J. F. Handley’s research while affiliated with University of Liverpool and other places

(1) Areas which had previously been reclaimed from colliery spoil and urban clearance materials, were dressed with nitrogen, phosphorus and potassium in factorial combination to fourteen sites; each site showed a substantial and over-riding deficiency of nitrogen. (2) Retreatment in the subsequent year showed a continued major need for nitrogen and some deficiency of phosphorus on the colliery spoil. Considerable nitrogen deficiency was also found on two urban sites where topsoil had been used. (3) Some of the colliery spoil sites had become very acid due to oxidation of pyrite, but surface limestone treatments failed to penetrate and therefore failed to have any effect. Adequate limestone must therefore be added during initial reclamation. (4) Nutrients cannot be added in this manner and there is an obvious need for legumes and appropriate aftercare in reclaimed sites to build up nutrients to levels allowing adequate cycling. (5) Aftercare, extending for several years, must therefore be an integral part of all reclamation programmes.

An ecological approach must involve using natural processes and solutions for landscape ends - working with nature rather than against it. Sections cover: understanding ecological factors understanding ecosystem functioning ecological based design. -from Authors

In the establishment of a grass cover on china clay waste it is necessary, as in most land restoration, to supply fertiliser nitrogen in substantial amounts. However the objective of nitrogen accumulation is restricted in south west England by severe leaching. A series of experiments were devised to investigate the nitrogen retention from a range of fertiliser sources. When fertiliser-N was applied to established swards, three times as much nitrogen (about 90 per soil and vegetation at the end of the first season of establishment. Sodium nitrate was especially susceptible to leaching, in contrast to sources containing ammonium. Slow-release formulations and organic materials produced a lower sward growth throughout the first growing season but tended to give higher levels of residual-N in the sand waste. When fertiliser-N was applied at seeding less than 30 per cent of the nitrogen was retained in the cent of that applied) was retained. Most of this nitrogen was retained in the sand waste. There was little difference between different types of fertiliser: the main effect was to alter the amount of nitrogen in herbage tissues. Plant growth and a healthy grass sward could only be sustained in the absence of a legume component by repeated applications of fertiliser-N. When applications were discontinued sward degradation was shown by decreases in biomass. Losses in nitrogen from the sward biomass were more than accounted for by an increase in the nitrogen content of the sand waste. These results indicate that once fertiliser-N is retained by the sward ecosystem on sand waste, there are few further losses, presumably because of rapid microbial immobilisation of nitrogen in the sand waste. In view of the expense of land restoration using numerous maintenance applications of nitrogen, it is clear that legumes must be included in the seeds mixture for the reclamation of kaolin mining wastes in Cornwall. However, legumes are difficult to establish and more susceptible to drought than grass species. Results from these trials suggest that slow-release nitrogen fertilisers could enable a controlled level of grass growth, thereby avoiding competition between the legume and grass components. Alternatively grass swards could be rapidly established to stabilise the sand waste using soluble ammonium salts, and in the second season oversown with legumes.

Nitrogen accumulation was studied in mica and sand mining wastes of Cornwall after twelve forage legume varieties were established with the use of lime and fertilizers containing phosphorus and potassium. In the finetextured mica waste legume productivity and nitrogen accumulation were similar to those for upland pastures in Cornwall; but legume growth was limited by summer drought on the coarse-textured sand waste. Native perennial legumes well adapted to the British climate were the most productive and showed the highest potential for nitrogen fixation. More than 500 kg N/ha accumulated during the 2-year period whenTrifolium pratense andLotus corniculatus were established on mica waste, and more than 250 kg N/ha was accumulated by these legumes on sand waste.Trifolium pratense andLotus corniculatus were persistent on both the mica and sand waste, andMedicago lupulina showed an unusually high tolerance for competition from invading and sown grass on the sand waste.Trifolium repens andT. hybridum are recommended for waste sites where grazing is a part of management. Nitrogen accumulation on mica waste was consistent with N fixation rates expected from climatic conditions. Nitrogen fixation by free-living bacteria is limited by the low organic matter content of the wastes. The nitrogen fixation potential by legumes on sand wastes has been underestimated because leaching losses were not adequately evaluated. Since nitrogen accumulation rates by earlyTrifolium pratense andT. repens were 70 percent higher than the maximum rate estimated for natural legumesi.e. (Ulex europaeus) on sand waste, the use of forage legumes should reduce reclamation time considerably. re]19760512

Plant succession was investigated on sand waste heaps produced by kaolin mining in central Cornwall. It was found that relatively even aged, monospecific stands of vegetation were frequently present. The principal colonists were woody leguminous plants which, in some situations, were superceded by a massive growth of rhododendrons (Rhododendron ponticum) or native woodland species. Where legumes were absent, the waste was slowly colonised by Calluna vulgaris and other heathland species. The age structure of the vegetation was negatively and significantly correlated (r=−0.71) with the moisture deficit (evapotranspiration minus rainfall) during the spring and early summer. Drought, limited seed availability, and low nitrogen levels in the waste material are factors which contribute to the development of monospecific, even-aged legume communities of Ulex europaeus, Sarothamnus scoparius and Lupinus arboreus. Measurements were made of biomass and litter in five plant communities and nitrogen levels were determined in the soil/plant system within these communities and also in the soil of a woodland which had developed on sand waste. The low productivity and low rate of nitrogen accumulation in a stand of Calluna vulgaris contrasted with stands of the three woody legumes. Gorse (Ulex europaeus) accumulated nitrogen most rapidly and appeared to have preceded invasion by Rhododendron ponticum and transition to native woodland. Within the woodland and rhododendron thicket the soil nitrogen levels approached those characteristic of temperate climax woodland. The data indicate that the course of plant succession and the rate of soil development are strongly influenced by the biological properties of the colonising species. These processes are accelerated considerably following the invasion of woody legumes. re]19760512