creators_name: Askegaard, Margrethe
creators_name: Eriksen, Jørgen
creators_name: Olesen, Jørgen E.
type: journalp
datestamp: 2003-01-27
lastmod: 2009-08-20 14:18:47
metadata_visibility: show
title: Exchangeable potassium and potassium balances in organic crop rotations on a coarse sand
ispublished: pub
subjects: 2farming
full_text_status: restricted
keywords: Exchangeable potassium, potassium leaching, potassium balance, organic farming
abstract: Crops on sandy soils (<5% clay) are exposed to K deficiency due to the small release and high leaching losses of K. Reliable tools are needed to improve the K management in cropping systems with limited K input, such as organic farming where import of nutrients are restricted according to the EC regulations. We investigated K balances and exchangeable K (Kexch) changes in an organic crop rotation experiment. Potassium leaching decreased from 42 kg ha-1 in 1998/99 to 21 kg ha-1 in 2000/01 as an average of a crop rotation (spring barley, grass-clover, winter wheat and pea/barley) with manure application and without catch crops. In the same period, spring Kexch decreased from 5.0 to 3.0 mg K 100 g-1 soil (0-20 cm). The retention of the straw K left in the field after harvest increased with decreasing levels of Kexch. The cereal crops did not respond to K application but in the pea/barley mixture the pea yield increased by 46%. The concordance between measured K balances and changes in Kexch was weak. Exchangeable K is suitable as a tool for K management on a crop rotational basis, and a Kexch above 3 mg 100 g-1 soil in the autumn should be avoided to minimize K leaching.
date: 2003
date_type: published
publication: Soil Use and Management
number: 19
pagerange: 96-113
refereed: yes
citation: Askegaard, Margrethe; Eriksen, Jørgen and Olesen, Jørgen E. (2003) Exchangeable potassium and potassium balances in organic crop rotations on a coarse sand. Soil Use and Management (19), pp. 96-113.
document_url: http://orgprints.org/392/1/AEO2003.pdf