Effects of soil compaction on yield and fertilizer requirement of sugar beet

Abstract

SUMMARY: Five experiments (1967–9) on soils formed from calcareous drift examined the effects of soil compaction on seedling emergence and yield of sugar beet, also the interaction between compaction and response to nitrogen fertilizer (N) and phosphate fertilizer (P₂O₅). Some seedbeds were compacted in winter, others in spring and others prepared with the minimum of compaction; each was tested with 0·6, 1·2 and 1·8 cwt/acre N plus 0·8 cwt/acre additional P₂O₅. All plots were given a basal dressing of 0–8 cwt/acre P₂O₆and enough of other major nutrients.Compaction decreased seedling populations in four experiments but increased it in one year, when the weather was dry while the seeds were germinating. However, in every experiment compaction significantly decreased yield of roots and sugar. It also interacted with the fertilizer treatments, significantly on average, increasing nitrogen requirement and decreasing phosphate requirement. On average, 0·6 cwt/acre N and 1·6 cwt/acre P₂O₅gave the greatest yield without compaction and 1·2 cwt/acre N and 0·8 cwt/acre P₂O₆with compaction.