The distribution and abundance of Barbarea arcuata (Opiz ex J. et C. Presl) Rchb. were investigated throughout the territory of Latvia. The field survey was carried out to estimate the abundance patterns, and the herbarium materials were used to compile a distribution map. In total 411 localities were recorded in the period from 2015 to 2017. The species has been commonly found on roadsides, which accounts for 66% of the localities. Seventeen percent of the localities occurred in grasslands, 10% – in croplands, 4% – in fallows, 2% – on road embankment slopes, and 1% – on railway embankments. The highest density of B. arcuata were found in new fallows where it forms large populations. Whole field localities account for 5% of the total localities. Medium-sized stands are found in about 20% of localities and are mostly found in grasslands, roadsides, as well as croplands which include cereal fields and oilseed rape fields. Individual specimens are mostly found on roadside habitats and grasslands and account for 75% of the total number of localities. As dominant weed species it is found on fields of oilseed rape, cereal fields and fallows. Herbarium data and the Institute of Biology, University of Latvia lists of species show that B. arcuata distribution was frequent during the period from 1970 to 2014.

The most important reason for growing field crops is food consumption. Only some of the total amounts of field crop species are mostly used for cultivation in the largest part of arable land. These crops ensure high economic income. This is the reason why biological diversity has decreased. Crop rotation is considered to be an instrument of sustainable cropping system and this is confirmed again nowadays. Higher cereal yields have been gained by including oil crops or pulses in the rotation. Each field crop has its own calorific value (MJ kgE-1). Grains/seeds and above-ground biomass may have different calorific values because of their chemical composition. Research results from literature confirm that the average net calorific value of winter wheat (Triticum aestivum) and triticale (Triticosecale) grain and straw are ~17 MJ kgE-1, but the net calorific values for oilseed rape (Brassica napus ssp. oleifera) seeds and straw are – 25.70 MJ kgE-1 and 16.37 MJ kgE-1, respectively. Oilseed rape is also known as energy rich crop. It is reported that diversified crop rotations also have greater energetic productivity from above-ground biomass (grain/seed yield and by-products) if compared with crops grown in repeated sowings or in monoculture. Crop rotation in combination with different tillage methods (conventional tillage, reduced or minimum tillage and no-tillage) is the way to improve soil quality, but it is not clear whether the soil treatment method has a significant impact on the overall crop rotational energy productivity.

The field experiments were conducted at the Institute of Soil Science and Plant Cultivation – State Research Institute Experimental Station in Osiny in the years of 2015 – 2016. The aim of the study was to compare spring wheat (Triticum aestivum L.) yield depending on an integrated and intensive technology. The used production technologies differed as regards the nitrogen fertilization level, chemical protection against weeds, diseases, pests and the way of straw utilization. The following cultivars were selected for the research: ‘Arabella’ and ‘KWS Torridon’. The weather conditions differentiated the yield of spring wheat in individual years. A higher effectiveness of intensive technology, expressed with a higher grain yield compared to the integrated one, was recorded in 2015 – on average by 18.0%. The yield increase between intensive and integrated technologies resulted from a higher 1000 grain weight. Spring wheat cultivars showed a varied response to the production technologies used. Under the intensive technology, a significant yield increase was recorded for the cv. ‘KWS Torridon’, while the production technologies did not differentiate the yield of cv. ‘Arabella’. The quantity and quality of protein substances and the activity of amylolitic enzymes in grains were more dependent on the cultivar than on the production technique used. In the case of spring wheat cultivars ‘Arabella’ and ‘KWS Torridon’, the integrated production technology ensures obtaining grains of the quality suitable for processing.

In some regions of the world, there is a risk of limiting crop production due to the growing pressure of biotic and abiotic factors. It is mostly connected with the forecasted climatic changes. Hence, alternative methods for supporting plant growth are sought for, and among them, biostimulants can play a significant role. The three-year (2009 – 2011) field experiment with spring barley (Hordeum vulgare L.) was conducted in Poland to assess the response of grain yield, yield components, as well as the content and uptake of N, P and K in grain to differentiated times and to a dose of seaweed (Ecklonia maxima Osbeck) biostimulant Kelpak application. Preparation was applied in a dose of 2 L haE-1 at BBCH 22 (early treatment) or in a dose of 2 L haE-1 at BBCH 31 (late treatment), as well as two times, 1.5 L haE-1 each, in both phases. The study indicated that the biostimulant had a favourable effect on the root weight, grain number per spike, thousand grain weight and seed yield in early treatment as compared with the control. Early application also had a positive effect on N and P uptake in the grain yield. Favourable response of barley to the application of biostimulant shows the usefulness of the seaweed extract in the cultivation technology of this crop.

The aim of the article was to develop formulas, which can be used to model forecasts of production and economic effects of irrigated faba bean (Vicia faba var. minor), depending on drought severity level in a growing season. For the analysis we used data of ten-year (2005 – 2014) production effects of irrigated faba bean and indices calculated on the basis of meteorological data from the measuring point set in the vicinity of the experimental site in region of Bydgoszcz city, central Poland. Based on them, the most relevant relationships between irrigation productivity and chosen drought indices, calculated for a period of high water needs of the plant, were searched. Presented results have demonstrated that the non-irrigated faba bean yields depended significantly on drought severity level and showed very high variability in time. Irrigation contributed to a significant 49% increase in yields and their stability in the years. Due to this treatment, the coefficient of variation of the yield decreased from 55.1 to 19.6%. The production effects of irrigation depended significantly on moisture conditions over the period of high water needs of faba bean. In wet seasons, the increases in yields due to irrigation were insignificant and about three-fold lower, while in the dry periods – more than a half higher (57%) than the average increases. The results presented in the work are of great importance because they can be used to model forecasts of production, as well as to plan the development of irrigation systems in the given area.

Plant factories provide possibilities to get optimal yield of green leafy vegetables entire year independent from the season. The technology of light-emitting diode (LEDs) light has become one of the most powerful tools in photophysiological researches of various horticultural plants. In order to manage plant physiology and improve productivity, it is necessary to develop new LEDs technologies in horticulture. The aim of the study was to investigate different lighting intensities and elevated red light (660 nm) effect on tatsoi photosynthetic parameters. All plants were grown under the same light sources where overall photosynthetic photon flux density (PPFD) varied from 200 to 300 µmol mE-2 sE-1. Three days before harvesting red light intensity (640 and 660 nm) was increased until 132 µmol mE-2 sE-1 and 660 nm until 188 µmol mE-2 sE-1 at 16 hours photoperiod. In the last treatment merely 24 hours photoperiod was applied. The photosynthetic indices in tatsoi were determined by non-destructive methods using LI-6400XT portable photosynthesis system, OS5p fluorometer, DUALEX optical sensor and CID leaf spectrometer. Research was performed in 2017 – 2018 winter season. The obtained data revealed that the total photosynthetic photon flux density (PPFD) at level of 200 µmol mE-2 sE-1 was sufficient for optimal CO2 assimilation in tatsoi plants. The increased PPFD of LED light at pre-harvest stage resulted in reduced photosynthetic parameters of plants.

Healthy seeds are essential for the optimal plant population and yield, but seed-borne pathogens, such as Fusarium spp., may reduce seed germination, quality and cause damping-off of the seedlings. Fusarium graminearum is a dominant pathogen of cereal crops and can cause significant losses of grain yield and quality. It is important to evaluate the role of alternative inoculum source in crop rotation. The aim of this study was to assess the impact of F. graminearum infection on different plant seed germination and seed infestation. The research was conducted at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry, in 2017. Visually healthy seeds of bean (Vicia faba L.), pea (Pisum sativum L.), lupine (Lupinus angustifolius L.), soybean (Glycine max. (L.) Merr.), lucerne (Medicago sativa L.), white (Trifolium repens L.) and red (Trifolium pratense L.) clover were inoculated with 10 mL of F. graminearum suspension, adjusted to 1×106 conidia per mL. Seed infection was counted 2 and 6 days after inoculation (DAI), seed germination energy and reduction rate – after 3 DAI and germination index – 6 DAI. Results showed that all inoculated seeds were covered with typical to F. graminearum red-purple mycelium. The results of inoculated seeds with F. graminearum showed red-purple mycelium growth on the seeds (infection from 21.25 up to 100%). The results showed that germination energy decreased on pea (2.56%) and lupine (7.79%) seeds. Our results suggest that various plant seeds differently react to F. graminearum infection. The highest infection of F. graminearum was obtained on pea, lupine seeds and the least on red clover.

Farming outputs in agriculture depend on the nature of production, i.e. different farming systems generate different outputs. All these outputs are important for the society, and, therefore, require an integrated approach in view of the specific farming characteristics, where market and non-market outputs are taken into account. Therefore, the paper focuses on analysis of farming system outputs and methods of their evaluation. The objectives of this paper are to define the features of different farming systems and their outputs, then, to analyse the methods of evaluation of farming system outputs used in the studies. In order to achieve the research aim, analysis of economic scientific literature has been conducted; characteristics of farming systems and their outputs have been analysed; evaluation methods of the market and non-market farming system outputs, revealing their advantages and disadvantages, have been examined. Methods of systemic and logic analysis have been applied to analysis of the farming system outputs and their evaluation. The analysis has shown that intensive farming systems generate more market goods, while extensive farming systems – more public goods. Price-based methods are mostly used for the evaluation of market outputs of farming systems. Stated preferences methods are the most universal techniques used for the determination of the values from non-market farming system outputs. Hedonic pricing approaches are used for evaluation of specific agricultural public goods related to recreation or leisure and related to the particular groups of users.

The objective of this article is to assess farm efficiency and productivity change in specialised large farms located in the region of Mazowsze and Podlasie during the years 2014 − 2016. For this, we used the non-parametric Data Envelopment Analysis (DEA) method and Malmquist index. Calculations were performed for three types of large farms classified as: field crop, pig and dairy. The study shows that mean technical efficiency of large field crop, pig and dairy farms amounted to 80, 75 and 70%, respectively. Technical inefficiency of field crop farms come mainly from scale efficiency, while of pig and dairy farms equally from pure technical and scale efficiency. It shows that inefficient management practices had an impact on farm performance. Therefore, in order to increase competitiveness of farms, an improvement of management practices is required. In the studied period the share of farms operating under increasing return was as follows: 67, 72, and 81%, respectively for field crops, pig and dairy farms. The improvement of efficiency of those farms could be achieved by increasing their size. The results indicate that 8% of field crops, 12% of dairy and 16% of large pig farms were operating under decreasing scale efficiency, which means that those farms were operating above the optimal scale. The increase in their efficiency could be achieved through size reduction. In dairy farms the average annual productivity growth of 2% was recorded. In pig farms the productivity reduction of 5.4% was observed. It was the result of a decrease in technological efficiency.

Conducting agricultural activity in areas facing natural constraints (ANC) affects farms’ production and economic results. ANC payments were introduced to compensate farmers for higher costs and lost income. The aim of the study is to compare the production and economic results of farms receiving ANC support with other farms. It was hypothesized that ANC farms achieve lower production and economic results than other units. The analysis is based on Polish FADN data concerning 2015. The sample included 12,105 farms, of which 4,652 (38.43%) received ANC subsidies. To describe the characteristics of the surveyed farms, positional measures were used due to strong asymmetry. The Mann-Whitney U test was used to assess the significance of differences in distributions. The results indicate the existence of significant differences in the production potential, production and economic efficiency of farms receiving ANC payments and ones without them. Agricultural farms receiving ANC payments are characterized by a significantly smaller area of agricultural land, a lower share of arable land in the UAA and a smaller share of leased land. They also have lower production volume, lower land and labour productivity. They achieve relatively lower incomes. Nevertheless, the payments to a small extent reduce these differences. On this basis, it can be concluded that ANC payments in Poland do not provide full compensation for differences in the production and economic results of a farm with worse agri-environmental conditions. Therefore, the impact of the CAP on the economic results of farms located in ANC is relatively small.