Growth, nitrogen partitioning and nutritive value of fodder beet crops grown under different application rates of nitrogen fertiliser

Abstract

Nitrogen (N) supply needs to be closely matched to crop demand to achieve optimum N use efficiency (NUE). Sub-optimal N supply can lead to poor yields, whereas excess N application may cause nitrate leaching and environmental pollution. An experiment with five rates of N: 0, 25, 50, 100 and 200 kg ha −1 , was carried out at Lincoln, Canterbury, in New Zealand to define the effects of N supply on growth, N uptake and define how derived NUE may influence nutritive value of fodder beet production. Both dry matter (DM) yield and N uptake increased with N supply, by 39% and 129%, respectively, when 200 kg N ha −1 was applied, compared with the control plots. Leaf area index (LAI) also increased with N supply. However, the control crop did not attain critical LAI (LAI crit ) and those receiving 25 and 50 kg N ha −1 attained LAI crit for only a short period of time compared with crops supplied with ≥100 kg N ha −1 . This meant that they intercepted less radiation and subsequently had lower DM yield than the high N treatments. The specific leaf nitrogen increased 13% to 2.34 g N m −2 leaf when ≥50 kg N ha −1 was applied, compared with the control plots. The NUE decreased by 64% from 93 kg DM kg −1 N for the 25 kg N ha −1 plots compared with the 200 kg N ha −1 plots. Nitrogen rate had no effect on the nutritive value of fodder beet. The results suggest 100 kg N ha −1 was adequate for optimum DM production and N was important for canopy development and subsequent DM accumulation.Keywords: Beta vulgaris L.; critical leaf area index (LAI crit ); nitrogen use efficiency (NUE); uptake efficiency (NupE); utilisation efficiency (NutE); nutritive values and specific leaf nitrogen (SLN)

Transplanting as a means to enhance crop security of fodder beet

“…Pre-sowing/transplanting fertiliser and topdressings were applied as per common agronomic recommendations (e.g. Chakwizira et al 2014). Irrigation and herbicides were applied as required.…”

Shorter season options through transplanted fodder beet

“…On the same day, pelleted seeds were precision-drilled in eight rows (four on either side of the transplanted plots) using an air-seeder at the rate of 110,000 seeds/ha. Row spacing of precision-drilled plots was 0.5 m. Pre-sowing/transplanting fertiliser and topdressings were applied as per common agronomic recommendations (Chakwizira et al 2014). Irrigation and herbicides were applied as required.…”

Periparturient and early lactation performance and metabolism of replacement Holstein‐Friesian heifers out‐wintered on fodder beet or perennial ryegrass compared with winter housing

“…However, in studies conducted using sheep, (Twigge & van Gils, 1984). Fodder beet is generally low in protein, particularly in the bulb (Chakwizira et al, 2014;Clark et al, 1987), and in heifers fed fodder beet, BUN concentrations during the wintering period were low at 2.37 mmol/L, which may indicate a deficiency in rumen available N and consequently impair animal performance. The high ADG of the heifers fed fodder beet indicates that this was not necessarily the case.…”

“…The mean ME concentration of fodder beet was not determined, but values reported in the literature are generally high but variable. For example, Clark, Givens, and Brunnen (1987) conducted a series of six balance studies using wether sheep and reported the ME content of fodder beet to be 11.8 MJ/kg DM, although other studies have | 835 estimated the value to be substantially higher at approximately 13 MJ/kg DM (Chakwizira, de Ruiter, & Maley, 2014;Matthew, Nelson, Ferguson, & Xie, 2011). An average grass silage is reported to contain approximately 10.3 MJ ME/kg DM (Park, Gordon, Agnew, Barnes, & Steen, 1997), and in comparison, the quality of the grass silage used in this study was high at 11.0 MJ ME/kg DM, but lower than that of the perennial ryegrass.…”