Nitrogen dynamics under greenhouse conditions as influenced by method of alfalfa termination. 1. Volatile N losses

Mohr, Ramona M.; Janzen, H. H.; Entz, Martin H.

doi:10.4141/s96-025

Cited by 17 publications

(22 citation statements)

References 22 publications

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“…But, in a similar study (Mohr et al 1998), in uncropped soil containing terminated alfalfa which was incubated for 95 d, soil NO 3 --N accumulations were 51.3 and 37.8 mg NO 3 --N kg -1 for incorporated and unincorporated treatments, respectively (P = 0.03). Again, termination method had no effect on soil NO 3 -concentration.…”

Section: Effect Of Termination Methods On N Release From Alfalfamentioning

confidence: 72%

“…Procedures for alfalfa establishment and termination have been described by Mohr et al (1998). In brief, six plants of alfalfa (cv.…”

Section: Experiments 1: Effect Of Termination Methods On N Release Frommentioning

confidence: 99%

“…Mohr, R. M., Janzen, H. H. and Entz, M. H. 1998. Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2.…”

mentioning

confidence: 99%

“…Key words: Plant-available N, termination method, alfalfa, herbicide, tillage, growth chamber Mohr, R. M., Janzen, H. H. et Entz, M. H. 1998. Cinétique de l'azote en chambre de végétation selon la méthode de destruction d'une prairie de luzerne 2.…”

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“…Various studies have demonstrated that the available N supply is larger when legume residues are incorporated into the soil than when they are surface applied (McCalla and Russel 1948;McKay et al 1952;Wilson and Hargrove 1986). These differences were generally thought to be the result of enhanced mineralization of incorporated residues, although reduced volatile N losses from incorporated residue may also contribute to these differences (Janzen and McGinn 1991;Mohr et al 1998). …”

mentioning

confidence: 99%

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Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2. Plant-available N release

Mohr¹,

Janzen²,

Entz³

1998

Can. J. Soil. Sci.

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. 1998. Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2. Plant-available N release. Can. J. Soil Sci. 78: 261-266. Herbicide application has been proposed as an alternative to tillage for termination of established alfalfa (Medicago sativa L.) stands but it may alter the pattern and amount of N released from alfalfa residues. A controlled environment study was conducted to investigate the effect of termination technique on the availability of N to four barley (Hordeum vulgare L.) crops. Four treatments consisting of a factorial combination of two termination methods (chemical, mechanical) and two methods of residue placement (surface, incorporated) were established. Nitrogen uptake by the four consecutive crops of barley was measured during a 125-d period after termination. Termination method, particularly residue placement, strongly affected N release from alfalfa residues. Nitrogen accumulation by the initial barley crop accounted for >60% of cumulative N uptake in incorporated treatments compared with 39% and 24% for herbicide and tillage treatments in which alfalfa residue was surface applied. Herbicide application also slightly increased N uptake by the initial barley crop. Nitrogen uptake by subsequent barley crops was not affected by termination method; however, cumulative N uptake remained substantially greater for incorporated treatments throughout the 125 d experiment. Effects of residue particle size on N release from alfalfa residues were small. These results suggest that herbicide termination in which residue is retained on the soil surface may reduce the short-term plant-available N supply. Provided that mineralization is sufficient to meet the N needs of subsequent crops, maintaining a smaller reservoir of soil inorganic N may be beneficial in reducing the potential for leaching or denitrification losses. Le N absorbé par la première culture d'orge correspondait à plus de 60 % de l'exportation cumulative de N dans les traitements avec incorporation, contre, respectivement, 39 et 24 % pour le traitement herbicide et pour le traitement cultural avec localisation des restes en surface. La méthode chimique donnait également lieu à un léger accroissement de l'absorption de N par la première culture d'orge. L'absorption du N par les soles subséquentes d'orge était sensiblement la même indépendamment de la méthode de destruction utilisée, bien que l'exportation cumulative de N par chaque culture demeurat sensiblement plus forte dans les traitements avec incorporation tout au long de l'expérience. Les effets de la grosseur particulaire des restes sur la libération du N de la luzerne étaient de faible importance. Ces observations incitent à conclure que la destruction chimique serait susceptible de réduire la disponibilité à court terme du N assimilable. Pour autant que le degré de minéralisation soit suffisant pour satisfaire au besoin en azote des cultures subséquentes, le maintien d'un réservoir moins abondant de N minéral dans le sol aurait l'avantage ...

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Section: Effect Of Termination Methods On N Release From Alfalfamentioning

confidence: 72%

“…Procedures for alfalfa establishment and termination have been described by Mohr et al (1998). In brief, six plants of alfalfa (cv.…”

Section: Experiments 1: Effect Of Termination Methods On N Release Frommentioning

confidence: 99%

“…Mohr, R. M., Janzen, H. H. and Entz, M. H. 1998. Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2.…”

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confidence: 99%

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Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2. Plant-available N release

Mohr¹,

Janzen²,

Entz³

1998

Can. J. Soil. Sci.

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Influence of time and method of alfalfa stand termination on yield, seed quality, N uptake, soil properties and greenhouse gas emissions under different N fertility regimes

Malhi

Lemke

Schoenau

2009

Nutr Cycl Agroecosyst

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A field experiment was conducted in a 7-year old alfalfa stand to compare the influence of time and method of terminating alfalfa stands on crop yield, seed quality, N uptake and recovery of applied N for wheat (Triticum aestivum L.) and canola (Brassica napus L.), soil properties (ammonium-N, nitrate-N, bulk density, total and light fraction organic C and N), and N 2 O emissions on a Gray Luvisol (Typic Cryoboralf) loam near Star City, Saskatchewan, Canada. The treatments were a 3 9 3 9 4 factorial combination of three termination methods [herbicide (H), tillage (T), and herbicide ? tillage (HT)], three termination times (after cut 1 and cut 2 in 2003, and in spring 2004) and four rates of N (0, 40, 80 and 120 kg N ha -1 ) applied at seeding to wheat-canola rotation from 2004 to 2007.In the termination year, soil nitrate-N was considerably higher in T or HT treatments than in the H treatment and decreased with delay in termination. In the first crop year, seed and straw yields of wheat grown on T and HT treatments were significantly greater than H alone (by 1,055-1,071 kg seed ha -1 and by 869-929 kg straw ha -1 ), due to greater content of soil available N in T treatments. Yields decreased with delay in termination time. In general, yield and N uptake in seed and straw, and protein concentration tended to increase with increasing N rate. A greater yield increase occurred on the H compared to T and HT treatments from the first increments of N applied. Nitrous oxide emissions were generally low and there were no treatment differences evident when cumulative 4-year N 2 O-N losses were compared. Appropriate N fertilization was able to compensate for yield reductions due to delayed termination timing, but could not do so entirely for yield reductions on the H compared to T or HT termination method. The amounts of TOC, TON, LFOC and LFON after four growing seasons were usually higher or tended to be higher under H treatment than under T treatment in the 0-5 cm soil layer, but the opposite was true in the 5-10 cm or 10-15 cm soil layers.

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Nitrogen supply by cut-and-carry biomass for vegetable crops and subsequent cereals

Katroschan,

Hirthe

2024

Nutr Cycl Agroecosyst

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Nitrogen dynamics under greenhouse conditions as influenced by method of alfalfa termination. 1. Volatile N losses

Cited by 17 publications

References 22 publications

Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2. Plant-available N release

Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2. Plant-available N release

Influence of time and method of alfalfa stand termination on yield, seed quality, N uptake, soil properties and greenhouse gas emissions under different N fertility regimes

Nitrogen supply by cut-and-carry biomass for vegetable crops and subsequent cereals

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