Synopsis A laboratory technique is described for evaluating the winter‐hardiness of alfalfa. Seeds were germinated in solutions of sodium chloride and sucrose having known osmotic pressures. As osmotic pressures were increased the rapidity and amount of germination decreased, however, the decrease was more marked in the seed of hardy varieties.

Physiological problems in some Fife dairy herds were thought to be associated with mineral imbalance in grass cut for silage. Consequently trials at two sites were conducted to study the effects of three levels of nitrogen and phosphorus and two levels of potassium on yield and composition of pasture cut for silage.Nitrogen increased yield of herbage and reduced its clover content whereas phosphorus and potassium had little effect on yield or clover content. Herbage clover content and calcium concentration declined over the period of the experiment. Mean concentrations of calcium, magnesium and phosphorus were 5-8, 1-7 and 3-4 g/kg respectively. Concentrations of these minerals varied more with time of cutting and with season than with level of applied phosphorus and potassium.Nitrogen tended to reduce calcium concentration in mixed herbage and to increase magnesium concentration in the grass component; it did not affect herbage phosphorus concentrations, but narrowed the calcium-phosphorus ratio in the second cuts. Applied phosphorus increased herbage phosphorus concentration only at the site with the lower soil phosphorus status. Potassium tended to reduce magnesium concentration in clover and, at one site, in mixed herbage; it also tended to reduce herbage phosphorus concentrations in second cuts.Mineral uptake was increased by applied nitrogen. Mean annual uptake of calcium magnesium and phosphorus was 34, 10 and 20 kg/ha respectively.The effects of treatments on concentration and balance of these minerals are discussed in relation to ruminant requirements and maintenance of suitable levels of the minerals in the soil.It is concluded that normal applications of NPK fertilizer are not detrimental to satisfactory mineral balance in pasture.

SUMMARYBetween 1972 and 1976 a series of 15 trials was carried out at various climatically favoured sites throughout Scotland to assess the potential of new hybrid maize varieties of European origin under Scottish conditions. No meaningful differences were found between varieties in respect of dry-matter yield or maturity.Seed rates ranged from 100 to 200 × 103 seeds/ha giving final stands from 40 to 194 × 103 plants/ha. Regression analyses for the variety Dekalb 202 included in 54 treatments indicated that the relationship between plant population density and dry-matter yield was partly linear with an important quadratic function, suggesting an optimum of 179 × 103 (± 80 × 103) plants/ha. Plant population density accounted for 65·9% (P < 0·01) of the variance in dry-matter yield but was not significantly related to dry-matter content.Climatic variation between years had no overriding influence on growth and development. Dry-matter production for the variety Dekalb 202 sown in mid-May ranged from 2·86 (1972) to 14·54 t/ha (1975) with associated dry-matter contents of 15·1 and 24·1% respectively. In a few instances slightly higher dry-matter contents (maximum 28·6%) from mid-May sowings were associated with lower yields.Neither date of sowing nor accumulated temperature to harvest measured as Ontario Heat Units was significantly related to yield but date of sowing accounted for 29·5% (P < 0·01) of the variance in dry-matter content. Accumulated Ontario Units at harvest were not significantly related to dry-matter content.An interesting relationship between dry-matter yield and the date on which the crop had received 1379 Ontario Units was found. This relationship may be useful in selecting sites at which maize may be grown or to predict maximum potential final yield in any given season.

Nine experiments in the East of Scotland were completed in the years 1966, 1967 and 1968 to test the response of potatoes grown for ware to five levels of a 15^-15^-21 fertilizer applied at rates of 0, 4, 8, 12, 16 and 20 cwt per acre.

Fourteen trials on spring barley and eleven on winter wheat, grown in the east of Scotland, compared the effects on yield of liquified anhydrous ammonia and solid ammonium nitrate at various levels of application.For grain yield, the optimum N level in these trials was about 100-113 kg N/ha. The object of including in the trials N input levels higher than optimum was attained. Yield response to the two forms of N was similar for both wheat and barley at the different N input levels.Winter injection of anhydrous ammonia was less efficient than spring application. Injection of anhydrous ammonia into young wheat resulted in frequent reduction of plant population and, on occasion, loss of yield.At equivalent rates, anhydrous ammonia caused less lodging than ammonium nitrate; it also appeared to be less readily leached from the soil.Ammonium nitrate gave more rapid early growth and this led to a greater proneness to leaf disease.Considering the complexity of storage and injection equipment required to handle anhydrous ammonia, it is questionable if these agronomic advantages justify its use on cereals where rates of use do not also confer the benefits of cheaper unit cost of nitrogen.nitrate. Whitear (1970) obtained similar responses from small rates of anhydrous ammonia and of Anhydrous ammonia has been used as a nitrogen ammonium sulphate applied in spring to winter source for cereals in the U.K. for a number of years, wheat in East Anglia, but with double these rates, Jameson (1959) found little difference in efficiency ammonium sulphate was the more efficient ferbetween anhydrous ammonia and'Nitro-Chalk'for tilizer. Sim (1970) showed that tine spacing on winter wheat but he noted the risk of mechanical anhydrous ammonia applicators could be greater damage to the crop by the injection equipment, than that commercially practised without loss of Jeater (1966) found ammonium nitrate to be yield, and that depth of ammonia placement, rate slightly more efficient than anhydrous ammonia for of application and soil type had small effects winter wheat, whilst yields of spring barley from on barley yield. Lodging was less with anhydrous both sources of N were similar. At Rothamsted ammonia than with solid fertilizer and also with (Experimented Station Report 1968; Widdowson widely spaced as opposed to closely spaced injector & Penny, 1970), anhydrous ammonia and 'Nitro-tines. Chalk' were compared on spring wheat. At low Between 1967 and 1970,14 trials on spring barley application rates yields from the solid fertilizer and 11 on winter wheat were carried out in the east consistently exceeded those from anhydrous am-of Scotland to compare anhydrous ammonia with monia, but this advantage diminished at higher solid ammonium nitrate, either prilled (34 % N) or rates of N. The conclusions were that anhydrous in mixture with calcium carbonate (21-26 % N) at ammonia was slightly less efficient than ammonium various levels of application.