The growth of spring barley related to soil tilth produced on restored opencast and unmined land

Abstract

The main limitations to crop growth posed by restored opencast mine land derive from physical changes in the soil. The loss of soil structure makes the land prone to waterlogging and reduces soil workability. For spring cereals the main soil-management problem will be the production of an adequate seedbed. An experiment was therefore conducted on a clay loam soil to examine three alternative cultivation regimes for spring-barley production, these regimes contrasted autumn and spring ploughing and a tined cultivation on unmined land and restored land with and without drainage. Final yields were found to be determined by final ear numbers. This in turn derived from the initial plant population established, which varied with aggregate size distribution in the seedbed tilth. Unmined land produced more favourable tilths and hence higher yields, than either restored site irrespective of the tillage system. On all sites, autumn ploughing produced finer tilths than either spring working treatment. These trends persisted over 4 years and the tilth on all sites deteriorated over this period, though most noticeably on the unmined land. The stability of seedbed aggregates was correlated with soil organic-matter content, which varied across sites. Straw incorporation over 4 years was found to give only a minor enhancement of soil organic-matter concentration over straw burning. This difference did not noticeably affect crop yields or soil aggregation.