John de Ruiter

Fodder beet ( Beta vulgaris L.) is an important forage crop used for cattle wintering in New Zealand. Regional nitrogen (N) fertiliser experiments over two seasons (2016–2018) consisting of different N application rates (0–300 kg N/ha) and times of N application (sowing, canopy closure, and mid‐bulb development stage) were used to validate yield responses. Within site, there was a maximum of 3 t DM/ha difference in total biomass yield between control (no N) and high N treatments at maturity. Near maximum fodder beet yield was achieved in all sites with a rate of 100 kg N/ha applied as urea (split applications). Near optimum yields were achieved on higher fertility sites with preseason soil nitrate‐N + ammonium‐N (0–15 cm depth) of 75 kg N/ha or greater. Little additional fertiliser N was required for maximising crop yield. However, enhanced plant N concentration and crop N uptake were achieved with rates up to 300 kg N/ha. Fertiliser N management that stimulated full canopy expansion with optimum green leaf area (GLA) and GLA duration was required to maximise yield. Important management practices for maximising yield include the use of N fertiliser for earlier crop canopy closure and enhanced canopy duration during bulb development.

The effects of water stress on fodder beet ( Beta vulgaris L.) production in the field are confounded by the influences of variable inter‐ and intra‐season rainfall. In this study, a rain shelter experiment investigated the effect of water and nitrogen (N) stress on dry matter (DM) production, DM allocation and N partitioning in fodder beet (‘Rivage’). Two water‐management treatments, irrigated (replacement of the profile water lost weekly) and unirrigated (limited water applied only during fertigation), and three fertiliser N treatments (0, 50 and 300 kg N ha ⁻¹ (hereafter, 0N, 50N, 300N)) were evaluated during the 2016–2017 season. Under irrigation, the yield was greater ( P  = .02) for the 50N than 0N treatments (29.4 and 24.9 t DM ha ⁻¹ , respectively). Yield did not differ ( P  = .42) between irrigated 50N and 300N (30.6 t DM ha ⁻¹ ) treatments, indicating surplus N application to the latter. Water and N stress restricted leaf growth, lowered N uptake and reduced yield by 48%–51%. Surplus N in irrigated 300N treatments resulted in increased N uptake and leaf proportion but reduced the storage root proportion. These results demonstrate the plasticity of fodder beet biomass and N allocation in adapting to the availability of water and N.

Autumn grazing of high‐yielding forage crops such as fodder beet (FB) has increased in popularity in many regions of New Zealand. During grazing, large amounts of urinary nitrogen (N) is returned to the soil which is at risk of leaching. This study evaluated using two different catch crops of oats or Italian ryegrass (‘Italian RG’) to reduce the risk of N leaching both after FB grazing by lactating dairy cows and after lifting (i.e. un‐grazed FB) in autumn. During FB grazing, cows grazed either (i) high [40% of diet dry matter (DM), with pasture; FB40] or (ii) low (25% of diet DM, with pasture; FB25) FB allocations. Both Italian RG and oats reduced soil mineral N (0–90 cm depth) by 16%–37% by August, and 53%–58% by October, compared with a fallow control (115 and 100 kg N ha ⁻¹ for August and October, respectively). The greatest reductions in soil mineral N were from oats, largely attributed to higher DM yields resulting in greater N uptake. Furthermore, the total amounts of soil mineral N in the soil after grazing differed between FB allocation treatments and lifted FB (FB25 > FB40 > lifted FB), in proportion to urinary‐N inputs and associated dietary N intake.

Two fodder beet ( Beta vulgaris L.) cultivars (‘Rivage’ and SF Brigadier™) were evaluated in a field experiment to quantify the effect of cultivar and sowing date on growth physiology. The crops were sown on 19 September, 17 October, 17 November and 15 December in 2014. Crops were sequentially harvested and separated into storage root, leaf blade and petiole for analysis. Fodder beet growth was sigmoidal; the growth of leaf blades and petioles dominated the lag phase while storage root growth dominated the exponential phase. The appearance of the 25th leaf marked the beginning of the exponential phase. The maximum growth rate was not affected by the cultivar or sowing date. Total dry matter (DM) yield was the same for September‐ and October‐sown crops (2444 ± 164 g DM m ⁻² ); showing little advantage of early sowing because cold temperatures slowed canopy development. The November‐ and December‐sown crops produced 18% and 30% lower yield than the October‐sown crops. ‘Rivage’ partitioned 5% greater DM to the storage root, an indication of greater sink strength, than SF Brigadier. Information on the pattern of growth can aid management decisions for optimising yield, and is valuable for the improvement of fodder beet models.

A short‐term, dairy cow, grazing experiment was conducted in late‐lactation (autumn) to determine the effect of fodder beet (FB) and maize silage supplementation on dry matter and nitrogen (N) intake, urinary N excretion and milk solids (MS; milk fat + milk protein) production. Seventy‐two multiparous, lactating (224 ± 20.0 DIM; mean ± SD) Holstein‐Friesian cows were randomly assigned ( n = 24 per treatment; 8 per replicate) to one of three groups. Control animals were offered pasture (11 kg DM/cow/day) with maize silage (4 kg DM/cow/day; ‘Maize’). The other two groups were either offered pasture (11 kg DM/cow/day) with 25% FB (4 kg DM/cow/day; ‘FB25’) or pasture (9 kg DM/cow/day) with 40% FB (6 kg DM/cow/day; ‘FB40’). At the same supplement DM intake, diets containing maize silage or grazed FB had similar urinary nitrogen (UN) concentrations, but FB increased milk solids (MS) production. At 40% FB inclusion UN excretion was reduced but this came at the expense of MS production. Farmers need to exhibit caution when feeding fodder beet to lactating dairy cows to minimise the risk of adverse animal health effects. Feeding fodder beet allocations high enough to achieve significant environmental benefit is likely to compromise animal health and milk production.

Cereal forages provide both arable and livestock farmers with high yields of high quality dry matter to use as either standing or conserved strategic forage supplements where deficits occur when animal feed requirements exceed pasture growth. Crop & Food Research has breeding programmes for both single and multigrazing forage oats and triticales, and both green-chop and whole-crop silage forage oats, triticales and barleys. It also has an associated cereal forage management research and tech-transfer programme to ensure cereal forages achieve their potential under New Zealand's variable soil and climatic conditions. This has led to the development of new cereal forage cultivars, an increased understanding of their dry matter and quality development, and management support packages including a cereal silage booklet and maturity predictor for whole-crop cereal silage