scholarly journals Dynamics of alfalfa leaf area depending on nitrogen feeding type

Author(s):  
Marina Yurievna Kozyreva

The results of field studies for 2017-2019 of dynamics of assimilation surface of alfalfa crops depending on the type of nitrogen nutrition and symbiotic activity of crops are given. Tests with Medicago varia Mart. were carried out in environmental conditions of the pre-mountain zone of RNO-Alania (540 meters above sea level) on the black earth leached with close occurrence of pebbles. Mineral and symbiotrophic types of nitrogen nutrition of alfalfa plants were compared. The experience scheme included options: control - natural soil fertility; In-1800 - treatment of seeds with inoculum of strains of nitrogen-fixing bacteria selected in high mountain conditions (1800 m above sea level); Strain 425a - inoculation of seeds with industrial strain rhizotorphin (strain 425a); N30 - starting nitrogen dose; N30+In is the joint use of highland strains of bacteria and starting doses of nitrogen. Seeds were treated with the strains studied before sowing. Mineral nitrogen fertilizers were introduced annually early in spring in the form of starting doses. It has been established that the minimum areas of leaves on all variants are observed in the first year of life, in the second year of use of crops the maximum assimilation surface is formed in plants, in the third year - indicators gradually decrease. Every year, the maximum assimilation surface is formed by perennial leguminous herbs to the budding stage - the beginning of flowering (bevel has fallen). The dynamics of leaf surface build-up is directly proportional to the activity of symbiotic relationships with rhizobias. In variants with the highest symbiotic activity (In-1800 and N30+In) the area of leaves reaches maximum values and exceeds 40 thousand m ?/ha in certain years.

2020 ◽  
Vol 15 (1) ◽  
pp. 10-16
Author(s):  
Marina Kozyreva ◽  
Larisa Basieva

The experiments were carried out in 2017–2019 in the foothill zone of North Ossetia-Alania (540 m above sea level) on leached chernozem. The effect of the mineral and symbiotrophic types of nitrogen nutrition on the formation of the alfalfa symbiotic apparatus was compared to optimize the cultivation agricultural technique. The experimental design included the following options: control - natural soil fertility; In-1800 - seed treatment with the inoculum of nitrogen-fixing bacteria strains selected in high mountain conditions (1800 m above sea level); Strain 425a - seed inoculation with an industrial strain of rhizotorphin (strain 425a); N30 - starting dose of nitrogen; N30+In - combined use of high-mountain strains of bacteria and starting doses of nitrogen. Seeds were treated with the studied strains before sowing. The formation of nodules on the roots of alfalfa during inoculation of seeds with rhizobia strains occurred 1 ... 2 days earlier than in the control, which indicates their greater activity compared to the local microflora. The duration of the general symbiosis in the second year of life in the variants with inoculation with industrial and alpine strains reached 215 ... 216 days, which is 4 ... 7 days more than in the control and variant N30. The greatest number of nodules in all years was noted during seed treatment with the inoculum of alpine rhizobia strains, both in pure form (96 ... 248 units/plant.), and against the background of the use of starting doses of nitrogen (80 ... 243 units/plant.). The smallest mass of nodules in the experiment (40 ... 255 kg/ha) was recorded in the control and variant N30. The highest mass of nodules was formed by the second crop of the second year of sowing life and exceeded 300 kg/ha in all variants with pre-sowing seed inoculation with active rhizobia strains. The superiority of the In-1800 variant over control was 28.3%, and the differences with N30+In turned out to be insignificant. .


Author(s):  
Svetlana Vasil'evna Ivanova ◽  
Olga Vasil'evna Kurdakova ◽  
Aminat Msostovna Konova ◽  
Anna Yurievna Gavrilova

In the course of the experiment, the effect of increasing doses of nitrogen fertilizers on the yield of clover of the meadow variety Nadezhny, entered in the State Register of Breeding Achievements in 2012, was analyzed. A comparison is also made of this influence with the timothy of the meadow variety Leningradskaya 204. It was established that the pre-sowing introduction of mineral nitrogen for clover and timothy has influenced the productivity of these crops, but the nature of this effect varies depending on the type of grass. The introduction of N20 against the background of P30K90, which provided an increase in control of 51.2% for green mass and 33.6% for air-dry matter, was optimal for meadow clover of the first year of life. For grassland clover second year of life, the best option was N0P30K90, which gave an increase of 56.6% to the control on green mass and 50.6% on air-dry matter. A further increase in the dose of nitrogen on the options caused a decrease in yield increase. Timothy meadow for two years of life was traced responsiveness to the provision of nitrogen. The most productive in all respects was the option N120P30K90.    


2020 ◽  
Vol 4 (24) ◽  
pp. 72-80
Author(s):  
M.Yu. Kozyreva ◽  
◽  
L.Zh. Basieva ◽  
A.Kh. Kozyrev ◽  
◽  
...  

The issue of the use of mineral forms of nitrogen for legumes is still a source of debate among scientists. Under the environmental conditions of the foothill zone of RNO-Alania, the field experiments were laid to study the activity of the symbiotic system and the productivity of the alfalfa depending on the type of nitrogen nutrition and the presence of a virulent active strain of rhizobia. The research was carried out in 2017– 2019. Soil – chernozems leached. Objects: crops of Medicago varia Mart.; industrial strain of rhizotorphin 425a; inoculum of high-mountain strains of nodule bacteria; starting doses of nitrogen fertilizers. The dimensions of the symbiotic apparatus were studied according to the G.S. Posypanov method. The specific activity of symbiosis was 4.2 to 9.0 mg/kg. The maximum amount of air nitrogen (456.1 kg/ha) for three years of experiments was fixed by the symbiotic system of alfalfa in the variant with pre-sowing seed inoculation with high-mountain strains of nodule bacteria. This indicates their higher activity and competitiveness compared to the industrial strain of rhizotorphin 425a and indigenous strains of rhizobia from the pre-mountain zone of RNO-Alania. Mineral forms of nitrogen significantly inhibited the activity of the symbiotic system. As a result, the amount of fixed nitrogen decreased by 3.5–9.0 %. In the pre-mountain zone, under natural conditions, the growth and development of plants were provided with atmospheric nitrogen by 66 %, the rest of the need for the element (34 %) they satisfied with soil nitrogen. The maximum involvement of molecular nitrogen of the atmosphere in the biological cycle was distinguished by the variant with pre-sowing inoculation of seeds by virulent active strains of rhizobia, in which the share of air nitrogen participation in plant nutrition averaged 71–73 % over the three years of research.


2020 ◽  
pp. 50-56
Author(s):  
М.Ю. Козырева ◽  
Л.Ж. Басиева

Приведены результаты полевых исследований потребления азота посевами люцерны в зависимости от режима азотного питания и симбиотической активности посевов за 2017…2019 годы. Опыты с люцерной синегибридной проведены в экологических условиях предгорной зоны РСО-Алания на черноземе выщелоченном с близким залеганием галечника. Сравнивались минеральный и симбиотрофный режимы азотного питания растений люцерны. Установлено, что в год посева потребление азота посевами люцерны составило от 105,0 до 135,4 кг/га, при этом к первому укосу потребление было в 1,1…1,2 раза больше, чем ко второму укосу. На второй и третий годы пользования посевами потребление азота выросло в 1,7…1,9 раза в сравнении с показателями года посева. Показатели вариантов с естественными условиями (контроль) и внесением стартовых доз азотных удобрений (N30) были практически идентичными. Показатели вариантов с инокуляцией семян высокогорным инокулюмом (Ин-1800) и внесением стартовых доз азотных удобрений на фоне инокуляции (N30 + Ин) во второй и третий годы пользования посевами были практически идентичными. Объемы потребления азота в указанных вариантах составили свыше 235 кг/га, или на 25,6…27,1 % выше показателей контрольного варианта. В сумме за три года исследований посевы люцерны в контрольном варианте усвоили 483,3 кг/га азота. Стартовые дозы азотных удобрений (N30) увеличили данный показатель всего на 1,4 %. Предпосевная инокуляция семян способствовала увеличению потребления азота во всех вариантах: в варианте с промышленным штаммом ризоторфина (Шт. 425а) – на 17,8 %, с высокогорным инокулюмом на фоне внесения стартовых доз минеральных азотных удобрений (N30 + Ин) – на 24,6 %, с высокогорным инокулюмом в чистом виде (Ин-1800) – на 27,1 %. Ключевые слова: люцерна, режим питания, симбиотическая активность, минеральный азот, биологический азот, потребление азота. The results of field studies of nitrogen consumption in alfalfa crops depending on the nitrogen nutrition pattern and symbiotic activity of crops for 2017...2019 are presented. Experiments with the alfalfa purple were carried out in the ecological conditions of the foothill zone of the North Ossetia-Alania, on leached chernozem with a close occurrence of gravel. Mineral and symbiotrophic patterns of nitrogen nutrition of alfalfa plants were compared. It was found that in the year of planting, the nitrogen consumption of alfalfa crops ranged from 105.0 to 135.4 kg/ha, and by the first mowing, the consumption was 1.1...1.2 times bigger than by the second mowing. In the second and third years of crop use, nitrogen consumption increased by 1.7...1.9 times compared to the year of planting. The parameters of the options with natural conditions (control) and the addition of starting doses of nitrogen fertilizers (N30) were almost identical. In the second and third years of use of crops, parameters of options with inoculation of seeds with high-altitude inoculum (In-1800) and the addition of starting doses of nitrogen fertilizers within the background of inoculation (N30 + in) were almost identical. In these options, the amount of nitrogen consumption was more than 235 kg/ha, or 25.6...27.1 % higher than in the control variant. In total, over three years of research, in the control option alfalfa crops took 483.3 kg/ha of nitrogen. Starting doses of nitrogen fertilizers (N30) increased this indicator by only 1.4 %. Pre-planting inoculation of seeds contributed to an increase in nitrogen consumption in all options: in the option with the industrial strain of risotorphine (St. 425a) – by 17.8 %, with high-altitude inoculum within the background of adding starting doses of mineral nitrogen fertilizers (N30 + In) – by 24.6 %, with high-altitude inoculum in pure form (In-1800) – by 27.1 %.


Author(s):  
M. Iu. Kozyreva ◽  
L. Zh. Basieva

The paper shows the results of field experiments conducted in 2017-2019. The experiments were devoted to photosynthetic indices of alfalfa in relation to the type of nitrogen nutrition and symbiotic activity of crops. The experiments with alfalfa blue-hybrid were carried out in environmental conditions of the piedmont zone of RNO-Alania on chernozem leached soil with close occurrence of gravel. The researchers compared mineral and symbiotrophic types of nitrogen nutrition of alfalfa plants; they applied mineral nitrogen fertilizers and biospecimens on the basis of rizobium. In natural conditions (control group) the crops formed photosynthetic potential from 1701.3 thousand m²-days/ha per year of sowing to 3624.3 thousand m²-days/ha in the second year of sowing. Crop rates in the third year had intermediate values between the first and second years of crop use. The effect of starting doses of nitrogen fertilizers was observed during the sowing year in its early stages, when the symbiotic system is still underdeveloped and inactive. When estimating the annual average photosynthetic potential, starting nitrogen doses gave an advantage of only 1.6%. Presowing inoculation of seeds by active strains of strawberry bacteria provided the maximum positive effect, while high mountain strains of rizobium were more effective. Average annual parameter of photosynthetic potential varied from 2699.1to3189.4 thousand m² days/ha, increasing with the improvement of nitrogen nutrition. Inoculation of seeds by high-altitude strains of tuber bacteria increased photosynthetic potential to its maximum values or by 18.2%. In the same variant, as well as in the variant with the starting dose of nitrogen, the maximum values of net productivity of photosynthesis were achieved, which exceeded the values of the control variant by 0.09-0.11 g/m²- day.


Author(s):  
Carolina Lechosa-Muñiz ◽  
María Paz-Zulueta ◽  
Joaquín Cayón-De Las Cuevas ◽  
Javier Llorca ◽  
María Jesús Cabero

Background: It is clear that breastfeeding is the gold standard of infant feeding because of the many advantages it offers to both the child and the mother. Objective: to identity the main reasons for cessation breastfeeding declares by the mother themselves during the first year. Design: A prospective cohort study was conducted, recruiting 969 newborns in a third level hospital in Spain. The main maternal variables studied were: maternal age, parity, educational level, work occupation, smoking habit, gestational age, birth, weigh, feeding type, and duration of breastfeeding. All the participants were followed for a year to determinate the duration of breastfeeding and to know the reason of the abandonment. Results: At 6 months, the percentage of maternal lactation was cut in half and only 24.6% of these mothers maintain. Mainly 15.80% of the mothers decide to give up the exclusive maternal lactation of their own free desire, and 15.41% because they suspect hypogalactia. The work cause is the third reason of abandonment in both cases. Conclusions: Our results show the need to improve the health policies of promotion, protection and support the initiation of breastfeeding. In particular, our results show the importance of the work factor with particular emphasis on improving conciliation measures.


2009 ◽  
Vol 18 (1) ◽  
pp. 19-24
Author(s):  
Maggie-Lee Huckabee

Abstract Research exists that evaluates the mechanics of swallowing respiratory coordination in healthy children and adults as well and individuals with swallowing impairment. The research program summarized in this article represents a systematic examination of swallowing respiratory coordination across the lifespan as a means of behaviorally investigating mechanisms of cortical modulation. Using time-locked recordings of submental surface electromyography, nasal airflow, and thyroid acoustics, three conditions of swallowing were evaluated in 20 adults in a single session and 10 infants in 10 sessions across the first year of life. The three swallowing conditions were selected to represent a continuum of volitional through nonvolitional swallowing control on the basis of a decreasing level of cortical activation. Our primary finding is that, across the lifespan, brainstem control strongly dictates the duration of swallowing apnea and is heavily involved in organizing the integration of swallowing and respiration, even in very early infancy. However, there is evidence that cortical modulation increases across the first 12 months of life to approximate more adult-like patterns of behavior. This modulation influences primarily conditions of volitional swallowing; sleep and naïve swallows appear to not be easily adapted by cortical regulation. Thus, it is attention, not arousal that engages cortical mechanisms.


2001 ◽  
Vol 120 (5) ◽  
pp. A209-A209
Author(s):  
G RIEZZO ◽  
R CASTELLANA ◽  
T DEBELLIS ◽  
F LAFORGIA ◽  
F INDRIO ◽  
...  

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