Photosynthetic Potential Research Articles

Вплив способів зрошення на продуктивність кукурудзи

Modern methods of irrigation are considered as a key factor in the intensification of technologies for growing of grain corn. The productivity of the crop as a result of the optimization of water and nutrient regimes increases from 100 to 380% in comparison with non-irrigated conditions. The aim of the research was to study the effect of sprinkling, drip irrigation and subsurface drip irrigation on growth processes, the structure of the crop formation and the yield of grain corn. Field experimental studies were conducted on the lands of Kamyans'ko-Dnieprovs'ka research station IWPLM of NAAS during 2018-2020The obtained results confirm that the method of irrigation significantly affects the formation of basic biometric parameters, yield structure and productivity. It is established that the maximum parameters of growth processes (plant height, leaf surface area, as well as photosynthetic potential and net photosynthesis productivity) of corn are provided by drip irrigation. Significantly lower and similar values were determined for the conditions of subsurface drip irrigation and sprinkling, and the lowest parameters of corn productivity were obtained under natural moisture conditions. The highest yield of corn grain was obtained under drip irrigation – 20,69 t on ha, while under subsurface laying of irrigation pipelines it was significantly lower – 16,44 t on ha. In the variant with sprinkling, the decrease in grain yield by 0,62 t on ha compared to subsurface drip irrigation was within the least significant difference of the experiment (LSDА0,5 = 1,93). On the variant of conditional control (without irrigation), on average, for three years, a low yield level was obtained - only 3,85 t on ha, which confirms the significant risks and inexpediency of this crop in the Steppe conditions without irrigation. The results also confirm the existence of a close correlation between corn yield and leaf surface area of plants. The obtained dependence is described by a linear equation of the form y = 0,6227x – 14,133, and the coefficient of determination is R2 = 0,98.

Оцінка фотосинтетичної діяльності сортів пастернаку посівного в умовах Правобережного Лісостепу України

Due to the intensification of production of parsnip, the question arises to clarify the elements of cultivation technology that should ensure its high productivity. The use of varietal plant resources is one of the most important parts of agriculture - the basis of economic and social development of the state. The most efficient and cost-effective is the widespread introduction of new varieties and hybrids with a genetically determined level of adaptation to the conditions of soil and climatic zones of their cultivation. The indicator of the dynamics of the formation of photosynthetic productivity is the basis of the yield of each crop. The purpose of the research was to study the dynamics of leaf surface formation in varieties of parsnip in the conditions of the Right-Bank Forest-Steppe of Ukraine. The studied cultivars of parsnip sowing formed a high area of active assimilation surface, the dynamics of which depends on the stage of organogenesis, soil and climatic conditions of the year and varietal characteristics. With the highest average for the growing season leaf area (49.0-49.6 thousand m2 on ha), photosynthetic potential (1.79-1.83 million m2 per day on ha) and net productivity of photosynthesis - 5.56 g on m2 per day) were characterized by varieties Stymul and Pulse in terms of other varieties. It is established that in order to obtain stably high yield (44.4-45.4 t on ha) and marketability of root crops (85-93%) in the conditions of the Right-Bank Forest-Steppe of Ukraine it is necessary to sow highly productive varieties of parsnip sowing Stymul and Pulse.

Seed productivity of different Festulolium varieties

Festulolium is the first artificially created Poaceae forage culture. The advantages of this crop are good regrow capacity, high content of sugars and good winter hardiness. The authors investigated biological features and seed productivity of new varieties of Festulolium of different morphotypes in the conditions of the forest-steppe of the Central Chernozem Region of Russia. The material for research included 6 Festulolium varieties (the Aelita, VIK-90, Viknel, Debut, Izumrudnyi, and Sinta) bred in the Russian plant breeding centers, included in the State Register of the Russian Federation and admitted for cultivation in the territory of the Central Chernozem Region by the State Commission for Cultivation. Field experiments were carried out according to conventional procedures adopted in seed production of perennial grasses. Due to phenological observations the authors define that the duration of the vegetation period of Festulolium depends on the variety and weather conditions during the vegetation season. According to the results of observations it can be noted that in order to form the yield of seeds, the grass stands of different years of vegetation require an average sum of temperatures of 1283-1816°C and 128-181 mm of total precipitation. The most early-ripening variety was the Sinta followed closely by the Izumrudnyi variety. In the second and subsequent years of vegetation the plants of these varieties began to grow earlier than the plants of other varieties in the spring and were the first to reach the stage of full seed maturation in 83-88 days. Such varieties as the Debut, Viknel, VIK-90 were defined as late-maturing; their seeds ripened in 96-102 days. The most intensive linear growth, the greatest plant leafiness, leaf area, net photosynthetic productivity, photosynthetic potential and subsequent seed yield of 735.5 kg was demonstrated by the Izumrudnyi variety. Seed yield of the Sinta variety was slightly less (695.9 kg) followed by the VIK-90, Viknel and Aelita varieties.

Фотосинтетична діяльність посівів сої на дерново-підзолистих ґрунтах Західного Полісся

Formation of soybean sowings with the most developed leaf apparatus, which would be in the active state for a long time (maximal) both at the beginning and at the end of the growing season is an important prerequisite for high productivity of the crop. Aim of the study was to detect the effects of inoculation by preparation Legum Fix and foliar feeding by chelate microfertilizers Vuxal Oil Seed and Quantum-Oliyni on dynamics of leaf surface area and formation of photosynthetic potential of soybean varieties. Field studies were carried out on the basis of stationary rotation of the ALLC «Vasyuta» in the Kovel district of Volyn region. Field studies were carried out on soybean sowings varieties Cassidy (Canada) and EC Mentor (France). As result of conducted researches is established that the maximum sizes of the leaf surface of soybean crops was reached during the flowering period and at the beginning of beans formation, it decreased slightly in the phase of seed swelling, which, first of all, was caused by plants water availability, as lack of moisture led to suspension of plants growing processes and to weaken their photosynthetic activity. A larger area of leaf surface was formed by the early ripening variety EC Mentor, which, depending on variant of the experiment and period of plant growth, varied in the range of 21,5–45,7 thousand m 2 /ha. Fertilizing of soybean sowings by chelate microfertilizer Vuxal Oil Seed at the beginning and in full flowering (BBCH 60-66) with rate of consumption 2,0 l/ha and seed inoculation by Legum Fix in the day of sowing with dose 2,5 kg of preparation per 1,0 t of seeds contributed to formation of maximum assimilation surface of soybean sowings – 44,7 and 45,7 thousand m 2 /ha in varieties Cassidy and EC Mentor, respectively. Was noted, that during period of soybean varieties vegetation, the photosynthetic potential gradually increased and reached maximum values from the end of flowering phase to full swelling of seeds, further gradually decreasing from the phase of physiological maturity of seeds. Maximum photosynthetic potential of sowings - 2,450 and 2,445 million m 2 /ha, early ripening varieties EC Mentor and Cassidy were formed during period of flowering – full seed swelling with use of seed inoculation and fertilizing of sowings by chelate microfertilizer Vuxal.

Photosynthetic and Yield Characteristics of Winter Wheat under Two Rounds of Irrigation during Spring

To clarify the effect of photosynthetic and yield characteristics of winter wheat under 7500 kg/hm2 grain yield when irrigated twice in spring, field experiments were conducted in the low plain of Hebei Province, which is in the Helonggang Region, an area suffering from serious water scarcity. The photosynthetic and yield characteristics of winter wheat were studied by using 8 wheat varieties and by irrigating water twice during spring from 2018 to 2019 under the condition of 42.6 mm of precipitation during the wheat growing season. Results showed that the yield of wheat varieties was 7805.3–9435.0 kg·hm−2. Under the irrigation condition, the yield difference between strong gluten wheat and medium gluten wheat was irregular. In this study, both the average daily photosynthetic rate and photosynthetic potential were higher in Shinong 086 and lower in Shiluan 02-1, but the yield was higher in Shiluan 02-1. Varieties with high light efficiency need to be selected to obtain a high yield of wheat. Moreover, agronomic measures should be optimised, a reasonable population structure should be established and the contradiction between population development and ontogenesis must be addressed. The above conclusions can provide a theoretical basis for guiding wheat variety selection and supporting technology formulation.

ВЛИЯНИЕ ГУСТОТЫ СТОЯНИЯ РАСТЕНИЙ И ПРОТРАВИТЕЛЯ СЕМЯН НА ФОТОСИНТЕТИЧЕСКИЙ ПОТЕНЦИАЛ КУКУРУЗЫ

ВЛИЯНИЕ ГУСТОТЫ СТОЯНИЯ РАСТЕНИЙ И ПРОТРАВИТЕЛЯ СЕМЯН НА ФОТОСИНТЕТИЧЕСКИЙ ПОТЕНЦИАЛ КУКУРУЗЫ

The Influence of Climate Change on Oat Productivity in the Steppe Zone of Ukraine

Purpose. To assess the impact of climate change on oat productivity in the steppe zone of Ukraine. Methods. Statistical, mathematical modeling. Results. It is established that the seed sowing and of seedling emergence will be postponed to an earlier date. More favorable conditions are expected for the formation of seedling emergence, growth and development of plants during the period of "seedling - heading". Reduced background temperature will lead to a decrease in the value of total evaporation and a decrease in moisture demand by 47–58 mm. The moisture content of the first vegetation period will be significantly higher than in the middle perennial years. Agroclimatic conditions of the second half of the vegetation period of oats will develop at low temperatures and uneven moisture across the territory. The demand for moisture will increase everywhere by 12–28 mm. The supply of moisture will decrease. Using the model of the formation of the yield of agricultural crops, the influence of changes in the agro-climatic conditions of the growing season on the indicators of photosynthetic productivity of oat crops and the formation of the yield was assessed. Conclusions. It was concluded that a possible increase in the yield of oats in the Steppe zone of Ukraine under the implementation of climatic scenarios and early sowing terms. Changes in agroclimatic conditions in the implementation of climatic scenarios will lead to changes in the photosynthetic activity of oat crops: the relative leaf area will increase, the increase in total plant mass will increase, the photosynthetic potential of crops will grow during the growing season. Proposed cartographic schemes of the expected yield of oats in the Steppe zone of Ukraine.

Agronomic and physiological evaluation of eight cassava clones under water deficit conditions.

Cassava (Manihot esculenta Crantz) is an important crop in Africa, Asia, Latin America, and the Caribbean. This species grows adequately in drought conditions and is ideal to ensure food safety in marginal environments, such as soils with low fertility and low rainfall conditions. Complementary irrigation practices can be used, or genotypes with good yield potential can be identified against these conditions to enhance productivity in those environments. For this reason, this research aimed to study several physiological mechanisms and agronomical characteristics in eight cassava clones under prolonged water deficit. The experimental design was a split-plot where the principal plot was composed of three irrigation treatments (7, 15, and 21 days without irrigation, DWI) and the secondary plot by the eight clones. The results showed that cassava plants against drought conditions (21 DWI) decreased their growth, foliar expansion, and partially closed the stomata, avoiding water losses through transpiration. The variables of the net assimilation rate of CO2, yield, and biomass accumulation were not affected by the maximum drought period. The best clones under drought were Guajira, Guajira 3, Guajira 4, Concha Rosada, and MeVen 77-1. The frequency of irrigation 15 DWI increased the variables of gas exchange and vegetative growth. This behavior is due to the ability to tolerate complex conditions through morphological and physiological mechanisms, among them, long life leaf, stomatal control, and high photosynthetic potential.

Festulolium seed productivity depending on sowing methods and seeding rates

The effectiveness of animal husbandry depends on stable provision of animals with high-quality and inexpensive feed. The most affordable source of feed is perennial grasses. New varieties of forage grasses with improved characteristics are an important reserve for fodder production. The intergeneric festulolium hybrid is a valuable forage crop for field and meadow grass sowing which can be used for green fodder, hay, silage, haylage, cultivated hayfields and pastures. The scientific development of cultivation techniques is required to ensure high and sustainable seed yields. An important element of the cultivating technology is the rate of sowing seeds and the method of sowing. In the studies conducted in 2006–2009, the biological characteristics and seed productivity of festulolium were studied at different seeding rates. According to the results of the studies, it can be noted that sowing of festulolium by traditional (15 cm) or inter-row (30 cm) methods at a seed rate of 6.0 kg/ha allows for the formation of a sparse and weakly lodging grass stand. The photosynthetic apparatus of festulolium assimilated most productively when using conventional and inter-row methods of sowing at seeding rates of 6.0 and 9.0 kg/ha, as evidenced by the maximum value of the photosynthetic potential - 1029-1090 thousand m2×day/ha. Excessive thickening of crops (12.0 kg/ha) adversely affects the formation of elements of the crop structure and reduces their productivity. It was found that the highest yield of festulolium seeds with the traditional (604.3 kg/g) and inter-row (652.3 kg/ha) sowing methods were obtained at a seeding rate of 6.0 kg/ha and plant density of 130–133 pcs/m2.

Leaf area and photosynthetic potential of the chickpea crops for cultivation in South of Ukraine

Leaf area and photosynthetic potential of the chickpea crops for cultivation in South of Ukraine

Influence of processing of crops of a winter rye by growth factors on crop productivity and grain quality

The research on studying of influence of growth such as Epin, Immunotsitofit and Zir-con on crop productivity and grain quality of winter rye has been conducted. It is re-vealed that processing of winter rye by growth stimulants Epin significantly increases crop productivity and improves quality of grain. Productivity of sowings of agricultural crops depends on size and duration of the functioning of a photosynthetic apparatus of plants. Photosynthetic potential of sowing is closely correlated both with biological and economic productivity of plants. Researches have shown that processing of winter rye crops by growth stimulator Epin significantly increases the heavity and improves grain quality.

Peculiarities of influence of growing technology elements on the photosynthetic activity of sugar beet crops

Purpose. To determine the influence of elements of cultivation technology on the photosynthetic activity of sugar beet crops.Methods. Field, laboratory.Results. Studies show that by the third decade of June, sugar beet plants on average have formed a leaf surface at the level of 3.5 thousand cm2/plant, which is sufficient for effective photosynthesis. But in the third decade of July, it increased and on the average in the experiment on the ungrounded variants amounted to 4.1, and in the fertilized 5.3 and 5.5 thousand cm2/plant. The analysis shows that as of the third decade of August, the area of the leaf surface was maximum compared to other time intervals, amounting to 4.4, and 6.0 and 6.3 thousand cm2/plant fertilized respectively. Photosynthetic potential for the period from the third decade of June to the third decade of July in the version without the use of mineral fertilizers the best were: Sofia, Umansky BS97, ICB 0801, Vesto and Zluka, using N150P150K150: Hero. Sofia, Uman BS97, ICB 0801, Vesto and Zluka, but for the introduction of N300P300K300: Hero. Sofia, Uman ES97, ICB 0801, Vesto, Zluka and Uman ES90. But from the third decade of July to the third decade of August, the photosynthetic potential was 0.95–2.63 million m2 × days/ha, due to the fact that the leaf area increased slightly, by 0.3–0.8 thousand. cm2/plant. In terms of net photosynthesis performance in the period from the third decade of July to the third decade of August, the maximum values were in the experiment compared to other intervals. So, the best dry matter per unit area of leaf surface accumulated the following hybrids: Hero (5,21–7,25), Constant (3.09–4.94), Mace (3.67–5.68), Romulus (3,27–4.54) and Uman FM90 (2.87–4.33 g/m2 per day).Conclusions. It was established that in the third decade of August the maximum leaf area was in hybrids: Alexandria, Umansky Emergency 90, Zluka, ICB 0801, Romulus, Quarto and Sofia. But from the third decade of August to the third decade of September, the maximum values of photosynthetic potential were in the following hybrids: Sofia (1.68), Ukrainian World Cup72 (1.13), Romulus (1.35), Quart (1.35) and Zluka ( 1,13). From the third decade of September to the third decade of October, the best net photosynthesis productivity was observed in hybrids: Vesto (0.42–1.19) and Quart (0.98–1.08 g/m2 per day).

Frost damage to maize in northeast India: assessment and estimated loss of yield by hyperspectral proximal remote sensing

Frost in the uplands of northeast India frequently damages maize, leading to poor yields or even complete crop failure. We studied the feasibility of using reflectance spectra from a handheld radiometer and a camera on board a drone at 80 m above the crop to assess physiological changes, differential responses of crop to nutrient managements (N, P, and NPK) and also predicted the likely losses of grain yield caused by one night’s frost damage in 90-day-old maize crop in Meghalaya, northeast India. A portable single-beam field spectroradiometer (model SVC-HR-1024) was used to measure radiation in the range of 350 to 2500 nm with varying bandwidth at 1 m above the crop. All measurements (both before and after frost) were made strictly between 11:00 and 13:00 h, when the sun was almost overhead. Similarly, a Parrot Sequoia multispectral camera sensing in four wavebands was mounted underneath a drone (DJI Matrix 600 model). We compared the measured spectra with those recorded on the same crop before the frost and also measured several biochemical constituents in the leaves on the two occasions for comparison. The frost damage increased the reflectance in the photosynthetically active visible and infrared regions with a strong peak at 2100 nm while it caused a sharp decline in the near-infrared (between 720 and 1350 nm) and shift in the red edge. It caused a decrease in the normalized difference vegetation index as measured by the radiometer from an average of 0.36 to 0.13 and a decrease from 0.5 to 0.31 as measured from the drone. The yield in frosted year was on average 870 kg ha^{− 1} less than in the previous frost-free year on the same plots. Frost injury reduced leaf pigments (chlorophyll and carotenoids), nitrogen, and grain yield by a greater magnitude in P-stressed and NPK-deficient maize crops over N-stressed and stress-free (with NPK) plants. Spectral reflectance and vegetation indices also varied significantly. We could also assess quantitatively the crop’s loss of photosynthetic potential from the hyperspectral reflectance measurements and from the low-flying drone. The latter technology should enable farmers to monitor and assess frost damage immediately and to predict the likely losses of yield.

Эколого-физиологические особенности реакции сосны обыкновенной на уровень плодородия почвы как показатель адаптации к условиям среды

Comprehensive ecological and physiological studies (on the organism level) of plant response of Scots pine to changes in soil fertility were carried out in order to obtain quantitative parameters of the leaf apparatus and root system functioning and nature of their interrelation. Biological productivity was calculated according to V.M. Lebedev and E.V. Lebedev (2006), net productivity of photosynthesis – according to A.A. Nichiporovich (1955), and mineral productivity – according to V.M. Lebedev (1998). The response of 2–3-year-old scots pine plants was studied for fertilization with 30, 60, 120 and 240 kg/ha of nitrogen against the fertilizer application rate of Р60К60 under the conditions of a microfield experiment on gray forest soil. An increase in the level of nitrogen nutrition led to a change in the ecological and physiological parameters of the root system and leaf apparatus functioning: the ratio between root and photosynthetic potential, nitrogen absorption by the unit of the active surface of roots per day, net productivity of photosynthesis, and biological productivity of plants. The nitrogen status slightly affected the net productivity of photosynthesis, however drove up an increase in biological productivity by 1.2–1.5 times. An increase in the nitrogen status led to a change in the ratio between the values of root and photosynthetic potentials in favor of the leaf apparatus. A high positive correlation (0.931–0.992) between the photosynthetic potential and increase in dry mass; and a high negative correlation (–(0.843–0.963)) between the ratio of root potential to photosynthetic potential and nitrogen uptake were established. The maximum of pine biological productivity was observed at a nitrogen rate of 120 kg/ha. A further increase of the nitrogen status led to a decrease in biological productivity and was found to be toxic. The response of pine to a decrease in soil fertility (due to its slow response) was determined as a result of a retrospective comprehensive ecological and physiological analysis of tabular phytomass data compiled by V.A. Usol’tsev (2002) for tree stands growing in the European and Asian parts of Russia in the age range from 10–20 to 150–300 years. The natural decrease in soil fertility of pine stands with the age from 25 to 100 years in all the regions caused a decrease in nitrogen uptake by 18.5–84.5 times, and net productivity of photosynthesis by 3.4–18.0 times. The correlation between plant age, nitrogen uptake, and net productivity of photosynthesis ranged from –0.714 to –0.870 and –0.894 to –0.991, respectively. The decrease in the activity of photosynthetic apparatus and root system adversely affected the biological productivity, which fell from 2.8 to 4.0 times depending on the region. The relationship between biological productivity and age was high negative (correlation coefficient ranged from –0.572 to –0.783). The relationship between mineral productivity with biological productivity and net productivity of photosynthesis in all cases was high positive from 0.907 to 0.994 and from 0.757 to 0.932, respectively. Starting from the age of 25, the plants adapted to a decrease in soil fertility by increasing the ratio of root to photosynthetic potential, which grew from 4.8 to 12.5 times during ontogenesis depending on the region. This nonspecific reaction is confirmed by the high positive correlation (from 0.947 to 0.997) of the ratio of root to photosynthetic potential with the tree age.For citation: Lebedev V.M., Lebedev E.V. Ecological and Physiological Features of the Scots Pine Reaction to the Soil Fertility Level as an Indicator of Adaptation to Environmental Conditions. Lesnoy Zhurnal [Russian Forestry Journal], 2019, no. 6, pp. 92–103. DOI: 10.17238/ issn0536-1036.2019.6.92

Size matters – Microalgae production and nutrient removal in wastewater treatment high rate algal ponds of three different sizes

High rate algal ponds for coupled wastewater treatment and resource recovery have been the focus of much international research over the last 15 years. Microalgal biomass productivity reported in full-scale studies (1-ha or greater) have often been substantially lower than that reported from smaller scale ponds in similar climates, regardless of the season or the dominant microalgal species used. The disconnect between smaller-scale and full-scale productivity is unclear and uncertainty remains regarding the applicability of smaller scale studies to full-scale systems. In order to better understand the differences in reported productivity, the performance of three different size wastewater treatment high rate algal ponds (5 m2, 330 m2 and 1-ha) were assessed with respect to nutrient removal and microalgal productivity over three seasons. Both daily areal nutrient removal and biomass production were affected by the size of the pond. NH4-N removal via nitrification/denitrification decreased with increasing pond size, with the highest removal rate in the 5 m2 pond and the lowest in the 1-ha. Microalgal areal productivity was maximal in the 330 m2 pond, suggesting that a combination of mixing frequency and higher photosynthetic potential under low light conditions were the main drivers of enhanced productivity in this pond compared to the 5 m2 (mesocosm) and 1-ha (full-scale) ponds. The lowest daily nutrient removal and biomass production occurred in the 1-ha (full-scale) pond. Our results suggest that, based on the current design and operation of high rate algal ponds, the optimum size for maximum productivity is considerably smaller than the current full-scale systems. This has implications for commercial scale systems, with respect to capital and operational costs.

Dynamic of Accumulation of Dry Substance and Formation of Photosynthetic Surface of Pea According to the Fattening Food Dose

     The objective of study is to appreciate the influence of different manure of dynamic accumulation of dry substances on the local variety of pea. It has been establish a considerable influence of manure on the photosynthetic potential of plants and photosynthesis production of pea (Pisum Sativum LS).Methodology and results : four dose, only or combined, Nitrogen, phosphorus, and Potassuim have been brought on the variety plantation local of pea. Organic manure were brought under form of rot manure. The dynamic of increasement daily  means of dry substance at plantation air during vegetation of pea presented an interest. The resultats show that the combined contribution (N25 P30 K30) has increased the production of local variety pea. The analyse of photosynthetic potential of plants of all period of germination to the formation of bud show that, this indication is more arise in the variants with the average dose of NPK and with the use of residual effects of organo-mineral system of 1677,2 m2 /ha the day to 1685.1 m2 /ha the day. The biggest mass of dry substance of pea plantation is formed during the period full maturity, which is formed in functionof manure dose studied (400,0-576,9 g/m2).Conclusion : the manure influence positively the increasement of accumulation of the dry substance by the pea plantation. This work illustrate the effect of photosynthetic variations in period of interphase of grains maturity dependent of mineral nutrition  and climatics conditions.

Probing the Effect of Panchagavya, Vermicompost and FYM on Photosynthetic Potential of Triticum aestivum

Probing the Effect of Panchagavya, Vermicompost and FYM on Photosynthetic Potential of Triticum aestivum

Agroecological assessment of the effectiveness of irrigation of tomato using electrolyzed water

Aim. The purpose of the research is to quantify the agroecological response of plants and the bio‐productivity of crops to irrigation using electrochemical water treatment technology. Material and Methods. The study was carried out using the tomato (Solanum lycoparsicum, hybrid Pink Paradise F1) in a protected ground culture as an example. The experimental site is located in the dry‐steppe zone of light chestnut soils of the Lower Volga region (48о56΄46˝N44о51΄45˝E). The magnitude of the electrochemically initiated shift of the redox potential of irrigation water and the options for combining the use of electrochemically treated water were taken as variable experimental factors. Results. It was established that the magnitude of the electrochemically initiated shift of the redox potential of irrigation water has a predominant effect on the estimated biometric indicators: the coefficient of variation of the indicators for this factor reached 9.5‐38.0%. The influence of the method of using electrochemically treated water is estimated at 4.12‐10.24%, but regarding net assimilation the significance of this factor is not statistically proven. The highest estimates of linear growth – 2.21 m, maximum leaf area – 43.4 thousand m2/ha, accumulated biomass – 13.39 t/ha, photosynthetic potential – 3617 thousand m2 days/ha and tomato biological yield – 140.0 t/ha, obtained by the combined use of a catholyte for vegetation and fertilizer irrigation with an electrochemically initiated shift of the redox potential (‐500) mV. Conclusion. The studies have proved the statistical significance of the biometric response of tomato plants to the use of water with electrochemically altered redox potential for vegetation and fertilizer irrigation.

EFFECT OF NITROGEN FERTILIZER DOSE AND ROW SPACING ON AMARANTH PRODUCTIVITY

Amaranth is a valuable food and feed crop that can solve the problem of vegetable protein in animal husbandry. The aim of the research was to study elements of amaranth cultivation technology: the dose of nitrogen fertilizers (without fertilizers, N15, N20, N25) and the row spacing (15, 30, 45 cm). The work was carried out on sod-podzolic medium loamy gleyic soil on the experimental field of FSBEI HE Yaroslavl State Agricultural Academy in 2018. The studied parameters were determined according to generally ac-cepted methods. The use of nitrogen fertilizers contributed to a significant increase in leaf area and pho-tosynthetic potential of amaranth crops at the highest values of the background N20 – 4.7 thousand m2 / ha and 324.08 thousand m2 / ha × days, respectively. Increase in row spacing when sowing amaranth raised the leaf surface area value, accumulation of dry aboveground mass, photosynthetic potential, ger-mination and safety at maximum values in the variant with a row spacing of 45 cm. abundance of weed flea, cereal aphid and sunflower fire. Sowing amaranth with a width of 45 cm between rows caused a sta-tistically significant decrease in the number of studied pests, as well as the number and dry weight of young and perennial weeds. The use of nitrogen fertilizers in a dose of 25 kg AI / ha contributed to a sig-nificant decrease in the yield of amaranth green mass from 145.12 q / ha on the «no-fertilizer» variant to 127.93 q / ha, with maximum values for the background N20 – 156, 55 kg / ha. Thus, the greatest effi- 128 ciency was shown by the introduction of nitrogen fertilizers at a dose of 20 kg ai / ha when sown with a row spacing of 45 cm.

Способи підвищення адаптивних здатностей рослин кавуна до негативних абіотичних чинників Південного Степу

The purpose. To justify the selection of effective mechanisms to increase the resistance of watermelon to the action of stress factors of soil and climatic conditions of the Southern Steppe of Ukraine. Methods. Field — for determination in the conditions of the southern steppe of Ukraine subject of research in relation to ecological and technological factors; measuring and weighing — to determine the area of the assimilation surface, the mass of the root system, the yield of watermelon; laboratory — for evaluation of various schemes of pre-planting treatment by plant growth regulators of watermelon seeds, determination of content in leaves of watermelon of saline chlorophyll; statistical — for conducting a dispersion analysis of research results. Results. On the basis of the conducted laboratory studies, the length of the seedlings, the effective extinctions of soaking the watermelon seeds in the solutions of growth regulators were selected. It was established that due to the influence of growth regulators the physiological processes of the development of watermelon plants are activated, in particular, the index of photosynthetic potential of the sowing increases, the total mass of the root system increases, the chlorophyll content in the leaves increases. The result of stimulating the development of watermelon for the influence of plant growth regulators is to increase the productivity of the crop.Conciusions. According to the results of laboratory and field studies, it should be noted that the use of the Quimicas Mepistem SL complex helps to increase the water resistance of the watermelon to unfavorable conditions in the south, in particular, the content of the total chlorophyll in the leaves increases by 41%, the weight of the root system increases by 33% and increases the photosynthetic potential of sowing is 6% in comparison with the control variant and, consequently, yields increase by 18%.