4.1 Soil Factors and Treatments affecting Trace Elements in Crops and Herbage

Abstract

Despite the extensive knowledge of animals' dietary requirements for trace elements and detailed research into the uptake by plants of nutrients from the soil, it is surprising that the production of animal feedstuffs, having an appropriate trace-element content, still presents a considerable challenge to the agronomist. The present paper draws attention to some of the problems involved, using data from the many years of field-experiment research at the Macaulay Institute for Soil Research. These experiments have been largely restricted to the system of intensive agriculture prevailing in north-east Scotland, where heavily-grazed pasture and conserved herbage are the principal components of animal diets. The 6-7 year crop rotation most commonly practised includes a 3-4 year period of grass ley. The factors discussed have a wider relevance although their relative significance under conditions of low stocking rates, for instance on the rough or natural grazing on hill-land in the U.K. and other countries, will clearly be different.