Fertilization System Research Articles

Combined organic and inorganic fertilization increases soil network complexity and multifunctionality in a 5‐year fertilization system

AbstractMicrobial communities regulating multiple ecosystem functions in agricultural ecosystems remain unclear, limiting our ability to predict how agricultural systems will respond to nutrient management. Here, we assessed the effects of 5‐year different fertilization treatments (CK, no‐fertilization; M, organic fertilization; MNPK, combined inorganic and organic fertilization; NPK, inorganic fertilization) on the bacterial and fungal composition, co‐occurrence networks complexity and the relationship of keystone taxa with soil multifunctionality. Our results showed that fertilization shifted the bacterial and fungal community composition. The increased nodes of degree and decreased average path length with the application of organic fertilizer suggested a more stable network. The improved soil multifunctionality was also observed in combined organic and inorganic fertilization treatment, which positively correlated with the fungal community composition rather than bacterial, indicating that fungi are important in driving soil functions. Notably, the keystone taxa fOTU3995 and fOTU2868 belong to Sordariomycetes and were correlated with soil organic carbon, total nitrogen, total phosphorus, and alkaline phosphatase. These indicated that the keystone taxa play an important role in increasing in soil nutrient, C cycling, and P cycling. Together, our findings highlight that combined organic and inorganic fertilization increases the network complexity and soil multifunctionality, further confirming the role of keystone taxa Sordariomycetes in driving soil multifunctionality. This suggested that combined organic and inorganic have the potential to preserve agroecosystem sustainability and strengthen the role of microorganisms in ecosystem functions.

Changes in crop rotation productivity and stability of agrocenoses with prolonged use of fertilizers

The article considers the results of many years of field experiment (1968-2018) conducted in the Central part of the Non-Chernozem zone of Russia (Vladimir region). The research was carried out during eleven rotations of the four-field grain crop rotation. The study shows the effect of use of organic and mineral fertilizers applied in various doses and combinations on crop rotation yield, fertility of sod-podzolic sandy loam soil. It was found that the organomineral fertilizer system (manure 10 t/ha + N50P25K60) provided stable crop rotation productivity (on average for eleven rotations) at the level of 39.9 c. e./ha, or 79.7 % higher than the control without fertilizers. The mineral fertilizer system at medium doses of fertilizers (N50P25K60) was at the level of the organomineral system. The organic system was inferior in efficiency to the mineral system, both at medium doses (manure 10 t/ha) and at elevated doses (manure 20 t/ha). At the same time, the long-term use of organic fertilizers provided an increase in the humus content, depending on the dose of litter manure, by 16-36 % compared to the initial values. The use of organic fertilizers led to the stabilization of the content of available forms of potassium in the soil at an average and elevated level, respectively. Stabilization of the content of mobile phosphorus in the soil at the level of average supply was noted in mineral, organomineral and organic fertilizer systems, respectively, with low and medium doses. When using increased doses of fertilizers, there is a further increase in the content of nutrients in the soil. Growing crops in crop rotation without the use of organic and mineral fertilizers gradually led to a decrease in yield. The use of fertilizers provided greater stability of crop yields over the years of the study compared to the variant without fertilizers. The soil in the variants with organic (manure 20 t/ha) and organomineral (manure 10 t/ha + N50P25K60) fertilizer systems was characterized by high values of the main physiological groups of microorganisms. The ratio of the number of amylolytic and proteolytic microorganisms was 1.1-1.2, that indicated a balance in the processes of mineralization of organic matter in the soil and its humification.

Productivity of oat (Avena sativa L.) as affected by fertilization

Purpose. To identify varieties of oat (Avena sativa L.) by yield in the northern part of the Right Bank Forest Steppe of Ukraine, establish the efficiency of sulfur in the fertilization system and the specifics of the impact of nitrogen, phosphorus, potassium and sulfur application rates on crop productivity. Methods. Field studies were carried out at the Agronomic Research Station of the National University of Life and Environmental Sciences of Ukraine (Kyiv region) in 2021–2023 in typical low-humus chernozem soils according to the scheme of a two-factor experiment: factor A: variety [‘Neptun’ (control), ‘Lehin Nosivskyi’, ‘Svitanok’, ‘Zakat’, ‘Zubr’, ‘Albatros’, and ‘Aivori’]; factor B: fertilization system. According to the scheme of the experiment, the application of NPK) and N8P24K24S9 fertilizers was foreseen. Equalization of the nitrogen dose with the introduction of N8P24K24S9 was carried out by the introduction of ammonium nitrate. Ammonium nitrate was also used for nitrogen fertilization at the microstage BBCH 31–32. Results. The yield of oat varieties on average over three years yielded from 2.28 t/ha in the control option for the cultivation of the ‘Neptun’ variety to 5.54 t/ha for the cultivation of the ‘Aivori’ variety and the introduction of N120P120K120S45 + N30. A yield increase ranged from 0.32 to 2.83 t/ha, depending on fertilizers. Among the seven studied oat varieties, the most productive was the 'Aivori' variety, the yield of which, depending on the year and the fertilization system, varied from 2.38 t/ha in the control version in 2022 to 5.98 t/ha when applying N120P120K120S45 + N30 in 2023. The yield increase on average for the application of N120P120K120S45 + N30 was 2.73 t/ha compared to the control and 0.66 t/ha with the option where an equivalent rate of macronutrients was applied, but without sulfur. All oat varieties show a positive reaction to sulfur by increasing productivity, but its growth varies against the background of different rates of fertilizer application. Yield increases in varieties ‘Zakat’, ‘Zubr’ have a positive correlation dependence on the use of sulfur against the background of increasing rates of nitrogen, phosphorus and potassium application. Conclusions. Oat varieties are characterized by a specific reaction; however, all respond positively to increasing rates of fertilizers and the introduction of sulfur into the nutrition system, which increases the resistance of oats to lodging and the level of nitrogen use. The combined introduction of sulfur with macroelements provides a significant increase in yield, which is due to more efficient use of nitrogen by plants. Optimizing nitrogen-sulfur nutrition ensures increased efficiency of mineral fertilizers.

Cropping rotation improved the bacterial diversity and N-cycling genes in tobacco fields through a 19-year long-term experiment

Soil microorganisms play crucial roles in various processes within the soil ecosystem, such as nutrient cycling, organic matter decomposition, and maintenance of soil structure. However, their responses to fertilization and different cropping systems in tobacco soils remain poorly understood. In this study, we conducted a 19-year-long field experiment on rice-tobacco rotation cropping (R) and continuous tobacco cropping (C), with three fertilization treatments: no fertilizer (NF), chemical NPK fertilizer (NPK), and composted pig manure (OM). The composition, co-occurrence patterns, N-cycling genes (nifH, AOA-amoA, AOB-amoA, nirS, nirK, and nosZ) of the bacterial communities as well as the soil properties were analyzed in the soils after tobacco was harvested. The pH and available potassium (AK) in the rotation cropping soil were significantly lower than those in continuous cropping soil, while the α-diversity index, and the abundance of nifH, nirS, nirK, and nosZ genes were opposite. The phyla Chloroflexi, Desulfobacterota, MBNT15, and Nitrospinota, as well as number of low-abundance genera, were significantly enriched in rice-tobacco rotation cropping. Partial least squares path model (PLSPM) indicated that cropping systems had a greater influence on the variations in bacterial communities compared to fertilization practices. These findings enhance our understanding of the significance of land management and fertilization in shaping the soil bacteria of tobacco. The rice-tobacco rotation cropping system demonstrated greater benefits to soil microorganisms and N-cycling genes compared to continuous cropping system.

The Effect of Internet of Things Based Drip Fertilization System with Cultivation Model on Harvest Results and Quality of Red Lettuce (<i>Lactuca sativa</i> L. var. Crispa)

The Effect of Internet of Things Based Drip Fertilization System with Cultivation Model on Harvest Results and Quality of Red Lettuce (<i>Lactuca sativa</i> L. var. Crispa)

Efficiency of the compensatory scheme of using Organic Acid Nano-Complex microfertilizers in spring wheat cultivation technology

In recent years, significant advances in nanotechnology have increased the ability to produce nanoparticles of physiologically important metals on a large scale, which are now used to improve fertilizer formulations to increase uptake by plant cells and minimize nutrient losses. Fertilizers with nanostructure can increase the efficiency of nutrient use through mechanisms such as targeted delivery, slow or controlled release. The aim of the research is to substantiate a compensatory scheme for the use of biodynamic nanofertilizers (nanocomplex micronutrient fertilizers with organic acids) by partially replacing the main macrofertilizers in the spring wheat fertilization system. The research was conducted on the basis of the educational and scientific laboratory Department of Plant Industry of the National University of Life and Environmental Sciences of Ukraine. In research, there were used the methods of field experiments of A.O. Rozhkov, notching method and scanning method for determination of leaf surface area. The studies showed that it is possible to replace within 30-40% of the recommended amount of mineral fertilizers with biodynamic nanofertilizers in the spring wheat fertilization system. In general, the use of nanofertilizers increased wheat growth and improved yield and yield components. Substitution of mineral fertilizers, Innoparmis Agroscience Biodynamic fertilizers, provides a more favourable 86-88% survival rate of spring wheat plants during the growing season. By replacing 34% of the recommended rate of mineral fertilizers, the content of photosynthetic pigments in wheat leaves increases by 5% and the leaf surface area increases by 7%. The created compensatory schemes for the use of biodynamic nanofertilizers by partial (34% in the wheat fertilization system) replacement of the main macronutrients can increase the yield of spring wheat by 9.9%. The proven possibility of replacing mineral fertilizers with biodynamic nanofertilizers in the fertilization system of agricultural crops will reduce environmental pollution and the economic dependency of using mineral fertilizers against the background of their rapid increase in price in recent years

Combining organic and chemical fertilizer plus water-saving system reduces environmental impacts and improves apple yield in rainfed apple orchards

Combining organic and chemical fertilizer plus water-saving system reduces environmental impacts and improves apple yield in rainfed apple orchards

Effect of Water-Fertilizer Coupling on the Growth and Physiological Characteristics of Young Apple Trees

China has the largest apple-growing area and fresh fruit production in the world; however, water shortages and low fertilizer utilization rates have restricted agricultural development. It is a major challenge to obtain scientific and reasonable irrigation and fertilization systems for young apple trees in semi-arid regions of northern China. A 2-year field bucket experiment with four irrigation levels of W1 (75–90% Fs, where Fs is the field water holding capacity), W2 (65–80% Fs), W3 (55–70% Fs), and W4 (45–60% Fs), and three fertilizer levels of F1 (27-9-9 g N-P2O5-K2O), F2 (18-9-9 g N-P2O5-K2O), and F3 (9-9-9 g N-P2O5-K2O) was conducted in 2019 and 2020, so as to explore the effects of different water and fertilizer treatments on the growth and physiological characteristics of young apple trees. The results showed that the plant growth, leaf area, and dry matter of young apple trees at each growing period reached maximum values under F1W2, and they showed a positive linear relationship with relative chlorophyll content (SPAD), net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), water consumption, and water use efficiency (WUE). With the growth of young apple trees, water-fertilizer coupling could significantly increase the leaf SPAD of young apple trees. Pn, Tr, and Gs reached the maximum value under F1W1, and although they decreased under F1W2, the water use efficiency increased by 2.3–25.7% and 4.0–23.8% under F1W2 compared with other treatments in two years, respectively. The water consumption of young apple trees increased with the increase of irrigation and fertilizer, and both dry matter and water productivity reached the maximum value under F1W2, which increased by 0.8%, 14.6% in 2019, and 0.6%, 11.1% in 2020 compared with F1W1, while water consumption decreased by 12.2% and 9.4% in both years. In conclusion, F1W2 treatment (soil moisture was controlled at 65–80% of field water holding capacity, and N-P2O5-K2O was controlled at 27-9-9 g) was the best coupling mode of water and fertilizer for young apple trees in semi-arid areas of northern China.

Water Fertilizer Integration Equipment Research Status and Development Trend

Integrated water and fertilizer technology can accurately adjust the mix of water and fertilizer on demand, and then through the irrigation system, water and fertilizer are delivered to the roots of the crop in quantity, on time, and with precision. As an important part of the integrated system of water and fertilizer, the fertilizer has a critical influence on the quality of the fertilizing system. Nowadays, the development of intelligent agriculture has become a general trend of agricultural development. By exploring the development process of water and fertilizer mixing, this paper sorted out the research status of various kinds of fertilizers in China, compared different mixing methods of water and fertilizer, and analyzed and summarized the excellent working performance of different fertilizers. Secondly, the current research emphases were discussed, including precision fertilization technology, intelligent control, comprehensive utilization of resources and circular agriculture. Then, the development trend of integrated water and fertilizer equipment is put forward, including the improvement of precision fertilization, the development of multifunctional integrated equipment, and the application of data management and decision support system. Through continuous technological innovation and application, the integrated equipment of water and fertilizer is expected to play a greater role in the agricultural field.

Effect of Chemical Fertilizer with Compound Microbial Fertilizer on Soil Physical Properties and Soybean Yield

Compound microbial fertilizer is a new type of environmentally friendly slow-release fertilizer that can effectively improve the physical and chemical properties of the soil, significantly improve the ecological environment, and promote the sustainable development of agriculture. In this study, we conducted a field experiment to evaluate the impact of different applications of chemical fertilizer combined with composite microbial fertilizer on soil physical properties and soybean yields at Heshan Farm, Heilongjiang Province, China, during 2021–2022. Soybean varieties “Jinyuan 55” and “Keshan 1” were treated with three treatments implemented as follows: T1 (conventional fertilization), T2 (50% N fertilizer + compound microbial fertilizer), and T3 (0 N fertilizer + compound microbial fertilizer). Compared to conventional fertilization (T1 treatment), the application of composite microbial fertilizers (T2 and T3) resulted in a decrease in soil bulk density and an increase in porosity. Notably, we observed that moderate application of the composite microbial fertilizer (T3) led to a decrease in the volume fraction of clay particles and an increase in the volume fraction of sand particles. Furthermore, all treatments exhibited high content of agglomerates larger than 5 mm at 0–20 cm. The application of composite microbial fertilizers (T2 and T3) promoted the formation of large soil agglomerates and reduced the presence of micro-agglomerates smaller than 0.25 mm. In 2021–2022, The soybean yield increased by 13.02% in the T2 treatment compared with the T1 treatment and decreased by 9.34% in the T3 treatment. We concluded that the appropriate application of compound microbial fertilizer can help protect black soil, enhance the self-repair capability of black soil, and improve soybean quality in abnormal precipitation years. These results provide an actionable basis for constructing and developing green fertilizer systems for the soybean industry.

Influence of fertilization systems on the productivity of soybean plants (Glycine max L.)

Soy (Glycine max L.) is the leading protein-oil crop in world agriculture. This is a unique food, fodder, technical and medicinal culture, which became the basis for the production of vegetable protein and oil in the world. The intensity of growth of the assimilation surface and its size are significantly influenced by a number of both natural and organized factors, one of which is the provision of plants with a complete set of mineral nutrition elements and trace elements. One of the effective ways to provide plants with a sufficient amount of macro- and microelements is seed treatment before sowing and foliar fertilization feeding with chelated fertilizers. Soy is a strategic crop of world agriculture, which is capable of solving the food problem of protein deficiency in human nutrition, and needs significant attention in the agriculture of Ukraine. Despite the fact that in terms of production volume, the country ranks first in Europe and eighth in the world, its yield is not high enough, therefore the task of finding innovative directions for the development of crop production is quite urgent. The individual seed productivity of soybean plants is determined by the optimal combination of the main elements of the crop structure — the number of beans on one plant, the number of seeds in a bean and the weight of seeds from one plant. It is a dynamic quantity and changes according to certain soil and climatic conditions of the region, specifics of the growing season of plants and elements of growing technology. The formation of highly productive soybean agrophytocenoses in order to increase the productivity and stability of production largely depends on many factors, the main of which are the genotype of the crop, weather and climate conditions, and production technologies. The results of research on the individual seed productivity of soybean plants on gray forest soils depending on the technological processes of cultivation are given. It was established that the maximum increase in the number of seeds from one plant (14.0 pcs., or 34.0%) was obtained for the fertilization system, which involves the application of mineral fertilizers in the dose of N45Р90К90, prioritization of by-products of the predecessor with inoculation of seeds before sowing. It was found that the maximum increase (4.8–5.0 units, or 23.8–24.8%) of the number of beans on one plant to absolute control was obtained in variants with the introduction of mineral fertilizers in the dose of N45Р90К90 and prioritization of by-products of the predecessor. The maximum mass (7.6 g) from one plant was obtained with the fertilization system, which provides for the application of mineral fertilizers in the dose of N15Р30K30, prioritization of by-products of the precursor and siderate biomass for seed inoculation before sowing.

Fertilisation system influence on the main agrochemical indicators of soil and productivity of white cabbage

Fertilisation system influence on the main agrochemical indicators of soil and productivity of white cabbage

Variation Characteristics and Expression State of Nitrogen and Phosphorus Metering Ratio of Rice in Black Soil under Film Mulching and Irrigation Methods

In order to investigate the effects of film mulching and water-saving methods on soil inorganic nitrogen, nitrogen content of rice organs, nitrogen-phosphorus metering ratio, and nutrient limitation during rice yield formation, two water-saving irrigation methods and black biodegradable film mulching were adopted. The effects of water-saving film mulching on NH4+-N and NO3−-N in 0 to 60 cm soil, nitrogen accumulation and ratio, and nitrogen-phosphorus metering ratio in rice organs were analyzed. The nitrogen-phosphorus-limiting state of rice growth under water-saving film mulching was determined. The results showed that water-saving and film mulching methods could weaken the leaching of NH4+-N and NO3−-N and enhance the nitrogen uptake of rice. The water-saving method of mulching could reduce the metering ratio of nitrogen and phosphorus in rice organs. The panicle maturity process had been in a state of nitrogen limitation, and the effect was gradually enhanced. The nitrogen and phosphorus metering ratio of panicles was positively correlated with NH4+-N accumulation in the 0 to 60 cm soil layer and nitrogen accumulation of rice organs, and negatively correlated with soil NO3−-N accumulation under film mulching and water-saving methods. The correlation between stems and leaves’ nitrogen and phosphorus metering ratios and influencing factors was basically opposite to that of panicles’ nitrogen and phosphorus metering ratio. This study can provide a reference for the formulation of a fertilization system under film mulching in the black soil region of northeast China.

Humus state and nutrient regime of typical chernozem depending on fertilisation in short crop rotations

The fertiliser system is the most effective factor in the intensification of crop cultivation technologies. The basis for scientifically sound fertiliser application systems, along with obtaining the planned level of yield of the appropriate quality, is the study of the organic matter content and soil nutrient regime during crop rotation. The purpose of this study was to determine the mineral nitrogen, mobile phosphorus, exchangeable potassium, and humus content in typical chernozem under different fertilisation systems in short-term crop rotations. To solve the problem of soil fertility, an important approach is to conduct field and laboratory research to determine changes in the humus state according to Tyurin, nitrogen, phosphorus, and potassium regimes of the soil according to Machigin, and dispersion methods to determine the reliability of experimental data. As a result of the research, it was found that the highest humus content in the soil was recorded under the organic-mineral fertilisation system at the end of the second rotation in the grain crop rotation by 0.13% compared to the fruit crop rotation. The use of a mineral fertiliser system in a row crop rotation reduced the humus content by 0.12%. An increase in the humus content of typical chernozem was recorded under fruit crop rotation and grain-row crop rotation. The organic-mineral fertilisation system tended to increase the mineral nitrogen content of the soil compared to the other systems. The mineral nitrogen content of the mineral fertilisation system decreased by 5.5 mg/kg of soil compared to the unfertilised variant. Under the organic-mineral and mineral fertilisation system, the content of mobile phosphate increased in all crop rotations. The content of mobile phosphorus in the tilled crop rotation was substantially reduced compared to the fruit crop rotation and grain-row crop rotation. The highest content of exchangeable potassium in the soil was recorded under the mineral fertilisation system. The materials of the publications are of practical importance in the analysis of the main elements of mineral nutrition of typical chernozem in short crop rotations

A large‐scale survey reveals agro‐ecological factors influence spatio‐temporal distribution and epidemics of maize leaf blight: Implications for prioritizing sustainable management options

AbstractIntroductionProductivity of maize (Zea mays L.) is predominantly constrained by diseases, weeds, and insect pests. The northern leaf blight (NLB) disease, caused by Exserohilum turcicum, inflicts significant maize yield losses in the tropics and humid tropics, including Ethiopia. A large‐scale field survey was conducted to assess the spatio‐temporal distribution of maize NLB in southern Ethiopia, and to determine the association of maize farming practices and agro‐ecological factors with NLB epidemics during 2016–2019.Materials and MethodsA total of 814 maize farms were assessed in 12 major maize‐producing districts. During the assessment, data related to the disease, crop, farming practices and agro‐ecological factors were collected. The associations of disease severity with independent factors were determined using the ordinal logistic regression model.ResultsThe results showed that all studied districts and zones recorded high (≥85%) NLB prevalence over the 4 years, and the disease continues to be a major threat to maize production. Variable disease severity was recorded across districts/zones during the study periods. The highest (75.45%) mean severity was recorded from Boreda, followed by Konso (75.36%), Bonke (71.61%) and Derashe (71.30%), while Mihirab Abaya (33.25%) and Arba Minch (38.285%) districts recorded the lowest mean severity. In the multiple regression model, zone, altitude, cropping year, land preparation, NPS fertilization, weeding practice, growth stage and cropping system were highly significantly (p < 0.0001) associated with disease severity.ConclusionMaize cultivation at an altitude of ≤1500 m with intermediate to good weeding practices, recommended NPS (51–100 kg ha–1) fertilization, mixed‐ and intercropping systems, sparse plant (≤20 plants m‒2) population, and vegetative to blistering growth stages had significant relationships with low (≤25, 26%–50%) disease severity, and can be considered as management options to reduce NLB pressure and yield losses to sustainably ensure maize production and productivity.

Growth Parameters of Apple Trees of the Aidared Variety Depending on the Rootstock and the Effect of Long-term Fertilization in Monoculture

Background: The results of studies of the influence of long-term fertilization on the parameters of growth parameters of apple trees of the Aidared variety on seed and vegetative M.4 rootstocks during repeated cultivation on dark gray podzolic soil were considered. Methods: The research was conducted during 1990-2016 in the apple tree plantation of the Uman National University of Horticulture in an experiment with long-term use of different fertilization systems. Result: It was found that the length of shoot growth of the experimental variety depended on the age periods of growth, rootstock and fertilization options. During the period of growth and fruiting, shoot growth was weak (19.4-22.2 cm) in all variants on both rootstocks due to the impact of soil toxin and difficult weather conditions on the re-grown trees. During the fruiting and growth periods, shoot growth was the largest, while during the fruiting period it decreased again, which was due to an increase in fruit yield and lack of moisture for normal growth of experimental trees. A significant increase in tree crown volume (by 38 %) during the fruiting period was observed on the seed stock compared to the vegetative M.4.

A Review of Fluid Flow Applications and Hydraulic Performance of Sustainable Drip Irrigation to Improve Water Resource Management

Fluid flow applications to improve water resource management towards sustainable irrigation are one of the main targets of engineers nowadays, especially with global climate change. The performance assessment of the irrigation system is an important area of research to improve water resource management. Through drip irrigation systems, this review evaluated the application uniformity of water and nutrients to sustain agricultural production and protect the environment’s natural resources. To achieve these goals, the adequate use of nutrients and water must be emphasized by utilizing sufficient water and nutrient management approaches, including a drip irrigation system that supplies the inputs immediately to the crop’s root zone. The process operating pressure and the drip line length are the two most crucial aspects that affect the uniformity of the water and nutrient distribution in fields. Inconsistent or inadequate applications of fertilizers and water in the fields contribute to the incorrect supply of useful water and nutrients in the soil profile along the drip line length resulting in a significant decrease in crop yields and poor product quality. The main cause behind the operating pressures in a “micro-irrigation system” is the inadequate distribution of fertilizers and water in the fields. Therefore, the effects of such non-uniform distribution must be carefully quantified and studied to understand the reasons behind soil degradation and groundwater contamination, which occurs due to excess nutrient leaching from the crop’s root zone. Data on the distribution and movement of water and nutrients in the soil is essential for designing efficient fertilization systems. Drip irrigation can reduce water exposure and input costs, making agribusiness more resilient, profitable, and successful. This paper discusses the uniformity of the nutrients and water application for crops grown in various agro-climatic regions. In addition, an effort was made to compare the findings’ quality of various commonly used methods of water and nutrient application under different climatic conditions.

Influence of pH and dissolved oxygen control strategies on the performance of pilot-scale microalgae raceways using fertilizer or wastewater as the nutrient source

Dissolved oxygen concentration and pH are controllable and cost-effective variables that determine the success of microalgae-related processes. The present study compares different control strategies for pH and dissolved oxygen in pilot-scale microalgae production systems. Two 80 m2 raceway reactors were used, one operated with freshwater plus fertilizer and the other with wastewater as the nutrient source. Both were in semi-continuous mode at a fixed dilution rate of 0.2 day−1. A comparison between the classical On-Off and more advanced pH control strategies, such as PI and Event-based control, was performed, focusing on biomass productivity and the influence of all the process parameters on microalgae growth; "No control" of pH was also assayed. The results show that Event-based control was the best algorithm when using freshwater plus fertilizer. In contrast, no significant differences were observed using the different control strategies when wastewater was the nutrient source. These experiments were performed through selective control strategy, prioritizing pH over dissolved oxygen; however, it was demonstrated that they did not allow to achieve satisfactory dissolved oxygen removal results, especially for the fertilizer system. After modifying the gas diffuser configuration and improving the mass transfer, independent on-off strategies have been developed, permitting effective control of both variables and increasing productivity by up to 20% in both systems. Concluding, a detailed analysis of the energy demand for each strategy implemented in terms of gas consumption and gas flow to biomass ratio is provided.

Participation of vitamin D endocrine system in human fertility

Interest is growing in the knowledge of the mechanisms of action of vitamin D in very different areas of pathology. In recent years, very different actions of vitamin D have been discovered. Far from being a simple vitamin, it is a hormonal complex that acts in very different parts of the body equipped with hormonal receptors for vitamin D. It controls more than 900 different genes making it. It represents up to 3% of the total human genome. There is a deficit in levels of 25 (OH)D in populations around the world, including young couples affected by fertility problems. In the field of infertility, it has shown beneficial actions on the evolution of polycystic ovary syndrome. It is capable of decreasing the growth of uterine fibroids and correlates well with anti-Mullerian hormone. It has also been shown to improve oocyte quality and the embryo implantation rate in assisted reproduction: Its adequate levels in pregnancy reduce the risk of gestational diabetes and improve perinatal outcomes: The objective of this manuscript is to review the most important aspects that relate to the endocrine system. of vitamin D with fertility and pregnancy.

Improvement of the tillage system in the conditions of irrigation of the Tersko-Sulak substructure

Relevance. The main reason for the decrease in crop yields during soil compaction is the deterioration of conditions for the formation of a powerful root system and its active activity, therefore, the physical properties of soils are important in increasing the effective fertility of soils and obtaining high yields of cultivated crops. Proper regulation of the agrophysical properties of soils is the main task of tillage. The aim of the study is to study the influence of the tillage system on the phases of development of winter wheat in the irrigated plain zone on the agrophysical indicators of meadow-chestnut soil and grain productivity.Methods. The field experiment was carried out in the irrigated zone of the Tersko-Sulak substructure on meadow-chestnut soil. The scheme of the experiment includes a system of tillage (irrigation half-steam and half-steam) and fertilizers (at 3 levels of mineral nutrition for winter wheat).Results. The use of irrigation half-steam and half-steam treatment systems in irrigated agriculture of the Tersko-Sulak substructure has a beneficial effect on the agrophysical properties of the soil, which are able to resist the erosion of arable land from water erosion, contributes to the productivity of winter wheat. Characterizing the evaluation of the study on tillage systems for winter wheat cultivation, the predominant indicators for the semi-steam treatment system are associated with a better content of productive moisture, agrophysical properties of soils and the introduction of mineral fertilizers, which affected the increase in yield and grain structure. Thus, an adaptive system of meadow-chestnut soil treatment under irrigation conditions has been determined.