relation: https://orgprints.org/id/eprint/32708/
title: Phosphorus deficits by long-term organic farming?
creator: Løes, Anne-Kristin
creator: Ebbesvik, Martha
subject: Farm nutrient management
description: Long term studies (1989- ) on an organic dairy farm show decreasing topsoil concentrations of extractable phosphorus (P-AL), and a low P surplus on farm level. The average P-AL value, 100 mg kg-1 dry soil is still above optimal (70 mg), but has decreased by more than 50% since 1989. Perennial ley yields tend to decline, and variations in soil P concentrations contribute to explain ley yields. This may call for additional P application on fields with low P status. However, for soils with medium (30-70) or low (< 30) P-AL, no relationship was found with yield level. Further, in a field experiment located on this farm, on low P soil with low and high applications of slurry over 5 years, applied P increased P concentrations in plant material rather than in soil. Future farm management should utilise locally available P sources to close the P gap by bringing back P removed in farm products, to avoid long-term P deficiency in soil.
publisher: ISOFAR, TIPI and NCOF (India)
contributor: Rahmann, Gerold
contributor: Andres, Christian
date: 2017-11
type: Conference paper, poster, etc. 
type: NonPeerReviewed
format: application/pdf
language: en
identifier: /id/eprint/32708/1/Loees%20and%20Ebbesvik%202017%20OWC.pdf
identifier:    Løes, Anne-Kristin and Ebbesvik, Martha    (2017) Phosphorus deficits by long-term organic farming?   In: Rahmann, Gerold and Andres, Christian (Eds.)  Innovative research for Organic Agriculutre 3.0. Proceeedings of the Scientific Track, Organic World Congress 2017, ISOFAR, TIPI and NCOF (India), pp. 531-534.