Environmental factors and cultural measures affecting the nitrate content in spinach

Breimer, T.

doi:10.1007/bf01063766

Cited by 46 publications

(17 citation statements)

References 89 publications

(72 reference statements)

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“…ha -~. This agrees with Gysi et al (1989), but is in contrast to B6hmer (1980), Breimer (1982), Greenwood et al (1982) and H~ihndel (1984). Reasons might be that the latter authors considered N O 3 in deeper soil layers as available and that yield levels were different.…”

Section: Discussionsupporting

confidence: 65%

“…The useable soil depth is assumed to be 40-60 cm for both spinach and kohlrabi (B6hmer, 1980;Breimer, 1982;Greenwood et al, 1982;H~ihn-del, 1984). This, however, is in contradiction to the root distribution of both crops, which at maximum root growth (harvest time) have less than 5% of their total root length below a soil depth of 30 cm (Heins and Schenk, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…Optimum N fertilizer recommendations for spinach also vary from 150-250kgNha- (B6hmer, 1980;Breimer, 1982;Gysi et al, 1988;Greenwood et al, 1982;H/ihndel, 1984). One reason for such a large variation may be due to the different definition of the useable soil layer for the measurement of the Nmi .…”

Section: Introductionmentioning

confidence: 99%

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The significance of root development of spinach and kohlrabi for N fertilization

Heins

Steingrobe

1991

Plant Soil

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N fertilizer recommendations are based on the Nmi n c o n t e n t in the useable soil layer. However, for spinach, information from the literature differs for both depth of useable soil layer and N fertilizer recommendations. The objectives of these experiments were to study the importance of different soil zones for N supply to spinach and to kohlrabi, and to examine the relationship between N supply in the useable soil layer and yield of spinach.Field experiments with both crops showed that about 80% of total root length was in the upper 0-15 cm soil layer and less than 5% below 30 cm. Spinach roots were present in the 15-30 cm layer only during the last 2 weeks before harvest, whereas kohlrabi roots penetrated this layer already 4 weeks before harvest. Placement of NO 3 below 30 cm depth did not influence root distribution. The top layer contributed about 80% to total N uptake for both crops. The 15-30cm soil layer can maximally contribute 40-50 kg N ha-i. It is concluded that N fertilizer recommendations for both crops should be based on the Nmi n content of the 0-30 cm soil layer.Maximum yield of spinach (300dt f.m. ha -1) was obtained at 150 kgN supply ha -~. The nitrate residue was 50 kg N ha-~ at 0-30 cm in this treatment. It is argued that the nitrate residues at harvest could be decreased by delaying the harvest for a few days, at slightly suboptimal N supply.

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Section: Discussionsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

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The significance of root development of spinach and kohlrabi for N fertilization

Heins

Steingrobe

1991

Plant Soil

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“…13,14 However, at a higher temperature and at lower light intensity (characteristic of a greenhouse during the winter season), higher nitrate content was reported in spinach. 15 Further, from a biochemical perspective, the pungency of onion was found to be very high when nitrate was applied as the nitrogen source, and the familiar taste of onions is associated with the pyruvate concentration. 16,17 A significant reduction in the pyruvate concentration when ammonium was the only nitrogen source has been reported.…”

Section: Discussionmentioning

confidence: 98%

Influence of nitrogen fertilizers on yield and antifungal bioactivity of Tulbaghia violacea L.

Heever¹,

Allemann

Pretorius

2008

Hum Exp Toxicol

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Tulbaghia is known to have antifungal properties that can be used in the treatment of both human and plant pathogens and is used in traditional medicine in South Africa. Increasing demands for plant material makes it necessary to cultivate this species on a large scale. Unfortunately, cultivation can lead to a reduction in the biological activity of plants making them unsuitable for use. In light of the lack of knowledge regarding the agronomic requirements of this plant, the aim of this study was to determine the effect of several rates and two forms of nitrogenous fertilizer on the yield and biological activity of Tulbaghia violacea. Plants were cultivated in sand while the basic fertilization used was the same as that of garlic (20 kg P ha−1, 75 kg K ha−1), a plant from the same family, containing similar active ingredients. Nitrogen was applied once at the beginning of the trial at rates of 30, 60, 120, and 180 kg ha−1 in the form of either nitrate or ammonium. Vegetative growth was quantified in terms of number of leaves and leaf area as well as root and leaf dry mass, while harvested material was tested for antifungal activity. The results indicated that compared with the untreated control, increasing N-rates in both the nitrate and ammonium forms increased leaf number and leaf area as well as both root and leaf dry mass. However, at a rate above 60 kg ha−1, and especially at 180 kg ha−1, the nitrate form stimulated growth more markedly than the ammonium form, whereas antifungal activity decreased sharply and almost linearly as the application rate was increased. Although growth was not stimulated to the same extent by the ammonium form, it increased the in-vitro antifungal activity at different levels during different times of the growing season. From an ornamental perspective, nitrate is the preferred nitrogenous form but, from a bioactivity perspective, ammonium is recommended.

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“…In these regions, agriculture is confronted with the @)direct side effects of current management leading to nutrient losses to the environment (Isermann, 1990;Bussink, 1992;, adverse effects on product quality (Breimer, 1982), high energy inputs (Fluck, 1992), production of greenhouse gases (Granli and Bmkman, 1994;Koops, Oenema, and Van Beusichem, 1996;Velthof, Brader, and Oenema, 1996), acidification (Oenema, 1990), etc.…”

Section: General Introductionmentioning

confidence: 99%

Soil and Plant Testing Programs as a Tool for Optimizing Fertilizer Strategies

Erp

Beusichem

1998

Journal of Crop Production

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Soil and plant testing programs are still based o n 'trial and error' methods and lack scientific underpinning in terms of relevant soil chemical and plant nutritional processes, and are site-specific. The programs are valuable when the objective is to diagnose and predict deficiencies of plant nutrients. The programs are less valuable for refined fertilizer strategies, like Integrated Nutrient Management, which are essential in the near future to satisfy changing agricultural, environmental, economic and legislative boundary conditions. A more scientific approach to soil and plant testing programs appears desirable. To reduce undesirable side-effects of fertilization on the environment, more empliasis should be placed on fertilizer type and on timing arid method of application. [Article copies availal~le for n feeefiorn The Haii~orth Docinnerlt Delivery Setvice: I -8OO-342-9678. E-niail address: getirfo@ hai.car~tii~ressiric. corn]

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Environmental factors and cultural measures affecting the nitrate content in spinach

Cited by 46 publications

References 89 publications

The significance of root development of spinach and kohlrabi for N fertilization

The significance of root development of spinach and kohlrabi for N fertilization

Influence of nitrogen fertilizers on yield and antifungal bioactivity of Tulbaghia violacea L.

Soil and Plant Testing Programs as a Tool for Optimizing Fertilizer Strategies

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