摘要:

Growth chamber experiments of canola (Brassica napusL.) and spring wheat (Triticum aestivumL.) were conducted using three soils testing low in extractable sulfate (9–12 mg/kg). Experiments were designed to determine how the three soils compared in plant available sulfur (S) and to test the effects of various rates of potassium sulfate (K2SO4) and gypsum on the elemental composition and dry matter yield of the two crops. Based upon plant response, the Queens sandy loam soil appeared to have the least amount of plant available S of the three soils. There was no yield increase associated with S applied to either crop. Canola plants in each soil responded to increased applications of S with greater S uptake and considerably lower nitrogen:sulfur (N:S) ratios. Of the three soils used, only the wheat plants grown in the Queens soil responded to S applications through increased S uptake and a lower N:S ratio. Both sources of S were equally effective in providing available S to the plants.

ISSN:0190-4167    

DOI:10.1080/01904169409364849

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Effects of several phenolic acids, tea seed cotyledon, and tea waste (factory waste) powder on the rate of nitrification in aerated solution cultures were investigated. Both phenolic acids and tea seed cotyledon powder reduced the amount of nitrate (NO3) produced from ammonium (NH4) or nitrite (NO2) oxidation significantly. When phenolic acids or tea seed powder were mixed with aerated NH4or NO2solutions under sterile (abiotic) conditions separately, there was a considerable loss of both NH4‐N and NO2‐N. It was concluded that the inhibitory effects of phenolic compounds on nitrification reported in literature are mainly due to fixation of NH4and volatilization of NO2by such chemicals resulting in a lower availability of substrates to nitrifying bacteria.

ISSN:0190-4167    

DOI:10.1080/01904169409364850

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A solution culture study was conducted to determine the effects of cadmium (Cd) application on the uptake of Cd, potassium (K), zinc (Zn), manganese (Mn), copper (Cu), iron (Fe) and on the growth of seedlings of three wheat (Triticum turgidumL. var Durum) cultivars, Kyle, Nile, and SC84–994. Cadmium application decreased shoot and root biomass, root length, and leaf area. Cadmium application did not produce any differences among cultivars in these growth parameters. There were differential cultivar responses in the uptake of Cd and K but not for Zn, Mn, Cu, and Fe uptake. A solution Cd concentration of 0.1 μM did not affect the concentration of Cd and K compared to zero Cd but at and above 0.5 μM Cd, Nile had a higher concentration and contents of Cd and K in root and shoot than SC84–994 and Kyle. Kyle and SC84–994 were not different in any of the elements tested except K concentration in shoot where the order was SC84–994<Kyle<Nile. Cadmium application increased the Cd concentration but decreased the concentration of K, Zn, and Mn in root and shoot, while the Fe and Cu concentrations in shoot and root were not affected. Cultivar differences were observed in the translocation of Cd from root to shoot. In SC84–994 and Kyle, 0.5 μmole Cd/L decreased the total Cd translocated to shoot, Further addition of Cd did not affect Cd translocation, whereas in Nile, increased Cd concentration in solution did not affect Cd translocation to the shoot. A modified version of Weibull frequency distribution [y = a exp.(b.Cdc)] was applied to explain the effect of Cd on plant growth parameters and on the uptake of K, Mn, Zn, and Cu in plants.

ISSN:0190-4167    

DOI:10.1080/01904169409364851

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Potassium (K), a plant nutrient with diverse roles to play in plant metabolism, is required in large amounts by most crops. It interacts with many other plant constituents to affect crop yield and quality. The magnitude of this interaction is high in areas of high cropping intensity, as in the tropics. The interaction of nutrients with K may be in the soil or in plant. Potassium modifies ammonium (NH4+) ion fixation in soils to restrict nitrogen (N) availability. On the other hand, an antagonistic effect between K and NH4absorption has been suggested in which K absorption is restricted. Similarly, magnesium (Mg) or calcium (Ca) deficiency occurs from ion antagonism in acid soils following K fertilization and in soils with high exchangeable K. Sulfur (S) has been reported to increase K absorption and productivity of oilseed crops. With increasing levels of applied or soil K, the severity of phosphorus (P)‐induced zinc (Zn) deficiency in corn has been observed to decrease. Application of K decreases manganese (Mn) content and iron (Fe) toxicity in rice. Application of K has been reported to decrease B levels in plants and to increase incidence of boron (B) deficiency. Top‐dressing with K fertilizer was reported to lower the copper (Cu) content of alfalfa forage. In root, sugar‐producing, or fiber‐producing crops, the sodium (Na) and K relationship is important with the specific response to either element depending on which element is in low or high supply. Molybdenum (Mo) stimulated K uptake in alfalfa and com. In intensive agriculture with high‐yielding single crops or with multiple crops per year, farm management must include strategies to maintain substantial K reserves in the soil and to balance K nutrition with other fertilization practices.

ISSN:0190-4167    

DOI:10.1080/01904169409364852

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

As a part of the study of environmental contamination by arsenic (As), we have undertaken the analysis of the effects caused by arsenic on the processes of absorption and accumulation of the micronutrient elements, boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in tomato (Lycopersicum esculentumMill, cultivar Marmande). Therefore, an experiment has been carried out in a hydroponic culture in which different levels of As were used (added in the form of sodium arsenite) in concentrations of 2, 5, and 10 mg/L together with the corresponding control plants. Contamination by As causes changes to take place in both the absorption and transport of all the micronutrients. A reduction in the absorption of B, Cu, Mn, and Zn is observed while there is an increase in the absorption of Fe. In all the cases, there is a reduction in the transport of these elements towards the aerial part of the plant, no doubt as a result of the structural damage caused to the plant.

ISSN:0190-4167    

DOI:10.1080/01904169409364853

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Seed samples of diploid, tetraploid, and hexaploidbuffalograss (Buchloe dactyloides) were collected from locations over a geograptucal latitudinal gradient from San Luis Potosi, Mexico to Lincoln, Nebraska in the United States. Seed samples and samples of vegetatively propagated clones were tested for salt tolerance and salt uptake. Under nutrient solution culture, young shoots separated from the established buffalograss clones were found to be more tolerant to salt than the seedlings. Significant difference was found in the percentage of seedling survivorship among the populations. Substantial genetic variation of salt tolerance was detected among the vegetatively propagated clones within buffalograss populations. Over all, the buffalograss can he considered to be a moderately salt sensitive species. Its wealth of genetic variation of salt tolerance represents a potential for rapid salt tolerance selection response. A salt exclusion mechanism was found in the tolerance mechanism of the buffalograss. A greater sodium (Na) concentration was found in the root tissue than in the shoot tissue, suggesting a preferential exclusion of Na taken up by the shoots. The negative correlations between the plant tissue potassium (K) concentrations and Na/K ratios indicate a partial substitution of K by Na, and there was a less substitution of K by the more salt tolerant plants than the less tolerant plants. Differential susceptibility to calcium (Ca) disorders at high Na/Ca levels was detected between the salt tolerant and salt sensitive buffalograss genotypes.

ISSN:0190-4167    

DOI:10.1080/01904169409364854

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Two cultivars of lettuce plants (Lactuca sativaL. cvs Berlo and Kirsten) were grown for two months in late fall in NFT under three different nitrogen (N)‐regimes but with the same total N concentration (13.4 mM). A reference treatment with a nutrient solution containing 94% nitrate (NO3) and 6% ammonium (NH4) was compared with urea and proteinate treatments in which 20% of the NO3of the reference treatment was replaced by either of these two N sources. Proteinate is a fertilizer produced in Turkey containing 8% amino acid N and 8% NO3‐N. For both cultivars the fresh weights of the harvested plants were unaffected by the N source as was also the total N uptake. Nitrate content, however, was considerably lower in the urea and proteinate plants, values for the three treatments ranging from 3314 to 4579 mg NO3/kg fresh wt making up from between 44.3% to 55.4% of the total plant N. Of the two cultivars, Berlo accumulated greater concentrations of NO3than did Kirsten. The accumulation of chloride (Cl) was in the reverse order of that of NO3with greatest concentrations occurring in the proteinate plants.

ISSN:0190-4167    

DOI:10.1080/01904169409364855

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Increasing atmospheric carbon dioxide (CO2) concentration could have significant implications on technologies for managing plant nutrition to sustain crop productivity in the future. Soybean (Glycine max[L.] Merr.) (C3 species) and grain sorghum (Sorghum bicolor[L.] Moench) (C4 species) were grown in a replicated split‐plot design using open‐top field chambers under ambient (357 μmol/mol) and elevated (705 μmol/mol) atmospheric CO2. At anthesis, leaf disks were taken from upper mature leaves of soybean and from the third leaf below the head of sorghum for analysis of plant nutrients. Leaf greenness was measured with a Minolta SPAD‐502 chlorophyll meter. Concentrations of chlorophyllsaandband specific leaf weight were also measured. Above‐ground dry matter and seed yield were determined at maturiry. Seed yield of sorghum increased 17.5% and soybean seed yield increased 34.7% with elevated CO2. There were no differences in extractable chlorophyll concentration or chlorophyll meter readings due to CO2treatment, but meter readings were reduced 6% when sorghum was grown in chambers as compared in the open. Leaf nitrogen (N) concentration of soybean decreased from 54.5 to 39.1 g/kg at the higher CO2concentration. Neither the chambers nor CO2had an effect on concentrations of other plant nutrients in either species. Further work under field conditions is needed to determine if current critical values for tissue N in crops, especially C3 crops, should be adjusted for future increases in atmospheric CO2concentration.

ISSN:0190-4167    

DOI:10.1080/01904169409364856

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Methanol applied to foliage has been reported to reduce water use of C3 crops. Two field experiments on peppermint measured both plant performance and soil water depletion for methanol, glycine, and an untreated control. No differences were found in dry matter yield, oil yield, plant height, leaf weight, or water use. Preliminary phytotoxicity studies showed no toxicity or necrosis at concentrations up to 99 percent methanol applied at a rate of 187 L/ha in the field.

ISSN:0190-4167    

DOI:10.1080/01904169409364857

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

After 18 years of growing in sodpodzolic soil, the extent of root system of pear cultivar ‘Beurre Loshitskaya’ on Quince A, C, and pear seedlings rootstocks were determined by excavation. Trees were planted at distances 5x3 m and had compact canopies. Orchard was clean cultivated with herbicide strips in the row. Mean specific mass of fibrous roots on Quince A and C surpassed the seedling rootstock by 56 and 29%, respectively. Pear seedling had much greater specific mass of scaffold roots but specific length of these roots was significantly smaller in comparison with Quince A and C, scaffold root mass was 17, 60, and 89%, respectively, in the 0–30 cm soil layer, but quince rootstocks had a higher density of fibrous roots in the layer of 30–60 cm. A significant difference was not noted in location of pear and quince roots in horizontal direction. Root density in the middle of the orchard alley was three to four times less than near the tree but specific mass of fibrous roots changed little beyond 1 m distance from the trunk to the middle of the row and was not related to rootstock. Fruit yield efficiency did not correlate with root system parameters for any of the rootstocks tested.

ISSN:0190-4167    

DOI:10.1080/01904169409364858

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor