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15AGRICULTURAL SCIENCES
THE INFLUENCE OF NITROGEN FERTILIZER ON THE DEVELOPMENT OF SEED PEAS AND
THE YIELD OF MIXED AGROCENOSES
Alyoshin M.A.
Perm State Agro-Technological University Named after D.N. Pryanishnikov
614990 Russia, Perm, 23, Petropavlovskaya St.
Abstract
The results of a 3-factor field experiment to establish the effect of nitrogen fertilizer on the development of seeded pea plants in mixed agrocenoses with oats and spring wheat are presented. When applying N30, the stimulating effect of nitrogen on the course of growth processes, changes in the biometric parameters of the root system and the above-ground part of pea plants were noted. A higher dosage of nitrogen (N45, N60) led to inhibition of the formation of the rhizobial apparatus on pea roots at the initial stages of development. The maximum grain yield in the experiment (3.17 t /ha) was obtained by cultivating a mixture of peas 40% + oats 15% + wheat 45% and applying N60.
Keywords: nitrogen fertilizer, seed peas, mixed agrocenosis.
Introduction. The lack of protein and nitrogen-containing compounds in the composition of concentrated and other types of feed for farm animals leads to an increase in non-production costs associated with a reduction in the diet. The most acceptable solution to this problem is the replenishment of field and fodder crop rotations with mixed agrocenoses of grain crops. Due to this, there will be an increase in the productivity of arable land, a qualitative change in the biochemical composition of grain entering the soil of crop-root residues [1].
The expansion of acreage occupied by mixed agrocenoses with the inclusion of annual legumes (peas, vetch) is a necessary source for improving the efficiency of the feed industry [2]. These crops are characterized by increased resistance to abiotic and biotic stresses, the most intensive use of natural life support factors, responsiveness to agricultural technologies and fertilizers used [3]. Optimization of nitrogen nutrition of plants of the cereal component of the mixture and, as a result, an increase in the protein content in its grain, is one of the examples of the formation of complementary relationships when growing cereals and legumes in mixed sowing [4]. The indicated parameters allow us to consider mixed agrocenoses as an environmentally safe alternative to the use of N-fer-tilizers. The latter, as is known, play a leading role in increasing yields and optimizing the biochemical composition of the crop [5].
Material and research methods. In 2021 a 3-factor field experiment was laid in the conditions of the experimental field of the Perm State Technical University, the 1. Dynamics of development of seeded
scheme of which is represented by the following options: Factor A is the proportion of seeded peas in the mixture, %: A0 - 20; A1 - 40. Factor B is the ratio of cereal components in the remaining seeding segment (oats + wheat): B0 - % + /; B1 - '/2 + !/; B2 - % + %. Factor C, nitrogen dose, kg/ha: C0 - N0, C1 - N30, C2 - N45, C3 - N60. The repetition in the experiment is 3-fold. The total area of the plot is 150 m2, the accounting area is 100 m2. The total area under the experience is about 2 hectares. Ammonium nitrate (34.4% d.v.) was used as nitrogen fertilizer, which was manually applied for pre-sowing cultivation. Sowing and the subsequent system of plant care in the experiment corresponded to the established system of agriculture for the conditions of the Perm Region. Harvesting was carried out by direct combining using the direct method of accounting for the harvest to achieve full ripeness of grain by all crops of mixed agrocenoses.
The experiment was laid on sod-fine-podzolic medium loamy soil with a low humus content (2.37%), close to a neutral reaction of the medium (pHm 5.8...6.2), high and very high availability of mobile forms of phosphorus and potassium.
Results and discussion. Any type and nature of the relationship of components in the composition of mixed agrocenoses is expressed by changing the intensity of their development, modifying biometric parameters, the size and quality of the crop. Particular attention in this matter is attracted by the process of development of the bean component (peas) and the symbiotic rhizobial apparatus on its root system (tab. 1).
peas in a mixed agrocenoses (Bi - V + V)
Doses of nitrogen fertilizer Stem length, cm Root system length, cm Number of nodules, pcs.
01. June 23. June 15. July 01. June 23. June 15. July 01. June 23. June 15. July
Ao - 20% peas
N0 27,5 63,4 79,5 10,3 15,1 16,8 119,8 139,8 63,5
N30 30,9 67,6 95,4 10,6 19,9 20,6 133,8 132,3 52,8
N45 30,4 54,0 84,2 11,8 20,5 22,0 148,3 129,3 45,7
N60 30,4 53,9 76,6 13,6 21,6 22,7 120,5 126,3 28,0
Ai - 40% peas
N0 26,6 44,0 67,8 14,8 20,0 20,8 86,5 84,3 41,3
N30 29,0 51,3 84,0 15,1 21,8 22,3 130,5 92,8 42,1
N45 30,0 50,5 72,3 17,0 20,3 22,7 127,0 92,1 31,1
N60 26,0 49,5 65,5 15,8 23,4 22,5 106,8 91,5 15,9
During the growing season, pea plants showed an increase in the length of stems and root system. A stimulating effect on the course of growth processes, changes in the bio-metric parameters of the root system and the aboveground part of pea plants was exerted by the use of nitrogen fertilizer at a dose of 30 kg d.v./ha When using a higher dosage (N45, N60), there was a tendency to decrease the intensity of linear growth of individual parts of plants. At a later date (July 15), an inhibitory effect from nitrogen fertilizer can be noticed.
A significant number of nodules on the root system of peas (Ao 119.8... 48.3 pcs., Ai 86.5...130.5 pcs.) was recorded a month after sowing. The first stable signs of nodulation on the root system of peas appear 2 weeks after sowing and the appearance of the first shoots. According to [6], thermal conditions at the initial stage of vegetation somewhat inhibit the development of nodule bacteria, despite the fact that their growth begins at 4-6°C. At low temperature conditions, the process of transition of bacteria to the state of bacteroids is delayed [7]. Nodules formed at low temperatures remain
physiologically younger for a longer time, but with a low ability to nitrogen fixation [8]. In the absence of nitrogen fertilizer application, the difference in the number of nodules on the root system of peas (Ao and A1) is associated with a more obvious manifestation of competition from the cereal components of sowing with their share presence of 80%.
The inhibitory effect of nitrogen fertilizer on the formation of the rhizobial apparatus on pea roots was noted at the initial stages of plant development. Subsequently, with suff-ciently intensive nitrogen consumption by cereal components of crops, this condition ceases to limit the nodulation process. At the end of the period of active nitrogen fixation, a more dramatic decrease in the number ofnodules on plant roots was observed when using nitrogen fertilizer. The decrease in the physiological activity of the symbiotic apparatus on the root system ofpeas was also evidenced by the shape and size of the nodules, the presence of pink color on their cut.
Not only their own productivity depends on the development of seed pea plants, but also the yield of grain from the entire agrocenosis (tab. 2).
2. The effect of nitrogen fertilizer on the yield of mixed crops, t/ha
Share of peas, % (factor A) Ratio oats + wheat (factor B) Nitrogen doses (factor C) Average by A, LSD05 main effects. = 0,28
N0 N30 N45 N60
20 % + % 1,91 2,10 2,36 2,73 2,38
'/2 + '/2 1,95 2,14 2,42 2,79
% + % 2,12 2,34 2,63 3,04
40 % + % 1,67 1,83 2,07 2,38 2,30
/ + / 1,89 2,08 2,34 2,70
% + % 2,22 2,44 2,75 3,17
Average by C, LSD05, main effects. = 0,17 1,96 2,15 2,43 2,80
Average by B, LSD05, main effects = 0,23 Bo 2,13
B1 2,29
B2 2,59
LSD05 for partial differences A 0,98
B 0,73
C 0,64
According to the data obtained, it can be said that the formed agrocenoses, with the inclusion of 20% and 40% of peas in the composition of the sown mixture, had a similar level of productivity. In the first case (A0), this was achieved due to a large segment (80%) of cereal components in the crop. Secondly, due to the higher yield of cereal components in sowing with 40% of peas. In the composition of mixed agrocenoses, the legume component is assigned the role of a donor of nitrogenous compounds, which it shares due to the delivery of part of the fixed nitrogen to the root system of cereal plants in the form of amino acid exudate.
Mixed agrocenoses with the predominance of spring wheat in the composition of the remaining segment of the mixture, which accounted for cereals, were distinguished by higher grain yields. This is due to higher yields, competitiveness, and in some cases, the aggressiveness of the "behavior" of this crop in relation to the consumption of nitrogen from the soil and mineral fertilizers.
Based on the main effects of factor C, it can be noted that when nitrogen fertilizer was applied, grain yields of all mixed agrocenoses increased. This is due to the high responsiveness of grain crops to the use of nitrogen ferti-
lizers, often due to its insufficient amount in the soil. Considering the totality of the factors under consideration, it should be noted that the maximum grain yield in the experiment (3.17 t /ha) was obtained by cultivating a mixture of peas 40% + oats 15% + wheat 45% and applying N60.
Conclusions. Thus, due to the use of nitrogen fertilizer in mixed agrocenoses at a dose of 30 kg d.v./ha., an increase in the intensity of growth processes and bi-ometric parameters of the vegetative aboveground mass and root system of pea plants is observed. Along with this, at the initial stages of pea development, the inhibitory effect of nitrogen fertilizer on the nodulation process and the formation of the root rhizobial apparatus is observed. Mixed agrocenoses formed when 20% and 40% of peas were included in the composition of the sown mixture had a similar level of productivity. At the same time, the bean component is assigned the role of a donor of nitrogenous compounds in their composition. The maximum grain yield in the experiment (3.17 t/ha) was obtained by cultivating a mixture of peas 40% + oats 15% + wheat 45% and applying N60.
References
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