ISSN:0010-3624    

DOI:10.1080/00103627009366242

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Squash (Cucurbita pepo), cucumber (Cucumis sativus) and sweet melon (Cucumis dudain) plants were grown in sand culture with N as the variable and were harvested at the early flowering stage. The plants at this time showed a definite gradation of symptoms from severe to no deficiency of N. The tops were separated into leaves and stems. Leaves were separated into young, mature and old and then subdivided respectively into petioles and blades. The petioles were analyzed for NO3‐N. The critical NO3‐N concentration for squash, cucumber and melon on a dry basis was 1000, 2000 and 3000 ppm, respectively. A relatively high concentration of NO3‐N in the nutrient solution decreased the growth of squash and cucumber plants significantly, but had no effect on melon plants. Melon plants can tolerate relatively high concentrations of N0,‐N in the plant tissues, while squash and cucumber cannot.

ISSN:0010-3624    

DOI:10.1080/00103627009366243

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Studies involving methylation, dissolution, infrared spectroscopy and gas‐liquid chromatography were conducted with humic compounds extracted from a Greenville loam and a Cecil sandy loam.

ISSN:0010-3624    

DOI:10.1080/00103627009366244

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Samples of two widely divergent soils, a Waupun silt loam and a Plainfield sand, deficient in P, were treated with 0, 20 or 80 ppm As and 0, 50, 100 or 300 ppm P in all possible combinations and cropped twice for 40 days to corn in the greenhouse. Arsenic had a much more pronounced toxicity to corn in the sand than on the silt loam. At the 80 ppm As level, P had little effect on As toxicity with the silt loam but enhanced toxicity with the sand and increasing rates of P increased As uptake by corn. At the 20 ppm As level, P did not affect As toxicity or uptake. Soil As extracted byNNH4OAc(pH 7.0) decreased with time but increased with increasing levels of applied P. Bray Pl extractable As was not greatly affected by applied P or time, and appeared to be a more suitable “available”; soil As test. From the results obtained, it would appear that P applications are not the solution to an As toxicity problem.

ISSN:0010-3624    

DOI:10.1080/00103627009366245

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Three tobacco varieties were grown under four soil fertility conditions. Leaf samples were taken at bloom stage from upper and lower positions and analyzed for eleven elements. Results show how leaf position and variety affect leaf mineral composition with variable soil conditions. Therefore, variety and leaf position should be clearly defined before leaf nutrient levels can have a suitable degree of diagnostic value. However, variety differences were of less importance because nutrient concentration differences were generally related to appropriate changes in yield measurements.

ISSN:0010-3624    

DOI:10.1080/00103627009366246

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

A method is described for determining the total N content of plant tissue by a modified Kjeldahl digestion employing a Technicon Auto‐Analyzer. It is faster than the manual AOAC Kjeldahl method. Reproducibility is not as good as that for the AOAC method, but coefficients of variability are comparable with those for the analyses of mineral elements in plant tissue by emission spectroscopy.

ISSN:0010-3624    

DOI:10.1080/00103627009366247

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Oats were grown in perlite and nutrient solution at temperatures varying from 10/5°C (day/night) to 36/31°C. The optimum temperature for growth of tops was found to be 27°C day/22°C night over an eight week period. Plant S content showed an inverse relationship with yield.

ISSN:0010-3624    

DOI:10.1080/00103627009366248

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627009366241

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor