Einfluß der Cl‐Ernährung auf Ertrag und Nitratgehalt von Spinat und Kopfsalat

Abstract

Zusammenfessung -Summary Durch gezielte CI-Ernahrung konnte das zum Hochstertrag fiihrende N-Angebot bei Friihjahrsspinat von 250 auf 200 kg Nha, bei Herbstspinat von 200 auf 150 kg Nha vermindert werden, ohne daS es zu ErtragseinbuSen kam. Das optimale C1-Angebot des Bodens (Cl-Gehalt in 0-60 cm Bodentiefe + C1-Dungung) lag bei ca. 350 kg Cl/ha, wobei jedoch ein Cl-Angebot in der Krume (0-30 cm) von ca. 300 kg CYha nicht uberschritten werden sollte, weil sonst Auflaufschaden auftreten konnen. Da die Boden der Versuchsstandorte zwischen 66 und 435 kg CYha enthielten, waren unterschiedliche Cl-Diingermengen erforderlich. Hierdurch wurde der Nitratgehalt bis zu 50% vermindert. Diese Abnahme im Nitratgehalt ist auf das um 50 kg Nha verminderte N-Angebot und auf eine verstarkte Reduktion des Nitrats zuriickzufuhren. Bei Kopfsalat fiihrte zusatzliche C1-Dungung bereits bei einem N-Angebot von nur 90 kg Nha zum hochsten Kopfgewicht. Die Reduzierung des N-Angebotes und die Verbesserung der C1-Versorgung bewirkten eine betrachtliche Abnahme im Nitratgehalt. Das C1-Angebot sollte 150 kg CYha in der Bodenschicht 0-30 cm nicht uberschreiten, weil Kopfsalat salzempfindlich ist . Effect of CI-supply on yield and nitrate content of spinach and lettuceThe N-supply for maximum yield could be reduced for spring spinach from 250 to 200 kg Nha, for autumn spinach from 200 to 150 kg Nha without yield depressions by optimized C1-supply. The optimal C1-supply consisting of C1-content in 060 cm soil depth and CI-fertilization was about 350 kg Clha. However, Cl-supply in top soil should not exceed 300 kg CYha in order to avoid emergence decreases. Different amounts of CI-fertilizer were necessary because soils of experimental sites contained chloride in the range of 66 to 435 kg Clha. The nitrate content was reduced up to 50% by C1-fertilization. This was caused by reducing the N-supply by 50 kg Nha and to an increased nitrate reduction.The heighest head weight of lettuce could be achieved with N-supply of 90 kg Nha and additional C1-fertilization. Reducing the N-supply from 120 to 90 kg N h a and improvement of C1-nutrition decreased nitrate content considerably. C1-supply should not exceed 150 kg CYha in 0-30 cm, because lettuce reacts sensitive to saline conditions. E in 1 e i tu n g Zu den Faktoren der Mineralstoffernahrung, die den Nitratgehalt von Pflanzen beeinflussen, zahlt neben der Hohe und der Form der N-Ernahrung die Versorgung mit anderen Nahrstoffen. Hiervon kommt dem Chlorid eine besondere Bedeutung zu, weil zwischen der Nitrat-und C1-Ernahrung Wechselwirkungen bestehen. So berichten CQ44-3263/86/03064303 $ M.50/0 0 VCH Vcrlagsgcseilschaft mbH, D-6940 Weinheim, 1986

Nutrient solution concentration and growing season affect yield and quality of Lactuca sativa L. var. acephala in floating raft culture

“…In the present study, increasing the nutrient solution concentration from 2 to 66 mequiv L −1 caused a linear increase in nitrate content, but the nitrate values in leaf tissues were never as high as the limit value of 4500 mg kg −1 FW imposed by the European Community. The high correlation between nutrient application rates (in particular N) and crop nitrate is in close agreement with the results of several earlier studies on lettuce grown in soil under both field39, 40 and greenhouse14, 41 conditions Moreover, low light levels are associated with nitrate accumulation in some leafy vegetables. For example, Chadjaa et al 42 and Gaudreau et al 43 reported that a reduction in light level was associated with reduced nitrate reductase activity and increased nitrate accumulation in lettuce and spinach.…”

Nitrate versus chloride nutrition effects in a soil‐plant system on the growth, nitrate accumulation, and nitrogen, potassium, sodium, calcium, and chloride content of carrot

“…Partial replacement of NO 3 by chloride decreased the NO 3 content of both shoot and storage root. The reducing effect of Cl is due to the competition between Cl and NO 3 as has been suggested by Kirkby and Knight (1977), Wehrman and Hahndel (1984), Hahndel and Wehrman (1986), Stienstra(1986), Vander Boon et al (1990, Giines et al (1994), and Inal et al (1995). In the present study, calcium chloride increased the storage root nitrate content as compared to KC1, however, Maynard et al (1976) and Barker and Maynard (1971) have stated that Ca had no effect on nitrate accumulation.…”

“…Chloride can partly replace NO 3 as an osmoticum (Roorda van Eysigna, 1984;Bloom-Zandstra and Lampe, 1983). Increasing the concentration of Cl in the nutrient medium can depress NO 3 uptake by the competition between these two ions (Hahndel and Wehrman, 1986;Stienstra, 1986;Van der Boon etal., 1990;Gunes etal., 1994).…”

“…Chloride can partly replace NO 3 as an osmoticum (9,10). Increasing the concentration of chloride in the nutrient medium can depress NO 3 uptake by the competition between these two ions (11)(12)(13).…”

The effect of chloride and nitrogen on nitrate accumulation and yield in beetroot (Beta vulgaris var. conditiva)

“…Nitrification inhibitors together with ammonium and urea fertilizers tend to decrease the nitrate accumulation, but high rates ofnitrogen application involve a risk of ammonium toxicity (Goh and Vityakon 1983, Hähndel andWehrmann 1986 a). Kallio et al (1980) found that nitrapyrin caused a 30 % reduction of nitrate content.…”