Concrete is one of the most popular construction materials in the world. The concrete properties depend from many factors. One of them is aggregates quality, which can be defined as an impurity level. The most unwanted materials in fine aggregates are clay and soil particles. These particles can impure aggregates due to irregular sands in quarry and during the digging process. In the present paper were estimated how impurity impact the properties of concrete. During the research the aggregates were impured with clay and soil particles. The change of fresh concrete workability, hardened concrete density, compression strength, water absorbability and frost resistance were evaluated. The results show that aggregates impurity with clay and especially with organic materials (soil) is very dangerous. The concrete workability, frost resistance is decreasing. The clay and soil have a different effect on hardened concrete density and compression strength. Soil decreased both parameters while well mixed clay increased these characteristics. However, generalizing all results, can be stated, that keeping the same level of concrete workability it is necessary to raise water and cement ratio and it will give strength loss effect.

Potato (Solanum tuberosum L.) is mostly suitable for growing in moderate climate conditions at temperature 20 ° C. Yields are influenced by many factors: soil characterization, available nutrients, distribution of pests and weeds, agrotechnology, genotype or variety and climatic conditions during the vegetation period. In recent years summary of meteorological conditions (precipitation and air temperature), showed that stressful conditions during the vegetation period had a diverse influence on the growth and development of plants.  Excess or lack of humidity in soil or drought and heat affected the size and shape of the potato tubers. The heat stress is the problem of agriculture in many regions of the world in the last years. The aim of the study was to evaluate cultivars and clones from the breeding material under the stress conditions at the Stende Research Centre. The field trials were set up due to project of the Latvian Ministry of Agriculture: "Evaluation of breeding material to implement integrated and organic agriculture crop production technologies"(2015-2018). The article summarizes results of nine potato clones and nine varieties in both integrated and organic systems during 2017-2018, when 2018 was one of the driest and hottest in the last 100 years. The evaluation of the varieties and breeding material phenological phases in two years showed that germination and flowering differed from year to year.  Due to hot and dry weather conditions flowering was weak for several varieties and the bud flowering was observed. In 2018 germination for some varieties was slower compared to the previous year, but for many varieties (‘Lenora’, ‘Prelma’, ‘Imanta’) and breeding material germination was not delayed (Table 1). The earlyest germination and flowering were observed for variety 'Monta'. Earlier germination compared to other varieties and clones was recorded to S01085-21 and S03067-33 and the variety ‘Rigonda’.  In the organic field earlier germination was observed for the varieties 'Rigonda', 'Monta', 'Prelma' and clones S01085-21, S07169 -35. The yield of varieties and breeding material lines in both years was good but still lower tuber yields were obtained in the integrated growing system and only one line (S01085-21) and variete ‘Gundega’ had significantly higher yield in comparison 2017. In the organic growing system tuber yields of all varieties and breeding material lines were significantly lower than the 2017 year. Yield reduction is not significant for 3 breeding material lines: S10063-128, 19922.29 and S2008-6.5.

Since 1999, a long-term field experiment has been done at the Experimental Station of Vytautas Magnus University (former Aleksandras Stulginskis University) at 54º52′50 N latitude and 23º49′41 E longitude. The soil of the experiment site is Epieutric Endocalcaric Endogleyic Planosol (Endoclayic, Aric, Drainic, Humic, Episiltic) according to WRB (2014). The objective of our investigations was to assess the long-term impact of reduced intensity tillage systems, straw and green manure combinations on productivity and economical evaluation. A short crop rotation was introduced: winter wheat, spring barley, spring rape. The results were obtained in 2000-2017. Sustainable agroecosystems are able to maintain their condition, productivity and biodiversity, as well as their integrity over time and in the context of human activity and use. The sustainability of agroecosystems is inseparable from the stability of their productivity. In order to illustrate this, we estimated crop productivity differences % from the year 2000 to 2017. In terms of crop productivity, all the tested long-term complex measures of different intensities were similar, both when comparing with average productivity that year and when estimating cumulative differences com-pared with deep ploughing.  

Investigations were carried out in the production fields of agricultural company Linas in Ringaudai eldership, Kaunas district. Spring wheat variety 'Koksa' was grown on non-damp, light loamy soil with a mobile phosphorus content of 173 mg kg-1 and a potassium content of 139 mg kg-1. Soil acidity - pH 6.9-7.0. The ozonator was attached on the trailing sprayer JARMET. During the studies, the concentration of ozone-saturated water and the spray rate were determined so as not to damage the crop, pollute the environment, or harm humans or animals. The speed of the sprayer was 6 km h-1. The application was performed 2 or 4 times. It was determined that treatment of spring wheat with ozonated water, although not always statistically significantly, however, reduced the occurrence of powdery mildew (Blumeria graminis), brown rust (Puccinia recondita), and inhibited the spread of aphids. A tendency for tan spot (Pyrenophora tritici repentis) and thrips decrease in the crop was observed. The aim of the study was to determine the effect of ozonated water application on the spread of spring wheat pests and leaf diseases.

Soil berms are typically built on the sides of ditches and are designed to purify water from agricultural fertilizers and to limit the transport of sediments to water bodies. However, for soils with fine particles, water filtration is limited and wet soil conditions can occur, which in turn reduces the soil's hydrologic conductivity capacity and hinders tree growth in the forest. The aim of the study is to develop a methodology for automatic modeling of the furrows in soil berms. Open source software QGIS and GRASS GIS is used in data processing. LiDAR data with minimum ground point density of 1.5 points per square meter were used in DEM creation. Local maximum analysis and further data filtration were used in determination of locations of soil berms. The results show that by making one furrow for every 185 m of ditches it is possible to reduce the area of the depressions by up to 91.8%.  

Fresh hardy kiwifruit (Actinidia kolomikta (Maxim. & Rupr.) Maxim.) possible to store for only two weeks at 0–5°C, therefore in order to maintain longer, the fruit have to be processed. The purpose of the study was to determine the quality of the Actinidia kolomikta fruit using research methods that are faster and easier, i.e. bioelectric Vincent method and biocrystallization. Four cultivars of Actinidia kolomikta fruits – ‘Landė’, ‘Paukštės Šakarva’, ‘Laiba’ and ‘Lankė’ – were investigated. Fresh, frozen and freeze-dried fruit were analysed. The amount of dry matter was determined by drying the samples to constant mass at 105 ºC, ascorbic acid was determined by titration with 2,6-dichlorphenol-indophenol sodium salt dehydrate. The pH and redox potential were measured by 781 pH/Ion Meter, electrical conductivity was measured by conductometer. P value as combined parameter was calculated according to the formula. Biocrystallization studies were carried out with fresh, frozen and freeze-dried fruits of all cultivars. The images derived from the encoded by sort samples were characterised with respect to the visual strength of form expression and were described by 10 criteria, criteria were evaluated using a 5-point scale. Research results showed that the dry matter and ascorbic acid content of A. kolomikta fruit significantly depended on the cultivar. Dry matter content of frozen fruit decreased from 4 to 7%, but increased during freeze-drying process by 6 to 7 times compare to the fresh fruit. Fruit processing methods increased pH, redox potential and P values. The lowest redox potential and P values were determined for fresh fruit, medium for freeze-dried and the highest for frozen fruit samples.

Enhanced forest growth may respond to the increasing demand for wood resources. Moreover, the forest is considered to be carbon storage, thus contributing to climate change mitigation. The forest soil fertilization, as well as forest drainage, thinning and regeneration may be an effective measure in increasing harvest rates. In the context of bio-economy, wood ash needs to be managed and can be utilized as an equivalent to potassium and phosphorus containing fertilizer. Ammonium nitrate can be used as fertilizer in forests on mineral soil since nitrogen is considered to be a tree growth limiting element in boreal forests. However, environmental aspects like leaching of the fertilizer should be taken into account. The aim of this research is to evaluate the impact of wood ash, ammonium nitrate and combined wood ash and nitrogen fertilizer impact on the chemical properties of soil water in dominated forest site types in Latvia. The trials were conducted in total in 16 forest stands. The fertilizers were spread in treatment plots, but the control plots were left untreated. The soil water samples were collected for two seasons. The pH, potassium, calcium, magnesium, phosphate and total nitrogen were determined in the soil water samples. Ammonium nitrate had an impact on the elevated concentration of total nitrogen in all experimental objects; although the significant differences between the control plot and treated plot were detected only in a part of experimental objects. The elevated concentrations of total nitrogen decreased after two months and remained above the control level. Interestingly, we observed a trend of both – increased and decreased concentrations of potassium, calcium, magnesium and phosphate. Nevertheless, only a part of the differences was statistically significant. The impact of wood ash on chemical properties of soil water was less pronounced in comparison to ammonium nitrate.

EU countries agreed upon increasing the use of renewable energy, which strongly stimulates usage of biofuels. Biomass ash is generated as a residue product in large volumes as a result of biomass combustion. Heavy metal content in the ashes is the main hinder for further ash utilization in agriculture, forestry and construction sector. Aim of this study was to assess potential of biomass ash to be used as pavement base, also to evaluate risks associated with heavy metals contained in ash as well as their leaching possibility. Ash elemental analysis showed that biomass was burned efficiently, and organic carbon content in ash samples was below 2%. The limiting trace element was cadmium, which concentration in ash exceeded maximum permissible value, restricting ash recycling in forestry or agriculture. Leaching test showed that there is no threat to the environment when such waste material is used in road construction as base layer. All leaching values were below permissible concentrations or even below ICP detection limits. Compaction tests of layers made from gravel/ash mixtures revealed that biomass ash could be successfully used in road construction industry. Results showed that the strongest mixed layer was from 80% gravel and 20% ash. The compaction of this mixture was the highest, only the second best result showed pure 100% gravel, while the least compacted was 50% ash and 50% gravel mixture.

. Alkaline soil additives used in this study, as cement kiln dust and lime mud, resulted in significant rise of the pH in contaminated soil and sludge mixtures, while buffering capacity of the sludge appeared to be much stronger than that of the soil. Total concentrations of the investigated trace elements in the tested samples in most cases were above limit values given in Lithuanian environmental normative documents HN 60:2015 and LAND 20:2005; Cd, Zn and Pb concentrations exceeding MPCs by 2-10 times. Nickel, cadmium and copper in the sludge appeared to be the most mobile elements, their EDTA-extractable fraction reaching 30-50% from the total. The tested industrial by-products in most cases significantly reduced trace element mobility. Immobilizing effect in the contaminated soil was from low to moderate, while impact on the reduction of Cd, Pb, Zn, Cr, Ni, As, Se, Hg mobility in the sludge was much stronger. Alkaline treatment was not so effective to reduce mobility of Cu and As in the soil, but immobilising effect of lime mud on these elements in the sludge was significant. A multivariate data analysis model with two principle components explained 94% of the data variation. The most distinctive factor, separating samples, was the origin of the two tested metal-rich substrates: contaminated soil and sewage sludge. Contaminated soil could be distinguished by high concentrations of As, Tl, Hg and Pb. Both alkaline treatments on sewage sludge were more effective, thus scores are further from the origin, although, difference between kiln dust and lime mud immobilising effectiveness was not so significant. Application of alkaline amendments: cement kiln dust and lime mud, proved to have strong immobilizing effect on the most of the investigated trace elements, and usage of local by-products for contaminated soil (sludge) remediation purposes could be seen as an environmentally friendly, cost-effective and safe disposal alternative.

International audience | Reproductive performances of the Creole goat, the meat breed of Guadeloupe in the Caribbean, are described from a database generated for 15 years (1973 to 1988) at an experimental farm of the Institut National de la Recherche Agronomique (INRA, Guadeloupe, French West Indies). The data contain information on 599 females, 2259 attempted matings, 2135 achieved matings and 1904 kiddings. Animals were reared under semi-intensive management conditions (on the basis of feeding system, health and culling policy). Main sources of variation were analysed: mating type (buck in permanence or buck effect), mating season (dry, intermediate and humid season) and rank of kidding. The Creole goat is a continuous breeder. On average 94.5 percent of exposed females were mated (defined as mating rate) and 90.5 percent of exposed females achieved a kidding (fertility rate). Their prolificacy reached 1.98 kids/kidding, with only 3.9 percent of kids born dead. These reproductive parameters varied essentially with rank of kidding but very poorly with the mating season. Productivity of these females was regularly high during their whole lifetime production. From the results obtained, it is concluded that Creole goats have very high reproductive performances, provided that animal husbandry and nutrition are adequate.