Macronutrient Fertilizers Research Articles

Changes in composition, yield, antimicrobial and antioxidant activities of the Ocimum tenuiflorum L. essential oils as affected by fertilizers

The purpose of this study is to evaluate the impact of multifunctional microbial fertilizer and inorganic macronutrient fertilizers N, P, K on plant biomass, essential oil yield, chemical composition, antimicrobial and antioxidant activities of tulsi (Ocimum tenuiflorum L.) grown in Hanoi, Vietnam. Among the four formulas tested, F2 emerged as the most favourable, comprising a basal fertilization of 10 tons of decomposed manure, 15 kg of multifunctional microbial fertilizer, 150 kg of P fertilizer, and 75 kg of K fertilizer, together with top dressing of 200 kg of N fertilizer and 75 kg of K fertilizer per hectare. This formula yielded the highest tulsi dry biomass (4.73 ton/ha), essential oil yield (0.831%), and essential oil production (39.29 L/ha), which were significantly different (p < 0.001) from those of the remaining formulas. In addition, the concentration of the essential oil main compound - eugenol (63.1%) of tulsi in F2 was also the highest, which may be the cause of the strongest antibacterial activity against Bacillus subtilis, Escherichia coli (IC50 of 320, 273 µg/mL, respectively), and antifungal activity against Candida albicans (IC50 of 400 µg/mL), as well as antioxidant activity (IC50 of 0.165 µg/mL) compared to the other formulas tested. The results suggested the role of both multifunctional microbial fertilizer and inorganic macronutrient fertilizers N, P, K on growth and essential oil biosynthesis in tulsi. These findings are important in identifying the most efficient fertilization formula for cultivating tulsi, serving the needs of the cosmetic and medicinal industries.

Effect of mechanochemically modified MoO3–ZnO on Mo supply to plants when co-granulated with macronutrient fertilizers

Molybdenum (Mo) is an essential micronutrient required for plant growth but is prone to leaching from neutral and alkaline soils. The use of slow-release Mo sources could potentially reduce leaching losses from soils and increase crop yields. In this study, we assessed mechanochemistry as a green method to produce slow-release Mo sources. Molybdenum compounds (MoO3 or (NH4)6Mo7O24·4H2O) were mechanochemically (MC) treated with ZnO to synthesize compounds with a Mo content of 1–36%. Reduced Mo solubility after MC treatment, compared to the initial Mo source, was obtained with the MoO3 source and these composites were used for co-compaction with macronutrient fertilizers. Macronutrient pellets with 0.2% Mo were compacted using the 4% Mo and 36% Mo (characterized as ZnMoO4) compounds. A column dissolution test showed that the 4% Mo compound in a macronutrient carrier (DAP and MAP) only released around 40% of the total Mo compared to 80% for a non-MC treated control over 72 h. Column leaching using two soils revealed that the release behavior of Mo was strongly related to the pH of the leachate, which was affected by both the soil pH and the macronutrient carrier. More Mo was released when the MC-treated compound was co-compacted with diammonium phosphate (DAP) compared to monoammonium phosphate (MAP). The MC-treated compound with 4% Mo showed significantly less leaching than the control without ball milling when co-compacted with both MAP and DAP. In a pot trial with simulated leaching, the uptake of Mo was greater for the MC-treated 4% Mo compound co-compacted into DAP than for the other Mo sources. Overall, our results indicate that MC-treated MoO3–ZnO could be used as a slow-release Mo source in high-rainfall areas.Graphical

Examining the Effect of Agrochemicals on Soil Microbiological Activity, Micronutrient Availability, and Uptake by Maize (Zea mays L.) Plants

Agricultural practices profoundly influence soil microbial populations and physicochemical properties, vital for crop growth and quality. This study aims to explore the impact of diverse agrochemical applications on soil microbial dynamics, physicochemical properties, and maize yield and proximate properties. Topsoil samples, collected at depths of 1 to 15 cm, were transported to Jimma University for maize cultivation. Over 120 days, soil and maize samples were collected at specified intervals for analysis, including soil pH, microbial populations, and nutrient content. Statistical analysis using one-way ANOVA (p < 0.05) was conducted. Soil bacterial and fungal populations were measured on days 5, 10, 20, 40, 80, and 120. The highest total mesophilic bacterial count (TMBC) was in compost-treated pots (G) and the lowest in those receiving macronutrient fertilizers and glyphosates (B). The highest total mesophilic fungal count (TMFC) was in pots with glyphosates and compost (F), and the lowest was in pots treated with macronutrient fertilizers and glyphosates (B). Pots treated with macronutrient fertilizers and glyphosates (B), macronutrient fertilizers (A), and micronutrient fertilizers (C) showed the lowest Fe and Zn levels. Maize in pots treated with macronutrient fertilizer combined with glyphosate (B) exhibited the lowest protein, fats, and carbohydrates. Notably, compost-treated soils showed the highest bacterial and fungal counts, Fe, and Zn concentrations, while micro-mineral fertilizer combined with glyphosate (B) depleted the soil. Agrochemical treatments negatively affected maize yield quality, indicating complex treatment-related changes in soil parameters.

The influence of foliar macronutrient on growth and yield of sweet corn grown in Rengam and Rasau soil series under greenhouse conditions

The purpose of this study was to determine the effects of different rates of macronutrients as a foliar applications on growth and yield performance of sweet corn cultivated in Rengam and Rasau soil series of Malaysia under greenhouse condition. The study comprised five treatments of macronutrient fertilization as a foliar application (0, 25, 50, 75 and 100 % NPK). The plant height, stem width, leaf number, leaf area and cob height of sweet corn grown in Rengam soil series were significantly influenced by foliar macronutrient application. Notably, a rise in cob weight of sweet corns cultivated in Rasau soil series was observed at the 75 % rate, reaching 75 g, compared to 68 g for sweet corn grown in Rengam soil series. The foliar application of 100 % NPK resulted in the highest total leaf area at 252.92 cm2 compared to all other treatments. Regarding the cob fresh weight and dry matter content of sweet corn cultivated in the Rasau soil series, significant improvement noted with the 75 % NPK treatment, however plants grown in the Rengam soil series and treated with 75 % NPK as a foliar application did not exhibit significant effects. The concentrations of Fe and Mn in the corn stem from both soil series significantly increased with macronutrients foliar application. In the corn leaves grown in Rengam soil series, the concentration of nutrients was significantly influenced by the rate of NPK used as a foliar application in this study. Notably, the increased of Ca content in the treated leaves was significantly higher compared to control plants. Additionally, the contents of P, K, Cu and Zn in the corn flower of the plants in the Rengam soil series were significantly elevated in treated plants compared to untreated ones. Conclusively, based on this greenhouse study, it can be inferred that two foliar sprays of macronutrient solution at rates of 75 % and 100 % NPK greatly enhanced the growth, yield and nutrient contents of sweet corn cultivated in the Rengam and Rasau soil series.

PreciPalm: An Intelligent System for Calculating Macronutrient Status and Fertilizer Recommendations for Oil Palm on Mineral Soils Based on a Precision Agriculture Approach

The measurement of the macronutrient values of an oil palm plantation is a complex and tedious task, particularly when dealing with large plantation areas. This situation complicates the process of the conventional measurement of nutrients by taking samples of oil palm leaves in the area being observed, causing delays in fertilizer recommendation and a lack of spatial diversity observation. Precision agriculture (PA) principles and approaches, which focus on assessing temporal and spatial variability, can be used to improve conventional measurement methods in terms of both accuracy and speed. This research aims to determine macronutrients, specifically nitrogen (N), phosphorus (P), and potassium (K) contents in oil palm leaves based on PA principles using the integration of remote sensing technology and machine learning to quickly obtain the macronutrient status from oil palm plantation areas. The Sentinel‐1A and Sentinel‐2A imagery data were analyzed and extracted to produce selected features, which are most influencing in the correlation between the imagery data and the leaf macronutrient values obtained from laboratory analysis. The random forest regression (RFR) model is used to produce correlation functions to compute macronutrient values. The use of the two satellites is to cope with cloud and smoke interference. The prototype system developed, named PreciPalm (Precision Agriculture Platform for Oil Palm), has been validated and implemented based on 2000 leaf sampling units representing several oil palm plantation areas in Indonesia, including Java, Sumatra, and Kalimantan. The observed system performance resulted in the measurement accuracy of 95.02%, 93.50%, and 82.52% for the nutrients N, P, and K, respectively. The novelty of PreciPalm is that it provides an ecosystem to transparently measure and observe the macronutrient status of oil palm in a timely, visual, spatial, and location‐specific manner, thereby improving oil palm nutritional management with more certainty and precision.

Macronutrient Fertilization and Cadmium Absorption in Two Cocoa Clones

Soil Cd is absorbed by roots and accumulated in cocoa plants, which represents a problem in the commercialization of beans. In order to evaluate whether the exogenous application of macronutrients (N, N-P, N-P-K, N-P-K-S, N-P-K-S-Mg, and N-P-K-S-Mg-Ca) mitigates the absorption, translocation, and accumulation of Cd in plants, soil pH and electric conductivity, dry root and shoot biomass, leaf gas exchange, chlorophyll content, and macronutrient bioaccumulation were evaluated in two cocoa clones (CCN-51 and EET-103) grown in a greenhouse. An increase in macronutrients gradually increased the extraction capacity of Cd in both clones, with the highest Cd values being obtained with the application of N-P-K-S-Mg-Ca. Macronutrient fertilization did not affect leaf gas exchange; however, it caused significant reductions of 30, 40, and 60% in chlorophyll content, shoot, and root dry biomass, respectively. The greatest translocation of Cd from the root to the shoot was obtained with treatments that included N in clone EET-103 and Ca in clone CCN-51. Fertilization with macronutrients did not decrease the absorption and accumulation of Cd in the cocoa seedlings, because a greater removal force of Cd from the adsorption complex towards the soil solution was caused by the exogenous application of Ca and Mg and an increase in soil acidity.

Agronomic Comparison of Mechanochemically Synthesized Zinc Borate and Other Boron Sources Granulated with Macronutrient Fertilizers

PurposeBoron (B) is an essential micronutrient required throughout the growth cycle of plants so effectively supplying crops with B using fertilizers is challenging. The purpose of this study was to assess the agronomic effectiveness of mechanochemically synthesized zinc borate as a slow release B source and compare it to commonly used B sources after incorporation with different macronutrient carriers.MethodsZinc borate synthesized using a green mechanochemical method as well as commercial B sources (borax, colemanite, and commercial zinc borate) were incorporated with various macronutrient fertilizers (monoammonium phosphate – MAP, muriate of potash – MOP and urea). The fertilizers were evaluated by a) assessing the solubility behaviour of these products; and b) comparing potential leaching losses, plant growth, and plant uptake through a greenhouse study.ResultsThe mechanochemically synthesized zinc borate, commercial zinc borate, and colemanite had similar dissolution rates when MAP was the carrier, but both zinc borates dissolved more B than colemanite when MOP and urea were the carriers. In the pot trial, high losses of B in leachates resulted in low B uptake by plants fertilized with soluble sodium tetraborate. All the slow-release B sources showed less B leaching and greater B uptake compared to the soluble B treatment, but more B was leached for the mechanochemically synthesized than for the commercial zinc borate.ConclusionsOur study indicates that mechanochemically synthesized zinc borate could be effective in matching plant demand for B and reducing leaching losses in high rainfall environments, particularly with urea as the carrier, while providing the benefit of lower waste stream production compared to commercial zinc borate sources.

Layered Transition Metal Molybdates as New Slow-Release Micronutrient Fertilizer Matrices for Zn, Cu, and Mo

Micronutrient availability in agricultural soils is an important driver for crop production, and for mobile micronutrients, slow-release fertilizers can more efficiently enhance crop nutrition. In this study, for the first time, layered transition metal molybdates (LTMs) are proposed as slow-release fertilizer compounds for the micronutrients molybdenum (Mo), zinc (Zn), and copper (Cu). A series of LTMs were successfully prepared in varying synthesis conditions, characterized (inductively coupled plasma optical emission spectrometry, X-ray diffraction, Fourier transform infrared, and scanning electron microscopy), and tested for solubility in water. For three selected LTMs (Zn–Mo, Cu–Mo, and Zn–Cu–Mo), the solubility as a function of solution pH was determined. The LTMs showed limited stability in acidic conditions. Therefore, co-compaction of LTMs with pH neutral or alkaline macronutrient carriers [muriate of potash (MOP), limestone, rock phosphate] was explored. A Zn-based LTM co-compacted in a MOP carrier showed a useful slow and almost constant release rate of both Mo and Zn in a column dissolution test (Mo release reaching 32% after 72 h), while a reference compacted MOP fertilizer with soluble Mo released 90% of Mo after 4 h. Hence, a Zn-LTM could prove useful as a slow-release fertilizer or raw material to incorporate into non-acidic macronutrient fertilizers.

A better use of fertilizers is needed for global food security and environmental sustainability

The massive use of fertilizers during the last decades allowed a great increase in the global capacity of food production. However, in the last years, several studies highlight the inefficiency and country asymmetries in the use of these fertilizers that generated environmental problems, soil nutritional imbalances and not optimal food production. We have aimed to summarize this information and identify and disentangle the key caveats that should be solved. Inadequate global management of fertilization produces areas with serious nutrient deficits in croplands linked with insufficient access to fertilizers that clearly limit food production, and areas that are overfertilized with the consequent problems of environmental pollution affecting human health. A more efficient use of nitrogen (N), phosphorus (P) and potassium (K) fertilizers for food security while preserving the environment is thus needed. Nutrient imbalances, particularly the disequilibrium of the N:P ratio due to the unbalanced release of N and P from anthropogenic activities, mainly by crop fertilization and expanding N-fixing crops that have continuously increased the soil N:P ratio, is another issue to resolve. This imbalance has already affected several terrestrial and aquatic ecosystems, altering their species composition and functionality and threatening global biodiversity. The different economic and geopolitical traits of these three main macronutrient fertilizers must be considered. P has the fewest reserves, depending mostly on mineable efforts, with most of the reserves concentrated in very few countries (85% in Morocco). This problem is a great concern for the current and near-future access to P for low-income countries. N is instead readily available due to the well-established and relatively low-cost Haber–Bosch synthesis of ammonium from atmospheric N2, which is increasingly used, even in some low-income countries producing an increasing imbalance in nutrient ratios with the application of P and K fertilizers. The anthropogenic inputs of these three macronutrients to the environment have reached the levels of the natural fluxes, thereby substantially altering their global cycles. The case of the excess of N fertilization is especially paradigmatic in several areas of the world, where continental water sources have become useless due to the higher nitrate concentrations. The management of N, P and K fertilizers is thus in the center of the main dichotomy between food security and environmentally driven problems, such as climate change or eutrophication/pollution. Such a key role demands new legislation for adopting the well-known and common-sense 4R principle (right nutrient source at the right rate, right time and right place) that would help to ensure the appropriate use of nutrient resources and the optimization of productivity.

Assessing the Impact of Co-fertilization of Silicon with Macronutrient Fertilizers on Yield, Nutrient Uptake, use Efficiency and Grain Quality of Rice in Sandy Clay Loam Soil

This study wanted to clarify the impact of silicon (Si) fertilization on nutrient uptake, silicon use efficiency, yield and quality of rice and to detect the rate and mode of application of Si fertilizer in silicon deficient soil. The field experiment was conducted with ten treatment combinationsof100% NPK,100% NPK + potassium silicate (PS)@ 0.25%,0.50% and 1.0% Foliar spray (FS) at tillering stage,100% NPK + PS@ 0.25% ,0.50% and 1.0%FS at tillering and panicle initiation stages,100% NPK + PS@ 50,100 and 150 kg Si ha-1soil application (SA). Application of 50 kg Si ha-1 through PS recorded the highest grain (6183 kg ha-1) and straw (6740 kg ha-1) yield, and higher uptake of macronutrients (NP&K) in rice and it was on par with foliar spray of 1% Si sprayed at tillering stage. Silicon uptake increased linearly with Si levels and the maximum uptake was recorded with 150 kg Si ha-1 and foliar spray at 1% Si. Foliar spray recorded higher Si use efficiency compared to soil application. Rice grain quality viz., protein, amylose and carbohydrate were significantly influenced by silicon addition. The results proved that both foliar and soil application of Si through potassium silicate in sandy clay loam soil could enhance the rice yield, nutrient uptake and grain quality by means of improving nutrient use efficiency.

Foliar micronutrient applications enhance growth and yield of huanglongbing (HLB)‐affected sweet orange

AbstractFlorida citrus production has declined by more than 70% because of Huanglongbing (HLB), and a major cause of tree decline is nutrient uptake limitations caused by HLB. This study was conducted on 6–9‐year‐old “Valencia” sweet orange [Citrus sinensis (L.) Osbeck] on Swingle rootstock in the central and southwest Florida to evaluate the effects of macronutrient fertilization and foliar application of Mn and Fe on growth and yield of HLB‐affected citrus trees in Florida. Seven treatments, including a control (standard fertilization), two levels of macronutrients (1× Macro and 2× Macro), and three levels of foliar micronutrients (F‐1×, F‐2×, and F‐4×), were arranged in a randomized complete block design in two locations for 3 years. Trees subjected to 1× Macro + F‐4× showed the highest average leaf Mn concentration for both sites through all years. The treatment that contained 1× Macro + F‐2× showed at least 4% increase in canopy volume for 2020 and 2021 at the central Florida site. However, trees subjected to 1× Macro + F‐2× showed at least 12% increase in canopy volume in 2020 in southwest Florida. In 2021, the trees that were subjected to 2× Macro + F‐1× resulted in 15% greater canopy efficiency than the control at the central Florida site. In 2021, citrus trees treated with 2× Macro + F‐1× increased yield at both sites. In general, the growth parameters and yield results showed that treatments subjected to supplemental fertilization over current recommendations have strong potential to increase citrus growth and yield.

Biomass ash-based soil improvers: Impact of formulation and stabilization conditions on materials’ properties

Biomass ash and sludge from pulp and paper industry have enormous potential to be recycled and used as components in soil improvers. Those materials can supply large amounts of nutrients and organic matter and its recycling avoids the need of landfilling. However, these wastes cannot be directly applied to soils. Some form of processing is required to ensure efficient soil pH correction, fertilization, guarantee soil protection, and reduce potential sanitary and environmental risks.In this study, different ash formulations (with or without addition of organic wastes) and stabilization conditions (indoors vs. outdoors) were tested to optimize physico-chemical properties of ash-based granules to be used as soil improvers. Biomass fly ash (BFA) was granulated in combination with different binding agents: distilled water, biological sludge (BS), biological sludge effluent (BSE), or composted biological sludge (CBS). All granulated materials were alkaline, ranging from pH 7.9 to 12.1. Their acid-neutralizing capacity ranged from 45 to 51 equiv. CaCO3, rendering them suitable as liming materials. Incorporation of organic materials (BS and CBS) enhanced water holding capacity (up to 38 %) and bulk porosity (up to 20 %). Stabilization outdoors resulted in a faster carbonation and consequent reduction of the granules pH. It also yielded a lower electrical conductivity and lower soluble salts content (Ca, Cl, K, and Na) than materials stabilized indoors. After processing and stabilization, some of these ash formulations fulfilled the criteria to be used as component for inorganic macronutrient fertilizers, liming materials or inorganic soil improvers under the EU Fertilizing Products Regulation.

UPTAKE OF MICROELEMENTSINOILSEED RAPE PLANTS UNDER MINERAL FERTILIZATION WITH NITROGEN AND PHOSPHORUS

With a large and growing demand in the market, rapeseed (Brassica napus subsp. napus.) is a crop with relatively high requirements for macronutrient fertilization. The aim of the experiment was to study the effect of mineral fertilization with different doses of nitrogen and phosphorus on the accumulation of microelements in the vegetative organs and grains of oilseed rape plants.The experiment was carried out in the long-term experimental fields of SCDA Livada. There were taken and analyzed 96 plant samples and the results were statistically processed. Fertilization with nitrogen and phosphorus led to statistically assured changes in the contents of microelements, mostly in the aerial parts of the rapeseed. Regarding their accumulation in the grain, there were obtained variations of contents that were not significant to all doses of fertilizer applied. The conclusions of the experiments showed that the evaluation of contents of manganese, iron, zinc, and copper in rapeseed plants can help in choosing the optimal dose of mineral fertilizers in order to assure balanced microelement composition in plants and thus, consequently to avoid their deficiency.

Conversion of anaerobic digestates from biogas plants: Laboratory fertilizer formulation, scale-up and demonstration of applicative properties on plants

This research paper presents a zero-waste method for preparing a fertilizer based on digestate from food residues. The waste was treated with a mixture of inorganic acids (sulfuric acid and phosphoric acid). The process allowed for sanitization with simultaneous production of free amino acids and short peptides. In preliminary studies, the effect of the order of addition of components (digestate hydrolysate, ash from incineration of sewage sludge) on nitrogen loss was observed during the neutralization/granulation process. The slow addition of ash to the hydrolysate minimizes nitrogen loss (0.6 g N/kg fertilizer) six times compared to the reverse order. Based on the optimal conditions, a large-scale fertilizer was produced, meeting the quality requirements of the EU Regulation for solid inorganic macronutrient fertilizer - PFC 1(C)(I)(a)(i). The physicochemical properties of the final fertilizer were investigated: microbiological analysis, granule strength tests, and bioavailability and leachability of nutrients in extraction tests. The effectiveness of the fertilizer was confirmed in 30-day pot tests, with results similar to those of the mineral fertilizer. The fertilizer obtained can be a substitute for traditional mineral fertilizers, which is a promising solution in the situation of rising natural gas prices and the availability of fossil raw materials.

Effect of macronutrient fertilization on olive oil composition and quality under irrigated, intensive cultivation management.

Intensive olive (Olea europaea L.) orchards are fertilized, mostly with the macronutrients nitrogen (N), phosphorus (P) and potassium (K). The effects of different application levels of these nutrients on olive oil composition and quality were studied over 6 years in a commercial intensively cultivated 'Barnea' olive orchard in Israel. Oil quality and composition were affected by N, but not P or K availability. Elevated N levels increased free fatty acid content and reduced polyphenol level in the oil. Peroxide value was not affected by N, P or K levels. The relative concentrations of palmitoleic, linoleic and linolenic fatty acids increased with increasing levels of N application, whereas that of oleic acid, monounsaturated-to-polyunsaturated fatty acid ratio and oleic-to-linoleic ratio decreased. These results indicate that intensive olive orchard fertilization should be carried out carefully, especially where N application is concerned, to avoid a decrease in oil quality due to over-fertilization. Informed application of macronutrients requires leaf and fruit analyses to establish good agricultural practices, especially in view of the expansion of olive cultivation to new agricultural regions and soils. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Magnesium-fortified phosphate fertilizers improve nutrient uptake and plant growth without reducing phosphorus availability

Magnesium (Mg) deficiency can significantly limit crop yield and quality. Separate application of straight Mg fertilizer is unattractive because of additional labor costs. Meanwhile, bulk blending Mg with other macronutrient fertilizers is also a suboptimal solution because bulk blended fertilizers often yield poor nutrient distributions. One rapid and economical alternative to alleviating Mg deficiency is to co-granulate macronutrient fertilizers with Mg. However, few commercial products have implemented this approach. One of the barriers hindering the production of Mg-fortified phosphorus (P) fertilizers is the assumption that precipitation of P with Mg will reduce P solubility. In this study, four Mg compounds, anhydrous magnesium sulfate (MgSO 4 ), magnesium oxide (MgO), anhydrous magnesium chloride (MgCl 2 ), and dolomite (CaMg(CO 3 ) 2 ), were co-granulated with mono-ammonium phosphate (MAP), and their granule strength, Mg and P availabilities, and agronomic effectiveness were evaluated. Results showed that there were no significant differences in P solubility between Mg-fortified MAP and MAP treatments. X-ray diffraction (XRD) indicated that the Mg species after co-granulation were boussingaultite (Mg(NH 4 ) 2 (SO 4 ) 2 ·6H 2 O), schertelite (Mg(NH 4 ) 2 H 2 (PO 4 ) 2 ·4H 2 O), magnesium hydrogen phosphate (Mg(H 2 PO 4 ) 2 ), and dolomite (CaMg(CO 3 ) 2 ). A pot experiment using an acidic soil demonstrated an average 9.6-fold increase in shoot Mg uptake, 3.0-fold increase in shoot P uptake, and 3.2-fold increase in soybean shoot dry matter in Mg-fortified MAP treatments, compared to those in MAP treatment. The current study provides a simple, effective, and low-cost approach for the addition of Mg to macronutrient fertilizers, to minimize Mg deficiency.

Agronomic fortification in finger millet (Eleusine coracana) for yield and quality improvement in red sandy loam soils

A field experiment was conducted during kharif 2015–18 to study the yield responses of finger millet [Eleusine coracana (L.) Gaertn.] to graded doses of macronutrient fertilizers (100% and 150% RDF) in combination with soil and foliar application of Zn and Fe, which are important for early establishment of finger millet. The experimental results indicated that significantly higher grain and straw yields of finger millet were recorded with 150% RDF+ZnSO4 0.5% foliar spray+FeSO4 0.2% foliar spray compared to 100% RDF. Soil available N, P2O5, K2O and plant macronutrient uptake were also found highest in the same treatment. Whereas the highest available Zn in the soil was recorded in the treatment 150% RDF+ZnSO4 soil application+FeSO4 0.2% foliar spray, and the highest available Fe was evidenced in the treatment 150% RDF+FeSO4 0.2% foliar spray. The grain zinc content was found highest with the treatment 150% RDF+ZnSO4 0.5% foliar spray, iron content in the grain was found highest with the treatment 150% RDF+ZnSO4 0.5 % foliar spray + FeSO4 0.2% foliar spray. The uptake of Zn and Fe were found highest with the treatment 150% RDF+ZnSO4 0.5 % foliar spray+FeSO4 0.2 % foliar spray. Hence, the treatment with 150% RDF+ZnSO4 0.5% foliar spray + FeSO4 0.2% foliar spray was considered to be the best treatment which was at par with 150% RDF+ZnSO4 @50 kg/ha soil application+FeSO4 0.2% foliar spray.

Layered Double Hydroxides as Slow-Release Fertilizer Compounds for the Micronutrient Molybdenum.

Molybdenum (Mo) is an essential plant micronutrient. Despite low plant Mo requirements, deficiencies are not uncommon and soluble Mo fertilizers are often applied. However, soluble Mo may result in poor Mo use efficiency due to strong sorption (acid weathered soils) or leaching (lighter-textured soils). Here, ZnAl layered double hydroxides (LDHs), loaded with molybdate (MoO4), were examined for their potential as slow-release Mo compounds. Chloride-exchanged LDHs with varying Zn/Al ratios (2, 3, and 4) were exchanged with MoO4. Zn2Al LDH indicated MoO4 intercalation, whereas Zn3Al and Zn4Al LDHs bound MoO4 merely on edge sites. Short-term Mo-LDH incubation identified sulfate, carbonate, and phosphate as the most competitive anions for MoO4 exchange. Long-term Mo-LDH incubation in simulated pH-neutral soil solutions demonstrated slow Mo release from Zn2Al LDH (half-life of 35 h), with a total Mo desorption of up to 85%. For Zn3Al and Zn4Al LDHs, Mo desorption was limited to <20%. Finally, several macronutrient fertilizers were tested as possible carriers for Mo-LDH fertilizer compounds.

Zinc and copper interactions under variable soil phosphorus and moisture conditions in selected Saskatchewan soils

This study evaluates the influence of phosphorus (P) fertilization (without and with added P fertilizer) and soil moisture (stress and no-stress) on efficacy, fate, and transformation of soil applied micronutrients such as copper (Cu), zinc (Zn), and Cu + Zn in a wheat and pea cropping sequence. Wheat was grown as first crop under controlled environment conditions in which micronutrient fertilizer treatments were applied, whereas pea was grown as following crop with recommended macronutrient fertilizers to understand the residual effects of micronutrient fertilization. The high-P fertilizer application and no-stress moisture condition produced the highest grain and straw yield of wheat. Without P fertilization, there were significant negative effects of a combined application of Cu and Zn on wheat yield in a Dark Gray Chernozem. Yield of the following pea crop did not show response to residual Cu and Zn. Micronutrient fertilization increased the Cu and Zn concentration in wheat and pea grain and straw and resulted in increased after-harvest availability and supply in soils. Apart from the increased concentration in labile fraction, a considerable amount of added Cu and Zn was occluded with organic matter and oxyhydroxide species, respectively. Molecular speciation analyses revealed that carbonate associated was the dominant form of Cu and Zn in the soils. Additional Cu species such as Cu-acetate and methoxide, and Zn species including Zn-sorbed montmorillonite species were identified. Insoluble Cu-phosphate and Zn-phosphate complexes were not identified by speciation analyses and do not appear to be a significant factor controlling Cu and Zn availability in these soils.

RESOURCES OF MAIN MACRONUTRIENTS IN NATURAL FERTILIZERS IN POLAND

Results of analysis of the consumption of particular macronutrients in natural fertilizers in Poland are discussed in the paper. Analysis included the consumption of nitrogen, phosphorus and potassium in particular types of natural fertilizers, both in relation to the fertilized area and agricultural land. The study period covered the years 2018-2019. The amount of macronutrient resources of natural fertilizers was determined at a voivodship level. As a result of data analysis, it was shown that more than 80% of NPK macronutrients were applied to the soil in the form of manure. In Poland, total NPK consumption in manure was estimated at about 80 kg/ha UAA, including 27.4 kg of N, 17.3 kg of P2O5 and 33.5 kg of K2O. The highest doses of NPK components in natural fertilizers, on a fertilized area, were applied in the Lubuskie, Podlaskie, Lubelskie and Warmińsko-Mazurskie voivodeships, as well as the Wielkopolskie Voivodeship. In none of the voivodeships did the average dose of nitrogen used in manure exceed the permissible level of 170 kg of N/ha. In terms of intensity of macronutrient fertilization from natural fertilizers, the Podlaskie Voivodeship came first, which confirms its importance in terms of animal production and its significance for the development of bioeconomy in Poland.