Distribution Of Plant Nutrients Research Articles

Hyperspectral Estimation of Nitrogen Content in Different Leaf Positions of Wheat Using Machine Learning Models

Remote sensing estimation of crop nitrogen content allows real-time monitoring of growth to develop scientific methods. However, most of the current remote sensing estimates of crop nitrogen contents have limitations in accurately reflecting the vertical distribution of nutrients in plants. Firstly, the original hyperspectrum is first-order differential (FD), second-order differential (SD), and continuous removal (CR), and the corresponding sensitive bands were screened by correlation analysis in this paper. Then, the spectral reflectance, vegetation indices, and wavelet coefficients were used as input features to construct models for estimating nitrogen content of flag leaf, upper 1 leaf, upper 2 leaf, upper 3 leaf, and upper 4 leaf based on partial least squares regression (PLSR), support vector machine (SVM), random forest (RF), and multiple linear regression (MLR), respectively. The results showed that the accuracy of nitrogen content prediction based on wavelet coefficients was the highest. The combination of MLR and SVM with wavelet coefficients had high accuracy and robustness in the prediction of nitrogen content at different leaf positions. Additionally, the prediction accuracy of nitrogen gradually increased as the leaf position of winter wheat increased. The study can provide technical support for remote sensing estimation of nutrient elements at vertical leaf position of crops. The study can provide a reference for prediction of other crops.

Manganese Uptake to Wheat Shoot Meristems Is Differentially Influenced by Arbuscular Mycorrhiza Fungal Communities Adapted to Acidic Soil

Soil acidity is a strong promoter of the bioavailability of Al, Fe, and Mn, whose concentrations can sometimes reach toxic levels for plants. In agricultural soils, the use of arbuscular mycorrhizal fungi (AMF) has shown a protective influence on wheat growth under Mn toxicity. The intact extraradical mycelium (ERM) promotes faster AMF colonization, leading to a higher wheat shoot weight, lower Mn uptake, and changes in antioxidant enzyme activity. Its effect on the uptake and distribution of plant nutrients according to the developmental stage of shoot organs has seldomly been analyzed. In the present study, Mn, Mg, Ca, and K were quantified by ICP–MS in leaves and apical meristems of wheat grown in soil with two different ERM consortia, developed from the native plants Lolium rigidum (LOL) and Ornithopus compressus (ORN). The ORN treatment induced the highest wheat shoot weights and the lowest Mn levels. In the leaves, no significant differences were detected for Mg, Ca, or K, but in the apical meristems, the ORN treatment slightly lowered the Ca concentration. The AMF associated with ORN was seen to enhance wheat weight partly by protecting the zones of active growth against high Mn levels in Mn toxic soils. The use of ORN in acidic soils with Mn toxicity provides a sustainable alternative and an efficient complement to current farming practices to lower the negative impacts of farming on the environment.

Green Synthesis of Phosphorous-Containing Hydroxyapatite Nanoparticles (nHAP) as a Novel Nano-Fertilizer: Preliminary Assessment on Pomegranate (Punica granatum L.).

Nano-fertilizers are innovative materials created by nanotechnology methodologies that may potentially replace traditional fertilizers due to their rapid absorption and controlled distribution of nutrients in plants. In the current study, phosphorous-containing hydroxyapatite nanoparticles (nHAP) were synthesized as a novel phosphorus nano-fertilizer using an environmentally friendly green synthesis approach using pomegranate peel (PPE) and coffee ground (CE) extracts. nHAPs were physicochemically characterized and biologically evaluated utilizing the analysis of biochemical parameters such as photosynthetic activity, carbohydrate levels, metabolites, and biocompatibility changes in Punica granatum L. Cytocompatibility with mammalian cells was also investigated based on MTT assay on a Vero cell line. Dynamic light scattering (DLS) and zeta potential analysis were used to characterize the nHAPs for size and surface charge as well as morphology using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nHAPs were found to have different shapes with average sizes of 229.6 nm, 120.6 nm (nHAPs_PPE) and 167.5 nm, 153 nm (nHAPs_CE) using DLS and TEM, respectively. Overall, the present results showed that the synthesized nHAPs had a negative impact on the selected biochemical, cytotoxic, and genotoxic parameters, indicating that the evaluation of nHAP synthesized by this approach has a wide range of applications, especially as a nano-fertilizer.

Nutrient Constraints in Arsenic Phytoremediation

Arsenic contamination has increased due to several environmental and anthropogenic activities. It is considered a carcinogen by the International Agency for Research on Cancer. It affects human health and causes various ailments and nervous system disorders. An environmental concern arises as arsenic enters the food chain through consumption of crops grown in arsenic affected areas. It has been observed that uptake of arsenic in plant parts is affected by the concentration of nutrients. Addition of nutrients either enhances the uptake of arsenic or the uptake of arsenic is reduced. Arsenic influences the nutrient uptake and distribution of nutrients in plants by either competing directly with nutrients and/or altering metabolic processes. The role played by nutrients has a direct bearing on the arsenic remediation of the crops and hence, it will be of significance to crop growers in reducing the arsenic content in crops. This review reports about the mobility, bioavailability and plant response to the presence of nutrients and their effect on arsenic phytoremediation. In this review, major emphasis has been made to contemplate the effects of nutrients like phosphorus, nitrogen, ferrous, calcium, potassium, sulphur and selenium in arsenic phytoremediation.

The Effect of Foliar-Applied Manganese in Mineral and Complex Forms with Amino Acids on Certain Defense Mechanisms of Cucumber (Cucumis sativus L.) Against Powdery Mildew

Manganese (Mn) is an essential micronutrient with positive effects on enhancing plant tolerance against fungal diseases. On the other hand, it has been suggested that metal–amino acid complexes are more effective than mineral sources in supplying Mn and improving the translocation and distribution of these metal nutrients in plants. Meanwhile, certain amino acids, that is, lysine and methionine, play an important role in crop resistance to biotic stresses. Little information is, however, available regarding the effect of foliar-applied Mn in mineral and complex forms with amino acids on crop tolerance to powdery mildew caused by Podosphaera fuliginea. In this nutrient solution experiment, the effect of foliar-applied Mn, in the form of MnSO4, Mn-methionine (Mn-Met) and Mn-lysine (Mn-Lys), on certain defense mechanisms of cucumber (Cucumis sativus L. cv. Espadana RZ) against powdery mildew was investigated. Different Mn sources were applied as foliar spray 4 days before and 6 days after inoculation with P. fuliginea. The results revealed that Mn application prior to pathogen inoculation decreased the disease in the treated and newly growing leaves; however, the efficiency of Mn–amino acid complexes in disease suppression was greater than that of MnSO4. Post-inoculation spray of Mn had no effect on the disease reduction of the newly growing leaves, but all Mn sources diminished disease severity equally in the treated leaves. In such leaves, regardless of the application time, the higher content of cell wall lignin was found in the plants treated with MnSO4, in comparison with those treated with Mn–amino acid complexes. In the newly growing leaves, the foliar application of Mn–amino acid complexes before inoculation resulted in a significant increase of leaf cell wall lignin content, whereas MnSO4 was ineffective. Pre-inoculation spray of MnSO4 led to increasing PO and PPO activities in the treated leaves, whereas Mn–amino acid complexes had no significant effect on the activity of these enzymes in the same leaves. Application of Mn-Met and Mn-Lys after pathogen inoculation led to a significant decrease of PPO activity in the treated leaves. In general, the results of the present study revealed that the time of Mn foliar application could have a considerable effect on controlling cucumber powdery mildew. Foliar application of Mn before infection with P. fuliginea could strengthen the defensive structures of the plant and help to prevent the disease incidence.

Dry-Matter Allocation and Nutrient Uptake Dynamic in Pepper Plant Irrigated with Recycled Water by Different Nitrogen and Potassium Rate

As a consequence of increasing water demand, lack of natural water resources, and use of high amounts of fertilizers in the greenhouse crops in arid and semi-arid areas, the use of reclaimed municipal wastewaters is a valuable option, although the knowledge of plant nutritional requirements becomes more important to avoid imbalances caused by the nutrients present in reclaimed wastewater and to attain efficient nutrient use. An experiment was conducted with greenhouse-grown sweet pepper (Capsicum annuum L. var. Aifos) on a sand-mulched sandy loam soil and fertigation with recycled municipal wastewater and inorganic fertilizer treatments. Five treatments were applied: control with no nitrogen (N) or potassium (K) supplied (N0K0) and four different doses of N and K as the mean elements with possible imbalances: N1K1, N1K1.5, N1.5K1, and N1.5K1.5. N1K1was the recommended rate under local conditions (125 kg N ha−1 and 193 kg K ha−1). Eight plants per treatment were collected at five growth stages (0, 56, 84, 113, and 155 days after the seedling transplant, DAT). Dry matter (DM) and N, phosphorus (P), K, calcium (Ca), and magnesium (Mg) concentrations in fruit, leaf, stem, and pruning wastes were measured for each sampling date. For all treatments, the period of largest extraction of nutrient by plant occurred from 113 to 155 DAT, which coincides with the greatest accumulation of dry matter. Plant nutrient distribution showed that fruit is the largest sink of N, K, and P. The NK levels showed no effect on DM and nutrient uptake in the periods of vegetative growth, fruiting, and fruit growth. Nutrient uptakes by the plant were not affected by NK level applied. The NK rates could be lowered significantly without reducing DM and nutrient total uptake by plant during vegetative growth, flowering, and early fruit development periods, when using reclaimed municipal wastewater. The fertigation with greater rates of N and K for the harvest period can be considered as an adequate and sustainable procedure to grow greenhouse pepper.

Influence of Salinity and Fertilization Level on the Nutrient Distribution in Tomato Plants under a Polyethylene Greenhouse in the Mediterranean Area

The experiment was conducted in a polyethylene greenhouse with the ‘Pitenza’ variety of tomato crop on a sand‐mulched sandy loam soil using trickle irrigation. The experimental design was two‐factorial with four randomized blocks. The treatments applied were the result of a combination of two irrigation water qualities (C2S1 and C3S2) and three fertilization levels: F1, half of the recommended rate; F2, the recommended rate [i.e., 7.1 mmol L−1 of nitrate (NO3 −)–nitrogen (N), 0.5 mmol L−1 of phosphoric acid (H2PO4 −)–phosphorus (P) and 3.1 mmol L−1 of potassium (K+)], and F3, double the recommended rate. Total content of nutrients [N, P, K, calcium (Ca), magnesium (Mg)] and sodium (Na) were determined for different plant parts (pinch rest, harvested fruit, developing fruit, leaf, and stem) for the whole season. Also, the relative sink strengths between fruit and vegetative plant parts were calculated. The main mineral constituent of the tomato plant was K, surpassing the N content, and the minor constituent was P. With the same level of fertilization, the influence of salinity was significant at F1 (half of the recommended rate) and F2 (the recommended rate) but not at the highest level. Plant nutrient distribution showed the same behavior for N, P, and K, the fruit being the nutrient sink. On the other hand, the same tendency was observed for Ca and Mg, stored mainly in the leaf. Nevertheless, Na presented low levels in young tissues, whereas the levels were higher and similar in fruit, leaf, and stem.

ACCUMULATION AND DISTRIBUTION OF NITRATE–NITROGEN AND EXTRACTABLE PHOSPHORUS IN THE SOIL PROFILE UNDER VARIOUS ALTERNATIVE CROPPING SYSTEMS

ABSTRACT Cropping systems can influence the accumulation and distribution of plant nutrients in the soil profile, which can affect their utilization efficiency by crops and pollution potential in the environment. A field experiment was conducted on a Dark Brown loam soil at Scott, Saskatchewan, Canada to assess the effects of input level, cropping diversity and crop phase on the accumulation and distribution of nitrate–nitrogen (N) and extractable phosphorus (P) in the soil profile at the end of 1995 to 2000 growing seasons. The 54 treatments were combinations of three input levels (organic—ORG, reduced—RED and high—HIGH), three cropping diversities (low diversity—LOW, diversified annual grains—DAG, and diversified annual and perennials—DAP), and six crop phases chosen from fallow (tillage-fallow or chem-fallow), green manure [lentil—Lens culinaris Medicus or sweet clover—Melilotus officinalis (L.) Lam], spring wheat (Triticum aestivum L.), canola (Brassica napus L. and Brassica rapa L.), fall rye (Secale cereale L.), field pea (Pisum sativum L.), spring barley (Hordeum vulgare L.), flax (Linum usitatissimum L.), oats (Avena sativa L.), and bromegrass (Bromus inermis Leyss), alfalfa (Medicago sativa Leyss) mixture hay. Soil was sampled from the 0–15, 15–30, 30–60, and 60–90 cm depths in each crop phase from 1995 to 2000, with additional depths 90–120, 120–150, 150–180, 180–210, and 210–240 cm taken from the wheat phase in 2000. In general, there were greater amounts of nitrate–N with HIGH input compared to ORG or RED inputs, especially under LOW diversity. The nitrate–N in various soil depths suggested some downward movement of nitrate–N to the deeper soil depths when HIGH input was compared to ORG input. In LOW cropping diversity, green manure or fallow usually had more nitrate–N in soil than other crop phases. In DAG and DAP cropping diversities, nitrate–N varied with crops and on average it had maximum concentration after wheat or canola in DAG and after hay followed closely by wheat in DAP. The ORG input level had greater nitrate–N than RED or HIGH inputs in some instances, most likely due to relatively low extractable P in soil for optimum crop growth under ORG input. Extractable P in the 0–15 and 15–30 cm soil depths tended to be greater under HIGH or RED inputs compared to the ORG input level in many cases. In summary, there was no consistent effect of cropping diversity on extractable P in soil under ORG input, but LOW diversity tended to show more extractable P compared to DAG and DAP diversities in some cases of RED and HIGH inputs. The green manure/fallow, HIGH input and LOW diversity treatments tended to result in higher nitrate–N and extractable P levels compared to the corresponding treatments, and the effects were more pronounced on nitrate–N than extractable P and in shallow compared to deeper soil layers.

Mineralization and distribution of nutrients in plants and microbes in four arctic ecosystems: responses to warming

Mineralization and nutrient distribution in plants and microbes were studied in four arctic ecosystems at Abisko, Northern Sweden and Toolik Lake, Alaska, which have been subjected to long-term warming with plastic greenhouses. Net mineralization and microbial immobilization were studied by the buried bag method and ecosystem pool sizes of C, N and P were determined by harvest methods. The highest amounts of organic N and P were bound in the soil organic matter. Microbial N and P constituted the largest labile pools often equal to (N) or exceeding (P) the amounts stored in the vegetation. Despite large pools of N and P in the soil, net mineralization of N and P was generally low during the growing season, except in the wet sedge tundra, and in most cases lower than the plant uptake requirement. In contrast, the microorganisms immobilized high amounts of nutrients in the buried bags during incubation. The same high immobilization was not observed in the surrounding soil, where the microbial nutrient content in most cases remained constant or decreased over the growing season. This suggests that the low mineralization measured in many arctic ecosystems over the growing season is due to increased immobilization by soil microbes when competition from plant roots is prevented. Furthermore, it suggests that plants compete well with microbes for nutrients in these four ecosystems. Warming increased net mineralization in several cases, which led to increased assimilation of nutrients by plants but not by the microbes.

New insights into organic-mineral particles: composition, properties and models of molecular structure

Organic-mineral soil particles are formed and altered as a result of pedogenic processes and anthropogenic impacts on soils. They can be isolated from bulk soil samples by physical disaggregation followed by particle size and/or density fractionation. This review summarizes methodological advances and the characteristic features of the chemical composition of organic matter in these different fractions. It is demonstrated how soil texture and soil genesis determine the contents of organic C (Corg) in size-separates and their distribution in typical profiles of four important major soil groups. Data from numerous field studies were compiled to show that the proportions of Corg bound in clay fractions increased under soil uses which reduce the soil organic matter (SOM) content. Coarser and lighter particles are relatively enriched in native or manured soils. Contents of humic substances, lignin oxidation products, carbohydrates, lipids, and forms of organic N determined by wet-chemical methods indicate that the chemical composition results from specific functions of the organic-mineral particles in the turnover of SOM. This is also reflected by 13C-nuclear magnetic resonance and analytical pyrolysis, the applications of which to the study of organic-mineral particles are summarized and compared for the first time. The summarized chemical characteristics of organic-mineral particles have direct effects on other properties such as soil aggregation and the resulting physical behaviour of soil. Moreover, the adsorption and distribution of plant nutrients, as well as the binding capacity for a wide range of pollutants, clearly show that the organic matter is a key factor for the physicochemical reactions at organic-mineral surfaces. Along with evidence for the different mineralizability of Corg and organic N, and enzymatic properties, the accumulated knowledge of their composition, structure and properties provides a basis from which to develop molecular models of organic-mineral particles. Molecular modelling and visualization of humic colloids, SOM and its complexes (organic-mineral particles) with biological substances, metals and xenobiotics are discussed. These model complexes offer a basis for the conceptual development of SOM macromolecules, mineral soil particles and the computer-assisted design of organic-mineral particles. Molecular-mechanics calculations and geometrical optimization are employed to obtain energy minimized, stable conformations which allow the determination of atomic distances, bonds, angles, torsions, stretches, etc., at nanochemical level. As a result, exact descriptions of three-dimensional structures can be proposed. The total (potential) energy of the organic matter complexes and macromolecules can be determined simultaneously, and energy derivatives for bond-, angle-, dihedral-, van der Waals′, stretch-bend, and electrostatic energies calculated. Moreover, quantitative structure-activity relationship software is employed to calculate relevant molecular properties such as surface, volume, atomic charges, polarizability, refractivity, etc. It is this combination of atomic/molecular structural data and energy derivatives that opens up new insights into binding sites and transport forms between biological and/or xenobiotic substances and SOM. The resulting potential, and limits, for modelling of organic (humic) macromolecules, organic-mineral particles and mineral surfaces are delineated.

The effect of prior history of superphosphate application and stocking rate on faecal and nutrient distribution on grazed natural pastures.

Soil samples and sheep faeces were collected from sites which were systematically distributed within paddocks in a long-term grazing trial on temperate rangeland on the Northern Tablelands of New South Wales. The soil samples were analysed by standard techniques for a range of plant nutrients. Most of the plant nutrients examined accumulated strongly in the sheep camp areas. The rate of superphosphate application affected the distribution of plant nutrients and stocking rate affected faecal distribution. It was concluded that both these factors could affect both production and composition of grazed natural pastures.

The Effect of Fire on Nutrients in a Chaparral Ecosystem

The distribution of nutrients in plants, litter, and soil were studied before and after a prescribed burn in southern California chaparral. Total N, P, K, Na, Mg, and Ca were measured. The various nutrients were distributed differently in the plant parts and the litter before fire and this affected their redistribution by fire. Measurable losses of only 2 nutrients occurred–N (146 kg/ha) and K (49 kg/ha). Erosional losses of nutrients during the first rainy season after fire are also reported.

Distribution of plant nutrients in the Kaituna River

Abstract The distribution of phosphorus and inorganic nitrogen in the Kaituna River and some of its inputs was examined during 1975. Under low flow conditions about 60 kg.d"1 of phosphorus enters the top of the river from Lake Rotoiti. The discharge to the sea, some 50 km downstream, approximates 300 kg.d−1, about 77 kg.d−1 of this total coming from the Auckland Farmers’ Freezing Company works at Rangiuru. By the year 2000 an additional 107 kg.d−1 of phosphorus may be added to the top of the river in treated sewage effluent from Rotorua city. Inorganic nitrogen concentrations increase along the length of the river; about 40 kg.d−1 enter the top at Okere Falls and under low flow conditions about 950 kg.d−1 discharge to the sea. By the year 2000 the river may be carrying an additional 1000 kg.d−1 of nitrogen derived from Rotorua's treated sewage. The effect of the additional nutrient load on the trophic status of the river is likely to be slight, because water passes from Okere to the sea in about a day.