The effect of farmyard manure on the fertilizer requirement of sugar beet

RESP-601

Comparisons of liquid and solid fertilizers and anhydrous ammonia for sugar beet

RESP-612

Uptake of magnesium and other fertilizer elements by sugar beet grown on sandy soils

RESP-641

Effects of nitrogen fertilizer, plant population and irrigation on sugar beet: III. Water consumption

RESP-636

The effects of magnesium fertilizers on yield and chemical composition of sugar beet

RESP-594

Effects of nitrogen fertilizer, plant population and irrigation on sugar beet: I. Yields

RESP-636

The relationship between exchangeable soil magnesium and response by sugar beet to magnesium sulphate

RESP-623

Comparisons of kieserite and calcined magnesite for sugar beet grown on sandy soils

RESP-667

Sodium and potassium relationships in sugar beet

RESP-619

Nitrogen requirement of sugar beet grown on mineral soils

The effect of nitrogen fertilizer on the yield of sugar beet was tested in 170 experiments done between 1957 and 1966; results of 88 experiments, some testing five and six amounts of N, have not previously been published. On most sites, nitrogen increased sugar yields sharply and almost linearly up to an optimum beyond which yield changed little or decreased only slightly up to 1·8 cwt N/acre, the largest amount tested. In the two series of experiments giving most information, the mean increase from sub-optimal amounts of N was 2·5 cwt sugar/0·1 cwt N/acre. Usually 0·4–0·8 cwt N/acre was enough for maximum yield; more was needed on a few sites and on about a fifth of them nitrogen fertilizer was not needed. In 7 of the 10 years, the average optimum was 0·6–0·8 cwt N/acre; less was needed in the other years, the driest three years of the decade. In most, though not all, years, site-to-site differences in response between 0·9 and 1·8 cwt N/acre were no greater than could be expected from experimental error alone; much of the apparent difference in response between seasons were also attributable to this source. After taking account of experimental error, there were substantial between-site differences in response to amounts of N up to 0·9 cwt/acre, but attempts to explain them in terms of weather, soil and husbandry factors had little success. There was slight evidence of diminished responses to N where sugar beet followed crops other than cereals, and of responses somewhat greater than average on Chalky Boulder Clay soils of the Hanslope and Stretham Series; no other relationships were large or consistent enough to be useful for prediction. As between-site differences in response are largely unpredictable, and because a grower risks much greater crop losses by applying too little N than by applying too much, the recommended dressing is 1·0 cwt N/acre, substantially more than is needed, on the average, to obtain maximum yield. More N should be given on soils of the Hanslope and Stretham Series and on light sands poor in organic matter; less need be applied where crop residues are likely to supply much nitrogen. RESP-613