ISSN:0010-3624    

DOI:10.1080/00103627409366503

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

An established stand of Ranger alfalfa was topdressed with equal rates, but different combinations, of N, P, and K. Five harvests were taken and the material analyzed for cation concentrations.

ISSN:0010-3624    

DOI:10.1080/00103627409366504

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Existing colorimetric manual methods for copper and iron have been adapted for simultaneous analysis by an automated method. Fifty samples per hour can be assayed. Calculation of results as parts per million in dry matter has been eliminated by a standardized weighing technique of the plant material.

ISSN:0010-3624    

DOI:10.1080/00103627409366505

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Spinach was grown in the greenhouse in soil with the pH adjusted to 5.0, 5.5, 6.0, 6.5, and 7.0, N fertilizer rates of 0, 50 and 200 mg N/Kg soil, and Mo fertilizer rates of 0, 0.3 and 1.2 mg Mo/Kg soil. The NO3‐N concentration of the tissue increased with fertilizer N or a rise in pH from 5.0 to 7.0. The addition of Mo at either rate reduced the NO3concentration of spinach grown at pH 5.0 and 5.5 but had no effect on plants grown at pH 6.5 or 7.0. At pH 6.0 the 1.2 mg Mo/Kg soil rate was effective at the 50 and 200 mg N/Kg soil fertilizer rates but had no effect on spinach grown without a N application. At the same pH, the 0.3 mg Mo/Kg soil rate had no effect on NO3content of spinach grown with the 50 mg N/Kg rate but did reduce the NO3content of spinach grown without N added or with the 200 mg N/Kg soil. The 1.2 mg Mo/Kg soil rate was more effective than 0.3 mg Mo/Kg rate in reducing NO3content of spinach grown with 200 mg N/Kg soil at pH 5.0–6.5 inclusive but gave variable results when no N or 50 mg N/Kg soil was added. Molybdenum did not affect the total N or NO2concentrations of the plants.

ISSN:0010-3624    

DOI:10.1080/00103627409366506

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

An improved version of a soil incubation apparatus which can be used in various aerobic and anaerobic soil incubation studies is described. This apparatus facilitates periodical sampling of gas as well as any gas absorbent without disturbing the gas‐tight atmosphere. Maintenance of any partial pressure of oxygen is possible in aerobic or partially aerobic incubation studies. Assemblage of this incubation set‐up is simple and does not require expensive equipment.

ISSN:0010-3624    

DOI:10.1080/00103627409366507

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The seasonal patterns of foliage nutrient concentrations and contents were monitored for two growing seasons in an 11‐year—oldPinus el1iottiistand. In the first growing season after needle initiation, N, P, K, Mg, and Zn concentrations decreased, but this was followed by an increase in the fall and winter months. Another drop in concentration of all elements, except P, occurred in the second growing season. Decreases in total contents indicated that this drop was a result of translocation to other tissues. In contrast to the mobile elements, the concentration and fascicle contents of Ca, Mn, and Al increased with aging of the needles.

ISSN:0010-3624    

DOI:10.1080/00103627409366508

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Sudangrass (Sorghum sudanense, ‘Piper’ Stapf) was grown in the greenhouse in a slightly calcareous sample of Shano silt loam. The purpose of the study was to evaluate plant response to Mg and to determine any changes in Mg nutrition following individual or composite application of Mg, Ca, K and Na as nitrate compounds. The concentration of Mg in plant tissue decreased following K application and increased with each increment of Mg applied irrespective of variations in the proportions of Ca and Na included in the treatments. A base treatment including Ca, Na, and K applied with or without Mg showed a significant yield response to Mg. The Mg response was attributed to a more favorable ionic balance in the growth medium with respect to Mg because the soil was not particularly Mg deficient. Application of Mg in this case lowered the plant K concentration significantly, increased the concentration of Mg, and gave a lower K/(Ca+Mg) ratio in the foliage than was obtained without Mg. Results suggest that high levels of other nutrient cations may adversely affect the Mg nutrition of crops growing on alkaline soils not abundantly supplied with available Mg.

ISSN:0010-3624    

DOI:10.1080/00103627409366509

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Incubation tests were run to compare nitrification rates of soil from different depths of a Piano silt loam (Typic Arguidoll). Nitrates accumulated most rapidly during the first week of incubation (5 ppm NO3‐N/day) in samples taken from 15 cm of the soil surface. A reduction in rate to 2 to 3 ppm NO3‐N/day after the first week could be due to reduced NH4substrate. Nitrates did not accumulate during the first three weeks of incubation for subsoil samples taken below 30 cm. After three weeks the accumulation rate was 1.2 ppm No2‐N/day or less. It is concluded that nitrification is largely confined to the Ap horizon in the Piano silt loam.

ISSN:0010-3624    

DOI:10.1080/00103627409366510

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A number of procedures were tested for determining carbonate‐C in soils and limestones, using a simple technique for digesting and collecting the CO2, previously described by the author10. Some of the procedures appeared suitable for removing and quantifying carbonate‐C prior to the determination of organic‐C. Depending on the digestion solution and the length of treatment, between 0.25 and 0.68%of the organic‐C in cultivated mineral soils was released as CO2during the digestion, and thus included in the figures for carbonate‐C.

ISSN:0010-3624    

DOI:10.1080/00103627409366511

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A field experiment was conducted on an alkaline calcareous soil of Agronomy farm of the College of Agriculture, University of Udaipur to study the effect of sulphur on crop yield, leaf elemental composition, chlorophyll synthesis and activities of haematin enzymes. Application of elemental sulphur 21 days before planting with and without 0.1 per cent foliar sprays of H2SO4. increased crop yield by 137 to 197 per cent. Application of all these treatnents had no effect on nitrogen, phosphorus and potassium content of leaves but sulphur content was signficantly increased. Iron content of green leaves was decreased significantly 4 to 5 times together with an increase in the activity of catalase and peroxidase enzymes. Chlorosis in these soils appears to be on account of a reduced physiological availability of iron after absorption.

ISSN:0010-3624    

DOI:10.1080/00103627409366512

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor