OWL-Asparagus-Final-Report-2022-07.pdf (1.68 MB)

Collaborative Research Towards Best Practice Nitrogen Management in Asparagus Cropping: Final report

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posted on 2024-06-21, 03:57 authored by Dan Bloomer
Key findings: • Current nitrogen fertiliser recommendations are based on limited trial work. • Nutrient deficiency symptoms are not common and careful fern and root testing are needed to see if they exist • While analysis of fern growth to assess nutritional status is recommended, little guidance on interpretation is given • Soil testing should take in the whole root depth, but there are few guidelines to establish fertiliser rates • While sufficient nitrogen fertiliser to grow healthy fern should be applied during the establishing years, once established application, if any, should be based on replacing nutrients removed during harvest • Research showed 75 kg-N/ha could support a crop for three years without a detectable change in fern nitrogen concentration • Fertiliser should be applied close to fern growth which is when uptake occurs. This will minimise leaching risk, especially on shallow or low water holding soil types • Fresh root mass is highly variable with a minimum at the end of harvest, and a maximum at the end of fern growth. We found the root mass in summer at the end of harvest was 26,300 kg/ha, increasing to 91,700 kg/ha in winter after fern growth • At the end of fern growth, about 80% or more of the nitrogen in the system was found in the roots • Data we collected are generally in line with published research


Funded by the New Zealand Ministry for Business, Innovation and Employment's Our Land and Water National Science Challenge (Toitū te Whenua, Toiora te Wai) as part of project Rural Professionals Fund 2021–22


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