Is It Possible to Control the Nutrient Regime of Soils with Different Texture through Biochar Substrates?

Understanding nutrient management is essential to ensure healthy and adequate food production, especially in the context of biochar applied to soil with different soil textures. Additionally, farmers are beginning to understand the importance of nutrient management and there are still several knowledge gaps in this area. Several studies on biochar showed its positive effects, especially in sandy and nutrient-poor soils. There is still a lack of information on the impact of biochar on nutrient regimes in texturally different soils with sufficient nutrient supply and favorable soil chemistry. This study investigates the effect of two biochar substrates (a) biochar blended with farmyard manure (BS1), and (b) biochar blended with farmyard manure and digestate (BS2) applied at rates of 10 and 20 t ha−1 alone or in combination with fertilization on the changes in sorption capacity and nutrient regime of two texturally different soils: (a) sandy Arenosol, and (b) loamy Chernozem, (both in western Slovakia) which have a favorable nutrient content. The results showed that in sandy soil, the BS2 at rate of 20 t ha−1 increased the sum of basic cations (by +112%) and CEC (by +93%) compared to the control. In sandy soil, the content of total P increased by +35 and +16% in BS1 20 t ha–1 and BS2 20 t ha−1, respectively, when compared to the unfertilized control. The content of total P increased by +18% in BS1 20 t ha−1 after fertilization compared to the fertilized control. In loamy soil, the content of total P increased significantly by +53 and +14% in unfertilized treatment BS2 20 t ha−1 and fertilized treatment with BS1 at 20 t ha−1 compared to the respective controls. Available Ca increased in sandy soil by +50 and +53% in fertilized treatments with BS2 at 20 t ha−1 and BS1 at 20 t ha−1, respectively, when compared to fertilized control. In loamy soil, available Mg increased by +13% in fertilized treatment with BS1 applied at 20 t ha−1. In conclusion, BS application at a dose of 20 t ha−1 had a stronger positive effect on soil sorption parameters in sandy soil than the application dose of 10 t ha−1. The same BS application rate significantly increased total P in both soils.

The impact of thermal stress and nutrient availability on the physiology and proteome of symbiotic dinoflagellates

<p>Scleractinian corals, which form the building blocks of tropical reefs, are reliant on a mutualistic symbiosis with phototrophic dinoflagellates of the family Symbiodiniaceae for their metabolic needs and survival. Unfortunately, when subjected to environmental stress this symbiosis can destabilise, culminating in coral bleaching (the loss of symbionts from coral tissue). The most prominent cause of coral bleaching is elevated sea surface temperatures as a result of global warming. However, local stressors such as eutrophication can determine coral reef resilience. Although the physiological responses to temperature and nutrient enrichment are well characterised, the cellular mechanisms underlying these responses are not well understood. This thesis aims to further the understanding of the physiological and cellular responses of Symbiodiniaceae to both thermal stress and nutrient availability. The Symbiodiniaceae species used in this study was Breviolum minutum (ITS2 ‘type’ B1), the homologous symbiont of the model cnidarian Aiptasia. The first objective of this thesis was to compare the physiological response to a rapid versus slow temperature increase, in two strains of the Breviolum minutum (culture IDs: NZ01 and FlAp2), by measuring a range of physiological parameters in cultures exposed to an increase in temperature from 25 to 35°C, either immediately or over one-week. The physiological measurements taken were: population growth, chlorophyll fluorescence and concentration, photosynthetic and respiratory oxygen flux, and alkaline phosphatase activity (APA). Measurements of chlorophyll fluorescence and oxygen flux demonstrated that NZ01 was able to maintain photosynthetic efficiency and metabolic balance at 35˚C, while FlAp2 was experiencing lethal thermal stress. This divergence in physiological plasticity between strains was emphasised by different heating rates. FlAp2 showed more significant thermal stress at a slower heating rate, exemplified by reduced photosynthetic rates relative to cultures exposed to a rapid temperature increase. Alternately, NZ01 cultures exposed to a slow versus rapid heating rate demonstrated greater thermal acclimation, as alkaline phosphatase activity was elevated, and unlike cultures exposed to a rapid temperature increase, respiration and gross photosynthetic rates were equal to cultures at control temperatures. The intraspecies variability in thermal tolerance demonstrated in this thesis adds to the data supporting the intra-species physiological plasticity of the Symbiodiniaceae family. The second objective of this thesis was to determine the influence of nutrient supply on the proteomic response to elevated temperature of B. minutum (using the FlAp2 strain). This was achieved by utilising novel proteomics techniques (Liquid chromatography-electrospray ionisation – tandem mass spectrometry, LC-ESI-MS/MS) and various physiological measurements to corroborate trends of protein expression (population growth, chlorophyll fluorescence and concentration, photosynthetic and respiratory oxygen flux, and alkaline phosphatase activity). Algal cultures were exposed to either ambient (dissolved inorganic nitrogen: DIN ~1.8 µM, dissolved inorganic phosphorus: DIP ~0.2 µM), imbalanced (DIN ~26 µM, DIP ~0.5 µM), or enriched nutrient regimes (DIN ~3 µM, DIP ~0.55 µM), at either 25 or 34˚C. Although it was hypothesised that there would be an interaction between the influence of temperature and nutrient availability on the Symbiodiniaceae proteome, this was not found. However, separately these environmental stressors had a strong influence on protein abundance. Temperature caused a reduction in photosynthesis proteins, ribosomal proteins, metabolic proteins (Calvin cycle/glycolysis) and proteins involved in biosynthesis, and a relative increased abundance of chaperonin proteins and proteins involved in cellular redox homeostasis. Interestingly, the Symbiodiniaceae proteome under the ambient and enriched regimes was very similar, while the proteome under the imbalanced nutrient regime was different to these comparatively balanced regimes. This trend highlights the importance of the nitrogen to phosphorus ratio in determining the cellular response of Symbiodiniaceae to nutrient enrichment. Under an imbalanced nutrient regime, there was a down-regulation in photosynthetic and Calvin cycle proteins and an upregulation of proteins involved in protein translation, energy-generating metabolic pathways and storage-product turn-over. Consistent with previous studies, proteomic and physiological data indicated that B. minutum might have been experiencing phosphorus deficiency under an imbalanced nutrient regime. However, photochemical efficiency and metabolic balance was maintained, indicating metabolic adaption to the skewed nutrient ratio. This thesis provides insight into the physiological and cellular response of Symbiodiniaceae to both temperature and nutrients, highlighting potential avenues of research that could be directed to facilitate the knowledge-based management of coral reefs. The intraspecies plasticity demonstrated in chapter two highlights the need to characterise physiological variability within Symbiodiniaceae species, as this could confer an adaptive advantage to the coral holobiont. In conjunction, the proteomics results of chapter three indicate that the relative availability of nitrogen to phosphorus determines the response of Sybiodiniaceae cellular physiology to nutrient availability. This emphasises the importance of determining the threshold of nitrogen to phosphorus that has a negative influence on the coral holobiont, facilitating the setting of ecologically relevant nutrient input limits by coral reef management.</p>

The impact of thermal stress and nutrient availability on the physiology and proteome of symbiotic dinoflagellates

<p>Scleractinian corals, which form the building blocks of tropical reefs, are reliant on a mutualistic symbiosis with phototrophic dinoflagellates of the family Symbiodiniaceae for their metabolic needs and survival. Unfortunately, when subjected to environmental stress this symbiosis can destabilise, culminating in coral bleaching (the loss of symbionts from coral tissue). The most prominent cause of coral bleaching is elevated sea surface temperatures as a result of global warming. However, local stressors such as eutrophication can determine coral reef resilience. Although the physiological responses to temperature and nutrient enrichment are well characterised, the cellular mechanisms underlying these responses are not well understood. This thesis aims to further the understanding of the physiological and cellular responses of Symbiodiniaceae to both thermal stress and nutrient availability. The Symbiodiniaceae species used in this study was Breviolum minutum (ITS2 ‘type’ B1), the homologous symbiont of the model cnidarian Aiptasia. The first objective of this thesis was to compare the physiological response to a rapid versus slow temperature increase, in two strains of the Breviolum minutum (culture IDs: NZ01 and FlAp2), by measuring a range of physiological parameters in cultures exposed to an increase in temperature from 25 to 35°C, either immediately or over one-week. The physiological measurements taken were: population growth, chlorophyll fluorescence and concentration, photosynthetic and respiratory oxygen flux, and alkaline phosphatase activity (APA). Measurements of chlorophyll fluorescence and oxygen flux demonstrated that NZ01 was able to maintain photosynthetic efficiency and metabolic balance at 35˚C, while FlAp2 was experiencing lethal thermal stress. This divergence in physiological plasticity between strains was emphasised by different heating rates. FlAp2 showed more significant thermal stress at a slower heating rate, exemplified by reduced photosynthetic rates relative to cultures exposed to a rapid temperature increase. Alternately, NZ01 cultures exposed to a slow versus rapid heating rate demonstrated greater thermal acclimation, as alkaline phosphatase activity was elevated, and unlike cultures exposed to a rapid temperature increase, respiration and gross photosynthetic rates were equal to cultures at control temperatures. The intraspecies variability in thermal tolerance demonstrated in this thesis adds to the data supporting the intra-species physiological plasticity of the Symbiodiniaceae family. The second objective of this thesis was to determine the influence of nutrient supply on the proteomic response to elevated temperature of B. minutum (using the FlAp2 strain). This was achieved by utilising novel proteomics techniques (Liquid chromatography-electrospray ionisation – tandem mass spectrometry, LC-ESI-MS/MS) and various physiological measurements to corroborate trends of protein expression (population growth, chlorophyll fluorescence and concentration, photosynthetic and respiratory oxygen flux, and alkaline phosphatase activity). Algal cultures were exposed to either ambient (dissolved inorganic nitrogen: DIN ~1.8 µM, dissolved inorganic phosphorus: DIP ~0.2 µM), imbalanced (DIN ~26 µM, DIP ~0.5 µM), or enriched nutrient regimes (DIN ~3 µM, DIP ~0.55 µM), at either 25 or 34˚C. Although it was hypothesised that there would be an interaction between the influence of temperature and nutrient availability on the Symbiodiniaceae proteome, this was not found. However, separately these environmental stressors had a strong influence on protein abundance. Temperature caused a reduction in photosynthesis proteins, ribosomal proteins, metabolic proteins (Calvin cycle/glycolysis) and proteins involved in biosynthesis, and a relative increased abundance of chaperonin proteins and proteins involved in cellular redox homeostasis. Interestingly, the Symbiodiniaceae proteome under the ambient and enriched regimes was very similar, while the proteome under the imbalanced nutrient regime was different to these comparatively balanced regimes. This trend highlights the importance of the nitrogen to phosphorus ratio in determining the cellular response of Symbiodiniaceae to nutrient enrichment. Under an imbalanced nutrient regime, there was a down-regulation in photosynthetic and Calvin cycle proteins and an upregulation of proteins involved in protein translation, energy-generating metabolic pathways and storage-product turn-over. Consistent with previous studies, proteomic and physiological data indicated that B. minutum might have been experiencing phosphorus deficiency under an imbalanced nutrient regime. However, photochemical efficiency and metabolic balance was maintained, indicating metabolic adaption to the skewed nutrient ratio. This thesis provides insight into the physiological and cellular response of Symbiodiniaceae to both temperature and nutrients, highlighting potential avenues of research that could be directed to facilitate the knowledge-based management of coral reefs. The intraspecies plasticity demonstrated in chapter two highlights the need to characterise physiological variability within Symbiodiniaceae species, as this could confer an adaptive advantage to the coral holobiont. In conjunction, the proteomics results of chapter three indicate that the relative availability of nitrogen to phosphorus determines the response of Sybiodiniaceae cellular physiology to nutrient availability. This emphasises the importance of determining the threshold of nitrogen to phosphorus that has a negative influence on the coral holobiont, facilitating the setting of ecologically relevant nutrient input limits by coral reef management.</p>

Impact of the depth of fertilizer localization on the nutrient regime of Luvic Chernic Phaozem and yield of spring barley

The purpose of the research is to determine the impact of the depth of local application of mineral fertilizers on the nutrient content in the arable layer of soil and the yield of spring barley. The studies were carried out during 2018 - 2020 in a temporary small-plot experiment. Soil – chernozem podzolized loamy (Luvic Chernic Phaeozem). The application of N60P60K60 in the form of nitroammophoska or a mixture of ammophos, ammonium nitrate and potassium chloride was compared to a depth of 10-12 cm and 20-22 cm from the soil surface. The row spacing of barley crops was 15 cm; the fertilizer tape was placed at a distance of 4-5 cm away from the row. Mixed soil samples were taken from fertilizer tapes twice during the growing season of barley (in the first half of the growing season and after harvesting). The weather conditions were quite contrasting: in 2018 it was dry at the beginning of the growing season and during grain ripening, in 2019 was dry only during the formation of grain, and in 2020 - rather humid and relatively cool during almost the entire growing season. At the beginning of the growing season of barley in 2018, the highest content of mineral nitrogen in the soil was found with a shallow location of the fertilizers, but in 2019-2020 - in case fertilizer tapes at 20-22 cm from the surface. Location of fertilizer at a depth of 20-22 cm also provided a higher level of mobile phosphorus and potassium in the soil than applying at a depth of 10-12 cm. After the barley harvest, the highest accumulation of mineral nitrogen in the soil in 2018 was found with shallow application and in 2019-2020 - with deeper application. A tendency of more accumulation of chlorophyll in plants was observed with an increase in the depth of fertilization. Local application of fertilizers gave a reliable increase in yield in all variants of the experiment. However, the increase was twice as high when placing the fertilizer tape was at a depth of 20-22 cm as at a depth of 10-12 cm. Application of nitroammophoska to a depth of 20-22 cm was more effective than mixtures of simple and complex fertilizers. It was concluded that the hydrothermal conditions of the growing season and the depth of the location of fertilizers mutually affect the nutrient regime of the soil. The advantage of deep fertilization is more significant under insufficient moisture.

Agrophysical and agrochemical properties of dark grey forest soils under different systems of basic tillage

The effect of long-term use of different systems of basic tillage of dark grey forest soils on the agrophysical properties, nutrient regime and yield of grain crops in grain-fallow crop rotations was determined. The study was carried out in the conditions of the Northern Trans-Urals in a stationary experiment in 1996-2018. The traditional moldboard and resource-saving systems of basic tillage were studied. The experiment took place during the third-sixth rotations of two grain-fallow crop rotations spread in time and space: bare fallow - winter rye - spring wheat - spring vetch - spring barley; bare fallow - winter rye - spring wheat - spring wheat - spring barley. When cultivating a grain crop that completes a grain-fallow crop rotation, in the fourth field after the fallow with a legume forecrop (spring vetch), it is advisable to use systems of basic tillage with elements of minimization. These include non-moldboard and combined tillage with subsurface loosening by a plow with SibIME tines to a depth of 20-22 cm differentiated with stubble-mulch at 12-14 cm and disk harrowing at 10-12 cm. The studied tillage systems ensured the conditions of the water regime, soil composition and nutritional regime close to the moldboard tillage system. The yield of barley almost equal to the moldboard system was formed: against the background of natural land fertility - 2.97-3.03 t/ha, with the use of N40P40P40 - 3.47-3.65 t/ha. Application of tillage systems with minimization elements in a grain-fallow crop rotation without planting a leguminous crop with a given crop for a repeated grain crop (wheat) led to the following results. Productive moisture availability in the soil layer 0-1.0 m decreased by 8.6-28.0%, the nutrient regime worsened significantly, especially nitrogen (by 15.5-43.8%) and phosphorus (by 39.1-51.1%), with the negative differentiation of soil fertility, and reduction of grain yield by 0.09-0.40 t/ha.

Influence of irrigation and fertilizer rate on changing the nutritional regime of mixed crops (sorghum and pea) soil on stubble

Relevance. The article quotes questions of the influence of fertilizer rates and the number of irrigations on the change in the nutrient regime of the soil when growing mixed crops of pea and sorgho in the conditions of the Karabakh zone of Azerbaijan. In this regard, one of the main issues considered was the development on a scientific and practical basis of the nature of changes in the nutrient regime of the soil and the effect of optimal fertilizer rates and the number of irrigations on crop yields in mixed crops in long-irrigated gray meadow soils.Methods. To study the effect of irrigation and fertilizer rates in mixed crops on changes in the nutrient regime of the soil, soil samples were taken from two soil layers (0-30 and 30-60 cm) after cutting. In the soil samples taken, compounds of nitrogen, phosphorus and potassium that are readily absorbed by plants were analyzed.Results. Analysis of soil samples shows that the application of mineral and organic fertilizers against the background of different amounts of irrigation fundamentally affects the effective fertility of the soil. In general, in the phase of flowering and panicle formation under the influence of irrigation and fertilizers, effective soil fertility was observed compared to the control variant without fertilizing, which remained at a sufficient amount. And this indicates that the plant showed a high demand for this nutrient. The decrease in the number of nutrients in the panicle formation phase indicates its connection with the removal of high yields. Analysis of soil samples during the study shows that the introduction of mineral and organic fertilizers against a background of varying amounts of irrigation has fundamentally affected the effective soil fertility.

Nutritional regime of gray forest soil аt different anthropogenic loads

The aim of the research is to establish the peculiarities of the formation of the nutrient regime of gray forest soil with different systems of basic cultivation, fertilization and sealing of by-products of crops in short-rotation 4-field grain crop rotation – winter wheat–corn for grain–barley–soybean. Evaluate the quantitative inflow of biomass, participation in the formation of the nutrient regime of gray forest soil, especially the differentiation of 0–40 cm of soil layer depending on the distribution of nutrients in different tillage soil systems. The studies were carried out in a long-term stationary experiment of the department of soil cultivation and weed control of the NSC «Institute of Agriculture of the NAAS», founded in 1969. The fertilization system consisted of the application of mineral fertilizers N65Р58К68 kg acting things per 1 ha of crop rotation area. As an organic fertilizer, we used by-products of crop rotation, where during 2009–2013 received an average of 5,17–5,50 t/ha, and 2014–2017 – 6,65–7,76 t/ha of crop rotation. The existing yield of the main product significantly influenced the volume of the non-commodity part, with the growth of the main product, the growth of by-products also took place in direct proportion. Nitrogen removal averaged 105 kg/ha, and with biomass it returned on average 55,4 kg/ ha, nitrogen with a full mineralization cycle, in general, this corresponds to 45–47 % of the share of costs. In general, the return of phosphorus from by-products for the rotation of 5 received an average of 12,0–16,7 kg/ha and 4-field crop 26 rotation 19,5–22,0 kg/ha, which was 35–40 % of the total removal harvest. The soil received many times more potassium from the biomass of agricultural crops than part of the cost of the main product, due to the attraction of the maize leaf mass, from which an average of 177–253 kg/ha enters the soil, and for crop rotation – 61,4–95,4 kg/ha per hectare of sown area. Key words: gray forest soil, soil nutrient regime, recycling of nutrients, main and by-products of crops.