Applying nitrogen fertilizers for spring barley

Abstract

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...

The timing of nitrogen application for spring barley

“…In this case over 100 mm of rain fell between sowing and the emergence stage at which the first top dressing was applied and it is likely that a considerable proportion of seed-bed N would have been lost by nitrification and leaching. Early sowing and high rainfall were also reported by Widdowson et al (1961) in at least some of the cases where yield improvements were recorded. Applying the N to spring barley as a divided treatment with part as a top dressing is therefore unlikely to improve yields except with early sowing and the consequent risk of a period of high rainfall following sowing.…”

“…Widdowson & Cooke (1958) found in a series of experiments from 1954 to 1956 that mid-May dressings of N gave lower yields than the equivalent seed-bed dressings in wet seasons, increased lodging, reduced grain quality and delayed ripening. However, in experiments from 1957 to 1959 Widdowson, Penny & Williams (1961) used smaller amounts of N top dressing applied at an earlier stage in late April or early May. When the total N application did not exceed 75 kg/ha the divided application consistently outyielded the equivalent combine-drilled or broadcast dressings', but by the relatively small amount of about 125 kg grain/ha.…”

“…The work of Widdowson et al (1961) suggests that a top dressing applied before early May can improve yields, but that later applications are more likely to be detrimental. However, few experiments have been made with a wide range of different timings in order to establish the point at which top dressing ceases to be of value.…”

The value of liquid digested sewage sludge. III. The results of an experiment on barley

“…More ' lodging' occurred in the fertilizer plots than on sludge or control plots. Widdowson, Penny & Williams (1961) concluded that on spring barley, dressings of nitrogenous fertilizer containing more than 0-6 cwt. (67-2 lb.)…”

Effect of nitrogen fertiliser application timing on grain yield and grain protein concentration of spring barley

“…GPC, moisture content and specific weights were determined using a whole grain analyser (Infratec 1241 grain analyser -Foss, Hillerod, Denmark) on sub-samples of approximately 2 kg obtained from each plot during combine harvest. GPC be advantageous (Widdowson et al, 1961;Easson, 1984). Where application of majority of the N dose is delayed until the crop has entered the stem elongation phase, the yield can be reduced and GPC increased (Easson, 1984).…”