Diurnal changes in the nutritive composition of four forage species at high and low N fertiliser

Abstract

<jats:p>Chicory and plantain have been suggested as alternative grazed forages to perennial ryegrass for New Zealand dairy systems. While diurnal changes in plant chemical composition have been described for ryegrass there is currently little information for herbs. This experiment aimed to compare the effect of nitrogen inputs (low and high) and harvesting time (am versus pm) on the chemical composition of four forages (ryegrass, plantain, chicory and white clover). The effect of harvest time was greater than N fertiliser inputs on chemical composition for all forages. Ryegrass showed the greatest increase in water soluble carbohydrate diurnally, at the expense of neutral detergent fibre and to a lesser extent crude protein. This suggests afternoon allocation of ryegrass may be beneficial to improve the nutritive value of pasture on offer; allocation timing is less important for white clover, chicory and plantain. Keywords: chicory, clover, crude protein, plantain, ryegrass, water soluble carbohydrate</jats:p>

Can alternative forages substantially reduce N leaching? findings from a review and associated modelling

“…For herb species, chicory and plantain, Minnee et al (2017) measured greater soluble carbohydrates (14%) compared with perennial ryegrass (7%). Conversely, Box et al (2017a) reported greater WSC for perennial ryegrass (23%) compared with chicory (19% WSC) or plantain (20% WSC). The discrepancy in ranking between herbs and grasses may be a product of the environmental conditions or analytical procedures as the two studies report carbohydrates in different terms.…”

“…In perennial ryegrass, the majority of these carbohydrates are extractable in water and are primarily fructan and sucrose (White 1973). Interestingly, although Box et al (2017a) measured more WSC in ryegrass compared with herbs, a greater proportion of the total DM for plantain was not accounted for. In plantain, for instance, L-arabinose accounts for 20-25% of the sugars (Brautigam and Franz 1985;Kardošová 1992) but it is unlikely to be detected in routine laboratory methods for WSC using anthrone reagents (Jiang et al 2019).…”

“…Recent research trials in warm (Waikato) and cool (Canterbury) regions of NZ were established to identify which forages, and management practises, resulted in lower herbage N (or crude protein concentration, which is assumed to be 16% N). Results regarding nutritive value and management responses have been published for the cool (Box et al 2017a;Martin et al 2017a;Martin et al 2017b) and warm (Dodd et al 2017) regions. In the cooler region, with long-term average air temperature differing by ∼4 degrees C compared to the warm region, grasses had the lowest herbage N concentration (mean of 2.7% for perennial ryegrass, Italian ryegrass, tall fescue, cocksfoot and prairie grass) followed by herbs (mean of 3.1% for chicory and plantain).…”

“…declines as plants mature and accumulate carbohydrate (Fulkerson et al 1998;Bryant et al 2012;Martin et al 2017b). There is a diurnal pattern in plant nutritive characteristics, whereby accumulation of water soluble carbohydrates during the daytime often dilutes and so reduces plant N concentration, and there is local evidence for this for a number of pasture species including legumes (Box et al 2017a). Furthermore, a recent proof-ofconcept grazing study (Bryant et al 2014) using ryegrass-clover pastures, highlighted the use of extending the regrowth interval, and offering the daily pasture allocation in the afternoon, could reduce herbage N intake and urinary-N concentration compared with a short regrowth period and morning allocation.…”

Plantain silage quality under variable management practices

“…Two experiments investigating the effects of regrowth interval (Study 1), fertiliser and additives (Study 2) on plantain silage, were conducted under irrigation at the Lincoln University Research Dairy Farm, Canterbury, New Zealand (43º64'S, 172º46'E). The plantain pastures (cultivar 'Tonic') were established following cultivation in March 2014 and were rotationally grazed with dairy cows (Box et al 2017). On 14th November 2016 the experimental area for both studies (0.60 ha) was mown to 6 cm.…”