Lacy Phacelia Research Articles

Distinct metabolite classes in root exudates are indicative for field- or hydroponically-grown cover crops.

Plants release a large variety of metabolites via their roots to shape physico-chemical soil properties and biological processes in the rhizosphere. While hydroponic growth conditions facilitate accessibility of the root system and recovery of root exudates, the natural soil environment can alter root metabolism and exudate secretion, raising the question to what extent the quantity and composition of root exudates released in hydroponic growth systems reflect those recovered from soil-grown roots. Using a root washing method, we sampled root exudates from four field-grown cover crop species with wide taxonomic distance, namely white mustard, lacy phacelia, bristle oat, and Egyptian clover. A set of primary metabolites and secondary metabolites were analysed in a targeted and untargeted LC-MS-based approach, respectively, for comparison with exudates obtained from hydroponically cultured plants. We found that hydroponically cultivated plants released a larger amount of total carbon, but that the recovery of total carbon was not indicative for the diversity of metabolites in root exudates. In the field, root exudates from phacelia and clover contained 2.4 to 3.8 times more secondary metabolites, whereas carbon exudation in hydroponics was 5- to 4-fold higher. The composition of the set of metabolites identified using the untargeted approach was much more distinct among all species and growth conditions than that of quantified primary metabolites. Among secondary metabolite classes, the presence of lipids and lipid-like molecules was highly indicative for field samples, while the release of a large amount of phenylpropanoids, organoheterocyclic compounds or benzenoids was characteristic for clover, mustard or oat, respectively, irrespective of the cultivation condition. However, at the compound level the bulk of released metabolites was specific for cultivation conditions in every species, which implies that hydroponically sampled root exudates poorly reflect the metabolic complexity of root exudates recovered from field-grown plants.

Effect of Sowing Date on the Development of Lacy Phacelia (Phacelia Tanacetifolia Benth.).

Experiments with lacy phacelia (Phacelia tanacetifolia Benth.) were carried out in the period 2017-2021, during which the effect of sowing date on the stand development was assessed (height, coverage, accomplishment of individual growth stages, and weed infestation). It was demonstrated that the sowing date affects the stand growth and development. In earlier sowing dates, plants developed slower than in later sowing dates but reached a greater average height (926 mm). The lowest height (802 mm) was exhibited by plants from May (sowing 3). The third sowing date also showed the worst stand canopy closure and at BBCH 31, the stand canopy closure in Sowing 1, 2, and 3 was 82.3%, 77.8%, and 67%, respectively. The third sowing date was also the highest weed infestation. The effect of sowing date on yield and yield parameters was also monitored (weight of a thousand of grains and germinative capacity). Based on the measured data, it can be concluded that the influence on the weight of thousands of grains was minimal and in germinative capacity. Significant differences were recorded only in first year in which the germinative capacity of plants from the later sowing dates was reduced.

Influence of Flowering Characteristics, Local Environment, and Daily Temperature on the Visits Paid by Apis mellifera to the Exotic Crop Phacelia tanacetifolia

The opportunity to introduce Phacelia tanacetifolia is still being debated, even if the species is already employed, as it is often sown in rotational set-aside schemes or to support pollinators. Therefore, we need further evidence on its effects on the environment and its attractiveness towards pollinators. This work aims at confirming its appeal towards the honeybee in a mixed agricultural and urban environment in the north of Italy, during late spring and early autumn flowering. We assessed flowering characteristics and honeybee visitation rates by employing observational plots; we recorded resource preferences and behaviours by focal observations and video records; finally, we annotated other flower visitors. Each plant is characterised by one or more flowering stems on which not all flowers open at the same time: an increased number of flowers is, therefore, due to an increase in the number of available flowering stems. Honeybees were highly interested in lacy phacelia resources, especially in nectar collection: pollen collection may not be sufficiently rewarding for bees to dedicate time to it. The only correlation we found was between visitation rates and temperature. Other insects were recorded visiting the flowers: these were especially Hymenoptera; Coleoptera and Lepidoptera were also abundant, while relatively few individuals of Hemiptera and Diptera were recorded. Our results indicate that the mass-flowering of the species is certainly of interest to local pollinators and can be considered to counteract their decline when sown as a single species or in flower mixtures. However, further studies are needed to assess the competition of this plant with native species and its ability to self-regenerate when not purposely planted.

Effect of Catch Crops and Tillage Systems on the Content of Selected Nutrients in Spring Wheat Grain

This paper presents the effects of catch crops (white mustard, lacy phacelia, and a mixture of legumes—faba bean + spring vetch) and two tillage systems (plough tillage and no-tillage) on some quality parameters of spring wheat grain. A field experiment in growing spring wheat in monoculture was conducted in the period 2016–2018 in Czesławice (central part of the Lublin region, Poland). An assumption was made that the nutritional composition of wheat grain could be influenced already at the stage of selection of agronomic practices by modifying the soil chemical and enzyme composition—being the “starting point” for grain quality. It was proven that all the catch crops tested in this study contributed to an improvement in the chemical composition of the soil used in the experiment (a significant increase in humus, P and Mg content). Both the catch crops and the conservation (no-tillage) system stimulated the activity of soil enzymes: dehydrogenase and urease. This resulted in more favorable soil conditions for spring wheat grown in monoculture. The cultivation of the catch crops (particularly white mustard) indirectly contributed to an increased content of dietary fiber and o-dihydroxyphenols in wheat grain. Moreover, the content of most of the amino acids determined and the essential amino acid index (EAAI) in wheat grain were found to be more favorable in the treatments with the catch crops. The highest content of all the macro- and micronutrients analyzed in wheat grain was found in the catch crop treatments (especially that with white mustard). It should be noted that spring wheat responded favorably to the reduced tillage system (no-tillage). Since the grain content of o-dihydroxyphenols, magnesium, calcium, copper, manganese, iron, selenium, and some amino acids (especially essential ones: Lys, Met, Trp) was found to be higher compared to plough tillage.

Catch crop mixtures have higher potential for nutrient carry-over than pure stands under changing environments

Winter catch crops are grown to scavenge nutrients over a period of unfavorable growth conditions and to conserve nutrients for subsequent release to the following main crop. Since environmental conditions have a strong impact on the growth and nutrient capture in roots and shoots of individual catch crop species, we anticipated that mixtures will be more durable and efficient in nutrient capture due to compensatory effects among component species. We tested this hypothesis and determined the nitrogen and phosphorus accumulation in the shoots and roots of four catch crop species grown in pure vs. mixed stands at two sites for two or three years. Element concentrations were determined in the root and shoot biomass of each species and used to calculate the nutrient pool fixed in the root or shoot biomass. A qPCR-based technique was applied to quantify the root biomass of individual species based on species-specific DNA sequences. Despite considerable variation across environments, the overall plant biomass of white mustard (Sinapis alba), lacy phacelia (Phacelia tanacetifolia) and bristle oat (Avena strigosa) was similar and higher than that of Egyptian clover (Trifolium alexandrinum). While pure stands varied 6- to 24-fold in shoot biomass depending on environmental conditions, the variation was only ~3-fold for catch crop mixtures, with less pronounced variation in the root biomass. In general, the root biomass was comparable to the shoot biomass in each species. Roots contributed 26–46% of the nitrogen and 36–48% of the phosphorus to the total accumulation of these nutrients in the catch crop biomass, thus emphasizing the importance of plant roots as belowground nutrient pool for potential carry-over of nutrients to the subsequent crop. Although the mixture was mostly dominated by two of the four species, namely mustard and phacelia, it captured similar or even larger amounts of nutrients than the best-performing pure stand under any growth condition. This was the case for shoot- and for root-bound nutrients. Our results indicate that catch crop mixtures have higher durability than pure cultures to environmental variations. The amount of nitrogen captured by the mixture meets the average postharvest nitrogen that is left over by a wide range of cash crops, thus emphasizing that catch crop mixtures represent an efficient nutrient management tool in crop rotations.

The effect of cover crops on soil moisture in ploughless and traditional tillage in the cultivation of carrot

In a view of the predicted drought that has appeared in recent years and water shortage in the growing season, which is getting worse every year, the problem of water retention in the soil and increasing its humidity becomes of exceptional importance. The field experiment was carried out in 2009–2012 on grey brown podzolic soil developed from loess formations covering the cretaceous marls with a granulometric composition corresponding to medium dusty loam. The aim of the study was to assess the impact of various species of cover crops and the method and date of mixing their biomass with the soil on the soil moisture in ploughless carrot cultivation. The experimental design included seven cover crop species (spring rye, common oat, common vetch, white mustard, lacy phacelia, buckwheat, fodder sunflower) and six kinds of soil tillage. The effect of cover crops and tillage on soil moisture was modified by the course of the weather and varied depending on the year of research, sampling date and soil layer. In spring, the highest layer of soil (0–20 cm) not cultivated before winter (NTz) accumulated the most water, and the least after pre-winter ploughing (Oz). In the 0–40 cm layer, the lowest humidity was in the soil ploughed before winter (Oz), and the highest after no-till (NTz) and after subsoiling before winter (GLz). The ridge cultivation performed in the spring caused the soil to dry out. In the remaining variants of no-ploughing tillage, soil moisture in the 0–40 cm layer was similar to that of conventional cultivation. Cover crops exerted a significant influence on the soil moisture in carrot cultivation at all test dates, increasing its moisture content compared to cultivation without cover crops. The rye cover crop had particularly favourable effect on the soil moisture.

Environmental Benefits of Catch Crops Cultivation

Abstract The role of catch crops in modern agriculture has increased in recent years. In addition to a production of animal feed, they have a positive impact on quality of soil. This study determined the suitability of selected stubble catch crops (white mustard, lacy phacelia, and a mixture of faba bean + spring vetch) to improve production, economic and energy effects of spring wheat grown in 3-year monoculture relative to the control treatment (without catch crops). Two tillage systems were used: conventional tillage and no-tillage (conservation tillage). A field study was conducted over the period 2014-2016 at the Czeslawice Experimental Farm, Lubelskie Voivodeship, Poland. The study proved the high suitability of catch crops to increase the spring wheat yields (under both tillage systems). Regardless of the catch crops, the productivity of wheat was higher under conventional tillage. The catch crops (in particular white mustard) and the conservation tillage system contributed to an improved energy efficiency index of production. The white mustard catch crop also had the most beneficial effect on the economic profitability of spring wheat production. This was due to the low cost of cultivation of this catch crop and its beneficial impact on obtaining high yields of spring wheat.

The effect of cover crops on composition and diversity of weeds in an apricot orchard

Apricot, Turkey's exports is the important role played by fruit, the weeds are the main factors that cause problems in the apricot orchards. This study was carried out in Malatya between 2014-2016 in order to determine the effects of cover crops on the control of weeds that cause problems in these areas and also on species distribution, diversity and dominance. As annual winter cover plants in the study: Vicia villosa Roth (hairy vetch), Vicia pannonica Crantz (Hungarian vetch), V. pannonica + Triticale (V.pannonica 70% + Triticale 30%) mixture and Phacelia tanacetifolia Bentham (lacy phacelia) and Fagopyrum esculentum Moench (buckwheat) was used as a summer cover plant. Weed diversity index (H) and Simpson's dominance index (Sd) values were also calculated in the study. In addition, applications were subjected to canonical discriminant analysis. The highest value of the weed diversity index (H) in the two-year period was obtained from the weed control plots. It has been determined that perennial weeds (Convolvulus arvensis and Sorghum halepense) are the dominant species in cover plants and there are also differences between practices. It has been determined that annual weeds are generally suppressed and their diversity has decreased significantly in the plots except for F. esculentum. The results obtained from the canonical discriminant analysis showed that the highest numbers of weed species in the 1st and 2nd years were found in the weedy control plots and that the cover crops suppressed the weeds.

The influence of catch crops on fungal diversity in the soil and health of oat

The aim of the research was to determine the quantitative and qualitative composition of soil-borne fungi in the cultivation of oat, as well as to assess the healthiness of this cereal. The experiment considered spring barley and potato as forecrops, and white mustard or lacy phacelia cultivated after spring barley as catch crops before oat. The population of fungi showing antagonistic effect towards selected fungi pathogenic to cereal was determined. The most fungi (pathogenic and antagonistic) were found in the soil under oat cultivation after spring barley, while the least after potato. The cultivation of oat after spring barley with the use of catch crops significantly influenced a reduction in the number of fungi obtained from the soil. On the other hand, catch crop cultivation increased the share of antagonists in the soil fungus population. Among the species recognised as antagonistic, Clonostachys rosea, Trichoderma viride, T. koningii, and T. harzianum predominated. The introduction of catch crops, especially white mustard, also positively influenced the healthiness of oat. The average disease index for the tested oat cultivars grown after potato and after spring barley with white mustard and lacy phacelia as catch crops was 11.02, 12.78 and 15.90, respectively, whereas after spring barley it was 21.75.

The Effects of Catch Crops and Tillage Systems on Selected Physical Properties and Enzymatic Activity of Loess Soil in a Spring Wheat Monoculture

This study was aimed at comparing physical soil quality parameters and soil enzymatic activity in a three-year spring wheat monoculture affected by the incorporation of biomass of selected catch crops into the soil using two systems of tillage (conventional plough tillage and conservation tillage). We tested the suitability of the following catch crop plants: white mustard, lacy phacelia, and mixed legumes (faba bean + spring vetch) and compared these to the control treatment. This research was carried out in the period 2014–2016 in Czesławice (central Lublin region, Poland). Catch crops promoted improved soil structure, soil particle-size distribution, soil bulk density, and soil moisture content. Tillage systems had a smaller impact on the soil physical parameters. Plough tillage contributed to improved soil moisture content in a deeper layer (15–20 cm). On the other hand, the above-mentioned tillage system influenced adversely soil compaction and bulk density. Catch crops caused an improvement in the soil particle size distribution, resulting in a higher percentage of the finer soil fractions. Moreover, the catch crops positively affected soil bulk density and soil compaction. The study has proven that enzymatic tests are good indicators to discriminate between soil sites under study in dependence on the catch crop and tillage system. Conservation tillage significantly stimulated the activities of the studied enzymes, especially in the topsoil layers. A particularly wide range of dehydrogenase and urease activity was obtained in the soil sown with the white mustard catch crop. The other catch crops (lacy phacelia and faba bean + spring vetch) also stimulated enzymatic activity. The obtained results show the positive role of catch crops and conservation tillage in bringing about positive changes occurring in the soil environment.

Element content in ten Croatian honey types from different geographical regions during three seasons

Concentrations of 20 elements were measured in ten honey types collected from four main geographical regions of Croatia during three beekeeping seasons. The four regions differ by their geography, ecology and climate. Significant differences in the element concentrations between honeys of different botanical origin were found for Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Mo, Na, Pb and Zn (p<0.05). The highest mean concentrations of elements were found in honeys: floral Cd, Cr; acacia Mo; honeydew Al, Cu, K, Ni; chestnut Ba, Ca, Mn, Na; forest Fe, Mg; sunflower Cu; linden Pb, Co; sage Se; lacy phacelia Zn. Differences in the element content of honeys originating from the same region collected in different seasons was found for the honeys: floral Al, Ca, K, Zn; acacia Ba, Ca, Cu, Mg, Mn, Na, Zn; honeydew Cu, K, Mn, Pb; chestnut Al, Ba, Cu, K, Mn, Na, Pb; sunflower Cu; linden Ba, Ca, Mn. Also, regional differences in the element content of honeys collected within the same season was found for: floral Al, Ca, K, Mg; acacia Ca, K, Mg, Mn, Na, Zn; honeydew Cu, K, Mn, Pb; sage Ba, Ca, K, Mg, Mn; chestnut Ba.

Simultaneous HPLC-ELSD determination of sugars and cyclitols in different parts of Phacelia tanacetifolia Benth.

Three cyclitols (allo-inositol, scyllo-inositol and myo-inositol) and seven sugars (xylose, d-mannose, d-glucose, sucrose, D-(+)-turanose, D-(+)-melezitose monohydrate and D-(+)-raffinose pentahydrate) were determined in different morphological parts of lacy phacelia by high performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD) method in 30 min. The applied analytical method is rapid, simple, sensitive, low cost, reliable and suitable for profiling of major sugars and cyclitols in Phacelia tanacetifolia Benth. (lacy phacelia) parts. Pressurized liquid extraction and solid phase extraction were used as extraction and purification methods. The obtained results showed significant differences in the quantities and distribution of cyclitols and sugars found in the investigated morphological parts. The quantities of the identified cyclitols in lacy phacelia ranged between 1.07 and 4.68 mg/g of dried plant, while for sugars in the range of 1.07–25.3 mg/g. However, flowers were richer in cyclitols and sugars compared to the seeds.

Nitrogen compounds in Phacelia tanacetifolia Benth. honey: First time report on occurrence of (−)-5-epi-lithospermoside, uridine, adenine and xanthine in honey

Lacy phacelia (Phacelia tanacetifolia Borkh.) honey composition was screened by UHPLC-DAD-QqTOF-MS. The targeted analysis revealed 6 major nitrogen compounds including aromatic amino acids (tyrosine, phenylalanine), purine derivatives (adenine, xanthine), nucleoside (uridine) and rare non-cyanogenic cyanoglucoside, (−)-5-epi-lithospermoside ((2Z)-2-[(4R,5R,6S)-4,5-dihydroxy-6-(β-d-glucopyranosyl)oxycyclohex-2-en-1-ylidene]acetonitrile). Their identity was confirmed by different analytical tools: HRMS, co-chromatography with standard compound or comprehensive NMR experiments. All the compounds, except amino acids, were reported and determined in honey for the first time. The amount of the compounds was quantified in 16 unifloral phacelia samples: adenine (18.45 ± 4.63 mg/kg), xanthine (10.53 ± 2.98 mg/kg), uridine (42.84 ± 9.26 mg/kg), tyrosine (14.66 ± 10.22 mg/kg), (−)-5-epi-lithospermoside (70.61 ± 31.37 mg/kg) and phenylalanine (20.41 ± 11.99 mg/kg). The (−)-5-epi-lithospermoside content is significantly correlated with P. tanacetifolia pollen percentage (R2 = 0.5612, p < 0.001) and it is proposed as a potential marker of botanical origin for phacelia honey.

Effectiveness of the application of metamitron in lacy phacelia (Phacelia tanacetifolia Benth.) crops

A field experiment on the application of the herbicide Lawina 700 SC (the active ingredient metamitron – under different application regimes) was carried out in Priluki near Minsk, Belarus, over the period 2011–2013. It was proved that herbicide application in lacy phacelia crops is not always justified. With intensive growth, the crop plant itself competes with weeds and the application of herbicides is not advisable. It was only in one out of the three years that the weeds delayed and disturbed the growth of phacelia, their harmfulness proved to be significant, and herbicide application had a measurable effect. It turned out that the difference in biological and economic effectiveness between a single and double application of metamitron was insignificant and the phytotoxic effect was not found to increase. The most appropriate herbicide application regime that protected lacy phacelia against annual dicotyledonous weeds was a single application of metamitron (1.4 l∙ha-¹) at the 1–2 true leaf pair stage. The study also showed that the herbicide metamitron, applied both before emergence and after emergence of phacelia, may exhibit phytotoxic activity against the cultured crop, slowing down plant growth and causing a decrease in the seed yield. The effectiveness of metamitron application before emergence – both at the rate of 1.4 l∙ha-¹ and at a higher rate (2.1 l∙ha-¹) – proved to be very unstable, in particular in the aspect of direct phytotoxicity of the herbicide on the crop plant, but also in the aspect of periodic accumulation of the biologically active substance in the soil.

Trap Crops in Onion to Reduce Onion Thrips andIris Yellow Spot Virus

Onion thrips, Thrips tabaci Lindeman, a primary insect pest of onions, Allium cepa L., worldwide, reduces yield and transmits a devastating Tospovirus, Iris yellow spot virus. Costly and frequent insecticide application and increased resistance of onion thrips to insecticide prompted interest in alternative pest management options. Three trap crops, lacy phacelia (Phacelia tanacetifolia Benth.), buckwheat (Fagopyrum esculentum Moench.), and carrot (Daucus carota L.) planted in commercial onion fields during two growing seasons were evaluated for attractiveness to onion thrips. Abundance of thrips adults, larvae, and eggs were monitored on trap crops and onion plants, and dispersing adults were counted on aerial traps 0, 0.8, 6.4, and 12.8 m from trap crop rows. All trap crops when flowering or with lush vegetation supported all life stages of onion thrips during at least 1 of 2 years; trends in preference by onion thrips varied. Incidence of Iris yellow spot virus was low ranging from 6.6 to 8.2% in year 2; however, in late September of the second year, incidence was greater near trap crops than at farther distances, as measured by enzyme-linked immunosorbent assay (ELISA). Trap crops were attractive to onion thrips adults in June and July which suggests promise for decreasing numbers of thrips on onion during critical periods of bulb sizing and spread of Iris yellow spot virus; however, the short distance of influence suggested need for larger plot sizes or better sampling methods. Potential for planting trap crops along field edges to attract migrating adult thrips early in the season is discussed.

The impact of stubble crop on spring barley weed infestation

The condition and degree of weed infestation were determined in a spring barely crop grown in a short-term monoculture after mulching the soil with plants grown as a stubble crop (the control treatment without cover crop – lacy phacelia, white mustard, sunflower). The field experiment was carried out in 2010–2013 on good rye soil complex using a split-block design in four replications. The obtained results (the mean from all years of the experiment) showed that the stubble crop, especially sunflower, reduced the diversity of weed species without causing at the same time changes in weed species dominance. In all the control treatments of the experiment, &lt;em&gt;Chenopodium album&lt;/em&gt; and &lt;em&gt;Fallopia convolvulus&lt;/em&gt; were the dominant species. The degree of spring barley weed infestation depended on the species grown in the cover crop. White mustard and lacy phacelia slightly increased the number of weeds but their fresh matter significantly increased. However, the sunflower cover crop significantly increased the number of weeds without any substantial differentiation of their fresh mass.

Organic mulching, irrigation and fertilization affect soil CO2 emission and C storage in tomato crop in the Mediterranean environment

Carbon stock and CO2 emissions in agricultural systems are highly affected by the management of applied practices in arable farms, such as fertilizer use, irrigation, soil tillage, cover crop management, etc. This study evaluated the effects of various organic mulches, nitrogen fertilization and irrigation levels on soil CO2 emissions, soil carbon sequestration and processing tomato production in the Mediterranean environment. The field experiment was carried out with five main treatments, three cover crops of hairy vetch (HV), lacy phacelia (LF) and white mustard (WM) transplanted in autumn and cut in May to be used as mulches, plus barley straw mulch (BS) and conventional (C) (bare soil). After tomato transplanting, the main plots were split into two nitrogen fertilization treatments (0 and 100kgNha−1) and the sub-plots were then split again into three irrigation levels (irrigation water 100%, 75%, 50% of evapotranspiration). In all treatments, a general effect was observed in the temporal fluctuations of soil CO2 emissions throughout the observation period which were significantly influenced by soil temperature and water content. The temporal fluctuations of the soil CO2 emissions were attributed to climatic conditions and the peaks achieved optimal conditions of soil temperature and water content for soil respiration. A larger amount of TOC was observed in the mulching treatments than in the control after tomato harvesting (on average 1.44% vs 1.33%, respectively and on average 1.43% in HV trastment), probably due to the residual biomass of the cover crops and a greater growth of the tomato. Although the soil carbon output as cumulated CO2 emissions did not show statistically significant differences between the treatments, the soil carbon balance enabled us to estimate the highest net carbon contribution to the soil in HV determined by inputs and input/output ratio. However, except for the BS in 2013, the input/output ratios were >1 in all mulch treatments. In the Mediterranean environment, agronomical practices, such as the use of hairy vetch mulch on notilled soil, a slight reduction of irrigation water (−25%) and a rationalized use of N fertilizer potentially could shift the C balance in favor of soil C accumulation.

Soil quality, microbial functions and tomato yield under cover crop mulching in the Mediterranean environment

An experiment concerning the biological and chemical responses of soil to cover crop mulching was carried out in two adjacent experimental fields (2012 and 2013) under different climatic conditions in the Mediterranean environment (Central Italy). The Monthly Aridity Index was calculated in order to verify the relationship between soil properties and climatic factors under three different cover crop mulches: Vicia villosa Roth (HV), Phacelia tanacetifolia Benth. (LP), and Sinapis alba L. (WM). A conventional management was also included in the experimental fields as control (C). Soil samples were collected at 0–20cm depth after the transplanting and the harvesting of tomato (May and August, respectively), in order to assess the initial and residual effects of mulching on soil quality. In the two experimental years, the amount of precipitation from May to August was 110mm in 2012 and 172mm in 2013. The average values of AI were 18 and 49 in 2012 and 2013, respectively. LP mulching was sensitive to low precipitation levels in terms of aboveground decomposition rate (the variation of dry matter from May to August 2012 was −53% in LP, 64% in HV and 69% in WM) and a lower tomato yield compared to the control in 2012 (4.2kgm−2 in LP and 5.2kgm−2 in C). WM mulching was sensitive to low precipitation in terms of soil nutrient storage (from May to August 2012 the variation of soil C was 19% in WM., 6% in C, −5 % in LP and 10% in HV; the variation of soil N was 44% in WM, 2% in C, −2% in LP and 13% in HV). Soil microbial activity and functional diversity were strongly affected by the climatic conditions in all mulching treatments. In particular, precipitation influenced soil C availability, which enhanced microbial functional diversity. In short, the effects of lacy phacelia, white mustard and hairy vetch mulching on soil quality, microbial functions and tomato yield were influenced by summer precipitation and temperature in the Mediterranean environment.

Weed infestation of spring barley (Hordeum vulgare L.) depending on the cover crop and weed control method

&lt;p&gt;The aim of this 3-year field study was to evaluate the effect of some stubble crops and weed control methods on the species composition, number and air-dry weight of weeds in a spring barley crop grown in short-term monoculture. The study was conducted in the period 2009–2011 at the Uhrusk Experimental Farm, on mixed rendzina soil classified as very good rye soil complex. It included stubble crops which were ploughed under in each year (control treatment without cover crop, white mustard, lacy phacelia, a mixture of legumes – narrow-leaf lupin + field pea) and 3 weed control methods used in spring barley crops (mechanical, mechanical and chemical, chemical weed control). &lt;em&gt;Veronica persica &lt;/em&gt;was the weed species that occurred in greatest numbers in the spring barley crop sown after stubble crops. All cover crops reduced the numbers of &lt;em&gt;Avena fatua &lt;/em&gt;which was the dominant species in the control treatment. Chemical as well as chemical and mechanical weed control significantly reduced the numbers of &lt;em&gt;Avena fatua&lt;/em&gt; compared to the treatment where only double harrowing was used for weed control. The stubble crops did not reduce weed infestation of spring barley. Compared to the control treatment, the ploughing-in of white mustard and the mixture of legumes reduced the dry weight of weeds by 49.1 and 22.7%, respectively. Mechanical weed management proved to be less effective in reducing the number and dry weight of weeds compared to the other weed control methods. A significant negative correlation was found between the dry weight of weeds in the spring barley crop and the dry weight of the ploughed-in white mustard cover crop under the conditions of chemical weed control as well as in the case of the mixture of legumes when complete mechanical and chemical weed control was used.&lt;/p&gt;

Role of sweetclover and phacelia in agriculture ecology improvement for droughty left-bank areas of Saratov region

Ecological pollution and physical degradation of soil depend strongly on anthropogenic action on it. The role of such legumes as biennial yellow sweetclover, annual white sweetclover, and plants of Boraginaceae family—lacy phacelia and blue curls—in improvement of physical and chemical soil properties was investigated. An ecologically safe way for soil fertility increase under droughty conditions is offered. Use of both species of sweetclover and one species of phacelia tanacetifolia as green manure in crop rotations are recommended.