Cutting management of willows (Salixspp.) and leguminous shrubs for forage during summer

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Abstract An experiment was conducted to determine the potential value of shrubs for providing fodder for ruminants during periods of feed insufficiency. The work was undertaken at a moist and a dry site in the lower North Island of New Zealand in 1992/93 with four shrub species: Chamaecytisus palmensis (tagasaste); Dorycnium rectum (erect dorycnium); Salix kinuyanagi (kinuyanagi willow); and Salix matsudana x alba (hybrid willow). Five cutting regimes were adopted which varied in cutting frequency and height, with. the latter being either a low (L) or high (H) cutting height. There was a single low cut (L) in April at the end of the growing season, 2 cuts (LL and HL treatments) in February and April, and 3 cuts (LLL and HHL treatments) in December, February, and April. Three cuts during the season were investigated only at the moist site. Whole plant yields over the 1992/93 growing season were highest from a single cut in April. However, 2‐ and 3‐cut treatments sometimes gave yields as high as those from a single cut (P < 0.05), particularly when the first cut was high. C. palmensis (7.7–16.71 dry matter (DM)/ha) and D. rectum (0.1–4.8 t DM/ha) were the highest‐ and lowest‐yielding species, respectively, at each site, with Salix spp. (1.0–9.9 t DM/ha) having intermediate yields. C. palmensis had the highest quality forage with in vitro organic matter digestibility (OMD) of 77–85% and total nitrogen (N) content of 26–40 g N/ kg DM, and it was unique among the species in having consistent high quality throughout the season at both sites. The Salix spp. and D. rectum had an average total N content of 25 g N/kg DM. S. kinuyanagi (46%) andD. rectum (53%) had lower OMD than S. matsudana × alba (71%), perhaps because of the formers’ relatively high lignin contents (67—95 g/kg DM). It was concluded that C. palmensis particularly, and Salix matsudana × alba, could be valuable for supplying supplementary forage during the summer in dry areas.