Добірка наукової літератури з теми "Zn fertilisers"

The grain yield benefits of applying micronutrient fluid fertilisers over conventional granular products in calcareous sandy loam soils have been agronomically demonstrated. An understanding of the fundamental mechanisms and reactions occurring following application of these products to soils is critical to improve fertiliser management. We therefore examined the diffusion, solubility, and potential availability of manganese (Mn) and zinc (Zn) from both granular and fluid forms of Mn and Zn fertiliser in an alkaline calcareous and alkaline non-calcareous soil using laboratory incubation experiments in conjunction with an isotopic dilution technique with 54Mn and 65Zn. Enhanced mobility, solubility, and/or potential availability of Mn and Zn from fluid fertilisers were observed in comparison to Mn or Zn from granular fertilisers in both soils after 5 weeks of incubation. Differential behaviour of fluid and granular fertilisers for Mn and Zn appeared to be independent of their effects on soil pH. Most (~90%) of the Mn in granular fertiliser dissolved and diffused out of the granule but was retained within 4 mm of the point of granular placement, whereas most (~85%) of the Zn in the granular Zn fertiliser source remained in the granule. Our data suggest that the superior agronomic effectiveness of fluid Mn and Zn fertilisers observed in calcareous soils under field conditions may have resulted from the enhanced diffusion (Mn) and/or solubility/availability (Mn, Zn) of these micronutrients in soil when applied in fluid form.

This study aimed to determine whether >80 years of fertiliser application has led to recognisable changes in the trace metal (Cd, Cu, Mo, Ni, Pb, Sr, Th, U, Zn) chemistry of topsoils (0–0.10 m) from sugarcane land, northern Queensland, Australia. The metal concentrations of commercial nitrogen (N) and potassium (K) fertilisers currently used in northern Queensland were generally lower than those of phosphate fertilisers and fertiliser blends. Composite topsoil samples (0–0.10 m depth) taken from canelands had higher median Cd, Mo, Pb, Sr, Th, U, and Zn concentrations than topsoils from forested areas of the catchment. Niobium, Ta, and Ti were confirmed as refractory immobile elements and used as reference elements for the evaluation of trace metal enrichments. Bivariate plots of trace metal/immobile element ratios verified that Cd, Mo, Pb, Sr, Th, U, and Zn are enriched in sugarcane soils compared with background forest soils. Isotopic ratios for Pb, Sr, and U highlight that fertilisers, cane soils, and forest soils have isotopically distinct compositions. Phosphate fertilisers currently used in the agricultural industry possess the most radiogenic 87Sr/86Sr, 234U/238U, 207Pb/206Pb, and 208Pb/206Pb ratios. Background forest soils have the highest 87Sr/86Sr, 207Pb/206Pb, and 208Pb/206Pb and lowest 234U/238U ratios. By contrast, cane soils exhibit 207Pb/206Pb and 208Pb/206Pb ratios that appear on a mixing line between the isotopically distinct background soils and phosphate fertilisers. Also, cane soils possess 234U/238U ratios similar to phosphate fertilisers. Thus, the application of phosphate fertilisers to canelands has resulted in higher Cd, Mo, Pb, Sr, Th, U, and Zn concentrations and more radiogenic Pb, Sr, and U isotope ratios in cane soils. Trace metal ratios and the Pb, Sr, and U isotopic composition of topsoils and fertilisers are useful tools to recognise fertiliser-derived trace metals in agricultural landscapes.

The yield potential of cassava with optimal mineral nutrition was evaluated in a lateritic red earth that was replaced after bauxite mining at Weipa, Queensland. There were 9 field experiments. In 8 separate experiments, 5 rates each of nitrogen (N), potassium (K), magnesium (Mg), sulfur, copper, zinc (Zn), boron or molybdenum fertilisers were banded into the soil. In the phosphorus (P) experiment, triple superphosphate and rock phosphate were compared, each with 5 rates of P banded, broadcast or spot-placed into the soil. After 2 wet seasons (66 weeks after planting), maximum tuber yields were produced by the banded application of 200 kg P/ha as triple superphosphate, 20 kg Mg/ha and 8 kg Zn/ha. With rock phosphate, only the broadcast placement produced an increase in the yield of cassava, maximum yields being achieved with 400 kg P/ha. In addition, there was evidence that 100 kg N/ha and 300 kg K/ha were needed for maximum yields. Therefore, based on the results of these individual experiments over 2 seasons, 100 kg N/ha, 200 kg P/ha as triple superphosphate or 400 kg P/ha as rock phosphate, 300 kg K/ha, 20 kg Mg/ha and 8 kg Zn/ha are the fertiliser recommendations for cassava grown in replaced soil at Weipa. In addition, early Zn deficiency symptoms (not related to any applied fertilisers) may necessitate a foliar spray of 4 kg Zn/ha as well as the soil-applied Zn fertiliser. However, the use of dolomite at 80 kg Mg/ha may have decreased the tuber yields and/or increased the requirements for certain soil-applied fertilisers. An average yield of 26.0 t/ha of tubers (fresh weight) was obtained with a 51-week growing season, and the recommended rates of fertilisers. This yield was reasonable when compared with 32 t/ha of fresh tubers predicted by a growth model for cassava, grown in North Queensland for 52 weeks without irrigation.

Three liquid zinc (Zn) fertilisers were mixed with the upper 1.5 cm of columns representing 3 different soil profiles: Aquic Haploxeralf, of an acid nature and with hydromorphic problems; Calcic Haploxeralf, of a neutral nature; and Typic Xerorthents, of a calcareous nature. They were periodically irrigated for 60 days. Most of the applied Zn remained in the top of the soil when it was added as Zn-lignosulfonate plus EDTA or Zn-2-hydroxy-1,2,3-propanotricarboxilate. When Zn-EDTA plus fulvic and humic acid fertiliser was applied, Zn migrated and distributed throughout the soil resulting in losses of Zn by leaching of 2.29% in acidic soil, 27.36% in neutral soil, and 10.5% in calcareous soil of the Zn applied. The 3 fertilisers produce sufficient concentrations of the bioavailable Zn forms in the Ap horizons (DTPA and Mehlich-3 extractable Zn) for the cultivation of different plants. In the calcareous soil, which contained free CaCO3, the amount of Zn extracted by Mehlich-3 was higher than in soils with no free CaCO3. Distribution of Zn in the soil was studied at the beginning and end of the experiment by means of one sequential fractionation and showed that added Zn remained in more labile fractions for uptake by plants in the acid and neutral soils when compared with the control. When Zn was added to calcareous soil, no amount of Zn was detected in the water-soluble plus exchangeable fraction at the end of experiment for any Zn fertiliser source.

The effect of fertilisation with fermented pig slurry on the quantitative and qualitative parameters of two kinds of tomatoes was assessed by means of pot trials. These trials were carried out between the years 2005 and 2008. Each trial involved four treatments, namely (a) control without fertilisation, (b) fertilisation with mineral fertilisers, (c) 50% nutrients in mineral fertilisers and 50% in fermented pig slurry, and (d) fertilisation with fermented pig slurry only. Besides the yield parameters, the following characteristics were monitored: dry matter content, vitamin C content, titratable acidity, nitrogen compounds, nitrates and selected elements (Pb, Cd, As, Zn and Hg) contents. The fertilisation method showed no statistically significant influence on many parameters (titratable acidity, Hg, As, dry matter, vitamin C and nitrates contents). These results showed that anaerobically fermented pig slurry can be a suitable alternative to the use of mineral fertiliser. They also showed that its use as an organic fertiliser did not impair the hygienic quality and safety of the vegetable products grown, as all tomato samples fulfilled the tested heavy metals and nitrates legislation limits. The fertilisation method showed a statistically significant influence on the yield. Diffe-rences occurred between the organic and mineral methods in the case of Cd, and between non-fertilised and organic methods in the case of Zn. The fertilisation method also significantly influenced N-compounds content in tomatoes. A statistically significant influence of the year was found with all parameters except zinc and vitamin C contents. The influence of cultivar was also found, but only in the case of zinc and dry matter contents.

Environmental contextZinc, an essential micronutrient often applied to crops as a fertiliser, can be difficult to analyse in plants due to limitations of conventional techniques. Here, we use radiotracers and a non-destructive imaging technique to visualise how zinc applied as a nanofertiliser moves within wheat plants over time. This is an important step towards developing cost-effective fertilisers to help solve one of the world’s most widespread plant deficiencies. AbstractZinc (Zn) deficiency affects half of the world’s arable soil and one-third of the world’s human population. Application of Zn foliar fertilisers to cereal crops can be an effective way to increase grain Zn content; however, commonly used formulations can scorch the leaf (e.g. soluble Zn salts) or are prohibitively expensive (e.g. chelated Zn, ZnEDTA). Zinc oxide nanoparticles (ZnO-NPs) may offer an efficient and cost-effective alternative, but little is known regarding the mechanisms of Zn uptake and translocation within the plant. Foliar-applied Zn is analytically challenging to detect, locate and quantify, as it is omnipresent. Furthermore, any single analytical technique does not have the detection limit or spatial resolution required. In this study, the uptake and mobility of foliar-applied ZnEDTA, ZnO-NPs and ZnO microparticles (ZnO-MPs) to wheat (Triticum aestivum L.) were investigated using inductively coupled plasma mass spectroscopy (ICP-MS), synchrotron-based X-ray fluorescence microscopy (XFM) and radiotracing techniques using 65Zn-labelled formulations. The three techniques were compared to highlight limitations and advantages of each. We also report, for the first time, a novel time-resolved invivo autoradiography imaging technique that can be used to visualise 65Zn in live plants treated with foliar applications of 65ZnO-NPs and MPs. The images were supplemented by gamma spectroscopy analysis for quantification. The results of this study provide important insights into the analytical challenges faced when investigating foliar-applied Zn nanofertilisers in plants. Potential solutions using nuclear techniques are also discussed, which in turn may ultimately lead to the development of more efficient foliar fertilisers.

Summary. Zinc (Zn) deficiency limited the early growth of cassava (Manihot esculenta Crantz) in nutritional trials on a Zn-deficient lateritic red earth that was replaced after bauxite mining at Weipa (12°28"S, 141°53"E). The symptoms developed at 2 weeks after emergence, despite the band application of 0–32 kg Zn/ha and were not related to rates of Zn or other fertilisers applied to the soil. The Zn deficiency in the cassava plants was attributed to low Zn in setts before root access to soil and fertiliser Zn. Two techniques were studied to establish if they could be used to correct Zn deficiency early in the growth of cassava: one was the fertilisation of cassava plants before cutting the stems for planting setts, and the other was soaking cassava setts in Zn solutions for various times at 101 kPa (atmospheric pressure) or 51 kPa (partial pressure). Setts, after treatments, were planted into pots of lateritic soil from Weipa. Plants grown from setts soaked in ZnSO4 solutions varying from 17.4 to 348 mmol Zn/L did not develop Zn-deficiency symptoms, whereas, 62% of plants grown from either unsoaked setts or setts soaked in water developed symptoms. However, the prior fertilisation of cassava plants failed to decrease the incidence of Zn deficiency in plants and did not increase the Zn concentration in setts. Several treatments in Zn solutions were found to significantly increase the Zn concentration in setts, were not detrimental to shoot emergence nor the subsequent growth of plants, and provided an adequate Zn concentration in leaf blades. These treatments were: soaking in 17.4 or 69.5 mmol Zn/L for 5 h and in 69.5 mmol Zn/L for 0.5 h at 51 kPa; and soaking in 69.5 mmol Zn/L for 5 h and in 139 mmol Zn/L for 0.5 and 5 h at 101 kPa. These treatments could be used to overcome early Zn deficiency in cassava plants where the deficiency is a problem despite the soil application of Zn fertilisers.

Much of our knowledge of plant growth in response to soil nutrient supply comes from studies under homogeneous soil conditions. However, the adoption of reduced or nil tillage and shallow banding of fertilisers at the time of seeding causes spatially variable distribution and availability of soil nutrients in agricultural lands. Soil available nutrients, particularly the poorly mobile ones such as phosphorus (P), potassium (K), zinc (Zn), manganese (Mn), and copper (Cu), stratify within the fertilised topsoil. In water-limited environments where the topsoil is prone to drying, soil nutrient stratification may influence nutrient availability and plant uptake because of impeded root growth or reduced diffusion of immobile nutrients to the root surface, or more likely a combination of both factors. Placing fertilisers deeper in the soil profile could increase nutrient acquisition and utilisation by plants as fertiliser nutrients are in the moist soil for a longer part of the growing season. However, the effectiveness of deep placement of fertilisers may also be determined by soil texture, tillage, fertilising history, nutrient mobility, and crop species. In Mediterranean-type climates of southern Australia, a yield response of winter crops to deep fertiliser mostly occurs on infertile sandy soils in low rainfall regions. This contrasts with the responses of winter and summer crops in northern Australia on soils with optimum-to-high nutrients but subjected to rapid and frequent drying of topsoil because of high temperatures and high evaporation demand during the growing season. The pattern of nutrient accumulation by crop species (indeterminate v. determinate) and the mobility of mineral nutrients in the phloem would also modify the effectiveness of deep-placed nutrients under drought. The complexity of plant responses to subsoil nutrition may suggest that before adopting deep fertiliser practice in a paddock it is essential to understand the effects of edaphic and climatic conditions, soil management, and plant–soil interactions in order to achieve maximum yield benefit.

The performance of 7 commercial zinc (Zn) foliar nutrients sprays, based on sulfate (Top ZM), hydrated sulfate (Pivot Zinsol; Pivot Mangasol-zinc), oxide (Phosyn Zintrac), and ligninsulfonate (Spray-gro Zn PC; Spray-gro Zn/Mn PC; SJB), were assessed with and without addition of a horticultural petroleum spray oil (PSO), Ampol D-C-Tron NR. Foliar Zn deposition and absorption was quantified by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) after solvent washing and acid extraction. Effects on photosystem II were measured by chlorophyll fluorescence. Although none of the Zn sprays were soluble in PSO, all but Zn oxide could be suspended adequately before spraying. A partial emulsion break occurred with Zn sulfate and hydrated sulfates. All treatments increased the Zn content of leaves by an amount likely to alleviate Zn deficiency. Addition of PSO decreased deposition and absorption of Zn when used with the inorganic formulations or with Spray-gro Zn PC. Zinc deposition and absorption were increased by PSO in Spray-gro Zn/Mn PC, and were unaffected by PSO in SJB. Plant chlorophyll fluorescence and phosphorus content did not differ among treatments. The ligninsulfonates Spray-gro Zn/Mn PC and SJB were most compatible with Ampol D-C-Tron NR, and had relatively low potential for Zn pollution of the environment.

Plant testing of wheat crops in south-western Australia, sown using no-till for >7 years, often indicates marginal to deficient levels of the soil immobile elements phosphorus (P), copper (Cu) and zinc (Zn). In this region, P, Cu and Zn fertilisers are usually placed (drilled) with the seed while sowing crops. However, in no-till cropping, because the fertilisers are placed in the same rows as the seed during sowing, in the years after application the 3 elements are no longer mixed through the top 10 cm of soil. It may be more effective to deep band fertiliser below seed while sowing no-till crops. Alternatively, cultivating the top 10 cm of soil every 5–7 years would mix previously applied fertiliser P, Cu and Zn through the topsoil, which should improve the effectiveness of the fertiliser residues for the current and subsequent no-till crops. In field experiments in paddocks in south-western Australia sown using no-till for 7–11 years, we compared these 2 alternative methods to the standard no-till practice of drilling fertiliser with the seed in the same crop rows. No shoot or grain yield responses of wheat were obtained. The exception was that in 1 experiment cultivating the topsoil before drilling P with seed was more effective than drilling or deep banding P. Concentrations of P, Cu and Zn measured in wheat shoots or grain were either unaffected by treatment, or, compared with drilling fertiliser with seed, were larger for the other 2 methods, indicating these 2 methods were more effective at increasing the concentrations of the elements in plant parts. The 3 elements have been shown to have good residual values for crop production in the region. Therefore, we recommend that experiments should not be performed in existing no-till paddocks until the residual value of P, Cu and Zn applied in the old cropping system has become negligible, which could, for Cu and Zn in particular, take many years. In the second year, the experiments were used to compare 4 different ways of collecting soil samples from the top 10 cm of soil (standard soil sampling depth used in south-western Australia) to measure soil test P (Colwell), Cu (ammonium oxalate) and Zn (DTPA). The samples were either collected randomly within the plots (present method), always in the rows used to sow seed and apply fertiliser, always between the rows, or half in and half between the rows. Soil test values for P, Cu and Zn were unaffected by amount of element applied and method of application when samples were collected between rows, at random, or from all banded treatments where fertiliser was placed below the 0–10 cm sampling depth. Soil test values for samples collected in rows increased as the amount of fertiliser applied increased and were about double the values for samples collected half in and half between rows.

Zinc oxide nanoparticles (ZnO NPs) have unique physical and chemical characteristics which deviate from larger particles of the same material, due to their extremely small size, higher specific surface area and surface reactivity. The peculiar properties of ZnO NPs could potentially improve zinc (Zn) fertilizers for sustainable agriculture. This is based on the assumption that ZnO NPs provide a more soluble and bioavailable source of Zn in soil compared to micron- or millimetre- sized (bulk) ZnO particles currently used for Zn fertilizers in Zn deficient soils. However, a thorough understanding of the fate and reactions in soils and interactions of nanoparticles with plants of ZnO NPs is required prior to the recommendation for use of these novel materials. Therefore, there is a need to investigate dissolution, diffusion, transformation, partitioning and availability of manufactured ZnO NPs in soil to ensure safer and more sustainable application of ZnO NPs as a new source of Zn fertilisers for plants, and better management of their potential risks. Given inclusion of Zn in macronutrient fertilizers is the common procedure for their field application, ZnO NPs and bulk ZnO were coated onto macronutrient fertilizers (monoammonium phosphate (MAP) and urea) and dissolution kinetics, diffusion and solid phase speciation of Zn from coated fertilizers were evaluated. Coating of ZnO on macronutrient fertilizers significantly affected solubility and dissolution kinetics of the ZnO sources, but nano-sized ZnO did not show any enhanced solubility over bulk ZnO. The low pH value of ZnO-coated MAP granules resulted in greater and faster dissolution of ZnO compared to ZnO-coated urea granules. However, interactions of ZnO particles with phosphate in MAP granules likely resulted in precipitation of Zn-phosphate species. The high pH and ionic strength of the dissolving solution resultant from hydrolysis of urea likely promoted aggregation of any ZnO NPs released from coated urea granules and also hindered dissolution of ZnO. To evaluate changes in Zn speciation with coating of the ZnO sources and after incorporation of the coated-fertilizers into an alkaline calcareous soil, synchrotron-based micro X-ray absorption fine structure (μ-XAFS) method was used. The findings confirmed precipitation of Zn-phosphate species at the surface of MAP fertilizer granules irrespective of the size of ZnO particles used for coating. For coated urea, the Zn remained as ZnO species for both nano-sized and bulk ZnO coatings. Solid phase speciation in the fertilized soil varied with distance from the point of fertilizer application. Significant amounts of Zn(OH)₂ and ZnCO₃ species were identified in the soil some distance from coated urea and MAP, respectively, indicating dissolution/precipitation processes were active. Moreover, limited and comparable diffusion of Zn from coated fertilizers with nanoparticulate or bulk ZnO into soil was observed using micro x-ray fluorescence mapping (μ-XRF). Transformation of Zn at the surface of MAP granules, mass flow of water towards the hygroscopic fertilizer granules or strong aggregation of ZnO nanoparticles released from urea granules could have been the mechanisms which restricted Zn diffusion. Given that coating of ZnO on macronutrient fertilizers markedly reduced Zn solubility, reactions of ZnO NPs and bulk ZnO in soil were studied when applied as the pure oxides. Availability of Zn for durum wheat (Triticum durum) plants from nanoparticulate and bulk sources of ZnO was evaluated in an acidic and an alkaline soil using an isotopic dilution procedure (L value). Significant dissolution and plant acquisition of Zn from ZnO was observed (ca. 50 – 100 % of added), even with limited pre-incubation of soils with the Zn sources. However, no significant effect of particle size was observed on plant acquisition of Zn from the ZnO. Retention and dissolution of ZnO NPs and dissolved Zn species from ZnO NPs was further investigated in five soils with diverse physical and chemical properties. Strong retention of ZnO NPs and/or dissolved Zn species from ZnO NPs was found in all soils especially in alkaline and calcareous soils. The adsorption affinity of ZnO NPs was generally greater than that of soluble Zn, which suggested ZnO NPs were retained more strongly than soluble Zn in soils. Soil pH and clay content of soil were the most important soil properties affecting retention, although the number of soils used was too small to draw firm conclusions as soil parameters co-varied. Generally, nanoparticulate forms of ZnO appear to offer little advantage over bulk-sized ZnO as a source of fertilizer Zn to crops. Rapid dissolution of ZnO NPs and partitioning of dissolved Zn species derived from ZnO NPs and/or high retention of ZnO NPs in soils suggested that soil application of manufactured ZnO NPs would not appear to offer any benefits over bulk ZnO, whether applied in pure form or along with macronutrient fertilisers. However, from an ecotoxicological point of view, ZnO NPs would not be persistent in soil systems and hence their mobility in soil would be limited. Therefore the risks associated with application of ZnO NPs in soil would be similar to that of soluble Zn.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2012