Effects of biological fertilizers and the conditions of the year on the physiology and productivity of corn in Kazakhstan

Efeitos dos fertilizantes biológicos e das condições do ano sobre a fisiologia e a produtividade do milho no Cazaquistão

Abstract

Climate change and its impact on agriculture are important issues. The study aims to assess the effect of biological fertilizers on enzymatic activity, soil chemistry, and corn growth. Field experiments were conducted in the period from 2021 to 2023 in the Almaty region, Kazakhstan. The authors studied the P1241 corn variety and analyzed the content of chemical elements in the soil and the structural characteristics of plants. Field experiments were conducted in the village of Baltabai in 2021-2023. The P1241 corn variety was studied, and the factors of biological fertilizers, the content of chemical elements in the soil, structural indicators of plant growth and development, as well as yield were analyzed. The statistical analysis was carried out using the nonparametric Kruskall-Wallis criterion in the R Studio software. The results of the study confirm the positive effect of biological fertilizers on metabolic processes, soil chemical composition, and structural indicators of crop growth. The authors also identified the influence of the climate on the yield and structure of corn plants. The obtained data can be useful for the development of agricultural strategies and for practicing agronomists and soil scientists.

Keywords:
corn; climate influence; plant structure; chemical elements; yield

Resumo

As mudanças climáticas e seu impacto na agricultura são questões importantes. O objetivo do estudo é avaliar o efeito dos fertilizantes biológicos na atividade enzimática, na química do solo e no crescimento do milho. Foram realizados experimentos de campo no período de 2021 a 2023 na região de Almaty, no Cazaquistão. Os autores estudaram a variedade de milho P1241 e analisaram o conteúdo de elementos químicos no solo e as características estruturais das plantas. Foram realizados experimentos de campo na aldeia de Baltabai em 2021-2023. A variedade de milho P1241 foi estudada, e os fatores de fertilizantes biológicos, o conteúdo de elementos químicos no solo, os indicadores estruturais de crescimento e desenvolvimento das plantas, bem como a produtividade, foram analisados. A análise estatística foi realizada usando o critério não paramétrico de Kruskall-Wallis no software R Studio. Os resultados do estudo confirmam o efeito positivo dos fertilizantes biológicos nos processos metabólicos, na composição química do solo e nos indicadores estruturais do crescimento da cultura. Os autores também identificaram a influência do clima no rendimento e na estrutura das plantas de milho. Os dados obtidos podem ser úteis para o desenvolvimento de estratégias agrícolas e para a prática de agrônomos e cientistas do solo.

Palavras-chave:
milho; influência do clima; estrutura da planta; elementos químicos; rendimento

1. Introduction

Climate change is one of the most pressing issues today discussed in the global community. Traditionally, this issue is associated with global warming and an increase in the average annual air temperature on the Earth's surface (Abugalieva et al., 2016; Kiselev, 2019). Disturbances in the climatic balance lead to changes in the hydrological regime of soils, air circulation, and water in the oceans, which is accompanied by weather anomalies and participation in extreme events such as heat and cold waves (Guo et al., 2022; Suleimenova et al., 2021). With the increasing concentration of greenhouse gases since the beginning of the industrial era, global warming has been observed. Between 2001 and 2020, the average global temperature increased by 0.84-1.10°C compared to the period from 1850 to 1990 (Guo et al., 2022). It is projected that by 2030 the world's population will reach 8.3 billion people, which creates the need to increase food production. One way to achieve this goal is the effective use of fertilizer application methods, including bio-organic farming (WHO, 2023).

In this context, it is especially important to ensure optimal nutrition of crops and minimize nutrient losses. Corn, as a crop already adapted to various soil conditions and resistant to drought, plays an important role in ensuring food security (Hafez et al., 2021; Zhang et al., 2015). In Kazakhstan, the area of corn crops has increased significantly over the past decade, reaching 193.8 thousand ha in 2023 (Eldala, 2024). In the 2021/22 season, the production average was 1.1 million t and the production area was 206,870 ha. In the 2021/22 season, the yield per ha was 5,985 kg (Bolatova and Engindeniz, 2023).

For the effective use of nutrients, an important concept in the organic agriculture assessment system is to increase the overall efficiency of organic fertilizers by ensuring economically optimal nutrition of crops and minimizing nutrient losses from the field by increasing fertility and plant growth in calcareous soil (Mahmud et al., 2021; Nosheen et al., 2021; Sharma et al., 2022).

To use nutrients in the organic farming system effectively, it is important to increase the overall efficiency of organic fertilizers. This can be achieved by economically optimal nutrition of crops and reducing nutrient losses (Mahmud et al., 2021; Nosheen et al., 2021; Sharma et al., 2022).

A study conducted by Kenenbayev et al. (2023) in the Almaty region, Kazakhstan showed interesting trends in connection with the impact of climate and the use of biological fertilizers on soybean crops. Under normal humidification conditions in 2020 and 2022, there was a significant increase in the number of beans, their weight, as well as the weight of 1,000 seeds compared to the dry year 2021. This indicates the sensitivity of the soybean crop to humidity and underlines the importance of water regime management when growing this crop in the region under consideration. The climate did not affect nitrogen fixation in the soil and the composition of chemical elements in soybean plants. This may emphasize the stability of this process to fluctuations in humidity and highlight the importance of other factors in regulating this biological process (Kenenbayev et al., 2023).

Despite significant research on the effects of fertilizers on crops, no attention has been paid to the effect of weather conditions and biological fertilizers on the structure of the corn crop in southeastern Kazakhstan.

The study aims to assess the influence of biological fertilizer and year factors on various aspects of corn physiology and productivity, including enzyme activity (peroxidase and urease), the content of chemical elements in plants, structural indicators of growth and development, as well as yield.

2. Materials and Methods

Laboratory and field experiments were carried out in 2021-2023 at the farm of the Baltabai 2030 LLP, the village of Baltabai, the Almaty region (latitude 43° 30' 23.256” N, longitude 77° 32' 38.76” E). The climate of the region for the study period is indicated in Table 1.

Table 1
Climatic conditions during the study period (Baltabai 2030 LLP, Baltabai village, Almaty region, 2021-2023).

Month	Air temperature, °C				Precipitation, mm
	2021	2022	2023	Average long-term value	2021	2022	2023	Average long-term value
December	-7.3	1.3	-6.0	-7.6	12.0	14. 0	11.0	29.1
January	-6.5	-1.2	-7.9	-10.8	18.1	18.5	40.1	19.8
February	0.8	-2.8	-1.4	-8.5	64.5	34.0	26.9	21.9
March	3.7	4.2	6.9	0.7	89.2	102.1	55.4	48.8
April	11.0	15.2	10.3	10.4	35.6	42.0	70.8	56.5
May	17.4	17.9	15.5	16.4	45.3	89.2	40.2	61.6
June	20.8	24.2	22.8	21.2	12.6	42.0	12.3	53.9
July	23.3	28.0	25.3	24.1	18.8	14.6	18.7	26.6
August	22.9	27.0	23.0	22.1	7.7	17.0	48.1	21.3

The climate of the area is characterized as sharply continental. The area belongs to the foothill desert-steppe zone with absolute elevations of 550-700 m above sea level. The soil of the experimental site is ordinary gray soil. The humus value is 1.3-1.5%, and the total nitrogen content in the upper horizons is 0.10-0.13 (Kenenbayev et al., 2023).

Sowing was carried out at the optimal sowing time for this zone in three stages.

The object of the study was the P1241 corn variety, a simple hybrid of the AQUAmax line with a flinty dent grain type, late-ripening, with high potential yield and tolerance to drought and heat. The optimal density of herbage at the moment of harvesting was 70-75 thousand plants/ha. Sowing was carried out at the optimal time for this zone in three stages. The sowing of corn was carried out with a SPCh-6 seed spacing drill.

The following agrotechnical measures were carried out: After harvesting the previous crop (soybeans), mouldboard plowing was carried out to a depth of 21-23 cm. Pre-sowing soil preparation was carried out to a depth of 8 to 10 cm (1-2 times).

Seed treatment according to the experimental variants was carried out immediately before sowing, manually, according to the developed program, in conditions safe from the influence of ultraviolet rays on bacterial preparations (in a warehouse).

The water used for the preparation solutions had previously been separated from chlorine ions for at least a day. To improve the conditions of seed germination, the crops were rolled with 3KKSh-6 rollers. To improve aeration in the first decade of June, knifing was carried out. During the field season, three irrigations were carried out. The crop in the experiments was harvested by direct combining.

Experiment design:

• # Experiment variant

• 1 Control variant (without the use of biological tools);

• 2 Manure (30t/ha);

• 3 Vermicompost (2 t/ha);

• 4 The HansePlant complex including seed treatment before sowing (SeedSpor C: 2.0 ml/1 kg of seeds); application of starting fertilizer during sowing (Smart Start P: 150 kg/ha); the first leaf dressing in the 2-4 leaf phase (HanseBiosulfur: 5.0 l/ha); the second leaf dressing in the 6 leaf phase (Prairie Pride A: 3.0 l/ha + Prairie Pride B: 7.5 kg/ha + Absorb: 1.0 l/ha);

• 5 BioEcoGum including seed treatment before sowing: 0.25 l/100 kg; the first leaf dressing in the 2-4 leaf phase: 5 l/ha; the second leaf dressing in the 6 leaf phase: 5 l/ha;

• 6 Tumat including seed treatment before sowing: 30 ml/100 kg; the first leaf dressing in the 2-4 leaf phase: 1 l/ha; the second leaf dressing in the 6 leaf phase: 1 l/ha;

• 7 Agroflorin including the first leaf dressing in the 2-4 leaf phase: 0.25 l/ha; the second leaf dressing in the 6 leaf phase: 0.25 l/ha.

The yield from each plot was recorded with simultaneous determination of its humidity, followed by recalculation to the standard humidity of 14%.

The following indicators were evaluated:

• 1 The effect of the biological fertilizer factor on the enzymatic activity of the soil (peroxidases and ureases);

• 2 The effect of biological fertilizers on the content of chemical elements in the soil (electro conductivity (EC) µS/cm, mobile K mg/kg, N-NH4, N-NO3, exchangeable Ca mg/kg, mobile S mg/kg, mobile Mn mg/kg, mobile Cu mg/kg, mobile Zn mg/kg, mobile Mo mg/kg, water-soluble Na mg/kg, mobile B mg/kg);

• 3 The influence of the year factor on the structural parameters of corn plants (plant height, number of ears per plant, number of seeds per plant, seed weight per plant, weight of 1,000 seeds, weight of plants without ears);

• 4 The effect of the biological fertilizer factor on corn yield (plant height, cm; ear diameter, cm; number of seeds per plant, units; seed weight per plant, g; weight of 1,000 seeds, g; weight of plants without ears, g; grain-to-straw ratio);

• 5 The influence of the biological fertilizer year factor on corn yield.

Statistical analysis was performed using the R studio statistical software using a nonparametric Kruskall-Wallis criterion. The significance level was determined using the P-value, <0.05 (Dutbayev et al., 2022; Kuldybayev et al., 2023).

3. Results

Different fertilizers have different effects on the activity of peroxidase and urease, which emphasizes the importance of choosing a fertilizer depending on the specific needs of plants and soil conditions. The use of Agrofloring, BioEcoGumus, Manure, and Tumat shows positive results in stimulating the metabolic processes of plants and providing additional nutrients. Fertilizers with high enzyme activity can help improve plant growth and development. The use of Agrofloring, BioEcoGumus, Manure, and Tumat indicates a positive effect of the fertilizer on the metabolic processes of plants, while the peroxidase level increases from 9.10 to 10.15 (µg TPF g-24 hr) compared with the control variant, where this value equaled 7.43. All biological fertilizers (Agrofloring, BioEcoGumus, BioGumus, Hanseplant, Manure, Tumat) contributed to an increase in the level of urease (from 3 to 4 mg NH4+ -Ng-1 4 hr-1) compared with the control variant, where this indicator equaled 2.43 (Figure 1).

Figure 1
Box plot of the effect of the biological fertilizer factor on the enzymatic activity of the soil (peroxidase and urease) (2022-2023).

All fertilizers (Agrofloring, BioEcoGumus, BioGumus, Hanseplant, Manure, Tumat) significantly improved plant height compared to the control group without fertilizers. The number of ears per plant, the number of seeds, their weight, and the weight of plants without ears per plant were also significantly higher in the variants with fertilizers. The weight of seeds per plant and the weight of 1,000 seeds increased with the application of fertilizers, which indicates larger and heavier seeds. The results highlight the positive effects of Agrofloring, BioEcoGumus, Manure, and Tumat fertilizers on the growth and development of corn compared to the variant without fertilizers (Table 2).

Table 2
Effect of biological fertilizers on the structural parameters of corn plants (2022-2023).

	Fertilizer	Plant height, cm	Number of ears per plant, units	Number of seeds per plant, units	Seed weight per plant, g.	Weight of 1,000 seeds, g.	Weight of plants without ears, g
1	Agrofloring	258.41	1.10	683.24	250.59	366.79	304.79
2	BioEcoGumus	266.44	4.05	882.38	300.83	344.73	367.36
3	BioGumus	267.71	1.15	750.16	264.76	353.08	298.38
4	Hanseplant	272.39	1.26	817.49	298.10	365.40	350.91
5	Manure	274.88	1.55	896.48	299.45	337.83	397.16
6	Tumat	264.91	1.16	755.74	258.40	343.36	301.33
7	No fertilizers (control)	238.89	1.05	561.95	178.88	317.14	211.63
	P value	<0.01	<0.01	<0.01	<0.01	<0.01	<0.02

The use of Agrofloring, BioEcoGumus, Manure, and Tumat indicates a positive effect of fertilizers on the indicators of EC, K, N-NH4, N-NO3, exchangeable Ca, and mobile S in the soil compared with the control variant. These indicators have significantly increased, which may indicate the ability of these preparations to enrich the soil with the necessary elements for plant growth (Table 3).

Table 3
Effect of biological fertilizers on the content of chemical elements in the soil (2022-2023).

Fertilizer	Mobile K mg/kg	N-NH4	N-NO3	Exchangeable Ca mg/kg	Mobile S mg/kg	Mobile Mn mg/kg	Water soluble Na mg/kg	Mobile B mg/kg
Agrofloring	648.0	2.7	83.1	2,420.0	66.8	70.8	65.3	0.4
BioEcoGumus	415.6	6.1	43.4	2,222.7	27.6	61.6	22.2	0.2
BioGumus	461.4	7.1	41.9	2,127.5	35.6	65.5	27.5	0.6
Hanseplant	474.7	5.5	61.1	2,200.7	42.1	72.2	22.9	0.4
Manure	421.5	6.9	85.1	2,175.0	44.4	71.7	24.1	0.9
Tumat	693.2	5.0	121.5	2,320.0	65.8	75.8	71.3	0.5
No fertilizers (control)	551.5	3.2	59.1	2,183.5	30.5	69.4	34.1	0.4
P value	<0.01	<0.01	<0.01	0.02	<0.01	<0.01	<0.01	<0.01

The year factor has a significant impact on the structural parameters of corn plants. The results of the observations emphasize the importance of considering the climate and seasonal variations when analyzing plant productivity. One can note variations in height, seed count, plant weight, and other characteristics between years (Table 4).

Table 4
Effect of the year factor on the structural parameters of corn plants (2022-2023).

Year	Plant height, cm	Ear diameter, cm	Number of seeds per plant, units	Seed weight per plant, g	Weight of 1,000 seeds, g	Weight of plants without ears, g	Grain-to-straw ratio
2022	269.01	4.19	830.20	276.86	333.66	396.83	0.70
2023	257.74	4.37	697.64	252.00	360.15	240.75	1.05
P value	<0.01	<0.01	<0.01	0.015	<0.01	<0.01	<0.01

In 2022, corn plants showed higher plant growth and productivity rates with large and heavy ears, a large number of seeds per plant, and a low grain-to-straw ratio. Average plant height: 269.01 cm; ear diameter: 4.19 cm; number of seeds per plant: 830.20 units; seed weight per plant: 276.86 g; weight of 1,000 seeds: 333.66 g; weight of plants without ears: 396.83 g; grain-to-straw ratio: 0.70 (Table 4).

In 2023, there was a decrease in plant growth and productivity compared to the previous year. Corn plants had a lower number of seeds per plant, lower ear weight, and a markedly reduced grain-to-straw ratio. Average plant height: 257.74 cm; ear diameter: 4.37 cm; number of seeds per plant: 697.64 units; seed weight per plant: 252.00 g; weight of 1,000 seeds: 360.15 g; weight of 1 plant without ears: 240.75 g; grain-to-straw ratio high: 1.05 (Table 4).

The biological fertilizer factor has a significant impact on corn yield. The use of Agrofloring, BioEcoGumus, Manure, and Tumat shows a positive effect of the fertilizers on yield indicators compared to the control variant (11.6-13.1 t/ha versus 9.5 t/ha). These indicators were significantly higher, which may indicate the ability of these preparations to enrich the soil with the necessary elements for plant growth (Figure 2).

Figure 2
Box plot of the effect of the biological fertilizer factor on corn yield (2022-2023).

The year factor significantly influenced the yield of corn plants. There was a significant fluctuation in yields between years, which may be due to various climatic conditions, seasonal changes, and other factors. In 2021, the average yield of corn was 9.68 t/ha, in 2022, 13.17 t/ha, and in 2023, 12.93 t/ha (Figure 3).

Figure 3
Box plot of the influence of the biological fertilizer and year factors on corn yield (2022-2023).

4. Discussion

According to Toishimanov et al. (2023), the use of commercial organic fertilizers Agrofloring, BioEcoGumus, Manure, and Tumat in the Almaty region significantly increased the yield of corn and soybeans. Particularly good results were achieved with the use of HansePlant fertilizer, which led to an increase in corn seed yield by 47% and in soybean yield by 31%. These organic fertilizers also had a positive effect on the quality of fat, protein, fiber, and corn starch.

According to Kenenbayev et al. (2023), in the Almaty region in 2021, there was a low amount of precipitation in June and a high average daily air temperature during the period of grain filling and ripening compared to the same period in 2020 and 2022. This abnormal weather created critical abiotic conditions that affected the yield of soybean samples. In the dry year 2021, there was a significant decrease in indicators such as the number of beans, the number of seeds, their weight, and the mass of 1,000 seeds, compared with data for 2020 and 2022. Kenenbayev et al. (2023) also emphasize that the use of biological fertilizers, phyto-stimulators, and biological pesticides, known as microbial inoculants, represents an attractive and environmentally friendly alternative to the use of synthetic fertilizers and chemical pesticides in agriculture. Our results confirm the influence of the year factor on the yield and structural parameters of corn plants.

The sustainable agriculture method they are aimed at is focused on finding environmentally sound approaches to maintain a long-term ecological balance in the soil system and ensure human health (Sheteiwy et al., 2021). Studies show that when plants develop in the soil, they produce a variety of organic compounds that attract millions of microorganisms to the vicinity of the root zone. There may be more than 1 billion bacteria in the upper fertile soil layer weighing 1 g, which underlines the importance of the interaction of plants and microorganisms in the soil, having a significant impact on plant health and development (El-Shaboury and Elnefili, 2022; Sheteiwy et al., 2021). Our results showed that the use of biological fertilizers such as Agrofloring, BioEcoGumus, Manure, and Tumat had a beneficial effect on the enzymatic activity of peroxidase and urease. These fertilizers also have a significant effect on the chemical composition of the soil, increasing the content of various chemical elements. The use of biological fertilizers is also accompanied by an improvement in the structural indicators of corn growth and development, which is confirmed by an increase in plant height, the number of ears, seeds, and their weight, as well as other characteristics.

According to research by Matuszak-Slamani et al. (2022), water stress does not significantly affect the content of most macro-nutrients in the dry matter of soybean leaves, but it affects their assimilation by plants. The use of BioEcoGum, Biogumus, HanselPlant, Manure, and Tumat biological fertilizers can statistically significantly increase the number of root nodules per soybean plant, the mass of one nodule, and the number of nitrogen-fixing microorganisms in 1 g of soil compared with the control variant. The seeds contain cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) (Kenenbayev et al., 2023).

5. Conclusions

The study showed that the use of biological fertilizers such as Agrofloring, BioEcoGumus, Manure, and Tumat has a positive effect on the enzymatic activity of peroxidase and urease. These fertilizers also have a significant effect on the chemical composition of the soil, increasing the content of various chemical elements. There was an improvement in the structural indicators of corn growth and development when using biological fertilizers, which was confirmed by an increase in plant height, the number of ears and seeds, and their weight, as well as other characteristics.

The identification of the influence of the year factor on the yield and structural indicators of plants is also an important result. Significant fluctuations in yield between years emphasize the need to consider the climate and seasonal variations in the planning and analysis of agricultural activities.

Our study confirms the importance of using biological fertilizers to improve crop productivity and the need to consider climate variability when developing agricultural strategies. The findings provide useful information for agricultural practices and specialists in the field of soil science and crop production.

Acknowledgements

The paper was prepared within the grant funding for scientific research of the Ministry of Education and Science of the Republic of Kazakhstan for 2022-2024 on the project AP14871321 “Development and implementation of a green technology for corn cultivation that ensures an increase in soil fertility and the production of organic products”.

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Publication Dates

• Publication in this collection
  25 Oct 2024
• Date of issue
  2024

History

• Received
  14 May 2024
• Accepted
  26 Aug 2024