A greenhouse study comparing the physiological responses and uptake of coffee (Coffea arabica L.) plants to foliar applications of zinc sulfate (ZnSO4) and zinc nano-fertilizer (ZnO NPs) was ...conducted with the aim to understand their effects on plant physiology. One-year old coffee plants were grown in greenhouse conditions and treated with two foliar applications of 10 mg/L of Zn as either zinc sulfate monohydrate (ZnSO4 ‧ H2O) or zinc oxide nanoparticle (ZnO NPs 20% w/t) and compared to untreated control plants over the course of 45 days. ZnO NPs positively affected the fresh weight and dry weight (FW and DW) of roots and leaves, increasing the FW by 37% (root) and 95% (leaves) when compared to control. The DW increase was 28%, 85%, and 20% in roots, stems, and leaves, respectively. The net photosynthetic rate increased 55% in response to ZnO NPs treatment at the end of experiment when compared to control. ZnO NPs-treated leaves contained significantly higher amounts of Zn (1267.1 ± 367.2 mg/kg DW) when compared to ZnSO4-treated plants (344.1 ± 106.2 mg/kg DW), while control plants had the lowest Zn content in the leaf tissue (53.6 ± 18.9 mg/kg DW). X-ray micro-analyses maps demonstrated the increased penetrance of ZnO NPs in coffee leaf tissue. Overall, ZnO NPs had a more positive impact on coffee growth and physiology than conventional Zn salts, which was most likely due to their increased ability to be absorbed by the leaf. These results indicate that the application of ZnO NPs could be considered for coffee systems to improve fruit set and quality, especially in areas where Zn deficiency is high.
•ZnO NPs easily penetrate the leaf surface, compared to traditional ZnSO4.•ZnO NPs have a positive role on plant growth and physiology compared to ZnSO4.•ZnO NPs may have a significant impact on coffee fruit set and quality.
Cadmium (Cd) brings a devastating health hazard to human being as a serious consequence of agricultural and environmental contamination. We demonstrated the protective effect of silicon (Si) on ...cadmium (Cd)-stressed rapeseed (
L. cv. BINA Sharisha 3) plants through regulation of antioxidant defense and glyoxalase systems. Twelve-day-old seedlings were exposed to Cd stress (0.5 and 1.0 mM CdCl
) separately and in combination with Si (SiO
, 1.0 mM) for 2 days. Cadmium toxicity was evident by an obvious oxidative stress through sharp increases in H
O
content and lipid peroxidation (malondialdehyde, MDA content), and visible sign of superoxide and H
O
. Cadmium stress also decreased the content of ascorbate (AsA) and glutathione (GSH) as well as their redox pool. The activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and catalase (CAT) were decreased by Cd while ascorbate peroxidase (APX) and glutathione
-transferase (GST) activities were increased. The enzymes of glyoxalase system (glyoxalase I, Gly I and glyoxalase II, Gly II) were also inefficient under Cd stress. However, exogenous application of Si in Cd treated seedlings reduced H
O
and MDA contents and improved antioxidant defense mechanism through increasing the AsA and GSH pools and activities of AsA-GSH cycle (APX, MDHAR, DHAR and GR) and glyoxalase system (Gly I and Gly II) enzymes and CAT. Thus Si reduced oxidative damage in plants to make more tolerant under Cd stress through augmentation of different antioxidant components and methylglyoxal detoxification system.
Soil acidification in managed ecosystems such as agricultural lands principally results from the increased releasing of protons (H+) from the transformation reactions of carbon (C), nitrogen (N) and ...sulphur (S) containing compounds. The incorporation of liming materials can neutralize the protons released, hence reducing soil acidity and its adverse impacts to the soil environment, food security, and human health. Biochar derived from organic residues is becoming a source of carbon input to soil and provides multifunctional values. Biochar can be alkaline in nature, with the level of alkalinity dependent upon the feedstock and processing conditions. This review covers the fundamental aspects of soil acidification and of the use of biochar to address constraints related to acidic soil. Biochar is increasingly considered as an effective soil amendment for reducing soil acidity owing to its liming potential, thereby enhancing soil fertility and productivity in acid soils. The ameliorant effect on acid soils is mainly because of the dissolution of carbonates, (hydro)-oxides of the ash fraction of biochar and potential use by microorganisms.
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•In managed ecosystem, soil acidification results mainly from the carbon and nutrient cycling.•Acidification is a major soil constraint impacting soil health and heavy metal toxicity.•The level of alkalinity in biochar depends on the feedstock and processing conditions.•Biochar liming value is derived from carbonates, and hydro-oxides of the ash fraction.•Biochar ameliorates acid soils by suppling base cations and reducing aluminium toxicity.
Many biochars contain considerable amounts of plant nutrient elements in both water soluble and insoluble compounds but little is known of the rate of release of these elements to soil. This ...laboratory research incubated nine biochars produced from tropical plant wastes in ten tropical soils for eight weeks and measured changes in the amounts of K, Ca and P remaining in the biochars. Some K (8–64%) was soluble in water and 0–75% of this rapidly diffused into the soil together with 0–40% of the K present in poorly soluble compounds. Calcium in biochar was mostly insoluble and was conserved within grains. Considerable soil Ca was adsorbed by biochar due to exchange of Ca from soil induced by the large amount of K released to the soil from biochar. Some (0–75%) of the P in the biochars dissolved in soil including some of the water insoluble P. These various behaviors of plant nutrient elements can be explained on the basis of the diverse crystalline compounds present in biochars and their location within the micro-porous fabric of biochar. Clearly the behavior in soil of these plant nutrient elements in biochar is dissimilar to their behavior in common chemical fertilizers so that appropriate agronomic management strategies must be developed for biochar fertilizers. Soil properties cannot be used to predict the movement of elements from and into biochar grains.
•Some biochars made from tropical plant wastes contains large amounts of K, Ca and P.•K, Ca and P are present in crystalline compounds in biochar.•Much of the K in most biochars moves from biochar grains into the soil.•Much of the Ca and P in some biochars remain within biochar grains in the soil.•Biochar absorbs Ca from soil solution.
In the past few decades, the control of pests and diseases of cultivated plants using natural and biological measures has drawn increasing attention in the quest to reduce the level of dependence on ...chemical products for agricultural production. The use of living organisms, predators, parasitoids, and microorganisms, such as viruses, bacteria, and fungi, has proven to be a viable and sustainable pest management technique. Among the aforementioned, fungi, most importantly the insect-pathogenic species, have been in use for more than 150years. These include the most popular strains belonging to the genera
,
,
,
, and
. Their application is usually through an inundative approach, which inherently involves exposure of the fungal spores to unfavorable humidity, temperature, and solar radiation conditions. These abiotic factors reduce the persistence and efficacy of these insect-pathogenic fungi. Despite these limitations, over 170 strains have been formulated as mycopesticides and are available for commercial use. In the last few decades, numerous studies have suggested that these species of entomopathogenic fungi (EPF) offer far more benefits and have broader ecological functions than hitherto presumed. For instance, aside from their roles as insect killers, it has been well established that they also colonize various host plants and, hence, provide other benefits including plant pathogen antagonism and plant growth promotion and serve as sources of novel bioactive compounds and secondary metabolites, etc. In this light, the potential of EPF as alternatives or perhaps as supplements to chemical pesticides in plant protection is discussed in this review. The paper highlights the numerous benefits associated with endophytic fungal entomopathogen and host plant associations, the mechanisms involved in mediating plant defense against pests and pathogens, and the general limitations to the use of EPF in plant protection. A deeper understanding of these plant host-fungus-insect relationships could help unveil the hidden potentials of fungal endophytes, which would consequently increase the level of acceptance and adoption by users as an integral part of pest management programs and as a suitable alternative to chemical inputs toward sustainable crop production.
The aim of this study is to develop and test the applicability of a rapid in situ plant chemistry profiling technique to determine elemental composition of small-volume plant and soil samples ...obtained from a woody bioenergy crop species, Populus trichocarpa. Expanding the research tools available to characterize the nutrient element correlations among plant tissue types and soil depths is a critical need in the path of understanding productivity and adaptation of plants to variations in external abiotic and biotic factors and developing sustainable perennial bioenergy crops that are co-optimized for biomass valorization aboveground and carbon sequestration belowground. Several plant root, stem, and soil samples were tested using laser-induced breakdown spectroscopy (LIBS) to evaluate the presence and distribution of nutrient elements. Samples were tested as collected and after being dried and cross sectioned to evaluate the effectiveness of using LIBS for in situ analysis on plant samples. The collected LIBS spectra show the elemental peaks were the same in both the as collected and prepared samples for roots and stems. Qualitative amounts of elements such as H, C, N, O, Li, Na, Mg, K, Ca, Fe, Al, and Si were able to be identified rapidly in raw samples. Here in this report we demonstrate suitability of LIBS in obtaining rapid, in situ, elemental distribution in plant and soil samples, utilizing only small sample volumes and minimal sample preparation. This demonstration opens up a new rapid phenotyping avenue necessary to fill the asymmetrical knowledge gaps in belowground performance of plant systems.
Soil health is essential and irreplaceable for plant growth and global food production, which has been threatened by climate change and soil degradation. Degraded coastal soils are urgently required ...to reclaim using new sustainable technologies. Interest in applying biochar to improve soil health and promote crop yield has rapidly increased because of its multiple benefits. However, effects of biochar addition on the saline–sodic coastal soil health and halophyte growth were poorly understood. Response of two halophytes, Sesbania (Sesbania cannabina) and Seashore mallow (Kosteletzkya virginica), to the individual or co‐application of biochar and inorganic fertilizer into a coastal soil was investigated using a 52 d pot experiment. The biochar alone or co‐application stimulated the plant growth (germination, root development, and biomass), primarily attributed to the enhanced nutrient availability from the biochar‐improved soil health. Additionally, the promoted microbial activities and bacterial community shift towards the beneficial taxa (e.g. Pseudomonas and Bacillus) in the rhizosphere also contributed to the enhanced plant growth and biomass. Our findings showed the promising significance because biochar added at an optimal level (≤5%) could be a feasible option to reclaim the degraded coastal soil, enhance plant growth and production, and increase soil health and food security.
Biochar alone or co‐applied with fertilizer enhanced the growth (e.g. germination, root development, and biomass) of two local halophyte plants, primarily attributed to the enhanced nutrients availability (i.e. NAE and PAE), the elevated microbial activities in rhizhosphere and bacterial community shift towards the bacterial taxa responsible for C‐stabilizing in soil, phosphate solubilizing and N‐fixing. The co‐application of biochar and fertilizer (≤5%) had greater benefits for the halophyte growth than the biochar or fertilizer alone. The biochar‐enhanced plant growth and biomass in coastal wetlands could potentially buffer the negative effect of climate change, thus enhance soil health and food security. This is the first report on examining the rhizosphere microbial response (i.e. the shifts in bacterial community composition) to the biochar‐enhanced nutrient bioavailability for halophyte growth.
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•C and N contents in biochar increased by 32 and 69% compared to biomass.•Highest N (5.78%) and K (2.12%) contents were in chicken manure biochar.•Maximum P (5.06%) content was in ...biosolid biochar.•SSA of animal manure/biosolid biochars ranged from 96 to 111 m2 g–1.
Excessive amounts of animal manures and production of a large volume of biosolids pose serious environmental issues in terms of their safe disposal and management. Thermochemical treatment of bio-waste materials via pyrolysis can convert them into value-added products such as biochar-based fertilizers. In this study, fourteen biochars were produced from one biosolid and thirteen animal manures by slow pyrolysis at 300 °C. All feedstock and biochar samples were characterized by determining the yield, and physicochemical and surface properties, including the C-containing functional groups. Principal component and cluster analyses were used to classify the feedstock/biochar materials based on their mineral constituents. The biochar yield of various feedstocks ranged from 39 to 81%, with the highest yield for grain-fed cow manure. The highest N and K content was found in chicken manure biochar (57.8 and 29.2 g kg–1, respectively), while the highest P was found in biosolid biochar (40.5 g kg–1). The specific surface area of biochars ranged from 96.06–110.83 m2 g−1. Hierarchical analyses of the chemical compositions of feedstocks and biochars enabled grouping of the materials respectively into four and five distinguished clusters. Three principal components (PC) explained 86.8% and 83.3% of the variances in the feedstocks and biochars, respectively. The PC1 represented the content of the major nutrients (N, P and K), whereas PC2 and PC3 represented other nutrients (secondary and micronutrients) contents and physicochemical properties (pH and EC). The results of this study suggested that biochars produced from different manures and biosolids may potentially be a source of soil nutrients and trace elements. In addition, different biochars may be applied to different nutrient-deficient soils to avoid plausible nutrient and potentially toxic element contamination.
All crops are usually affected by phytosanitary and nutritional problems. It is known that fertilizers can elevate productivity and control of diseases, characteristics that make nutrients ...indispensable in combating hunger, and can help to reduce the use of fungicides and their negative impact on the environment. There are more than 15 elements considered essential for plants, including calcium, manganese, copper, and zinc, which will be detailed in this study in order to understand how they can affect the control of plant diseases.
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