摘要:

Total sulphur and extractable sulphate were determined in plant materials by inductively‐coupled plasma emission spectrometry. For total sulphur, plant material was digested in concentrated nitric acid only. For the sulphate determination, the plant material was extracted with water, sulphate was precipitated as barium sulphate, washed, and redissolved in (NH4)4‐EDTA. In the determination of sulphur no spectral interferences were observed, when using the 182.04 nm emission line. The data for total sulphur compared well with a set of certified reference plant samples. For extractable sulphate no such certified plant material is available, but it was established that the proposed procedure did not lead to losses nor interferences.

ISSN:0010-3624    

DOI:10.1080/00103628609367780

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A lime‐stabilized sewage sludge compost was used as a surface amendment to improve the soil and nutritional status of a number of established pear cultivars grown on an acidic, low ferility soil site. Leaf Ca status was significantly increased while trace metals were not elevated and in most cases decreased by sludge compost over the course of the study. Soil chemical properties were modified in a manner similar to liming. Addition of sludge composts, particularly low metal containing materials, appears to represent an acceptable aid in renovating established pear orchards located on poor soil sites. Leaf, fruit flesh or peel Cd were not significantly effected by the compost addition. The compost added twice the recommended level of available N the first year and sub‐optimum N the following two years. Leaf N, although significantly increased in the composted versus non‐composted controls, was below sufficiency levels by the third year after addition. This indicates that compost cannot fully supply required N from a one time application even over the short term.

ISSN:0010-3624    

DOI:10.1080/00103628609367781

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A glasshouse study was conducted to determine effects of lime and Mn applied to three Florida soils on plant Mn, growth, and chlorophyll concentration of ‘Tifway II’ bermudagrass (Cynodon dactylonxCynodon transvaalensis). Four replications of three lime rates (0, 1000, and 2000 mg CaCO3/kg as dolomite and Ca(OH)2for Astatula fine sand (Typic Quartzipsamment, hyperthermic, uncoated) and Pompano fine sand (Typic Psammaquent, siliceous, hyperthermic); 0, 2000, and 4000 mg CaCO3/kg as dolomite and Ca(OH)2for Myakka fine sand (Aeric Haplaquod, sandy siliceous, hyperthermic) and three Mn applications (none, 10 mg Mn/kg as MnSO4, and 5 mg Mn/kg as MnEDTA) were used in a randomized, complete block, factorial design. A wide range of plant Mn concentrations existed across treatments for each soil. Differences in plant Mn concentration did not cause significant differences in growth or chlorophyll concentration. The critical plant Mn concentration was not reached, but it appeared to be below 20 mg Mn kg for bermudagrass. Models for prediction of plant Mn concentration using soil pH and extractable soil Mn (Mehlich I, Mehlich II, DTPA‐TEA) were obtained. The applications of MnSO, and MnEDTA each resulted in increased plant Mn under acidic soil conditions. Neither Mn application resulted in increased plant Mn concentration in grass grown on Pompano fine sand with soil pH values of 7.0 or above.

ISSN:0010-3624    

DOI:10.1080/00103628609367782

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Linear sweep cathodic stripping voltammetric methods were modified to measure labile and total concentrations of Fe3+and Zn2+in the nanomolar range in soil solutions. Labile concentrations of Fe (25–220 nmol/L) and Zn (37–208 nmol/L) were measured in 0.5 mL aliquots of filtered (0.4 μm) distilled water extracts (solution:soil ratio= 1) of four agricultural soils. After decomposition of complexed forms of the metals by evaporation of the solutions in HNO3, total soluble Fe and Zn were measured. Labile Fe comprised approximately 1% of total soluble Fe, while labile Zn comprised 13–43% of total Zn in the four soil solutions. The methods provide a linear range of 5 ‐100 nmol/L and sufficient precision to detect concentrations of labile and total Fe and Zn likely to occur in soil solutions.

ISSN:0010-3624    

DOI:10.1080/00103628609367783

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effects of combining the Bray 1 extracting solution with ammonium chloride (NH4C1) for simultaneous extraction of P and K were studied in several experiments. For pooled data from the experiments in which the Bray 1 solution containing 0.5 mol L‐1NH4C1 was used, the relationship between the amounts of P and K extracted by the combined solution (PCand KC)and the amounts extracted separately by Bray 1 (PR) and 1Nneutral NH4OAc (KR) are given by PC= 2 + 0.906 PR, r = 0.988 and Kc= 14 + 1.033 KR, r = 0.944. Variations were observed in different experiments when the concentration of NH4C1 and the conditions of the experiment were varied.

ISSN:0010-3624    

DOI:10.1080/00103628609367784

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Influences of moisture, temperature (T), and photon flux density (L), on the concentrations and contents of macronutrients in 21‐day‐old tissue of four warm‐season perennial grasses were studied. Highest mean concentrations of N, P, and K occurred in dallisgrass (DAL). Lowest N, K, and S concentrations occurred in bahiagrass (BAH). Coastal bermudagrass (COA) was consistently lowest in P concentration. Concentrations of Mg were higher in thePaspalumthan theCynodonspecies, averaging 4.5 vs. 2.6 g/kg, respectively. Yields generally increased with increasing levels of moisture, T and L. Nutrient concentrations were generally higher at the higher moisture level. Increased growth temperatures most frequently lowered nutrient concentrations, although T was positively related to K, Mg, Ca and S concentrations in BAH and DAL. Linear T effects indicated that N concentrations decreased 0.5 to 1.2 g/kg for each 1°C increase. Photon flux density caused less variation in nutrient concentrations and less consistent effects than did T. Nutrient concentrations most frequently increased with increased L. Effects of T and L were about equally important at the two moisture levels. Nutrient contents generally increased as yield increased even in situations where T and L had negative influences on nutrient concentrations.

ISSN:0010-3624    

DOI:10.1080/00103628609367785

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effect of drying on the cation (CEC) and anion (AEC) exchange capacity, and on potassium (K) and magnesium (Mg) adsorption by three New Zealand soils was investigated. Air‐drying resulted in no significant changes in these properties compared with the field‐moist samples. Oven‐drying at 105°C significantly decreased the CEC and increased the AEC of most soils compared with air‐dried samples. The decrease in CEC was related to increased solubility of organic matter and a decrease in surface area on which charge could be developed. The increase in AEC was attributed to a decrease in soil pH.

ISSN:0010-3624    

DOI:10.1080/00103628609367786

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This study was conducted at two sites in Mississippi to determine whether petiole and leaf NO‐3monitoring could be used as a management tool in making fertilizer N recommendations for sunflower (Hellanthus annuusL.). Petiole and leaf samples were taken at the four leaf stage at both sites, and later at two week intervals at Brooksville. Petiole and leaf NO‐3at the four leaf stage was significantly influenced by rate of N application at both sites. The level of petiole and leaf NO‐3was highly correlated with rate of N application as well as with seed yield. The concentration of NO‐3in petioles and leaves was greatest at the four leaf stage and showed quadratic declines as the season progressed. Petiole and leaf NO‐3showed the highest correlations with rate of N application and seed yield at the four leaf stage than at any other sampling time at Brooksville, indicating that this was the “best” period for taking petiole and leaf samples. However, analysis of petioles and leaves at the four leaf growth stage for NO‐3may have limited potential of becoming a useful tool in making N fertilizer recommendations for sunflower. This is due to the sensitivity of both petiole and leaf NO‐3to time of sampling and locational differences, as well as lack of information on response of sunflower to N applied after this stage of growth.

ISSN:0010-3624    

DOI:10.1080/00103628609367787

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628609367779

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor