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In Britain, Lychnis viscaria is restricted to shallow soils on outcrops of basic igneous rocks and, in experiments, seedlings grow well on these soils but fail on soils from outcrops of sandstone, limestone and acid igneous rocks. The growth of seedlings in water-culture with purified salts shows that the species does not require an unusual balance of ions and its response to traceelements is normal. Seedlings will only grow on acid soils (other than on basic igneous rocks) if calcium carbonate, nitrogen, potassium and phosphate are provided, and on calcareous soils if phosphate is provided. There is evidence that L. viscaria can obtain phosphate from soils on basic igneous rocks even though other species show severe deficiency. [ABSTRACT FROM AUTHOR]

The large input of research effort on aspects of nitrate leaching over the last two decades has produced many innovative scientific and practical results. The MAFF Nitrate Programme has enabled considerableprogress to be made in unravelling much of the complexity of the grassland nitrogen (N) cycle, and identifying gaps as essential first stages in providing improved managements for N in grassland systems. From a practical standpoint, there have been key outputs which have allowed the identification of options for policy, and which should allowgrassland farmers to increase the efficiency of N use throughout their farming system and thereby improve the sustainability of their enterprises. As well as quantifying N transformations, transfers and losses, other important outcomes have been the development of user-friendly models of N cycling (NCYCLE and variants) and an easy to use field kit to determine mineral N in pasture soils. The use of modeling toproduce fertilizer recommendations with a Decision Support System and of new approaches developed within the Programme, in particular system synthesis desk studies, and 'farmlet' investigations to determinethe consequences of modifying N flows and losses, have allowed us toproduce solutions to satisfy the dual aims of meeting environmental and economic production targets. [ABSTRACT FROM AUTHOR]

Ceramic suction cups were used to obtain samples of soil solution from permanently grazed swards receiving 200 kg N/ha/y. The suction cups were installed in 1 ha plots at 10, 30 and 60 cm depth in a poorly drained, heavy clay soil in SW England. The plots were hydrologicallyisolated from each other by perimeter drains which channelled surface runoff water into v-notch weirs. In one treatment, artificial drainage by a system of field and mote drains also converged to outfalls through v-notch weirs, which enabled samples to be taken. Nitrate and a range of other ionic constituents were examined over a 12 month period in soil solutions taken from the suction cups and compared with leachate obtained from the field drains and surface channels. Field drain samples frequently exceeded the EC limit of 11.3 mg nitrate-N/l, but concentrations in suction cups obtained during the same period did not, and were up to ten-fold less. Although correlations for ions were found between different sampling depths and drainage samples, no clear patterns emerged. It was concluded that suction cups were inappropriate for the determination of the overall leaching losses in thissoil type, but provided useful data on changes in ionic concentrations which occurred in different soil horizons through to drainage outfalls. [ABSTRACT FROM AUTHOR]