A Nitrogen and Water Response Surface for Sprinkler‐Irrigated Broccoli 1

in response to increasing rates of pre-plant nitrogen. I Yield and quality. Can. J. Plant Sci. 89: 527Á537. Nitrogen management is critical to the production of broccoli (Brassica oleracea L. italica Plenck). Field trials were conducted in 2001 and 2002 to determine the rate of pre-plant nitrogen required to optimize broccoli yield and quality. Seven rates of nitrogen (0, 50, 100, 150, 200, 300, 400 kg N ha (1 ) as ammonium nitrate were broadcast and incorporated before transplanting two broccoli cultivars, Captain and Decathlon. Maturity of the heads was delayed by 5 d at 0 kg N ha(1 compared with the other rates of applied N. Marketable yield was maximized at 243 to 272 kg N ha(1 for yield expressed in t ha (1 and 171 to 187 kg N ha (1 for yield expressed as cases ha (1 . Averaged over cultivar and year the most economical rate of nitrogen (MERN) ranged from 298 to 309 kg ha(1 , 50 kg higher than estimates for the maximum marketable yield derived from quadratic plateau models. The incidence of misshapen heads decreased and floret color improved as nitrogen rate increased, but hollow stem and head rot also increased with high rates of nitrogen. Floret NO 3 ( -N concentration increased and vitamin C concentration decreased at high nitrogen rates. Applying the rates of nitrogen required to maximize yield may have negative economic and environmental consequences. However, restricting nitrogen also jeopardizes both yield and quality. Hence, the optimum amount of pre-plant nitrogen to apply to broccoli that balances yield, quality, economics and environmental concerns remains a complex issue. , les auteurs ont proce´de´a`des essais sur le terrain afin de de´terminer le taux de fertilisation azote´e requis avant la plantation pour optimiser le rendement et la qualite´de cette culture. Pour cela, ils ont e´pandu a`la vole´e puis incorpore´au sol de l'azote sous forme de nitrate d'ammonium a`sept taux (0, 50, 100, 150, 200, 300 et 400 kg de N par hectare), avant le repiquage des cultivars Captain et Decathlon. Comparativement aux autres taux, l'application de 0 kg de N par hectare retarde la maturation des pommes de cinq jours. Le rendement commercialisable atteint un maximum au taux de 243 a`272 kg de N par hectare quand on l'exprime en tonnes par hectare ou a`celui de 171 a`187 kg de N par hectare quand il est exprime´en cageots par hectare. Le taux d'application le plus e´conomique apre`s calcul de la moyenne par cultivar et par anne´e se situe entre 298 et 309 kg de N par hectare, soit 50 kg de plus que ce que les mode`les a`plateau quadratique estiment ne´cessaire pour parvenir au meilleur rendement commercialisable. L'incidence des pommes difformes diminue et la couleur des fleurons s'ame´liore avec la hausse du taux d'application, mais on note e´galement une hausse du nombre de tiges creuses et de pourriture de la pomme quand le taux d'application est e´leve´. La concentration de N-NO 3 ( dans les fleurons augmente tandis que celle de vitamine C diminue avec la hausse du taux d'application. L'application du ...

Section: T Hamentioning

confidence: 80%

mentioning

confidence: 99%

Broccoli growth in response to increasing rates of pre-plant nitrogen. I. Yield and quality

Bakker¹,

Swanton²,

McKeown³

2009

“…This differed from 2002, when at 14 d after planting, the rate of DM accumulation increased with high nitrogen rates but at 56 d after planting, the rate of DM accumulation was highest in the 0 kg N ha (1 plots. Magnifico et al (1979), Beverly et al (1986) and Bowen et al (1999) reported a similar pattern in DM accumulation over time, although values for DM varied among studies.…”

Section: Plant Growth and Tissue Nitrogen Analysismentioning

confidence: 81%

“…(1 (Cutcliffe et al 1968;Letey et al 1983;Beverly et al 1986;Shattuck and Shelp 1987;Zebarth et al 1995;Sanchez et al 1996;Thompson et al 2002a). Bakker et al (2009) applied seven rates (0 to 400 kg N ha…”

mentioning

confidence: 99%

Broccoli growth in response to increasing rates of pre-plant nitrogen. II. Dry matter and nitrogen accumulation

Bakker¹,

Swanton²,

McKeown³

2009

An understanding of plant nitrogen accumulation and soil nitrogen dynamics is needed to develop management practices that balance nitrogen requirements of vegetable crops with environmental protection. Field trials were conducted in 2001 and 2002 to determine the interaction of increasing rates of pre-plant nitrogen fertilizer with broccoli tissue nitrogen accumulation and soil nitrogen dynamics. Broccoli cultivars Decathlon and Captain were grown with seven rates of nitrogen (0, 50, 100, 150, 200, 300, 400 kg N ha-1) applied pre-plant as ammonium nitrate. Rate of nitrogen accumulation by the above-ground tissue biomass varied over time and among nitrogen treatments, ranging from 1 to 16 kg N ha-1 d-1. At harvest, tissue nitrogen was high, but nitrogen use efficiency was low when high rates of nitrogen were applied. Soil NO3--N content decreased from planting to harvest. At harvest, soil NO3--N increased with increasing rates of nitrogen, with the majority of NO3--N found in the top 0 to 30 cm of the soil. At 200 kg ha-1 applied nitrogen, plants recovered essentially all of the estimated available nitrogen and there appears to be little risk of nitrogen loss during the growing season. Approximately 130 kg N ha-1 was supplied by the soil during the cropping season. Soil and crop residues at harvest ranged from 96 to 330 kg N ha-1. This residual fertility poses a risk for nitrogen loss. Practical and cost-effective strategies are needed to manage residual nitrogen in the soil and crop residues to minimize loss and retain this nitrogen for subsequent crops. Key words: Brassica oleracea L. italica Plenck, nitrogen budget, nitrogen rates, nitrogen use efficiency, nutrient management

“…In most studies that included rates up to 336 kg N ha -1 , the response was positive and linear or quadratic (Cutcliffe et al 1968;Cutcliffe et al 1971;Hipp 1974;Letey et al 1983;Beverly et al 1986;Kowalenko and Hall 1987b;Shattuck and Shelp 1987;Tremblay 1989), although two studies found minimal or no yield response to N fertilization (Bracy et al 1995;Kahn et al 1991). In studies that included higher N rates (Greenwood et al 1980;Zebarth et al 1995) or low soil moisture (Beverly et al 1986), a maximum yield response was found beyond which yield declined with additional N applied. The actual yields produced in response to N fertilization differed greatly among these studies.…”

mentioning

confidence: 99%

Dynamics of nitrogen and dry-matter partitioning and accumulation in broccoli (Brassica oleracea var. italica) in relation to extractable soil inorganic nitrogen

Bowen¹,

Zebarth²,

Toivonen³

1999

. 1999. Dynamics of nitrogen and dry-matter partitioning and accumulation in broccoli (Brassica oleracea var. italica) in relation to extractable soil inorganic nitrogen. Can. J. Plant Sci. 79: 277-286. The effects of six rates of N fertilization (0, 125, 250, 375, 500 and 625 kg N ha -1 ) on the dynamics of N utilization relative to extractable inorganic N in the soil profile were determined for broccoli in three growing seasons. The amount of pre-existing extractable inorganic N in the soil was lowest for the spring planting, followed by the early-summer then late-summer plantings. During the first 2 wk after transplanting, plant dry-matter (DM) and N accumulation rates were low, and because of the mineralization of soil organic N the extractable soil inorganic N increased over that added as fertilizer, especially in the top 30 cm. From 4 wk after transplanting until harvest, DM and N accumulation in the plants was rapid and corresponded to a rapid depletion of extractable inorganic N from the soil. At high N-fertilization rates, leaf and stem DM and N accumulations at harvest were similar among the three plantings. However, the rates of accumulation in the two summer plantings were higher before and lower after inflorescence initiation than those in the spring planting. Under N treatments of 0 and 125 kg ha -1 , total N in leaf tissue and the rate of leaf DM accumulation decreased while inflorescences developed. There was little extractable inorganic soil-N during inflorescence development in plots receiving no N fertilizer, yet inflorescence dry weights and N contents were ≥50 and ≥30%, respectively, of the maxima achieved with N fertilization. These results indicate that substantial N is translocated from leaves to support broccoli inflorescence growth under conditions of low soil-N availability. De quatre semaines après la mise en pleine terre jusqu'à la récolte, l'accumulation rapide de la m.s. et de N observée dans les plantes correspondait à une exportation rapide du N minéral extractible du sol. Aux taux de fumure N élevés, l'accumulation de m.s. et de N dans les feuilles et les tiges à la récolte était semblable quelle que soit la date de la plantation. En revanche, les taux d'accumulation observés dans les deux plantations d'été étaient plus élevés avant et plus bas après l'initiation de l'inflorescence que dans la plantation de printemps. En présence d'apports de N de fumure de 0 à 125 kg ha -1 , la teneur en N total des tissus foliaires et le taux d'accumulation de m.s. dans les feuilles diminuaient à mesure que l'inflorescence se développait. Dans les parcelles ne recevant pas de fumure N, il restait peu de N minéral extractible dans le sol durant la formation de l'inflorescence, bien que le poids sec et la teneur en N de cette dernière étaient, respectivement, supérieurs ou égaux à 50 et 30 % des maximums obtenus en présence de fumure azotée. Ces résultats laissent voir qu'en régime de faible disponibilité de N du sol, une quantité appréciable de N est soutirée des feuilles du brocoli pour subve...