Agricultural Science and Practice

State of water-stable soil structure in the Central Forest-Steppe under agrogenic and postagrogenic maintenance

2023-02-23T23:09:03+02:00

Aim. To determine the regularities in the formation of water-stable structure and to obtain the objective integral information about the process of break-up and consolidation of the water-stable structure under agrogenic and postagrogenic load on the main soil types of the Central Forest-Steppe of Ukraine. Methods. The field method – the soils of chernozem type were investigated (seven chernozem-like soil types of different granulometric composition and humus content) in the central part of the Forest-Steppe of Ukraine, the laboratory analytical method (wet sieving of soil structure), the mathematical-statistical method (non-parametric statistics, factor, cluster, and fractal analyses). Results. The analysis of the water stability of the structure of chernozem-like soils in the Forest-Steppe demonstrates the perspectives of using modern statistical methods: fractal, factor, cluster methods, and the method of non-parametric statistics, which demonstrates their sensitivity to insignificant changes in the distribution of water-stable aggregates within the agronomically valuable interval. The soil types of postagrogenic maintenance form the distribution of water-stable aggregates, making up “prevailing” sizes of aggregates in the interval of sizes of 5–3 and 2–1 mm, which ensures the persistent state of the re-distribution where the index of Hurst has the values of H > 0.75. The agrogenic impact on soils changes the re-distribution of water-stable aggregates, destroying their natural distribution and ensuring the antipersistent state of the distribution with low stability (D > 1.43 and Н < 0.58). Under postagrogenic maintenance of soil types, there is a stable mutual connection between water-stable aggregates, structural units, and ESP (R = +0.78), and in the total of correlation relations, the direct and inverse correlation relations of R> ± 0.55 level are >30 % with the 1.5 to 1 ratio in favor of inverse proportion relations which ensures a high level of self-regulation for the hierarchical organization of the structural and water stable state. Conclusions. The determining index, characterizing the stability level of the water-stable structure, was found to be the content of water-stable aggregates of 3–1 mm and > 0.25 mm and the weighted average diameter of water-stable aggregates within the agronomically valuable interval of sizes that demonstrated a strong correlation (R = ± 0.76–0.96 ± 0.02) with fractal dimensionality (D > 1.4) and the index of Hurst (Н) which allowed for forming a gradation scale for the evaluation of the water-stable structure and the degree of agrogenesis manifestation of soils in the Forest-Steppe of Ukraine. In terms of the rate of agrogenesis manifestation via the formation of the degree of the water-stable structure, the soils of chernozem type were divided as follows: gray forest low-humus heavy-loamy light-clay soil on carbonate loess-like clay < typical low-humus heavy-loamy light-clay chernozem on loess-like clay < meadow-chernozem low-humus carbonate heavy- loamy soil on loess-like clay < typical medium-humus heavy-clay chernozem on loess.

Effectiveness of using the mixtures of herbicides flumioxazine and fluorochloridone in sunflower crops

2023-02-10T03:54:42+02:00

Aim. This work is devoted to the search for potential partners for the integrated application of flumioxazine in sunflower crops. This herbicide is an inhibitor of protoporphyrinogen oxidase (PPO) in weed plants. The resistance to this class of herbicides is not yet common today, compared to other classes. Therefore, the work is aimed at de- veloping flumioxazine-based herbicide compositions that effectively prevent the emergence of herbicide-resistant weed biotypes. Methods. The interaction effects, weed control efficiency, and crop selectivity were studied when flumioxazine was used in the mixtures with herbicides acetochlor and propisochlor (long-chain fatty acid synthesis (LCFAS) inhibitors), promethrin (electron transport (ET) inhibitor in photosystem 2 (PS 2) of chloroplasts) and fluorochloridone (inhibitor of carotenoid synthesis by blocking the activity of phytoendesaturases (PDS)) both in the experiments on sunflower crops and in greenhouse experiments using the model objects. Results. The studies have shown that when flumioxazine is applied with the ET inhibitor, promethrin, the interaction is antagonistic, resulting in poor weed control efficiency and sunflower yield decrease. The tank mixtures of flumioxazine with LCFAS inhibitors acetochlor and propisochlor provide high weed control efficiency but are low in selectivity for sunflowers. The interaction between flumioxazine and fluorochloridone within the recommended application rates is additive. The tank mixture of flumioxazine and fluorochloridone herbicides at the application rates of 55 and 500 g/ha, respectively, is selective for sunflowers. In terms of control efficiency of annual dicotyledons, this mixture of herbicides exceeded, and in terms of control efficiency of annual cereal weed species was only slightly inferior to the control integrated herbicide (metolachlor + terbuthylazine). In these application rates, flumioxazine and fluo- rochloridone provided sunflower yield on par with this complex herbicide. Сonclusions. Among the investigated herbicides, the optimal partner of flumioxazine for complex use in sunflower crops was the herbicide, inhibitor PDS, fluorochloridone. Given that flumioxazine and fluorochloridone differ in their phytotoxicity mechanisms but share a common spectrum of controlled weed species, the use of a mixture of these herbicides is a factor that minimizes the likelihood of the emergence of herbicide-resistant weed biotypes.

Responses of grapevines to planting density and training systems in semiarid environments

2023-02-10T03:54:43+02:00

Aim. To investigate the physiological and agrobiological responses of grapevines on different systems of training systems in row plantations depending on the planting density and the possibility of adjusting plants for non-irri- gated crop cultivation under cold semiarid climate. Methods. The field two-way experiment of 2 × 4 was applied to study the effect of two planting density variants (3 × 1.5 m; 3 × 1 m) and four vine training systems (when the horizontal cordon is located at the height of 0.4 m, 0.8 m, 1.2 m, 1.6 m) on the parameters of the leaf area, leaf index, water loss through transpiration, activity of the photosynthetic apparatus of leaves and the yield of Zahrei wine grape cultivar (Vitis vinifera L.). The experiment data were processed using the analysis of variance. Results. The increase in the density of vine row plantations per area units from 3 × 1.5 m to 3 × 1 m enlarges the total leaf area, the exposed leaf area, water loss through transpiration, and yield weight, but these indices decrease in the evaluations per plant. The responses of grapevine to the training systems are similar and independent from the ex- perimental variants of planting density. At the height of the cordon of 0.4 and 0.8 m, the vertical shoot positioning enhances the potential of the photosynthetic capacity of the plantations, but this potential is realized only during the years with lower water deficit for plants. Free-growing shootings on the cordons, located at the height of 1.2 m, form the canopy architecture with relatively low water loss through transpiration which has a positive effect on the activity of the photosynthetic apparatus and yield, especially in dry years. The downward shoot positioning on the cordons of 1.6 m decreases the leaf area of the vines and creates the canopy architecture with increased transpiration which enhances the effect of the water deficit and has a negative effect on the productivity of plants. Conclusions. The agronomic methods of planting and training systems for grapevines ensure the management of the character of spatial shoot location, the formation of certain canopy architecture, and setting the parameters of the leaf area; their optimization mitigates the negative effect of water deficit and provides for adapting the plants for non-irrigated crops under semiarid climate. The positive effect of compacting plantations on crop yield was determined without irrigation in semiarid environments. The variant of planting density of 3 × 1 m decreases the yield on the vines on average by 12.1–31.0 %, as compared to the variant of 3 × 1.5 m. Yet, more dense plantations are remarkable for their yield, which is 18.5–61.3 % higher depending on the training system for vines. Under dry conditions, the most efficient system is the training system with the formation of the horizontal cordon at the height of 1.2 m and free-growing shoots. The system optimizes the leaf area density, and forms the canopy architecture with rather low water loss through transpiration which has a positive effect on the activity of the photosynthetic apparatus of leaves during droughts. Under free growth, the yield of the plantations increases by 4.3–12.3 % on average as compared to the vertical shoot positioning and by 21.3 % – under their downward positioning.

Investigation of species composition of the fungi of the Fusarium genus and the resistance of the Chornobyl radio-mutants to fusarium head blight for the purposes of winter wheat

2023-02-10T03:54:43+02:00

Aim. To investigate the field resistance of collection spelt-like samples of the Chornobyl radio-mutants (RM) of winter wheat to Fusarium head blight and to determine the species composition of the fungi of the Fusarium genus in the Forest-Steppe of Ukraine. Methods. The resistance (in scores) of ten RM-samples of winter wheat to Fusar- ium head blight was determined in field conditions by visual inspection of plants using standard methods (Trybel et al, 2010). To determine the infection rate of the seeds, the biological method of seed germination in the rolls of filtration paper was used. DNA was extracted using the reaction kit AGROSORB NK (Agrogen Novo, Ukraine), according to the manufacturer’s instructions. The molecular identification of the species composition of the fungi of the Fusarium genus was conducted with the commercial test systems “Fuzarioz zlakiv” (AgroDiagnostica, RU) according to the manufacturer’s instructions, using the real-time PCR. Results. The results of evaluating the field resistance of ten spelt-like RM-samples of winter wheat to Fusarium head blight are presented. The species composition of the Fusarium fungi as of 2016–2018 in the Forest-Steppe of Ukraine, namely in Kyiv, Cherkasy, Sumy, Vinnytsia, Chernivtsi, Poltava, Kharkiv, Ternopil, and Khmelnytsky regions is presented. To study the spe- cies composition of the Fusarium fungi, 639 seed samples of winter wheat were taken from the farms located in the territory of nine regions in the Forest-Steppe zone. The results of molecular identification of the infection rate in the seed material demonstrate the presence of seven out of eight fungi species under investigation: F. avena- ceum, F. culmorum, F. graminearum, F. langsethiae, F. poae, F. sporotrichioides, F. tricinctum during the years of studies. Yet, F. culmorum, F. langsethiae were not identified in 2017, and F. cerealis was not found during the study years, in 2016–2018. It should be noted that the most frequent incidence was found for F. graminearum, F. avenaceum and F. tricinctum, which was within the range of 25.8–44.0 %, and according to (Zhdanova, 2002) it refers to the group of frequently dispersed species. The results of the PCR diagnostics of the species composition of Fusarium fungi in Kyiv region, where field studies were conducted to evaluate the resistance of collection spelt- like Chornobyl radio-mutants in 2016–2018 (Bila Tserkva Breeding Research Station (BTBRS) of the Institute of Bioenergy Crops and Sugar Beet of the NAAS (Mala Vilshanka village, Bila Tserkva district, Kyiv region) demonstrated the spreading of six species of Fusarium fungi: F. graminearum, F. avenaceum, F. sporotrichioides, F. poae, F. tricinctum, F. culmorum, among which high aggressiveness to the wheat spikelets was observed in F. avenaceum, F. culmorum, F. graminearum; medium aggressiveness – in F. poae, and low aggressiveness – in F. sporotrichioides, F. tricinctum. On the background of the obtained species diversity of the disease agent, we evaluated the field resistance in ten spelt-like RM-samples of winter wheat to Fusarium head blight, whose resistance fluctuated within 7.4–8.4 scores in the study years. Under the climatic conditions most favorable for the disease development, in 2016 (from the time of spring vegetation restoration on March 01, to full ripeness of grain on July 09, there was 404.2 mm of precipitation which exceeded the perennial indices by 175 %) the samples under investigation: RM-1, RM-3, RM-4, RM-5, RM-6, RM-9, RM-10 exceeded the resistance of the standard variety, Lisova Pisnia, – 7.0 scores. Conclusions. The field and laboratory studies related to the species composition and geographic distribution of the Fusarium fungi give grounds for the assumption of the presence of an expansive species complex of Fusarium fungi in the territory of nine regions in the Forest- Steppe of Ukraine: F. avenaceum, F. culmorum, F. graminearum, F. langsethiae, F. poae, F. sporotrichioides, F. tricinctum. A close association between the biology of the group of Fusarium fungi and weather conditions of their environment was used by us to investigate the resistance of ten collection spelt-like samples of the Chornobyl radio-mutants in 2016–2018 and to isolate five RM-samples of winter wheat (RM-9, RM-5, RM-6, RM-10, RM-4), which had higher resistance to Fusarium head blight than the standard variety, Lisova Pisnia, on average for three years of studies. It should be noted that in 2016, under weather conditions favorable for pathogen development, RM-3 and RM-4 were found to be reliably more resistant compared to the standard. The five spelt-like RM-samples of winter wheat (RM-9, RM-5, RM-6, RM-10, RM-4) with high resistance indices on average for the years of studies (2016–2018) are introduced by us to the breeding programs as the initial material to obtain varieties, resistant to Fusarium head blight.

Dynamics of climate changes and its effect on the performance of cereals according to satellite data

2023-02-10T03:54:43+02:00

Aim. To study the effect of climate changes on the performance of cereals. Methods. Remote, statistical, and analytic methods. Climate changes were determined by the sum of radiation temperatures of the earth’s surface, calculated using the data of the infrared range (10.3–11.3; 11.4–12.4 μm) of the high precision radiometer AVHRR of the meteorological satellites of the Earth, NOAA. The effect of climate changes on the state of vegetation, including the phenological parameters, such as the beginning, the end, and the length of the vegetation peri- od, was determined by the Normalized Difference Vegetation Index (NDVI) obtained using the data of infrared (0.72–1.1 μm) and red (0.58–0.68 μm) ranges of the abovementioned radiometer. The satellite data are openly accessed on the website of STAR NESDIS NOAA – Satellite Applications and Research of NOAA’s National En- vironmental Satellite Data Information Services of the National Ocean and Atmosphere Research Department of the USA – http://www.star.nesdis.noaa.gov/smcd/emb/vci/VH/. The dynamics of СО2 concentration in the air was determined using the satellite data of AIRS/Aqua (https://disc.gsfc.nasa.gov/datasets/AIRS3C2M_005/summary), the precipitation dynamics – using the data of ERA5 ECMWF/Copernicus Climate Change Service (https://devel- opers.google.com/earth-engine/datasets/catalog/ECMWF_ERA5_MONTHLY#description). The association be- tween the performance of cereals and satellite data was found by the method of correlation and regression analysis. Results. Using the satellite data, it was found that in 1982–2021, the sum of radiation temperatures of the earth’s surface reliably increased in the vegetation period (April–September), and the amount of precipitation tended to decrease in the zones of Polissia, Forest-Steppe, and Steppe. The highest tempo of warming was observed in the territory of the Steppe. In general, the warming had a positive effect on the state of vegetation, according to NDVI, and on the performance of cereals. However, in the recent decade (2010–2020), the positive effect of the warming on the vegetation state decreased, and according to the NDVI trend, there has been a tendency towards the negative effect of the further increase in the temperature, which is especially remarkable for the Steppe and Forest-Steppe. On the contrary, the warming in the Polissia zone created the conditions for the increase in the performance of agri- cultural cereals. Conclusions. From 1982 till 2021, there was a strong tendency towards the increase in the sum of radiation temperatures of the earth’s surface in the vegetation period and the decrease in the precipitation amount in Polissia, Forest-Steppe, and Steppe. According to the NDVI data, due to the warming, the length of the vegeta- tion period increased by 14–21 days on average, which had a positive effect on the vegetation. Since 2010, the acceleration in the warming tempo has been observed. The average annual increase in the sum of the radiation tem- peratures of the earth’s surface in the vegetation period is 15–16 °С – for Polissia, 14–18 °С for the Forest-Steppe, and 18–20 °С for the Steppe. According to this tendency, if the current regularity in the temperature increase in 1982–2021 is preserved in the nearest future, the temperature of the vegetation period will additionally increase, and the average sum of temperatures of the earth’s surface will reach 4000 °С in Polissia, which was notable for the Forest-Steppe in 1982–2021, 4440–4600 °С – in the Forest-Steppe, and up to 5800–5900 °С in the Steppe. In 1982–2000, there was a strong regularity of the positive effect of the warming during the vegetation period both on the vegetation state according to the NDVI index, and the performance of cereals in all three natural climatic zones. However, after 2000, due to the negative effect of high summer temperatures on the crops, the effect of the warming on vegetation considerably decreased, which was especially notable for the Steppe where the increase in NDVI compared to the previous period was on average 9.41 % in 1992–2001, and in 2012–2021 – 1.78 %.