The response of sugar beet to fertilizer and the effect of farmyard manure

Abstract

1. Forty-nine 33 factorial experiments in 1957–60 tested the response of sugar beet to 0·6,1·2, 1·8 cwt. N, 0·0,0·5,1·0 cwt. P2O5 and 0·8 1·6 2·4 cwt. K2O per acre. On forty-one of the sites, the experiment was repeated in the presence of 12 tons FYM per acre. There were also six trials in which the rates of mineral fertilizer had been altered to suit local conditions.2. Optimum dressings for sugar yield without FYM were 1·0 cwt. N, 0·5 cwt. P2O6 and 1·6 cwt. K2O per acre. This closely agrees with results of experiments made in 1934–39. Exceeding the optimum nitrogen dressing decreased sugar yield although the yield of tops was increased. The main value of dung for beet was in the N, P and K it provided. With FYM, optimum dressings were only 0·6 cwt. N, 0·0 cwt. P2O5 and 0·8 cwt. K2O per acre.3. Response to nitrogen differed greatly from field to field and the best guide to the nitrogen requirement of a field was the previous cropping. Beet which followed two or more cereal crops needed more nitrogen on average than beet which did not. Response to phosphate and potash did not differ much in different experiments and the national optimum would have been satisfactory for nearly all fields. The only use of soil analysis was to identify the very few fields which needed more than the average dressing of phosphate. The efficiency of phosphate and potash manuring could be slightly increased by taking soil type into account.