ISSN:
1573-0867
Schlagwort(e):
spinach
;
NO3-content
;
ionic balance
;
plant age
;
season of growth
;
soil moisture
;
soil pH
;
Mo-spraying
;
light intensity
;
temperature
;
K-dressing
;
P-dressing
;
varietal differences
;
N-dressing
;
plant-available N
;
N-form
;
NO3: NH4-ratio
;
nitrification
;
inhibitors
;
type of N-carrier
;
time of application of N
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
Notizen:
Abstract Environmental factors and cultural measures affecting the NO3-content in spinach were studied indoors, in water-, sand- and soil-culture experiments. In the field, the influences of variations in N-fertilizing practices and in spinach varieties were also tested. High NO3-contents in spinach were found with low light intensities, with low soil-moisture contents, and with high temperatures. NO3-contents increased with increasing K-dressing (less so with KCl than with K2SO4), but decreased with increasing soil pH. In pot experiments, positive results were obtained with sulphur-coated urea, with farmyard manure and with pigmanure slurry. Application of Mo as a spray onto spinach leaves, and variations in P-dressings and in soil P-status were found not to affect the NO3-content in spinach. In pot experiments, NO3-contents decreased with progressing plant age (in autumn less so than in spring). Within spinach plants, NO3-contents were highest in petioles and older leaves. Varietal differences in NO3-contents were observed in a pot- and a field experiment. In pot- and field experiments, partial or complete replacement of NO3-N by NH4-N in general caused the NO3-content in spinach to decrease. However, such a replacement was shown not always to result in lower NO3-contents. Additional factors involved are e.g. the use and effectiveness of nitrification inhibitors, the soil type and the amount of available N. The amount of N added and, in the field, the amount of N available in the soil before sowing, strongly affected the NO3-content in spinach. Under field conditions, nitrogen appeared to be taken up from the top 60 cm of the soil profile. The effects of variations in timing of nitrogen applications were absent in a pot experiment and not consistent in field experiments.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01063766
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