Does wintering on diverse pastures or kale crop affect N loss risk? Findings from a commercial case study dairy farm near Methven

<p dir="ltr">This case study describes farmer-led research comparing the practicalities and nitrogen (N) leaching risks from dairy winter grazing on kale or diverse pasture. Two herds of dairy cows grazed either a kale (n=360) or diverse pasture (n=60) paddock on a commercial dairy farm in Methven during June and July 2023. A perennial pasture mix was sown in August following winter grazing on kale. Soil cores were sampled to 15, 30, 60 and 90 cm depth increments in July and November 2023. Herbage yield and N content were measured in November. Following winter grazing in July, soil inorganic N in the 0-90 cm depth under the kale crop areas was two times greater than under pasture (138 vs 67 kg N/ha), and five times greater in November following re-growth of pastures (152 vs 29 kg N/ha). The lower soil inorganic N under pasture could be attributed, at least in part, to a lower stocking density and increased herbage N uptake (98 and 35 kg N/ha under respective pasture and kale paddocks). Pasture wintering demonstrated practical and environmental benefits over kale wintering, but further efforts are likely required to explore cost benefits.</p>