摘要:

High pressure liquid chromatography (HPLC)‐grade water was evaluated as an alternative extraction reagent to acid extraction of plant tissue. Green and red bell pepper fruit (Capsium annuumvar.annuumL.), cultivar Pip; sweet corn internodes (Zea maysL.), cultivar Florida Staysweet; cabbage wrapper leaves (Brassica oleraceaL. Capitata group), cultivar Solid Blue 770; peach leaves [Prunus persica(L.) Batsch], cultivar Coronet; and mixed leaves and stems of cotton (Gossypium hirsutumL.), cultivar Delta Pine 51; or okra [Abelmoschus esculentus(L.) Moench], cultivar Spineless Green Pod were extracted with HPLC‐grade water or 5 mM hydrochloric‐ (HCl), acetic‐, or citric‐acids. Ashed and fresh ground tissues were used for extraction with HCl. Cations and anions were determined by ion chromatography. In about 95% of occurrences, concentrations of ions in tissues extracted with HPLC‐grade water were equal to, or greater than, those extracted with acids. Therefore, extraction of plant tissues with HPLC‐grade water is recommended. Fewer waste disposal problems will also occur with water extraction of plant tissues.

ISSN:0010-3624    

DOI:10.1080/00103629809369943

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Fluidized bed combustion bottom ash (FBCBA) from coal burning power plants often contain substances that detrimentally affect plant growth [(e.g., boron (B)] when applied to soil. Leaf symptoms similar to B toxicity appeared when maize (ZeamaysL.) was grown during Year‐1 of a field experiment where FBCBA was incorporated (6,790 and 13,580 kg ha‐1) in an acidic soil (Aquic Hapludult). Soil extractable B increased with increased levels of FBCBA in Year‐1 and in Year‐2. Although levels in Year‐2 were lower than in Year‐1 they were still sufficiently high to raise concern about B toxicity. Acquisition of B in leaves of maize grown in Year‐1 was relatively high at the 5‐leaf stage of growth, and at a normal level in the ear leaf; ear leaf B in Year‐1 was greater than ear leaf B in Year‐2. Grain and fodder yields of plants grown with added FBCBA were reduced in Year‐1, but not in Year‐2. A greenhouse study was conducted to determine leachability of B through acidic soil (Typic Hapludult) columns whose surface had been treated with FBCBA at 0, 6, and 12 g kg‐1soil and leached with different amounts of water (25, 200, and 800 mm). Maize was also grown on the leached soil columns to determine effects of compounds leached from FBCBA on growth and B acquisition in leaves. The application of 800 mm of water reduced soil levels of B, and increased the amount of B leached from the columns. Maize shoot and root dry matter (DM) were enhanced with FBCBA. Increased DM associated with higher FBCBA levels may reflect increased soil pH in this acidic soil. Shoot B concentrations decreased with greater amounts of water used to leach columns. Shoot B concentrations were closely related to levels of B present in the 0–15 cm layer of soil in the column and field experiments.

ISSN:0010-3624    

DOI:10.1080/00103629809369944

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In a greenhouse experiment, the effect of fluoride (F) and phosphorus (P) addition on the growth and mineral composition of barley (Hordeum vulgareL.) was studied in three different soils, Cahaba sandy loam (acid), Weld loam (neutral), and Haverson silty loam (alkaline calcareous). Four levels of F [0, 100, 400, and 1,000 mg kg‐1soil as hydrogen fluoride (HF)] and three levels of P [50, 150, and 550 mg kg‐1soil as phosphoric acid (H3PO4)] were used. The effect of P addition on the native soil F and the capacity of soil to sorb added F was investigated. Addition of P released some of the native F from the soil samples that did not receive any F. The amount of F released ranged from 0.135 to 1.860 mg kg‐1soil. The amount of F released from the soils decreased with increasing P addition. Most of F added was sorbed by the soil solid phase. The amount of F sorbed ranged between 74.0% and 96.3% of the added F. For both the acid and neutral soils, increasing P addition increased F sorption at all F levels. In the case of alkaline soil, however, this effect was only clear at the low F level. The formation of insoluble F minerals may be enhanced by the addition of P to the soils. In the greenhouse experiment, F addition had a negative effect on dry matter yield (DMY) of barley grown on the acid and neutral soil while no effect was observed for the alkaline soil. These results may reflect the effect of F addition on the solubility of aluminum (Al) and other metals in the soils. On the other hand, increasing F addition from 50 to 550 mg kg‐1soil had no clear effect on DMY of plants in the three soils. The study also included the effect of F and P addition on their uptake by plants. Generally, addition of P depressed F uptake by plants grown on the three soils. On the other hand, increasing F addition depressed P uptake for the acid soil while no clear trend was observed for the neutral and alkaline soil. A significant positive effect of F addition on Al uptake was observed for both the acid and neutral soils. A highly significant correlation of 0.87 and 0.60 was obtained between soil extractable F and Al uptake for the acid and neutral soil, respectively. Addition of F to the alkaline soil resulted in minor increases in Al uptake. The effect of P addition, at different levels of F, on Al uptake was investigated for the three soils. For the acid soil, significant decrease in Al uptake was observed only at the highest F level. The effect of P addition on Al uptake was not clear in the other two soils.

ISSN:0010-3624    

DOI:10.1080/00103629809369945

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Three instrumental techniques, a colorimetric, fluorometric, and direct‐current plasma atomic emission spectroscopic (DCP‐AES) methods, for boron (B) determination were compared on the basis of precision and accuracy, detection limit, interference, linear working range (LWR), recovery of added B and time. These techniques were applied to the measurement of B in soil extracts, plant extracts, and water samples. The colorimetric method had the lowest (0.002 mg L‐1), and the DCP‐AES had the highest (0.1 mg L‐1) detection limit. The DCP‐AES has a LWR of 5 orders of magnitude (0–1000), whereas the colorimetric technique displayed a LWR varying from 0–4 mg L‐1. The DCP‐AES method had the best precision. This study shows, however, that any of the three techniques could be used for measuring B in soils, plants, and water samples on routine basis, provided method differences of 2% are not considered critical. Otherwise, the colorimetric and fluorometric methods appeared to be the most closely comparable.

ISSN:0010-3624    

DOI:10.1080/00103629809369946

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Nitrogen (N) use efficiency (NUE) of fertilizer N can be accurately estimated by tracing the fate of soil applied labelled fertilizer, but the quantity of N remobilization from non‐kernel components into kernels in maize (Zea maysL.) plants is difficult to determine. A field experiment involving stem infusion with labelled15N solution was conducted at Ottawa, Ontario (45°22'N, 75°43'W) for two years to determine whether stem infused15N could be used to quantify N remobilization and the contribution of remobilized N to the grain. A current stay‐green commercial hybrid was grown at three fertilizer N rates and infused with 30 mL15N solution [35.7 mmol N as15NH415NO3at 99.215N% atom enrichment (a.e.)] into the internode below the primary cob at anthesis. The control plants were infused with distilled water. Sampling occurred at 3 d, 2 wk and 5 wk after anthesis and at physiological maturity. Each plant was subdivided into ten components. Dry weight, total N concentration and15N% a.e. were determined for each component. Thirty mL of dilute N solution plus 10 mL of distilled water was taken up within 4 to 6 hours after infusion. At 3 d after infusion, infused15N moved out of the internode where it was infused, into dominant sinks, with more than 40% in the reproductive components (cob, husk, and kernels), 30% in leaves above the ear, and another 15 to 20% in the upper stem. By physiological maturity, 65 to 75% of infused15N was deposited in the kernels. Between 59 and 82% of kernel N was remobilized from non‐kernel components, whereas 18 to 41% was derived from N uptake during grain fill. These findings indicate that stem infusion is a useful technique to study N remobilization.

ISSN:0010-3624    

DOI:10.1080/00103629809369947

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Groundwater nitrate concentrations remained sharply different at two sites in the central part of the Florida peninsula over a two‐year observation period. Nitrogen (N) fertilization patterns, both quantity and application methods, and rainfall were approximately the same at both sites. The soil at the low groundwater nitrate site, at depths of 0 to 120 cm, had a higher cation exchange capacity (CEC) and contained more ammonium acetate‐extractable potassium (K), calcium (Ca), and magnesium (Mg). It also had a greater organic matter content, contained more clay in the 90 to 120‐cm layer and more nitrate in the 1 to 30‐cm layer. There was a sharp difference in depth to groundwater. At Site 1 (high nitrate levels) the water table remained steady at 4 m, while at Site 2 (low nitrate levels), it ranged from 0.9 to 1.1 m in the two wells monitored. The aquifer at Site 1 was unconfined, but was confined at Site 2 by increasing clay contents with depth.

ISSN:0010-3624    

DOI:10.1080/00103629809369948

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Flow injection analysis (FIA) is becoming an important automated procedure for the elemental analysis of agricultural and environmental samples. This paper reviews the application of the FIA technique for soil elemental analysis determinations, giving short descriptions of the required flow manifolds by highlighting some of their most important features.

ISSN:0010-3624    

DOI:10.1080/00103629809369949

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Nitrogen (N) isotope ratio mass spectrometry (IRMS) by Dumas combustion and continuous flow mass spectrometry has become a wide‐spread tool for the studies of N turnover. The speed and labor efficiency of15N determinations from aqueous solutions such as soil solutions or soil extracts are often limited by sample preparation. Several procedures for the conversion of dissolved ammonium (NH4+) or nitrate NO3‐to gaseous ammonia and its subsequent trapping in acidified traps have been elaborated in the last decades. They are based on the use of acidified filters kept either above the respective solution or in floating PTFE envelopes. In this paper, we present an improved diffusion method with a fixed PTFE trap. The diffusion containers are continuously kept in a vertical rotary shaker. Quantitative diffusion can thus be achieved in only three days. For solutions with NH4+levels of only 1 mg N kg‐1and NO3‐concentrations of 12 mg N kg‐1, recovery rates of 98.8–102% were obtained. By addition of15N labeled and non‐labeled NH4+and NO3‐it was shown that no cross‐contamination from NH4+to NO3‐or vice versa takes place even when one form is labeled to more than 1 at %15N while the other form has natural15N content. The method requires no intermediate step of ammonia volatilization before NO3‐conversion.

ISSN:0010-3624    

DOI:10.1080/00103629809369950

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The concentration of four pesticides (2,4‐D, atrazine, phorate, and terbufos) in soil solution during sorption experiments was measured using UV spectrophotometry, Gas Liquid Chromatography (GLC), High Performance Liquid Chromatography (HPLC), and radiotracer technique. The presence of water soluble organic matter in soil solution interfered with the measurement of pesticide using the UV spectrophotometry. The use of GLC, HPLC, and radiotracer technique involving14C gave a good estimate of the concentration of pesticide in soil solution. The pesticide remaining in soil can be quantitatively analyzed by extracting with a scintillation solution containing an organic solvent such as toluene or dioxane. Among the various centrifuge tubes glass tubes with Teflon caps sorbed negligible amount of pesticides and these tubes can be used for the sorption measurements.

ISSN:0010-3624    

DOI:10.1080/00103629809369951

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Spatial variation of bicarbonate soil test phosphorus (P) and bicarbonate soil test potassium (K) was studied by measuring soil test values for 40 individual soil samples collected from random locations within eight uniform 100 m by 100 m field sites in south‐western Australia. In addition, for five of the sites, spatial variation of the three P sorption indices (ammonium oxalate extractable iron, ammonium oxalate extractable aluminum, and the P retention index) and of organic carbon (C) was measured for 20 individual soils samples. Spatial variation was found to be large, with coefficient of variation (CV) exceeding 20% in most cases, and 50% in some cases. It is therefore essential to collect an adequate number of soil samples from uniform areas in paddocks in order to provide a representative composite sample to measure the soil properties.

ISSN:0010-3624    

DOI:10.1080/00103629809369952

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor