Previous experiments Cooke, 1958 andWiddowson, Penny, Williams &Cooke, 1959) showed that combine-drilling ammonium sulphate gave higher barley yields than did broadcasting similar dressings in the seed-bed. In general, drilling a single dose of nitrogen (0-25 or 0-30 cwt. N/acre) was quite safe and only slight checks to early growth were noted with a double dose (0-5 or 0-6 cwt. N/acre). Top-dressings of 'Nitro-Chalk' (applied in May) gave lower yields than drilled dressings in wet seasons (1954, 1956). In addition, top-dressings delayed ripening, increased lodging and produced a sample having smaller grains with a higher nitrogen content. Basal phosphate and potash were not drilled with the test treatments in these experiments, but were broadcast over the seed-bed after sowing. Therefore only the drilled nitrogen dressings were in contact with the seed. In view of these gains from drilling nitrogen and the obvious practical advantages of applying the full fertilizer dressing and seed in one operation, further experiments were done to examine the effects of including phosphate and potash with the drilled nitrogen dressings. It is often stated that heavy doses of compound fertilizers delay and reduce plant establishment in dry springs and on light soils; these experiments were intended to determine the level of manuring at which these adverse effects reduced yields.Our earlier experiments with barley on local soils also showed that there was little extra yield from nitrogen dressings supplying more than 0-6 cwt. N./ acre and this level was taken as the mean in our work. Yields from 0-3, 0-6 and 0-9 cwt. N/acre by combine-drill were compared with yields from equivalent broadcast dressings (which were taken as the standard).In 1957, most compound fertilizers applied to spring-sown cereals contained too little nitrogen, in relation to phosphate and potash, for many soils in arable areas; farmers who combine-drilled these compounds were unable to apply full dressings of nitrogen, because of limitations upon fertilizer delivery imposed by hopper capacity and gearing. In addition, the use of these fertilizers as a source of nitrogen involved the application of above optimum, and therefore wasteful, dressings of phosphate and potash. In practice, inadequate nitrogen dressings at sowing were supplemented with midseason top-dressings of a straight nitrogen fertilizer. As top-dressing was such a general practice and as our experiments in 1954 and 1956 showed that topdressing could have undesirable effects in wet seasons, we felt that further tests were required. To simulate practical conditions 'Nitro-Chalk' topdressings (0-3 cwt. N/acre) were used to supplement drilled dressings of 0-3 or 0-6 cwt. N/acre. By restricting top-dressings to this level, we hoped to minimize lodging and other factors associated with these mid-season dressings in our earlier experiments (inwhioh seed-bed nitrogen was supplemented with 0-5 cwt. N/acre top-dressing). Yields given by these divided dressings were compared with equivalent drilled or b...