Fertilisers for Hill and Upland Improvement

A brief account is given of the structure of the agricultural industry in the hills and uplands, the limitations to production of climate, soil and vegetation, the nutritional requirements of livestock and techniques for improving grassland production. A consideration of these factors shows that, despite problems, the potential for increased grassland production, particularly from the uplands, is very large and the use of fertilisers plays an essential part in improvement.

The use of the major and minor fertiliser elements are discussed in relation to the results of UKF Field experiments in the hills and uplands. The main conclusions are:

1. Some indigenous swards, such as Agrostis/Festuca, give good yield responses to nitrogen and quality is satisfactory provided the grasses are grazed at an early stage of maturity. The use of N for changing the botanical composition of a sward is discussed in relation to the results of a cutting experiment in which the proportion of perennial ryegrass increased from 15% to 72% over a period of three years. D-values were also increased by the application of N.

2. On reseeded swards, strategic applications of N in the spring and autumn gave substantial increases in DM yield without unduly suppressing the clover in the grazing trials. The value and limitations of clover and various grass species on hill sheep farms are also considered.

3. The importance of lime to correct the extreme acidity of many hill soils is emphasized, although applications to some experiments actually decreased the yield of indigenous hill swards dominated by acid-tolerant species.

4. Copper and cobalt deficiencies are serious problems in many hill areas. Experiments showed that soil applied Cu could not be relied upon to raise levels in the herbage sufficient for livestock requirements. On the other hand. Co applied to indigenous hill swards gave good results in all trials.

5. Water-soluble phosphate applied to indigenous hill swards gave better results than water-insoluble phosphates and the residual effects over four years were similar.

It is anticipated that future trends will be for fertiliser use in the hills to increase slowly but gradually. At lower elevations in the uplands, there is a large potential for increased usage and it is expected that higher rates of nitrogen will be applied as farmers change from hay to silage.