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Response of organically managed grassland to available phosphorus and potassium in the soil and supplementary fertilization: field trials using grass– clover leys cut for silage

Fortune, S; Robinson, J S; Watson, C A; Philipps, L; Conway, J S and Stockdale, E A (2005) Response of organically managed grassland to available phosphorus and potassium in the soil and supplementary fertilization: field trials using grass– clover leys cut for silage. Soil use and Land Management, 21 (21), pp. 370-376.

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Summary

Effective use and recycling of manures together with occasional and judicious use of supplementary fertilizing materials forms the basis for management of phosphorus (P) and potassium (K) within organic farming systems. Replicated field trials were established at three sites across the UK to compare the supply of P and K to grass–clover swards cut for silage from a range of fertilizing materials, and to assess the usefulness of routine soil tests for P and K in organic farming systems. None of the fertilizing materials (farmyard manure, rock phosphate, Kali vinasse, volcanic tuff) significantly increased silage yields, nor was P offtake increased. However, farmyard manure and Kali vinasse proved effective sources of K to grass and clover in the short to medium term. Available P (measured as Olsen-P) showed no clear relationship with crop P offtake in these trials. In contrast, available K (measured by ammonium nitrate extraction) proved a useful measurement to predict K availability to crops and support K management decisions.


EPrint Type:Journal paper
Keywords:Phosphorus, potassium, organic farming, grass, clover
Subjects: Soil > Nutrient turnover
"Organics" in general
Soil
Farming Systems
Farming Systems > Farm nutrient management
Research affiliation: UK > Organic Research Centre (ORC) - Elm Farm
UK > Department for Environment, Food and Rural Affairs (DEFRA)
Deposited By: Woodward, Lawrence
ID Code:7702
Deposited On:14 Mar 2006
Last Modified:12 Apr 2010 07:32
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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