The management of <i>Brassica</i> for winter forage in the sub‐tropics

Defining the critical nitrogen concentration (N c ; g N kg )1 ) for maximum growth of forage brassicas will aid in the fertilizer management of these crops. Typically, the N c value decreases with increasing crop biomass. In this paper, we used a nitrogen (N) response experiment with kale (Brassica oleracea) to define a critical N dilution (N c = 55AE3 · biomass )0AE47 ). However, at biomass <3AE4 t ha )1 , a constant N C of 31AE2 g N kg )1 was found. This N dilution curve compared favourably with published data sets for a range of forage brassicas but was substantially different from the established N dilution curve for oilseed rape (Brassica napus). This study also found a strong relationship (R 2 = 0AE81) between the nitrogen nutrition index (NNI) and the NO 3 content of forage brassicas from a range of data sets. The NNI is the actual N concentration of the shoot as a ratio of the N c from the established curve. The relationship between NNI and NO 3 contents was significantly different between leafy forage brassica crops and root forage brassicas. For each 0AE1 increase in NNI, the proportion of total N that was in the form of NO 3 increased by 2AE7% for leaf ⁄ stem brassicas and 0AE60% for root crop brassicas. The critical dilution curve defined in this study can be used to manage fertilizer N in forage brassica crops, so that growth can be maximized but the risk of high NO 3 concentrations in the forage can be minimized.

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“…, 1978; McDonald et al. , 1981; Sheldrick and Lavender, 1981; Kalmbacher et al. , 1982; Guillard and Allinson, 1989a; Kunelius et al.…”

Section: Resultsmentioning

confidence: 99%

Developing a critical nitrogen dilution curve for forage brassicas

Fletcher

Chakwizira

2011

Grass and Forage Science

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“…Previous studies on the effects of sowing date on the yield of maize (Andrieu, 1976; Birch et al. , 2008) and forage rape (Harper and Compton, 1980; Kalmabacher et al. , 1982) are inconsistent.…”

Section: Introductionmentioning

confidence: 99%

Effects of sowing date and nitrogen fertilizer on forage yield, nitrogen‐ and water‐use efficiency and nutritive value of an annual triple‐crop complementary forage rotation

Islam

García

2011

Grass and Forage Science

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Complementary forage rotation (CFR) systems based on non-limiting inputs of fertilizer nitrogen (N) (600 kg N ha )1 ) are perceived as uneconomic. An experiment was carried out in Australia to investigate the effects of rates and timing of N fertilizer and sowing date on yield, nutrient-use efficiency and nutritive value of a triple-crop (maize, forage rape, field peas) CFR system. Treatments were early-and late-sown maize grown with 0 or 135 kg fertilizer N ha )1 pre-sowing (N1) and 0, 79 or 158 kg N ha )1 post-sowing (N2). Forage rape was sown with 0 or 230 kg N ha )1 (N3) and field peas without N. Application of fertilizer N at N1, N2 and N3 increased CFR yield from 28AE5 to 48AE8 t dry matter (DM) ha )1 and irrigation water-use efficiency (IWUE) from 3AE4 to 6AE1 t DM per megalitre. Increase in yield and IWUE of CFR occurs at the expense of nitrogen-use efficiency (NUE) as applications of N at N1, N2 and N3 decreased NUE of CFR from 524 to 91 kg DM kg )1 N. Nutritive value, particularly metabolizable energy content of all forages, was similar among N treatments, and interactions between treatments were minimal. Results indicate that increase in NUE of CFR may occur at the expense of reduced yield, but increased IWUE need not compromise the yield of this CFR system.

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“…. that reported by Kalmbacher et al (1982) with a 35.6 cm row spacing seeded in January. Forage dry matter (shoot + roots) production was significantly different among cultivars, but did not differ significantly for cultivar x sampling dates (Table 1 and 4).…”

Section: --mentioning

confidence: 66%

Effect of Seed Priming and Soil Residue on Seedling Emergence and Forage Production of Brassicas

Rao¹,

Phillips²

1993

Journal of Sustainable Agriculture

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Emergence and establishment of Brassica spp. under adverse environmental conditions found in the Southern Great Plains appear to be major constraint in the production of spring forage. peld experiments, using 'Purpletop' turnip (Brassica rapa L.) and 'Qfon,' a turnip x Chinese cabbage hybrid [B. rapa L. x B. pekinensis (Lovr) Rupr.], were conducted on Dale silt loam (fine-silty, mixed, thermic, Pachic Haplustoll) soils near El Reno, Oklahoma.Unprimed seeds and seeds primed with PEG 8000 (polyethylene glycol 8000) were planted in burned and unburned plots of bermudagrass [Cynodon dacrylon (L.) pers. cv. Midland] sod at the rate of 2.5 kg ha-' in February 19i6 and 1987 with a no-till drill. After seedling emergence, N (100 kg ha-') and b (60 kg ha-') were broadcast to all plots. Seedling emergence 25 d after seeding was similar for both cultivars in 1986, but Purpletop exhibited greater (P < 0.05) seedling emergence than Qfon in 1987. Priming seeds with PEG increased (P < 0.05) seedling emergence over unprimed seed by 75 and 53% in 1986 and 1987, respectively. Priming seeds also improved forage dry matter production at 70 and 90 d after seeding.

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The management of Brassica for winter forage in the sub‐tropics

Cited by 20 publications

References 4 publications

Developing a critical nitrogen dilution curve for forage brassicas

Developing a critical nitrogen dilution curve for forage brassicas

Effects of sowing date and nitrogen fertilizer on forage yield, nitrogen‐ and water‐use efficiency and nutritive value of an annual triple‐crop complementary forage rotation

Effect of Seed Priming and Soil Residue on Seedling Emergence and Forage Production of Brassicas

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