Micronutrients (Fe,Mn, Zn and Cu) balance under long-term application of fertilizer and manure in a tropical rice-rice system

Purpose

The balance of micronutrients in soils is important in nutrient use efficiency, environmental protection and the sustainability of agro-ecological systems. The deficiency or excess of micronutrients in the plough layer may decrease crop yield and/or quality. Therefore, it is essential to maintain appropriate levels of micronutrients in soil, not only for satisfying plant needs in order to sustain agricultural production but also for preventing any potential build-up of certain nutrients.

Materials and methods

A long-term fertilizer experiment started in 1969 at Central Rice Research Institute, Cuttack, Odisha, India. Using this experiment, a study was conducted to analyze the balance of micronutrients and their interrelationship. The experiment was composed of ten nutrient management treatments viz. control; nitrogen (N); N + phosphorus (NP); N + potassium (NK); nitrogen, phosphorus and potassium (NPK); farmyard manure (FYM); N + FYM; NP + FYM; NK + FYM; and NPK + FYM with three replications. Micronutrients in soil (total and available), added fertilizers and organic manures and in rice plant were analyzed. Besides, atmospheric deposition of the micronutrients to the experimental site was also calculated. A micronutrient balance sheet was prepared by the difference between output and input of total micronutrients.

Results and discussion

Application of FYM alone or in combination with chemical fertilizer increased the diethylenetriamine pentaacetate (DTPA)-extractable Fe, Mn and Zn over the control treatment. The treatment with NPK + FYM had the highest soil DTPA-extractable Fe, Mn, Zn and Cu after 41 years of cropping and fertilization. Application of chemical fertilizers without P decreased the DTPA-extractable Zn over the control while the inclusion of P in the fertilizer treatments maintained it on a par with the control. The application of P fertilizer and FYM either alone or in combination significantly increased the contents of total Fe, Mn, Zn and Cu in soil mainly due to their micronutrient content and atmospheric depositions. A negative balance of Zn was observed in the N, NP, NK and NPK treatments, while a positive balance observed in the remaining treatments. The balance of Mn was negative in all the treatments, due to higher uptake by the rice crop than its addition.

Conclusions

Long-term application of chemical fertilizers together with FYM maintained the availability of micronutrients in soil and, thus, their uptake by rice crop.

     

Effects of Pseudomonas aeruginosa on the diversity of culturable microfungi and nematodes associated with tomato: impact on root-knot disease and plant growth

The available information on Pseudomonas biocontrol inoculants on the non-target fungal and nematode community is scant. The current paper addresses this issue and investigates the effects of biocontrol agents Pseudomonas aeruginosa IE-6 and IE-6S⁺ (previously shown to suppress several soil-borne plant pathogens) on soil microfungi and plant-parasitic nematodes as well as on the root-knot development and growth of tomato (Lycopersicon esculentum). Furadan, a granular nematicide was included as a treatment for comparative purposes. Treatments were applied to soil at the start of each 52-day-long tomato growth cycle, and their effects on the composition and diversity of rhizosphere and endophytic microfungi and plant-parasitic nematodes were examined at the end of first and fourth growth cycle. Several diversity indices were employed to assess community diversity. A total of 16 genera comprising 23 microfungal species were isolated from the tomato rhizosphere. The most abundant fungal species belonged to the genera Aspergillus, Fusarium, and Penicillium. With a few exceptions, fungi were neither exclusively inhibited nor specifically promoted by the application of treatments at any of the growth cycles studied. However, Paecilomyces lilacinus, an egg and female parasite of root-knot nematode, though exclusively absent in the controls was isolated from the treatments. Both general diversity and equitability of rhizosphere microfungi were greater at first compared to the fourth growth cycle while species richness remained uninfluenced across the growth cycles and treatments. However, Furadan and IE-6S⁺ treatments considerably abated general diversity and equitability. Of the microfungal species isolated from the rhizosphere seven were also recovered from surface-sterilized root tissue of tomato suggesting that all the endophytes are primarily rhizosphere organisms. Diversity of endophytic fungi was consistently lower compared with that of the rhizosphere. Both general diversity and equitability declined in all three treatments relative to controls in the root tissue but species richness remained unaltered. Diversity and equitability of plant-parasitic nematodes in soil were reduced by all three treatments over the controls at fourth growth cycle whilst species richness did not change at either growth cycle. The biocontrol agents significantly reduced root-knot development and enhanced shoot growth of tomato over the controls. The possible implications of fungal composition and abundance because of biocontrol by Pseudomonas application are discussed.     

Impact of calcium chloride concentrations and storage duration on quality attributes of peach (<Emphasis Type="Italic">Prunus persica</Emphasis>)

To investigate the impact of CaCl₂ concentrations and storage duration on quality of peach (Prunus persica), a research was conducted at postharvest Laboratory, Department of Horticulture, The University of Agriculture, Peshawar, Pakistan during 2012–2013. The experiment was laid out in Completely Randomized Design (CRD) with factorial arrangement repeated three times. The peach fruits (cv. Texas A 69) were harvested at physiological maturity stage from peach orchard, Horticulture Farm. The fruits were dipped in 0, 2 and 4% CaCl₂ solution for 10 min and transferred to cold storage having ±8–10°C with relative humidity of 80–85%. The application of CaCl₂ solution and storage duration significantly influenced the fruit quality of peach fruit. However, the application of CaCl₂ solution significantly reduced weight loss (4.98%), disease incidence (2.08%), total sugars (5.31%), TSS-Acid ratio (16.27), TSS(7.38⁰Brix) and increased the fruit firmness (2.21 kg cm^–2) titratable acidity (0.47%) and Ascorbic acid (5.35 mg/100 g) of peach fruits. The storage duration of peach fruit also significantly affected the fruit quality attributes during storage. The peach fruit stored for 30 days showed less fruit firmness (0.74 kg cm^–2) and titratable acidity (0.31%), Ascorbic acid (4.45 mg/100 g) and increased weight loss (19.74%), disease incidence (16.11%), total sugars (6.07%), TSSAcid ratio (27.62) and TSS(8.54⁰Brix) of peach fruit. Based on the findings of this study, it is concluded that the peach fruit should be treated with 4% CaCl₂ solution to retain the quality attributes for 30 days storage.     

Ultra-fast separation of wheat glutenin subunits by reversed-phase HPLC using a superficially porous silica-based column

A relatively new, unique column packing material for reversed-phase high-performance liquid chromatography (RP-HPLC) was evaluated for rapid separation of wheat glutenin protein subunits. The product named “Poroshell” by the manufacturer consists of a solid core and a porous coat instead of solid silica spheres used in conventional RP-HPLC column packing. This architecture favours rapid mass transfer, facilitating faster reversed-phase separations of biomolecules compared to conventional silica columns. The main objective of this study was to evaluate the quality of separations of glutenin subunits (GS), as well as to optimize conditions to produce the fastest possible run times without sacrificing resolution using a Poroshell 300SB-C₈ 2.1×75 mm column. The stability of GS separations over time was also assessed. Two different bread wheat genotypes were used for optimization of separation conditions and six more common and durum wheat genotypes possessing different subunit combinations were used for further evaluation. Glutenin protein was extracted with 0.08 M Tris–HCl buffer (pH 7.5) containing 50% 1-propanol under reducing conditions after pre-extraction of soluble proteins with 50% 1-propanol. Optimization of GS resolution and sample throughput by RP-HPLC was assessed in response to variation in eluent flow rate, acetonitrile (ACN) gradient, and column temperature. The best resolution of both HMW- and LMW-GS was obtained in 13 min using a 23–44% ACN gradient with a flow rate of 0.7 mL/min at 65 °C. Subunit elution times and integrated areas were highly repeatable even after several hundred injections. Highly satisfactory separation of HMW-GS and quantification of ratio of HMW- to LMW-GS were achieved in less than 4 min per sample using a modified HPLC gradient. Ratio of HMW- to LMW-GS was unaffected by the speed of the separations. As well, the elution order of HMW- and LMW-GS was unaffected by the rapid analysis, compared to conventional RP-HPLC separations, so no new learning was required for interpreting chromatograms and classification of subunits. The rapid RP-HPLC method using the Poroshell column appears to be very well suited for routine quantification of HMW-GS and LMW-GS especially for purposes of wheat quality screening and wheat cultivar development activities where large numbers of samples are typically encountered.     

Nitrate Reduction and Nutrient Accumulation in Wheat Grown in Soil Salinized with Four Different Salts

ABSTRACT

The effect of salinization of soil with Na₂SO₄, CaCl₂, MgCl₂, and NaCl (70:35:10:23) on the biochemical characteristics of three wheat (Triticum aestivum L.) cultivars (‘LU-26S,’ ‘Sarsabaz’ and ‘Pasban-90’) was investigated under natural environmental conditions. Twenty-day-old seedlings of all three cultivars were subjected to three salinity treatments: 1.3 (control), 5.0, and 10 dSm^?1 for the entire life period of plants. After 120 d of seed sowing, plant biomass production decreased by 49% and 65%, respectively, in response to 5 and 10 dSm^?1 salinity levels. Addition of salts to growth medium also had a significant adverse effect on plant height. Increasing salinity treatments caused a great reduction in nitrate reductase activity (NRA) of the leaf. The inhibitory effect of salinity on nitrate reduction rate was more pronounced at the reproductive stage than at the vegetative stage of plant growth. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ showed less reduction in NRA due to salinity compared with ‘Pasban-90.’ Ascending salinity levels significantly reduced potassium (K⁺) and calcium (Ca²⁺) accumulation in shoots, while the concentration of sodium (Na⁺) was increased. Salts of growth medium increased the shoot nitrogen (N) concentration, whereas phosphorous (P) concentration of shoots was significantly reduced due to salinity. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ proved to be the salt-tolerant ones, producing greater biomass, showing less reduction in NRA, maintaining low sodium (Na⁺), and accumulating more K⁺ and Ca²⁺ in response to salinity. These two cultivars also showed less reduction in shoot K⁺/Na⁺ and Ca⁺/Na⁺ ratios than in ‘Pasban-90,’ particularly at the 10 dSm^?1 salinity level.     

Morpho-physiological Responses of Tomato Genotypes Under Saline Conditions

Gesunde Pflanzen - Salinity is a&nbsp;complex abiotic stress that affects physiology and biochemistry of plants and significantly reduces both crop yield and quality. Considering the global...     

Effect of fulvic acids on lead-induced oxidative stress to metal sensitive Vicia faba L. plant

Lead (Pb) is a ubiquitous environmental pollutant capable to induce various morphological, physiological, and biochemical functions in plants. Only few publications focus on the influence of Pb speciation both on its phytoavailability and phytotoxicity. Therefore, Pb toxicity (in terms of lipid peroxidation, hydrogen peroxide induction, and photosynthetic pigments contents) was studied in Vicia faba plants in relation with Pb uptake and speciation. V. faba seedlings were exposed to Pb supplied as Pb(NO₃)₂ or complexed by two fulvic acids (FAs), i.e. Suwannee River fulvic acid (SRFA) and Elliott Soil fulvic acid (ESFA), for 1, 12, and 24?h under controlled hydroponic conditions. For both FAs, Pb uptake and translocation by Vicia faba increased at low level (5?mg?l^?1), whereas decreased at high level of application (25?mg?l^?1). Despite the increased Pb uptake with FAs at low concentrations, there was no influence on the Pb toxicity to the plants. However, at high concentrations, FAs reduced Pb toxicity by reducing its uptake. These results highlighted the role of the dilution factor for FAs reactivity in relation with structure; SRFA was more effective than ESFA in reducing Pb uptake and alleviating Pb toxicity to V. faba due to comparatively strong binding affinity for the heavy metal.     

High-density growth and crude protein productivity of a thermotolerant Chlorella vulgaris: production kinetics and thermodynamics

Current study investigated the fermentative production of cell mass and crude protein using an axenic culture of the thermotolerant strain of Chlorella vulgaris grown mixotrophically in an illuminated 10-l glass bioreactor. The process was then upscaled to 1,000-l bioreactor. The organism supported maximum specific growth rate, crude protein volumetric productivity, and specific productivity of 1.2?day^?1, 2.26?g?l^?1?day^?1, and 0.76?g?g^?1?day^?1, respectively, with urea as nitrogen source. Gibbs free energy, enthalpy, and entropy values for its formation were 74.3, 56. 2?kJ?mol^?1, and ?59.1?J?mol^?1?K^?1, respectively, in both reactors and corresponded to those of thermotolerant organisms. Algal biomass grown in 10-l bioreactor contained 0.52?±?0.03, 12.6?±?2.0, 60.0?±?4.5, 0.4?±?0.02, 4.5?±?0.2, 12?±?0.5, and 3.81?±?0.5% carotenoids, carbohydrates, crude protein, DNA, RNA, lipids, and total chlorophyll, respectively. Dry biomass supported good growth of fish larvae comparable with that on commercial diet.     

Relationship between rhizosphere acidification and phytoremediation in two acacia species

Purpose

Phytoremediation is the most sustainable and economical strategy for reclamation of the salt-affected soils. In order to investigate the relationship between phytoremediation and rhizosphere acidification, two experiments (greenhouse and field) were conducted using two acacia species viz. Acacia ampliceps and Acacia nilotica.

Materials and methods

In greenhouse experiment, both the species were exposed to 100 and 200 mM NaCl concentrations in solution culture. The release of organic acids from plant roots was determined after 14 and 28 days of the salt treatment. Shoot and root ash alkalinity was determined after harvesting the plants. In field experiment, both the species were grown on a saline sodic soil for 2 years. After every 6 months, plant growth data were recorded and soil samples were collected from different soil depths for physicochemical analyses.

Results and discussion

The results of greenhouse study indicated higher rhizosphere acidification by A. ampliceps than A. nilotica in terms of release of citric acid, malic acid, and tartaric acid along with ash alkalinity. The comparison of both the species in the field indicated higher amelioration in the soil properties like pH_s, EC_e, SAR, bulk density, and infiltration rate by A. ampliceps than A. nilotica.

Conclusions

It is concluded from these studies that A. ampliceps is more suitable species than A. nilotica for the phytoremediation of the salt-affected soils due to its higher rhizosphere acidification potential.