Accumulation Of Macronutrients Research Articles

The Ballast Effect of Terrigenous Lithogenic Particles From Rivers and Its Influence on POC Fluxes in the Ocean

AbstractLithogenic materials such as terrigenous lithogenic particles (TLP) can efficiently promote the formation and sinking of mineral‐associated marine organic matter, acting as important ballast and potentially playing an important role in the global carbon cycle. To assess the influence of TLP on fluxes of particulate organic carbon (POC) and other biogeochemical cycles, we construct TLP forcing fields based on global riverine suspended sediment data and then apply them to the Community Earth System Model, version 2 (CESM2) modified with the TLP ballasting effect term. Simulations forced by different concentrations of TLP transported in the surface ocean or along the bottom of continental shelves and slopes are conducted. When the TLP transports seaward along the bottom, simulated POC fluxes at 100 and 2,000 m decrease about 11% and 19%, respectively, for the global ocean, and about 9% and 12%, respectively, for the oceanic regions of continental margins. The initial abiotic ballast processes triggered by TLP input increase POC fluxes, causing additional removal and burial of dissolved iron in continental margins. This further enhances the accumulation of macronutrients in the upwelling regions and their advection transport to neighboring subtropical gyres, thus altering regional productivity when simulations reach quasi‐equilibrium. When consider the impacts of TLP in simulations, the simulated POC flux exhibits an increase in subtropical gyres but a decrease in tropical Pacific and mid‐high latitude regions. The present work highlights the importance of TLP in global biogeochemical cycles, suggesting that the amount of carbon sequestration might be overestimated without TLP in models.

The Effect of Various Tillage Methods and Meliorants Application against their Background on the Dynamics of Macronutrients Accumulation in the Winter Wheat Plants and their Output via Crop Yield

The article presents the results of two-year investigations related to the effect of different soil cultivation methods, application times of equal doses of mineral and organic fertilizers and bio-humus with bentonite application against their background on the dynamics of macronutrients accumulation and their removal/ output through the crop yield. Considering the changes in the winter wheat growth, development, and yield capacity under the effect of different soil tillage methods, as well as the applied fertilizers and bentonite in rainfed conditions, and also the nutrition characteristics, to get high and sustainable yield the cultivation of winter wheat should be implemented only through loosening method, while fertilization should be implemented by introducing natural rock bentonite into the soil either on the background of mineral fertilizers (N60P60K60) or bio humus (3.5 t/հa) in autumn, as a result of which the soil air, nutrition and humidity regimes improve, favorable conditions are created for the regular growth and development of the plant and 48.8-52 c/ha grain and 89-96 c/ha straw yield is ensured.

Agronomic and Genetic Strategies to Enhance Selenium Accumulation in Crops and Their Influence on Quality.

Selenium (Se) is an essential trace element that plays a crucial role in maintaining the health of humans, animals, and certain plants. It is extensively present throughout the Earth's crust and is absorbed by crops in the form of selenates and selenite, eventually entering the food chain. Se biofortification is an agricultural process that employs agronomic and genetic strategies. Its goal is to enhance the mechanisms of crop uptake and the accumulation of exogenous Se, resulting in the production of crops enriched with Se. This process ultimately contributes to promoting human health. Agronomic strategies in Se biofortification aim to enhance the availability of exogenous Se in crops. Concurrently, genetic strategies focus on improving a crop's capacity to uptake, transport, and accumulate Se. Early research primarily concentrated on optimizing Se biofortification methods, improving Se fertilizer efficiency, and enhancing Se content in crops. In recent years, there has been a growing realization that Se can effectively enhance crop growth and increase crop yield, thereby contributing to alleviating food shortages. Additionally, Se has been found to promote the accumulation of macro-nutrients, antioxidants, and beneficial mineral elements in crops. The supplementation of Se biofortified foods is gradually emerging as an effective approach for promoting human dietary health and alleviating hidden hunger. Therefore, in this paper, we provide a comprehensive summary of the Se biofortification conducted over the past decade, mainly focusing on Se accumulation in crops and its impact on crop quality. We discuss various Se biofortification strategies, with an emphasis on the impact of Se fertilizer strategies on crop Se accumulation and their underlying mechanisms. Furthermore, we highlight Se's role in enhancing crop quality and offer perspective on Se biofortification in crop improvement, guiding future mechanistic explorations and applications of Se biofortification.

Parsley production using organic fertilizers before planting and in top dressing

The objective of this research was to evaluate the effect of two organic fertilizers used before planting and in top dressing in the production of parsley. Seven treatments were evaluated, resulted from the factorial 2 x 3 + 1: two organic fertilizers (castor bean cake, and hoof and horn powder) x 3 modes of application (100% before planting; 100% in top dressing; 50% before planting and 50% in top dressing) + 1 control. The experimental design was in randomized blocks, with five replications and plots of 1 m2. Two harvests were done and in both the following characteristics were evaluated: the relative chlorophyll index ("Spad''), plant height, fresh (FW) and dry (DW) matter weight of shoot and macronutrients accumulation. There was no significant difference for the ‘’Spad” index in both harvests. For the other characteristics, the control was inferior to the other treatments. In the comparison among application modes, the treatment with castor bean cake, 100% before planting, was inferior to the other applications modes of this fertilizer for FW and DW. For hoof and horn powder, the 100% in top dressing application mode was superior to other applications. In the comparison between fertilizers, the hoof and horn powder was superior to castor bean cake in both harvests when application was done 100% before planting. The descending order of macronutrients accumulation was: K > N > Ca > P > Mg. Therefore, it is recommended to apply hoof and horn powder, 100% in top dressing application.

Relative role of soil nutrients vs. carbon availability on soil carbon mineralization in grassland receiving long-term N addition

High nitrogen (N) input often induces soil carbon (C) limitation, eutrophication of macronutrients, deficiency of base cations, and accumulation of toxic micronutrients. These changes are perceived to be critical factors in regulating soil C mineralization. Previous studies primarily focused on the individual effects of C, macronutrients, exchangeable base cations, and micronutrients on soil C mineralization. However, the relative importance of those factors in regulating soil C mineralization, especially in N-enriched ecosystems, remains unclear. To disentangle the relative contributions of aforementioned factors, lime and/or glucose were added to soils that were collected from a field experiment with historical N addition (6 years) at seven rates (0–50 g N m−2 year−1) in a grassland ecosystem. Lime and glucose were added to improve the soil C and key nutrient conditions. The responses of soil C mineralization rate to changes in soil C and macronutrients (N and P), exchangeable base cations (K+, Na+ and Mg2+), and micronutrients (Fe2+, Mn2+, Cu2+ and Zn2+) were examined. We found that lime addition decreased soil micronutrients, while glucose addition improved the soil available P and exchangeable base cations, especially at high historical N addition rates. The soil C mineralization was weakly associated with changes in soil nutrients, including the availability of N, P, exchangeable base cations, and micronutrients, which were conventionally and previously considered as the vital drivers of soil C mineralization. However, soil C mineralization strongly increased with glucose-induced enhancement of C availability and the subsequent enhancement of microbial biomass under increasing N addition rates. Based on the Structural Equation Model, the standardized total effects of C, macronutrients (N and P), base cations and micronutrients on soil C mineralization were 0.86, − 0.29, 0.15 and − 0.08, respectively. Findings from this study demonstrated that the N-induced significant changes in soil nutrients (e.g., eutrophication of N and P, base cations deficiency and accumulation of toxic macronutrients) mediated soil C mineralization, with C availability being the most critical driver for C mineralization in N-enriched soil. This study provides insight into the mechanistic understanding of the relationship between N input and terrestrial C cycling.

The effect of substances isolated from an aqueous extract of oak bark on the concentration of chemical elements in the body of broiler chickens

Relevance. A comprehensive study of the properties of plants containing phytobiotic components will make it possible to widely use plant extracts in animal feeding as biologically active additives of the latest generation based on raw materials of natural origin. The aim of the work is to study the effect of substances isolated from an aqueous extract of oak bark (BBVECD) on mineral metabolism in the body of broiler chickens.Methodology. The object of the study are broiler chickens of the Smena-8 cross. 120 heads of broiler chickens were selected for the experiment, which were divided into 4 groups by the method of analogues (n = 30). The control group received the basic ration (RR), I experimental — RR + BBVECD (1 ml/kg of live weight.), II experimental — RR + BBVECD (2 ml/kg of live weight.), III experimental — RR + BBVECD (3 ml/kg of live weight). The analysis of chemical elements in the obtained ash of the studied samples was carried out using the «Elan 9000» mass spectrometer and the «Optima 2000 V» atomic emission spectrometer.Results. The results obtained in the context of the effect of BBECD on mineral metabolism in broiler chickens should be discussed in the context of already available data that a number of compounds found in plant extracts may have the ability to chelate transition metal ions, especially Fe (II) and Cu (II), which is important. During the experiment, it was shown that the introduction of oak bark extract into the diet of broiler chickens mainly led to the accumulation of macronutrients (potassium — from 0.8 to 6.24%, magnesium — from 1.02 to 7.14%, phosphorus — from 5.31 to 7.9%) and essential trace elements in muscles (cobalt — 1.5 times, chromium — 3.67 times, lithium — 1.67 times, nickel — 4 times, silicon — 1.34 times), as well as to reduce the content of toxic and conditionally toxic elements in them: aluminum — 1.62 times, lead — 2 times. In this case, the most appropriate is the use of oak bark extract in a dose of 1 ml/kg of live weight of poultry.

Cover plants can contribute on macronutrient accumulation in agroforestry systems during off-season

Cover plants can contribute on macronutrient accumulation in agroforestry systems during off-season

Dry matter accumulation and macronutrient uptake in sugarcane varieties

The increase of the area cultivated with sugarcane has demanded information about the culture, mainly in relation to its nutritional needs. There are few studies that report the nutrient uptake in sugarcane, in addition, there are no reports of studies focused on the different periods of sugarcane growth and development. In view of the above, the objective of this research was to determine the macronutrient uptake and dry matter production in the shoots of two sugarcane varieties. The experiment was carried out in Vicentina, Mato Grosso do Sul, Brazil, during the 2017/2018 harvest, using two varieties of sugarcane (RB92579 and SP832847). The experimental design was in randomized blocks with two sugarcane varieties, nine collecting times (90, 120, 150, 180, 210, 240, 270, 300 and 330 days after planting (DAP) and 4 replications. Samples were collected from the shoots of 10 plants, which were divided into leaves, sheaths and stalks, then dried and weighed, and finally the samples were submitted to laboratory analysis to determine the nutrient concentrations in each organ. The accumulation of macronutrients in the shoots of both varieties followed the order: K > N > Ca > S>Mg > P. The export by the stalk followed the order K > N > Ca > S > P > Mg for RB92579 and K > N > Ca = P > S > Mg for SP832847. Maximum accumulation of nutrients and the maximum dry matter production occurred in the interval between 240 and 300 DAP. The variety SP832847 accumulated higher amounts of nutrients and dry matter in relation to RB92579, as well as the time required for the maximum accumulation was shorter.

Short-term cultivation limiting soil aggregate stability and macronutrient accumulation associated with glomalin-related soil protein in Eucalyptus urophylla × Eucalyptus grandis plantations

The relationship between glomalin-related soil protein (GRSP) and soil aggregation has been a hot topic of research for its close link to soil stability and quality. However, the short-term cultivation of Eucalyptus poses serious threats to soil stability and nutrient stocks, and the effects of GRSP on soil aggregate stability and macronutrient accumulation remain unclear. The aim is to clarify the potential mechanisms affecting soil aggregate stability and macronutrient accumulation in short-term Eucalyptus plantations. Five Eucalyptus urophylla × Eucalyptus grandis plantations with different cultivation periods (1–5 years) in this study were investigated, and a native evergreen broadleaf forest (0 year) was selected as control. The mean weight diameter index increased in the first 3 years and then significantly decreased during 5 years cultivation of Eucalyptus. Soil organic carbon (SOC) and total nitrogen also decreased after planting Eucalyptus for 3 years, but variation in total phosphorus was not obvious. The relative abundance of Glomeraceae and Claroideoglomeraceae decreased in the 5-year-old Eucalyptus plantations and was positively correlated with GRSP content. In pathway modeling, nutrient-acquisition enzyme activities positively affected GRSP and macronutrient content. Total GRSP (T-GRSP) had higher total effects than easily extractable GRSP on soil aggregate stability, and positively correlated with SOC in macroaggregates. Both T-GRSP and SOC had positive and direct effects on soil aggregate stability. Variance partitioning analysis further explained the contribution of GRSP and SOC to aggregate stability, particularly in >2 and 2–0.25 mm macroaggregates. Our results suggested that GRSP was directly associated with SOC content and soil aggregate stability, and was a potential key factor affecting soil aggregate stability in Eucalyptus plantations. Improving T-GRSP and SOC are efficient approaches for preventing the gradual deterioration of soil aggregate stability. Short-term cultivation should be carefully used in Eucalyptus plantations, and a new cultivation period is needed.

Foliar Selenate and Zinc Oxide Separately Applied to Two Pea Varieties: Effects on Growth Parameters and Accumulation of Minerals and Macronutrients in Seeds under Field Conditions

Though selenium (Se) and zinc (Zn) constitute essential nutrients for human health, their deficiencies affect up to 15% and 17% of the global population, respectively. Agronomic biofortification of staple crops with Se/Zn may alleviate these challenges. Pea (Pisum sativum L.) is a nutritious legume crop that has great potential for Se/Zn biofortification. Herein, two varieties of pea (Ambassador, Premium) were biofortified via foliar application of sodium selenate (0/50/100 g of Se/ha) or zinc oxide (0/375/750 g of Zn/ha) during the flowering stage under field conditions. While no significant differences were found in Se accumulation between seed varieties upon Se treatments, selenate enhanced the accumulation of Se in the two seed varieties in a dose dependent manner. Selenium concentration was most elevated in seeds of Ambassador exposed to 100 g of Se/ha (3.93 mg/kg DW compared to the control (0.08 mg/kg DW), p < 0.001). 375 g of Zn/ha (35.7 mg/kg DW) and 750 g of Zn/ha (35.5 mg/kg DW) significantly and similarly enhanced Zn concentrations compared to the control (31.3 mg/kg DW) in Premium seeds, p < 0.001. Zinc oxide also improved accumulations of Fe, Cu, Mn, and Mg in Premium seeds. Se/Zn treatments did not significantly affect growth parameters and accumulations of soluble solids and protein in seeds. Positive and significant (p < 0.01) correlations were observed between Zn and Fe, Cu, Mn and Mg levels in Premium seeds, among others. Consuming 33 g/day of pea biofortified with Se at 50 g/ha and 266 g/day of pea biofortified with 375 g of Zn/ha could provide 100% of the RDA (55 μg) for Se and RDA (9.5 mg) for Zn in adults, respectively. These results are relevant for enhancing Se/Zn status in peas by foliar biofortification.

Are anthropogenic soils from dumpsites suitable for arable fields? Evaluation of soil fertility and transfer of potentially toxic elements to plants

Background and purposeThe fertility of anthropogenic soils developed from dumpsites used for arable fields is not well-studied. The study aimed to evaluate the fertility of anthropogenic soils from an abandoned dumpsite in Awotan, Nigeria, by measurable indicators and the bioaccessibility of elements of selected plant species.MethodsThe study adopted multi-analytical approaches to determine the signatures of the soils and further parameterized the bioaccessibility of elements to plants.ResultsThe comparatively high content of Ca and Na in the anthropogenic soil contributed to the slightly alkaline soil reaction against the slightly acidic control. The high amount of organic matter is well-indicated by the enrichment of organic C and N in the anthropogenic soil. Waste deposition significantly contributed to the high accumulation of macronutrients (P, Ca, K, S) and micronutrients (Mn, Na, Fe) sufficient for maximum plant growth and yields, with an adequate C/N ratio supporting effective mineralization. The high cation exchange capacity of the anthropogenic soil contributed to cations binding. Indiscriminate waste deposition resulted in a high accumulation of potentially toxic elements (PTEs; Cu, Zn, As, Cd, Pb) above permissible limits in agricultural soils following WHO limits. Potential effects on lives are evident in the high PTEs accumulation in roots and leaves of Chromolaenaodorata, Saccopetalumtectonum, Passiflorafoetida, and Sennasiamea. These plant species exhibited various PTEs accumulation, especially for Cd and Pb.ConclusionAlthough anthropogenic soils remained fertile, the bioaccessibility of PTEs by plants indicates potential threats to consumers of crops and herbs produced from such sites.

Proportions of sewage sludge in the production and quality of Malpighia emarginata DC. seedlings.

Sewage sludge (SS) has nutritional contents and has been implemented in the cultivation of seedlings. This study aimed to evaluate the quality of Malpighia emarginata DC. seedlings produced in different substrates with SS. Treatments were implemented with the addition of SS, and after 180 days seedling the characteristics were measured: aerial part and root system length, stem base diameter, number of leaves, fresh and dry mass of aerial part and root, and total biomass. The Dickson Quality Index (DQI) was calculated and the macro and micronutrient content of the aerial part and root. The accumulation of macronutrients in the root system followed the order of N>K>P>Ca>Mg>S, and aerial part of N>Ca>K>P>Mg>S, in the two vegetative structures N and S were in lower concentration. For micronutrients, the accumulation in the root system occurred with Fe>Zn>Mn>Cu>B, and aerial part with Fe>Mn>Zn>B>Cu. It was noted that in the two vegetative structures the Fe content was more concentrated. The use of SS in the substrate formulation proved effective in obtaining viable seedlings for field planting, being recommended the treatment with 60% SS + 40% organic compost.

Quantifying biomass and whole crop macro-nutrient accumulation for six hard spring wheat genotypes grown under different nitrogen rates at ambient and elevated carbon-dioxide levels

Atmospheric carbon dioxide concentrations ([CO2]) are increasing, but little is known about how this will affect macronutrient (nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)) accumulation and partitioning in the aboveground biomass (AGB) for different hard spring wheat genotypes. We examined the responses of six spring wheat genotypes (‘Discovery’, ‘Duchess’, ‘Reliance’, PFR-3026, PFR-3019, PFR-2021) to two CO2 levels (ambient [aCO2] and elevated [eCO2]) and six nitrogen rates (N; 1–10 mM), at the stem elongation growth stage of wheat grown in controlled environment chambers. The AGB yield increased by 35.2% with increasing [CO2] when N rate was >2 mM. Increasing N supply also increased AGB by up to 3.2-fold over the entire N range applied. The AGB responses to N differed among the genotypes, being lowest for PFR-3019 (7.71 ± 0.11 g/pot) and highest for PFR-2021, PFR-3026 and Duchess at 8.84 ± 0.11 g/pot at both CO2 levels. Macronutrient concentrations decreased with eCO2 by 28.0% for Ca to 17.4% for P and K. Nevertheless, absolute nutrient uptake was higher for eCO2 treatments, because the AGB increase (20.0–52.0%) was proportionally higher than the 4.0–28.0% increase in nutrient uptake. The AGB non-response to [CO2] at N rates <2mM indicates that this nutrient deficiency was more limiting than the effects of CO2 level. Therefore, the impact of eCO2 in the future will depend on N fertilizer management. These results suggest that critical nutrient concentrations used to diagnose the nutrient status of wheat crops will need to be reassessed for eCO2 conditions.

Growth and macronutrient content of Habanero pepper (Capsicum chinense Jacq.) subjected to organic fertilization

Studies on the nutritional status of habanero pepper (Capsicum chinense Jacq.) in relation to organic fertilization are still incomplete and preliminary. The aim of study were to evaluer the effect of rates of organic fertilizer produced from Family agriculture waste on growth and nutritional status habanero pepper. The experiment was carried out in a greenhouse located at the Federal Rural University of Amazonia, municipality of Belém, State for Pará, Brazil. A completely randomized design (CRD) was used, with five treatments and four replications. Each experimental plot consisted of a pot with a volume of 3.6 dm3 of soil, in which the seeds were sown. Five doses of organic fertilizer were tested : 0%, 15% (525 g), 30% (1050 g), 45% (1575 g) and 60% (2100 g) of substrate volume, composed of a mixture of chicken manure (10%), duck manure (20%), cassava peel (15%) , cassava leaf (15%), bean straw (15%), rice husk (15%) and corn cob (10%), mixed in volumetric proportions in the substrate. To mix the different amounts of organic fertilizer, a Yellow Latosol with a sandy texture was used, removed from the surface layer (0-20 cm). The best results were achieved at 103 days using a dose of 60% of organic fertilizer. The content and accumulation of macronutrients in leaf tissues showed the following order: N˃K≥S˃Ca≥Mg˃P and N˃K˃S˃Mg˃Ca˃P. In the fruits, the content and accumulation of macronutrients presented the following order: N˃K˃S˃P˃Mg˃Ca.

Improving biochar properties by co-pyrolysis of pig manure with bio-invasive weed for use as the soil amendment

Over recent years, pyrolysis has grown into a mature technology with added value for producing soil improvers. Further innovations of this technology lie in developing tailor-made products from specific feedstocks (or mixtures thereof) in combination with adjusted mixing ratio-temperature regimes. In this context, co-pyrolysis of pig manure (PM) and the invasive plant Japanese knotweed (JK) at different mixture ratios (w/w) of 3:1 (P3J1), 1:1 (P1J1), and 1:3 (P1J3) and varying temperatures (400–700 °C) was studied to address the low carbon properties and heavy metals (HMs) risks of manure-derive biochars and beneficially ameliorate the bio-invasion situation by creating value from the plant biomass. Co-pyrolysis of PM with JK increased by nearly 1.5 folds the fixed carbon contents in the combined feedstock biochars obtained at 600 °C compared with PM-derived biochar alone, and all combined feedstock biochars met the requirements for soil improvement and carbon sequestration. The total HMs in PM biochars were significantly reduced by adding JK. The combined feedstock biochar P1J1 generated at 600 °C was the most effective in transforming Cu and Zn into more stable forms, accordingly reducing the associated environmental risk of heavy metal leaching from the biochar. In addition, the accumulation of macronutrients can be an added benefit of the co-pyrolysis process, and P1J1-600 was also the biochar that retained the most nutrients (P, Ca, Mg, and K).

Trichoderma longibrachiatum as a biostimulant of micropropagated banana seedlings under acclimatization

The use of growth-promoting microorganisms with biostimulant characteristics is an important biological asset for the acclimatization of micropropagated seedlings. The present study aimed to evaluate the efficacy of the application of Trichoderma spp. on the promotion of the growth of micropropagated banana seedlings during acclimatization. The experiment was performed in an 8 × 6 completely randomized design using the following treatments: water, seedlings fertilized with controlled-release fertilizer, commercial biological inputs (A: T. asperellum, B/C: T. harzianum), and LPPC299 and LPPC300 strains. Plant height, pseudostem diameter, number of leaves, total leaf area, root length, fresh and dry mass of the plant, and accumulation of sodium, macronutrients, and micronutrients were evaluated 60 days after inoculation. Strains LPPC299 and LPPC300 were subjected to molecular identification by DNA sequencing of the ITS/5.8S locus. In vitro detection of growth promotion-related mechanisms and mycelial growth of biostimulants were performed using scanning electron microscopy. LPPC299 and LPPC300 had a greater similarity to T. longibrachiatum. LPPC299 was able to promote greater pseudostem diameter, number of leaves, and total leaf area in banana seedlings. T. asperellum (A) favored seedling performance in terms of fresh and dry mass of the plants. The strains were able to produce siderophores, indoleacetic acid, and catalase in vitro. Seedlings inoculated with the strains accumulated Mn, S (LPPC300), and Mg (LPPC299). LPPC299 from the banana rhizosphere was efficient in promoting performance in banana seedlings, showing its potential as a biostimulant for this crop.

Macro and micronutrient accumulation in watermelon

The expansion of crop productivity such as watermelon can be reached by providing adequate nutrition in quantity and when plants need it most. It is known that well-nourished plants better resist biotic and abiotic stresses, being determinants for more sustainable management. In this sense, the objective of the present study was to evaluate the plant growth, the rate of nutrient absorption, the proportion of absorption, and estimate the quantity of exported nutrients by watermelon fruits. The experiment was implemented in randomized block design with eight treatments (phenological phases) - 33 and 40 (growth), 47 and 54 (flowering), 61 and 68 (filling), 75 and 82 (maturation) days after planting (DAP). Each evaluation consisted of plant collection for dry mass, macro, and micronutrient analysis in the shoot (leaves and stems), fruits, and the entire plant. The period between 61 and 68 DAP was the one with the highest plant dry matter increment. The accumulation of macronutrients in the plant shoot showed the following decreasing order: Ca&gt;N&gt;K&gt;Mg&gt;P&gt;S, in the fruits: K&gt;N&gt;P&gt;Ca&gt;Mg&gt;S and in the whole plant: K&gt;N&gt;Ca&gt;P&gt;Mg&gt;S. For micronutrients, the decreasing order of accumulation for the shoot and the entire plant were Fe&gt;Mn&gt;Zn&gt;B&gt;Cu, and for fruits were Fe&gt;B&gt;Zn&gt;Mn&gt;Cu.

Separate Effects of Foliar Applied Selenate and Zinc Oxide on the Accumulation of Macrominerals, Macronutrients and Bioactive Compounds in Two Pea (Pisum sativum L.) Seed Varieties.

Selenium (Se) and zinc (Zn) are important cofactors for antioxidant enzymes. Foliar Se/Zn application is a highly efficient strategy of plant biofortification. However, its effects on the accumulation of macrominerals, macronutrients and bioactive compounds in the pea plant (Pisum sativum L.) have been poorly investigated. A two-year pot experiment was performed to study responses of two pea varieties (Ambassador, Premium) to foliar-applied sodium selenate (0/50/100 g Se/ha) and zinc oxide (0/375/750 g Zn/ha) at the flowering stage. Concentrations of Ca, Mg, K, Na, soluble solids (SSC), protein, chlorophyll a and b, total chlorophyll, total carotenoids and total condensed tannins (TCT) were determined in seeds. Mg concentration in Ambassador and chlorophyll a concentration in Premium were positively affected, in part, by selenate and zinc oxide, respectively. Selenate and zinc oxide increased, in part, protein concentration in Premium. Highest protein concentration was found in Premium treated with 375 g Zn/ha (27.6% DW) vs. the control (26.6% DW). Significant (all p < 0.001) positive correlations were found, among others, between concentrations of Zn and Mg (r2 = 0.735) and between Zn and protein (r2 = 0.437) for Ambassador, and between Mg and protein (r2 = 0.682), between Zn and Mg (r2 = 0.807), as well as between Zn and protein (r2 = 0.884) for Premium. TCT significantly (all p < 0.05) and positively correlated with SSC (r2 = 0.131), chlorophyll b (r2 = 0.128) and total chlorophyll (r2 = 0.109) for Ambassador. This study provides new nutritional data on Se/Zn biofortified peas, important for improving agronomic biofortification of pea plants.

Growth and nutrient accumulation metrics of Diodia saponariifolia plants as a potential native cover crop in southeastern Brazil

Competition for resources between crops and weeds hinders the increase of production in agroecosystems. The trait-based plant species selection of cover crops can be a useful tool to suppress competing plants in addition to providing environmental services. Here, we assessed the growth and macronutrient accumulation metrics in Diodia saponariifolia (Rubiaceae) plants, a native cover crop found in family farming systems in southeastern Brazil. Under greenhouse conditions, three viable D. saponariifolia cuttings were planted per tray. The experimental design was entirely randomized, with treatments consisting of plant sampling times, at regular intervals of 7 days between 16 and 93 days after transplanting (DAT) and 15 days between 93 and 138 DAT. Based on dry mass and chemical analysis of leaves, stems, and roots; we fitted the logistic model to explore the metrics of growth and macronutrient accumulation. Overall, the increment in plant dry mass was slow about halfway through the experimental period, being subsequently replaced by a phase of rapid growth. The stem was the plant fraction with the highest relative biomass accumulation. The total macronutrient concentration followed the descending order of K > N > Ca > Mg > P, varying along the plant ontogeny. Considering the nutrient content, the estimated 200 g m−2 of aboveground dry mass, and 0.3 m2 of leaf area, it is suggested to perform the first mechanical weeding along the third month of growth. Our results suggest that D. saponariifolia has satisfactory agronomical features for its establishment as a cover crop in different agricultural contexts.

Intercrops of grass with legumes as green manure for agroecological systems

The stud article aimed to assess the accumulation and rates of nutrients in the biomass of the consortium of millet and leguminous plants for green fertilisation. The treatments were consortia of millet with four different leguminous plants: Cajanus cajan, Canavalia ensiformis, Mucuna aterrima, and Dolichos lablab. The treatments were distributed in a completely randomised design with four replications. The species of each consortium were planted in a line, at a distance of one metre apart. The aerial part of the plants was harvested after 90 days to determine the botanical composition, intercropping biomass, and the amount and accumulation of macronutrients in the biomass. The Millet mass did not differ among the consortia. However, among the legumes, M. aterrima has the highest mass (2806.31 kg/ha DM), which is reflected in the lower ratio of leguminous grasses in the millet consortium with M. aterrima (4.61). The consortia affected the rate and accumulation of P, B, and Fe. The biomass of the millet consortium with C. cajan presented the lowest rate. In addition, the accumulation of K, Mg, and Zn was low in this consortium. The biomass of millet intercrops with M. aterrima, D. lablab and C. ensiformis showed higher accumulations of K, Ca, and Mg. The highest accumulation of N was observed in the biomass of the consortium with M. aterrima (50.71 kg/ha). The rates and accumulations of Cu and Zn were higher in the consortium with M. aterrima. The consortium of millet with the leguminous plants is a sustainable alternative for fertilisation. The consortia with M. aterrima and D. lablab are the most promising ones, due to the higher proportion of plants.