Nitrate Fertilizer Research Articles

Ammonium-Based Compound Fertilisers Mitigate Nitrous Oxide Emissions in Temperate Grassland

Nitrogen fertiliser application represents the largest anthropogenic source of nitrous oxide (N2O) emissions, and the magnitude of these emissions is dependent on the type of fertilisers applied in the agroecosystems. Despite N-P-K compound fertilisers being commonly used in agricultural soils, a lack of information exists regarding their effects on N2O emissions. This study aims at examining the effects of different commonly used N-P-K compound fertiliser formulations with contrasting nitrate to ammonium ratios (0.05 to 0.88) on N2O emissions, yield, and nitrogen use efficiency (NUE) in temperate grassland and to compare these variables with common straight N fertilisers. Compound fertilisers with varying NPK inclusion rates (18-6-12, 10-10-20, 24-2.2-4.5, and 27-2.5-5), and calcium ammonium nitrate (CAN) and urea + N-(n-butyl) thiophosphoric triamide (NBPT) were applied at 80 kg N ha−1 to experimental plots in managed grassland on two occasions in a growing season. Fluxes of N2O during the experiment period, yield and NUE following two harvests were measured. The cumulative N2O emission from urea + NBPT, 18-6-12, 10-10-20, and 24-2.2-4.5 treatments were significantly reduced by 44%, 43%, 37%, and 31% compared with CAN treatment under conducive soil moisture condition. Under the same soil condition, 18-6-12 and 10-10-20 treatments showed higher yield, N uptake, and NUE although did not significantly differ from the other fertiliser treatments. Our results suggest that ammonium-based compound fertilisers have a potential to reduce N2O emissions while maintaining yields. Further long-term study is needed to capture the full magnitude of variations in N2O emissions, including ammonia (NH3) volatilization from nitrate and ammonium-based compound fertiliser applications from multiple soil types and under different climatic conditions.

The effects of calcium fertilizer on anthracnose and Rhizopus tuber rot of yam

Yam (Dioscorea spp) production is beset in the field and in storage by major fungal pathogens, namely Colletotrichum gloeosporioides that causes anthracnose in the field, and Rhizopus stolonifer that causes tuber rot in storage. Alternative control measures are imperative as conventional control of these pathogens is either ineffective or detrimental. This study investigated the effects of calcium fertilizer on the incidence and severity of anthracnose and Rhizopus rot of yam. Calcium nitrate fertilizer was applied to soils naturally infected with C. gloeosporioides, at the rates of 0, 3, and 4kg ha-1. D. rotundata variety Efuru was planted. The treatments were arranged in a randomized complete block design with three replicates. Anthracnose disease rating relied on natural endemic infection in the field, while inoculation of harvested yam tubers was carried out using R. stolonifer. There was no significant effect of calcium amendment of the soil on anthracnose severity in D. rotundata or on the agronomic parameters. D. rotundata tubers treated with 3 and 4kg ha-1 calcium soil amendments had reduced infection by R. stolonifer in storage compared to the control treatments. The study concluded that calcium applied to the soil had reduced storage losses by R. stolonifer in D. rotundata but had no influence on anthracnose severity in the field. Therefore, 3kg ha-1 of calcium nitrate applied to the soil can be used to improve D. rotundata tuber resistance to R. stolonifer, and is recommended for high-quality tuber storage.

Giant clam growth in the Gulf of Aqaba is accelerated compared to fossil populations.

The health of reef-building corals has declined due to climate change and pollution. However, less is known about whether giant clams, reef-dwelling bivalves with a photosymbiotic partnership similar to that found in reef-building corals, are also threatened by environmental degradation. To compare giant clam health against a prehistoric baseline, we collected fossil and modern Tridacna shells from the Gulf of Aqaba, Northern Red Sea. After calibrating daily/twice-daily growth lines from the outer shell layer, we determined that modern individuals of all three species (Tridacna maxima, T. squamosa and T. squamosina) grew faster than Holocene and Pleistocene specimens. Modern specimens also show median shell organic δ15N values 4.2‰ lower than fossil specimens, which we propose is most likely due to increased deposition of isotopically light nitrate aerosols in the modern era. Nitrate fertilization accelerates growth in cultured Tridacna, so nitrate aerosol deposition may contribute to faster growth in modern wild populations. Furthermore, colder winter temperatures and past summer monsoons may have depressed fossil giant clam growth. Giant clams can serve as sentinels of reef environmental change, both to determine their individual health and the health of the reefs they inhabit.

The Chloroplast of Chlamydomonas reinhardtii as a Testbed for Engineering Nitrogen Fixation into Plants.

Eukaryotic organisms such as plants are unable to utilise nitrogen gas (N2) directly as a source of this essential element and are dependent either on its biological conversion to ammonium by diazotrophic prokaryotes, or its supply as chemically synthesised nitrate fertiliser. The idea of genetically engineering crops with the capacity to fix N2 by introduction of the bacterial nitrogenase enzyme has long been discussed. However, the expression of an active nitrogenase must overcome several major challenges: the coordinated expression of multiple genes to assemble an enzyme complex containing several different metal cluster co-factors; the supply of sufficient ATP and reductant to the enzyme; the enzyme’s sensitivity to oxygen; and the intracellular accumulation of ammonium. The chloroplast of plant cells represents an attractive location for nitrogenase expression, but engineering the organelle’s genome is not yet feasible in most crop species. However, the unicellular green alga Chlamydomonas reinhardtii represents a simple model for photosynthetic eukaryotes with a genetically tractable chloroplast. In this review, we discuss the main advantages, and limitations, of this microalga as a testbed for producing such a complex multi-subunit enzyme. Furthermore, we suggest that a minimal set of six transgenes are necessary for chloroplast-localised synthesis of an ‘Fe-only’ nitrogenase, and from this set we demonstrate the stable expression and accumulation of the homocitrate synthase, NifV, under aerobic conditions. Arguably, further studies in C. reinhardtii aimed at testing expression and function of the full gene set would provide the groundwork for a concerted future effort to create nitrogen-fixing crops.

Application of calcium nitrate with phosphorus promotes rhizosphere alkalization in acid subsoil

AbstractCombatting subsoil acidity is a challenge as the incorporation of lime in subsurface layers may not be economically feasible. The use of nitrate to facilitate plant excess anion uptake has shown the potential to increase soil pH. A column experiment was carried out to demonstrate this root‐induced alkalization in various depths in an acid soil with pH 4.28 (0.01 M CaCl2). It consisted of two types of nitrogen (N) fertilizers (urea and Ca(NO3)2, both at 5 atom% 15N enrichment) banded at a depth of 0–10 cm, 10–20 cm or 20–30 cm, with phosphorus (P) fertilizer (NaH2PO4) at 150 mg P per column either applied to the N layers (N+P) or evenly mixed into the remaining layers without N addition (N‐P). Aluminium‐tolerant wheat (ET8) was used as test plants, receiving an initial N dose of 60 mg kg−1 soil at sowing and an additional dose of 30 mg kg−1 every 10 days from 40 days after sowing. Plants had a total N supply of 90 mg N kg−1 at 50 days and 180 mg N kg−1 at 80 days after sowing. The N+P treatments increased plant N uptake and increased rhizosphere and bulk soil pH. Nitrate placement increased pH of treated layers by up to 0.4 and 0.2 units in the rhizosphere and bulk soils, respectively, compared with the control at Day 80. Rhizosphere alkalization was greater with deeper N+P treatments as these encouraged the proliferation of deeper roots in the treated layer. The form of N and the application method of P fertilizer had no effect on shoot biomass over 80 days of growth. The N+P treatments had 7% higher 15N recovery of fertilizer in plants than the N‐P treatments. The current study also showed that P fertilizer enhanced rhizosphere alkalization induced by calcium nitrate. The results suggest that the use of nitrate fertilizer with P treatments can facilitate alkalization of acid subsoils.Highlights Phosphorus facilitates amelioration of subsurface soil acidity with nitrate fertilizer Placement of nitrate induces alkalization of acid soil at various depths Combined addition of nitrate and P at depth enhances nitrate uptake by wheat Balanced nutrient supply enhances excess anion uptake and rhizosphere alkalization

Oil-Based Polymer Coatings on CAN Fertilizer in Oilseed Rape (Brassica napus L.) Nutrition.

Fertilizer coating can increase the efficiency of N fertilizers and reduce their negative impact on the environment. This may be achieved by the utilization of biodegradable natural coating materials instead of polyurethane-based polymers. The aim of this study was to detect the effect of calcium ammonium nitrate (CAN) fertilizer coated with modified conventional polyurethane enhanced with vegetable oils on the yield and quality of Brassica napus L. compared to CAN fertilizer with a vegetable oil-based polymer and to assess the risks of nitrogen loss. Three types of treatments were tested for both coated fertilizers: divided application (CAN, coated CAN), a single application of coated CAN, and a single application of CAN with coated CAN (1:2). A single application of coated CAN with both types of coating in the growth stage of the 9th true leaf significantly increased the yield, the thousand seed weight, and oil production compared to the uncoated CAN. The potential of using coated CAN may be seen in a slow nitrogen release ensuring the nitrogen demand for rapeseed plants throughout vegetation and eliminating the risk of its loss. The increased potential of NH4+ volatilization and NO3− leaching were determined using the uncoated CAN fertilizer compared to the coated variants. Oil-based polymer coatings on CAN fertilizer can be considered as an adequate replacement for partially modified conventional polyurethane.

Efficacy of the Nitrification Inhibitor 3,4 Dimethylpyrazol Succinic Acid (DMPSA) when Combined with Calcium Ammonium Nitrate and Ammonium Sulphate—A Soil Incubation Experiment

The efficacy of the new nitrification inhibitor 3,4 dimethylpyrazol succinic acid (DMPSA) was tested with calcium ammonium nitrate (CAN) and ammonium sulphate (AS) fertilisers in an incubation experiment using a sandy loam soil and a sandy textured soil. The experiment was conducted over 80 days. For AS fertiliser, inclusion of DMPSA resulted in significantly less NO3−-N present after 19 days in both soils. In the case of CAN, inclusion of DMPSA resulted in significantly less NO3−-N present after 45 days in the sandy loam soil and after 30 days in the sandy soil. DMPSA is effective nitrification inhibitor when combined with CAN and AS, with a mean reduction of 61% and 58%, respectively, in the average daily nitrification rate over the study period. Over the 80-day incubation period in the sandy loam soil, only 35% NH4+-N was converted to NO3−-N for AS + DMPSA compared to 88% for AS. In the sandy soil, 92% NH4+-N was converted to NO3−-N for AS compared with only 9% for AS + DMPSA by day 80. The results demonstrate that DMPSA is an effective nitrification inhibitor when combined with CAN and AS.

Nitrogen and Sulphur Fertilisation for Marketable Yields of Cabbage (Brassica oleracea L. var. Capitata), Leaf Nitrate and Glucosinolates and Nitrogen Losses Studied in a Field Experiment in Central Slovenia.

A field trial of white cabbage (Brassica oleracea var. Capitata L.) was carried out under the humid temperate climate conditions in Central Slovenia to investigate the effects of calcium ammonium nitrate (0, 180 and 240 kg N ha−1) and gypsum (0 and 40 kg S ha−1) fertilisation on yield, yield quality (nitrate, glucosinolate levels and glucosinolate profile) and nitrogen use efficiency. The highest marketable yield, dry matter yield and nitrogen uptake were obtained at the highest nitrogen fertilisation rate when in combination with sulphur. For this treatment, the nitrogen surplus in the soil after harvesting was lower than for the same nitrogen fertilisation without sulphur application. For the combination N240S40, the sulphur addition significantly increased nitrogen use efficiency, which resulted in reduced nitrate content in the cabbage heads. The chemical forms of glucosinolates showed that 80–85% were aliphatic glucosinolates with the remainder as the indole group. For the aliphatic glucosinolates, significant interactions between nitrogen and sulphur fertilisations were reflected in increased levels of progoitrin and glucoiberin when sulphur was applied at the lower nitrogen fertilisation rates. For the indole group, the levels of glucobrassicin and the indole group itself decreased at higher nitrogen fertilisation rates, independent of sulphur fertilisation.

Health Risk Associated with Nitrate Exposure from Groundwater Intake Among Respondents of Keting Village, Bachok District, Kelantan State, Malaysia

Nitrate is one of the compounds of nitrogen found in the nitrogen cycle that is which originates from both natural and anthropogenic sources. Most rural areas in Kelantan state still depend on well water as their primary water source. Their main economic activity is agriculture which uses high amountsof nitrate fertilizer to nurture their crops. The increased use of nitrate fertilizers has a possible risk factor associated to health problems such as methemoglobinemia and cancers. Health risk assessment can be conducted to quantify the probability of harmful effects of nitrate to individuals or populations from certain human activities. To determine levels of nitrate in groundwater and to perform health risk assessment among respondents in Keting village, Bachok district, Kelantan state. A total of 47 respondents were chosen for this study and groundwater samples in duplicates were collected from the respondents’ houses. The samples werethen analyzed by using a portable Hanna Instrument multimeter model HI98191 and probe model HI4113. while a set of questionnaireswereusedto collect information for health risk assessment of the exposure. Nitrate levels in groundwater did not exceed the maximum concentration value of Drinking Water Quality Standard (44.3 ppm nitrate – NO3) with a mean ± sd of 5.34 ± 4.94 (ppm). Spearman’s rho correlation analysis shows that only depth of well (meter) is correlated (r = - 0.348) to nitrate levels (p0.05). The Hazard Quotient (HQ)for the study population was less than 1. In terms of nitrate, the groundwater analyzed in the study area was considered safe for drinking and cooking purposes. The result for HQ indicated that the non-carcinogenic risk related to nitrate was not significant to the study population. However, nitrate levels in drinking water should be concerned by the consumers as it will give bad health impact to them in long-term exposures.

Nitrate distribution pattern under conventional and trickle irrigation system

Nitrate is a highly mobile ions that moves with water. So that nitrate distribution around the driplines is strongly affected by irrigation and fertigation strategy. Nitrate movement under conventional flood irrigation system was observed 2 to 3.5 times faster as compared with trickle irrigation as well as NO3 "-N concentrations exceeded the threshold limit (i.e. 10 mg l-1) under traditional irrigation method, while stayed below the threshold limit under micro irrigation methods. Nitrate distribution was influenced by hydraulic properties, drip discharge rate, soil layering, timing of nutrient application and irrigation frequency. To maintain larger amounts of nutrient nearby emitter in highly permeable coarse-textured soils, nutrients must be applied at the starting of an irrigation cycle so that it is less susceptible to leaching losses. Study revealed that higher transpiration raised the NO3-N uptake by the plats. The study also revealed that urea moves promptly with irrigation water and urea–ammonium–nitrate fertilizer increased the nitrate concentration, near the drip line immediately after the drip fertigation due to the nitrification, while low concentrations was found near the periphery of the wetting zone.

Health Aspects, Growth Performance, and Meat Quality of Rabbits Receiving Diets Supplemented with Lettuce Fertilized with Whey Protein Hydrolysate Substituting Nitrate.

Lettuce (Lactuca sativa) was grown using a foliar spray with whey protein hydrolysate (WPH) as opposed to normal nitrate fertilization. Lettuce juice was prepared from lettuce cultivated without any fertilization, nitrate fertilization, or WPH. Sixty weaned, 4-week-old male V-line rabbits with an average 455 ± 6 g body weight were randomly divided into 4 groups (n = 15) and administered different lettuce juices. Rabbits administered WPH-fertilized lettuce showed significantly higher (n = 5, p < 0.05) body weight and carcass weight than those receiving nitrate-fertilized lettuce. Rabbits administered nitrate-fertilized lettuce were associated with significantly (p < 0.05) higher levels of liver enzyme activities (AST, ALT, and ALP), bilirubin (total, direct, and indirect), and kidney biomarkers (creatinine, urea, and uric acid). Rabbits administered WPH-fertilized lettuce avoided such increases and exhibited normal levels of serum proteins. Rabbits administered nitrate-fertilized lettuce manifested significantly (p < 0.05) lower RBCs and Hb levels than that of the other groups, while those receiving WPH-fertilized lettuce showed the highest levels. Liver and kidney sections of rabbits receiving WPH-fertilized lettuce witnessed the absence of the histopathological changes induced by feeding on nitrate-fertilized lettuce and produced higher quality meat. WPH-lettuce can substitute nitrate-fertilized lettuce in feeding rabbits for better performance and health aspects.

Oxygen isotope exchange between water and carbon dioxide in soils is controlled by pH, nitrate and microbial biomass through links to carbonic anhydrase activity

Abstract. The oxygen isotope composition of atmospheric carbon dioxide (CO2) is intimately linked to large-scale variations in the cycling of CO2 and water across the Earth's surface. Understanding the role the biosphere plays in modifying the oxygen isotope composition of atmospheric CO2 is particularly important as this isotopic tracer has the potential to constrain estimates of important processes such as gross primary production at large scales. However, constraining the atmospheric mass budget for the oxygen isotope composition of CO2 also requires that we understand better the contribution of soil communities and how they influence the rate of oxygen isotope exchange between soil water and CO2 (kiso) across a wide range of soil types and climatic zones. As the carbonic anhydrases (CAs) group of enzymes enhances the rate of CO2 hydration within the water-filled pore spaces of soils, it is important to develop understanding of how environmental drivers can impact kiso through changes in their activity. Here we estimate kiso and measure associated soil properties in laboratory incubation experiments using 44 soils sampled from sites across western Eurasia and north-eastern Australia. Observed values for kiso always exceeded theoretically derived uncatalysed rates, indicating a significant influence of CAs on the variability of kiso across the soils studied. We identify soil pH as the principal source of variation, with greater kiso under alkaline conditions suggesting that shifts in microbial community composition or intra–extra-cellular dissolved inorganic carbon gradients induce the expression of more or higher activity forms of CAs. We also show for the first time in soils that the presence of nitrate under naturally acidic conditions reduces kiso, potentially reflecting a direct or indirect inhibition of CAs. This effect appears to be supported by a supplementary ammonium nitrate fertilisation experiment conducted on a subset of the soils. Greater microbial biomass also increased kiso under a given set of chemical conditions, highlighting a putative link between CA expression and the abundance of soil microbes. These data provide the most extensive analysis of spatial variations in soil kiso to date and indicate the key soil trait datasets required to predict variations in kiso at large spatial scales, a necessary next step to constrain the important role of soil communities in the atmospheric mass budget of the oxygen isotope composition of CO2.

Experimental approach to assess fertilizer nitrogen use, distribution, and loss in pear fruit trees

Enhanced use efficiency of fertilizer nitrogen (N) is paramount for sustainable pear fruit production. Sufficient fruit N content is a major factor for pear fruit storage potential, but fertilizer N use efficiency in pear fruit trees is generally low. The objective of this work was to test a methodology to quantify N uptake, partitioning and leaching loss as influenced by different calcium nitrate (Ca(NO3)2) fertilizer timings. To this end, 10-year-old ‘Conference’ pear trees (Pyrus communis L.) were transplanted and grown in soil-filled pallet boxes subjected to different timing of fertilizer addition. A fraction of the calcium nitrate was labelled with 15N and applied one month before full bloom, during summer and post-harvest. By sampling newly formed biomass (i.e., leaves, fruit and flower buds), temporal dynamics in the N fraction derived from calcium nitrate fertilization were determined. Simultaneously NO3− leaching derived from calcium nitrate fertilization was quantified. Our data suggest that spring application of N was most efficiently partitioned to leaves, fruits and buds at the time of harvest with a mean percentage of calcium nitrate derived N (Ndff) of 9.2%, 20.4% and 18.6%, respectively. Summer application of calcium nitrate was far less efficient at the time of harvest with Ndff of 0.56%, 0.89% and 1.4%, respectively, and substantially higher NO3− leaching was observed compared to spring fertilization. Post-harvest application showed even higher levels of leaching. Applying a split fertilization scheme with 60 kg N ha−1 evenly spread over spring, summer, and post-harvest, about 9, 15 and 30%, respectively, of the fertilizer N had leached out as NO3− at the end of the growing season. This experimental approach may offer potential for detailed N budget studies for various fruit tree studies.

Growth and Yield Response of Groundnut (Arachis hypogea L.) to Inorganic Fertilisers at Luyengo, Middleveld of Eswatini

Groundnut is an important food and cash crop for smallholder farmers in Eswatini. However, its yield is very low partly due to poor soil fertility particularly calcium and phosphorus deficiencies associated with soil acidity. Thus, a field experiment was conducted to determine the effects of different inorganic fertiliser types on growth and yield of groundnut. The treatments were: a control with no fertiliser, [2:3:2 (22) at 300 kg ha-1], single superphosphate (100 kg ha-1), calcium nitrate (120 kg ha-1) and a combination of calcium nitrate (120 kg ha-1) and single superphosphate (100 kg ha-1). A randomised complete block design (RCBD) with three replications was used. Results showed highly significant (p&lt;0.01) differences among the fertiliser types on most of the growth parameters recorded. At 90% flowering, significantly highest number of leaves per plant (48.3), the tallest plant (42.17 cm), the highest canopy width (41.47 cm), the highest number of branches per plant (6.57) and plant dry biomass per plant (20.6 g) were recorded for treatments with calcium nitrate followed by the application of combination of calcium nitrate and single superphosphate. Similarly, most of the yield components and yield were significantly (p&lt;0.05) affected by the fertiliser types. Significantly highest numbers of total pods per plant (28.8), mature pods per plant (26.9), dry pod yield (950.6 kg ha-1), hundred seed mass (82.8 g), shelling percentage (70.6) and seed yield (671.6 kg ha-1) were recorded from a combination of calcium nitrate and single superphosphate fertiliser. Thus, combined application of 120 kg ha-1 calcium nitrate and 100 kg ha-1 single superphosphate fertilisers can be used to increase the productivity of groundnut in the study area.

K fertilizer alleviates N2O emissions by regulating the abundance of nitrifying and denitrifying microbial communities in the soil-plant system

Potassium (K) fertilizer additions can result in high crop yields of good quality and low nitrogen (N) loss; however, the interaction between K and N fertilizer and its effect on N2O emissions and associated microbes remain unclear. We investigated this in a pot experiment with six fertilizer treatments involving K and two sources of N, using agricultural soil from the suburbs of Wuhan, central China. The aim was to determine the effects of the interaction between K and different forms of N on the N2O flux and the abundance of nitrifying and denitrifying microbial communities, using static chamber-gas chromatography and high-throughput sequencing methods. Compared with no fertilizer control (CK), the addition of nitrate fertilizer (NN) or ammonia fertilizer (AN) or K fertilizer significantly increased N2O emissions. However, the combined application (NNK) of K and NN significantly reduced the average N2O emissions by 28.3%, while the combined application (ANK) of K and AN increased N2O emissions by 22.7%. The abundance of nitrifying genes amoA in ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) changed in response to N and/or K fertilization, but the denitrifying genes narG, nirK and norl were strongly correlated with N2O emissions. This suggests that N or K fertilizer and their interaction affect N2O emissions mainly by altering the abundance of functional genes of denitrifying microbes in the soil-plant system. The genera Paracoccus, Rubrivivax and Geobacter as well as Streptomyces and Hyphomicrobium play an important role in N2O emissions during denitrification with the combined application of N and K.

Evaluating the influence of pre-harvest hybrid treatments (compost manure and potassium nitrate fertilizer) on the mechanical properties of eggplant (cv. Bello) fruits

There is an urgent need for fruits enhancers due to rise in food insecurity globally. Eggplant (Solanum aethiopicum L.) fruit is one of the most widely consumed fruit in the world, and Nigeria in particular. The aim of this study was to evaluate the potential of using compost manure and potassium nitrate (KNO3) fertilizer as fruit enhancers in eggplant production. The research was carried out on Bello eggplant using seven different treatments. Apart from the control unit, compost manure was applied at the rate of 2500 and 5000 kg/ka; the KNO3 fertilizer was applied at the rate of 150 and 300 kg/ha; combined treatment of compost manure and KNO3 was applied at the rate of 2500 kg (compost) + 150 kg (KNO3) and 5000 kg (compost) + 300 kg (KNO3) per hectare. Fruits from all the treatments were harvested at peak maturity stage, and the mechanical properties determined, in accordance to international procedures. Results obtained from the mechanical test revealed that fruits produced with combined treatment had better failure force, failure energy and compressibility, compared to the control fruits, or the fruits produced with single treatment. Regarding the single treatment, the results revealed that fruits produced with compost manure had better compression properties than the fruits produced with KNO3. A failure force of 829.00 and 855.33 N were recorded in the fruits produced with compost manure at the two concentration levels respectively. Similarly, failure force of 798.33 and 831.67 N were recorded in the fruits produced with KNO3 at the two concentration levels respectively. This study results affirmed that combined treatment was better than single treatment, and the combined treatment can be used as fruits enhancer. Results obtained from this study can also be used to design and develop eggplant fruit harvesting, handling and packaging machines.

Chemical components of essential oils and biological activities of the aqueous extract of Anethum graveolens L. grown under inorganic and organic conditions

BackgroundIn sustainable agriculture, the use of farmyard manure (FYM) is of great interest to environmental security and is effective as a good nitrogen source for sustainable crop production. Therefore, determining the effective doses of FYM that will be an alternative to chemical fertilizers, is also important to improve soil fertility and produce healthy products. This study aimed to determine the effects of FYM and ammonium nitrate (AN) fertilizers on the biological value and essential oil content of dill (Anethum graveolens L.).MethodsDifferent doses FYM (7.5, 10, 12.5 and 15 t ha−1) and AN (30, 60, 90 and 120 kg ha−1) were applied by sowing and compared to a control group (no manure). We evaluated the chemical constituents as well as the biological activities of dill herbs and seeds growing at various doses of FYM and AN fertilizers.ResultsThe most abundant components of essential oils were found to be dill apiole (11.96 ± 0.83 and 18.65 ± 1.89%) and carvotanacetone (15.90 ± 2.34 and 21.76 ± 1.62%) in the leaves and seeds, respectively. Limonene (9.01 ± 1.11%), 4-isopropyltoluen (8.24 ± 0.89%), dill ether (9.13 ± 1.12%) and mycrene (7.44 ± 0.68%) were major essential oils components in herbs. The highest concentration of the essential oil components was determined as 12.5–15 t ha−1 in FYM and 90 AN applications. From the effective concentration (EC50) of the samples, it was seen that 60 kg ha−1 AN infusion, 120 kg ha−1 AN decoction as well as 7.5 t ha−1 FYM and 10 t ha−1 FYM essential oils had the highest DPPH, ABTS+ and superoxide anion radical scavenging activity as shown by the lowest value of EC50 compared to the control. Although the antioxidant activities of the samples were significantly lower than those of the reference antioxidant gallic acid, it was evident that they did show the antioxidative potential for hydrogen and a single electron donor activities, thus could serve as free radical scavengers, and act as reductant. In particular, the highest total phenolic content (18.36 ± 0.35 mg g−1) was found in the infusion extract after applying the 60 kg ha−1 AN fertilizer. Essential oils extracted from the seeds also exhibited strong antibacterial activity against Staphylococcus epidermidis, Enterococcus faecalis, and Pseudomonas aeruginosa. The highest antibacterial activity against all tested microbial species was observed with the 10 t ha−1 FYM application.ConclusionThe findings of the study suggest that the application of FYM has promising effects on dill leaf, seed, and herb and can be considered as a suitable substitute for chemical fertilizers when growing dill, a plant with increasing importance and demand.

Impact of Different Nitrogen forms on Soil Fertility and Cowpea Productivity under Conditions Saline Soil

The field experiment was carried out at the south-west portion of Shall El-Tina region, north Siena Governorate Egypt. The study investigated evaluations of different nitrogen fertilizers sources (ammonium nitrate, ammonium sulphate and urea fertilizers) and rates (100%, 75% and 50% recommended dose of all different nitrogen forms) alone or combined with bio-fertilizer (Rhizobium radiobacter sp.) strain on improve nutrients available and contents in cowpea productivity in newly reclaimed saline soil conditions during two summer seasons 2019 and 2020. The studies treatments were disturbed among the experimental plots in split design. The obtained results showed that using ammonium sulphate fertilizer was more effect on EC, pH, and available N, P, K, Fe, Mn and Zn values by increasing application rates compared with other treatments. Moreover, data recorded the applied ammonium sulphate75% with bio-fertilizer was increase of plant height, weight of 100 seeds, weight of pods (g plant-1), seeds yield (ton fed-1) have been affected by inoculation with bio-fertilizer combined with different nitrogen forms and different application rates than other treatments. The highest values of N, P, K, Fe, Mn and Zn concentrations and uptake in seeds were obtained with ammonium sulphate application combined with bio-fertilizer compared with other treatments. The increase of chlorophyll, protein contents in cowpea plants with decreasing soil salinity, while the increase of proline content was increasing soil salinity. The application of ammonium sulphate at application rate 75% N combined with bio-fertilizer improves soil properties and cowpea productivity under saline soil conditions.

Impacts of irrigation and nitrate fertilization scenarios on groundwater resources quantity and quality of the Almyros Basin, Greece

Abstract Irrigation and nitrate fertilization scenarios were combined and simulated for crop water irrigation demands and nitrogen applications based on experiments on crop cultivation practices. Two irrigation practices (deficit irrigation and rainfed conditions) were applied to the main crop types of the Almyros Basin, a coastal basin located in Thessaly, Greece. The Almyros groundwater system suffers from progressive water balance deficit, nitrate contamination and seawater intrusion due to groundwater abstractions for agricultural irrigation to cover crop water demands in the dry season. The impacts of the irrigation and nitrate fertilization scenarios on groundwater resources quantity and quality were simulated using an Integrated Modelling System consisting of models of surface hydrology (UTHBAL), groundwater hydrology (MODFLOW), crop growth/nitrate leaching (REPIC), contaminant transport (MT3DMS), and seawater intrusion (SEAWAT), for the historical period of 1991–2018. The results of the scenarios were evaluated with the indicators of Crop Water Productivity (CWP) for crop yields and irrigation water, Partial Factor Productivity (PFP) for Nitrogen Use Efficiency, and Economic Water Productivity (EWP) for the gross profits of the irrigation water.

Elucidating comportment of the glutamate and ornithine pathway on proline accumulation in rice under different nitrogenous nutrition

Proline is a multifunctional amino acid in plant cells known to be involved in growth and development, particularly under various environmental abuses. In this study, the contribution of the glutamate and ornithine pathway on proline accumulation in rice seedlings (Oryza sativa L. cv. XZX 45) under different nitrogenous nutrition was investigated. The main findings include the following: (1) the dynamic changes of free proline pool in studied seedlings parts were highly linked to the nitrogenous species during 48-h exposure, whereas ammonium treatments caused more proline accumulation than nitrate treatments, and the change in free proline in rice seedlings without nitrogen supply was identical to nitrate fertilization; (2) application of external arginine and glutamate caused over accretion of free proline in rice seedlings, amidst them arginine was more efficient than glutamate related to proline synthesis; (3) proline content in both rice tissues is linearly increased with external ammonium applied, while employment of nitrate did not change proline content. The maximum nitrogen fertilization of nitrate and ammonium caused significant decrease of proline in rice tissues when arginine and glutamate were used, and other doses of nitrogen fertilization did not change proline content significantly. Results presented here indicated that the ornithine pathway played notable role in the proline accumulation in rice seedlings than the glutamate pathway under different nitrogenous nutrition.