechin. Organic ‘Aldas’ apples also contained more hyperoside, avicularin and quercitrin than non-organic apples. On average, the total phenolic content of organic apples of both cultivars was 43% higher than that of apples from the integrated orchard. These differences could be explained by nitrogen nutrition: the N content in organically grown apple leaves was significantly lower than that in leaves from the integrated production system. Tree trunk diameter and yield of organic apple were less, and fruits were better coloured.

Relationship between spring barley productivity and growing management in Lithuania’s lowland

ABSTRACTPurpose: The current study was aimed to analyse the occurrence of water and nitrogen stress in spring barley and estimate their effects on the crop performance under low-input and conventional management.Materials and methods: Field experiments were conducted during 2007–2009 at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry on a sandy-loam soil. The management systems were: (a) conventional, with the application of fertilizers and pesticides adjusted to target 5 t ha−1 grain yield; and (b) low-input, without fertilizers and pesticides. Biomass and nitrogen concentration, leaf area index, soil moisture, drainage water runoff and ground water table were measured periodically during the growing season.Results: In all three experimental years, the annual precipitation was close or above the climate normal, but a large part of the rainfall (up to 310 mm) was lost through drainage contributing to the occurrence of temporary moisture deficit in late spring or summer. Water stress resulted in a lower spring barley biomass accumulation rate and lower biomass yield in the years characterized by sub-optimal rainfall distribution. Direct measurements of water retention in the soil and DSSAT model simulations gave relatively good indication of water stress occurrence. Under the low-input management, nitrogen nutrition level was a major constraint for spring barley biomass and grain yield formation.Conclusions: Under Central Lithuania’s conditions, spring barley frequently experiences temporary water stress, because a relatively high proportion of annual precipitation is lost during the non-growing period. This crop can benefit from anticipated increased precipitation and carbon dioxide levels if adequately provided with nitrogen.

Composition and Concentration of Phenolic Compounds of ‘Auksis’ Apple Grown on Various Rootstocks

AbstractThe trial was carried out at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2013-2015. Cv. ‘Auksis’ was tested on 12 rootstocks: B.396, B.9, M.9, M.26, P 22, P 59, P 61, P 62, P 66, P 67, PB.4, and Pure 1. Accumulation of phenolic compounds depended on fruit yield and average fruit weight. On average, significantly lower concentration among rootstocks occurred when apple trees had abundant yield and fruits were smaller. On average chlorogenic acid constituted 50% and total procyanidins 28% of total phenols in ‘Auksis’ fruits. Flavonoid concentration most depended on rootstock and the highest variation was recorded. More than 50% difference occurred between the highest total flavonoid concentration in apples on PB.4 and the lowest on M.9 rootstocks. Low variability of total procyanidin concentration among rootstocks was observed. Differences between the highest and lowest concentration was 15%. Total concentration of phenolic compounds differed among rootstocks by 29-35% depending on the year. Differences in accumulation of phenolic compounds depended on rootstock genotype but not on yield or fruit weight. PB.4 and P 67 rootstocks had the highest, and M.9, P 62 and M.26 had the lowest concentration of total phenol in ‘Auksis’ fruits

INVESTIGATION OF HEMP (CANNABIS SATIVA L.) FIBRE QUANTITY AND QUALITY AS INFLUENCED BY GENOTYPE AND SEED RATE

The investigation on hemp fibre quantity and quality as influenced by genotype and seed rate was carried out at the Upytė Experimental Station Lithuanian of the Lithuanian Research Centre for Agriculture and Forestry in 2014. Bi-factorial trial was carried out: Factor A – variety (A1 – USO 31; A2 – Bialobrzeskie); Factor B – sowing rate (B1 – 45 kg ha-1; B2 – 70 kg ha-1). Data showed that variety (genotype) had a significant influence on fibre content (after dew-retting as well after water-retting) – it was higher for variety Bialobrzeskie and amounted to 37.2 and 34.5%, respectively. Seed rate (or crop density) did not show significant influence neither on fibre content nor on fibre quality (flexibility, strength) parameters.

Changes in soil carbon, nitrogen and sulphur content as influenced by liming and nitrogen fertilization of three energy crops

The paper presents research findings, obtained through a long-term research programme “Productivity and sustainability of agricultural and forest soils” implemented by the Lithuanian Research Centre for Agriculture and Forestry.

Breeding Trends of Fruit and Vegetable Crops for Organic Production in Lithuania

At the Institute of Horticulture, Lithuanian Research Centre of Agriculture, Babtai, Lithuania, 27 fruit cultivars and 25 vegetable cultivars suitable for organic production were included in the National Plant Variety List and into the European Union Common Catalogue of Agricultural Plant and Vegetable Varieties. The cultivar development programs have focused on improving cold hardiness, resistance to diseases and pests, and yield, as well as on shipping, shelf life qualities, plant development, and biotechnological applications.

Effect of cover crops in smothering weeds and volunteer plants in alternative farming systems

Abstract Alternative farming systems such as sustainable and organic farming are used to produce premium price food products and retain the viability and fertility of soil. Field experiments were conducted at Joniskelis Experimental Station of the Lithuanian Research Centre for Agriculture and Forestry in 2006–2012. The research objective was to investigate the competitive ability of plants cultivated as cover crops: narrow-leafed lupine ( Lupinus angustifolius L.) in mixture with an oil radish ( Raphanus sativus var. Oleiferus Metzg.) (LUPRA); white mustard ( Sinapis alba L.) (WM); white mustard in mixture with a common buckwheat ( Fagopyrum exculentum Moench.) (WMBU) to smother weeds in organic and sustainable farming systems in soil with low (1.90–2.01%) (LH) and moderate (2.10–2.40%) (MH) humus content. Cover crops cultivated for green manure were investigated during the post-harvest period of winter wheat. This experiment showed that cover crops have a strong competitive ability to smother weeds and emerged volunteer plants. It also demonstrated that narrow-leafed lupine in combination with oil radish, cultivated in the organic farming system, was less effective at smothering weeds compared with white mustard cultivated as a sole crop or in combination with buckwheat. In a rotation without cover crop in soil with low and moderate humus content, the number and biomass of weeds was higher compared with the farming systems with cover crops. A correlation-regression analysis showed that the cover crops had a higher impact on the biomass of weeds and volunteer plants in soil with low humus content to compare with moderate humus content. The most effective inhibition of volunteer plant and weed biomass in soils with both humus contents was observed, when white mustard and a mixture of white mustard and buckwheat were used as cover crops. The practical implication of this research is suggestion, that cover crops could be successfully used as integrated weed control tool in farm fields.

Comparison of postharvest practices used for cereal straw decomposition in a clay loam soil

ABSTRACTDuring 2008–2011, model field experiments were carried out at the Joniškėlis Experimental Station of Lithuanian Research Centre for Agriculture and Forestry on a clay loam Endocalcaric Endogleyic Cambisol. The study was aimed to establish the comparison of various postharvest practices (mineral nitrogen fertiliser alone or together with a bioactivator Penergetic k, livestock slurry, red clover biomass and straw incorporation in the soil by a stubble cultivator at a 10 cm depth) on the acceleration of the initial (nine-month period) decomposition of winter wheat straw. During this period, straw mass decomposition intensity was 20.7–29.1%, carbon (C) concentration decreased by 6.5–22.8%, while an increase in nitrogen (N) by 1.1–2.2 times was observed. The highest straw decomposition rate was recorded when after straw incorporation autumn was warm and humid. That year straw mass C to N ratio (C/N) was 38–46. Under less-favourable autumn conditions, the highest decomposition of straw was achieved, having applied mineral N (with and without Penergetic) and livestock slurry and having incorporated the straw in the soil (C/N = 40–55). A slower decomposition rate was observed for the straw spread on the soil surface with mineral N addition or on undersown red clover.