?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Potassium+retention+and+leaching+in+an+organic+crop+rotation+on+loamy+sand+as+affected+by+contrasting+potassium+budgets&rft.creator=Askegaard%2C+Margrethe&rft.creator=Eriksen%2C+J%C3%83%C2%B8rgen&rft.subject=+Farming+Systems&rft.description=.+In+organic+farming%2C+potassium+(K)+deficiency+may+become+a+significant+problem+due+to+import+restrictions.+Knowledge+about+potential+K+leaching+in+systems+with+different+K+budgets+is+therefore+important+for+effective+agricultural+management.+We+investigated+the+effect+of+four+organic+farming+systems+(two+livestock+densities+in+combination+with+two+types+of+organic+manure)+on+crop+yields%2C+K+leaching+and+K+balances+in+a+six+course+crop+rotation+from+1993%2F94+to+1997%2F98.+Average+K+concentrations+in+soil+water+extracted+by+means+of+ceramic+suction+cups+at+1+m+depth+were+0.6+mg+K+l-1+corresponding+to+a+K+leaching+loss+of+1.5+kg+ha-1+yr-1%2Cwhich+was+less+than+expected+from+values+reported+in+the+literature.+Variation+in+K+budgets+from+%C3%A2%C2%80%C2%9312+to+%2B30+kg+ha-1+yr-1+did+not+affect+K+leaching.+In+an+additional+experiment+with+application+of+988+kg+K+ha-1+as+KCl%2C+K+leaching+accounted+for+only+0.2%25+of+the+applied+K+although+40%25+of+the+accompanying+Cl+was+leached.+The+main+part+of+the+applied+K+was+retained+in+the+topsoil.+It+was+concluded+that+K+leaching+was+a+result+of+the+fertiliser+history+rather+than+of+the+current+K+budget.++%0D%0A%0D%0A&rft.date=2000&rft.type=Journal+paper&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.identifier=http%3A%2F%2Forgprints.org%2F390%2F1%2FAE2000.pdf&rft.identifier=Askegaard%2C+Margrethe+and+Eriksen%2C+J%C3%83%C2%B8rgen+(2000)+Potassium+retention+and+leaching+in+an+organic+crop+rotation+on+loamy+sand+as+affected+by+contrasting+potassium+budgets.+Soil+Use+and+Management%2C+16%2C+pp.+200-205.&rft.relation=http%3A%2F%2Forgprints.org%2F390%2F