Lime and major nutrient fertilizers required to establish a perennial ryegrass/white clover pasture on a non‐calcareous gley in the Scottish uplands

Abstract

AbstractA field experiment with mixed swards of perennial ryegrass and while clover carded out in 1982–83 using small cut plots is described. With perennial ryegrass, lime slightly decreased annual dry matter (DM) production in 1982 (the sowing year) but increased it in 1983 (the first harvest year) by about 1 t ha‐1. Applications of N and P produced small increases in DM in 1982 and greater increases in 1983. In the latter season annual DM production varied from an average of 3·5 to about 10 t ha‐1 with 0 or 480 kg N ha‐1 applied in three equal‐sized dressings throughout the growing season. Application of 40 kg P ha‐1 in 1982 increased DM production by about 2·5 t ha‐1 in 1983 but higher rates had little effect. Fifteen mg extractable P kg‐1 soil seemed sufficient to support levels of production normally expected from ryegrass pastures in upland Scotland, Applications of K did not affect DM production. N increased tiller weight and sward height of ryegrass; lime and P tended to increase tiller weight but this effect was not statistically significant. Leaf appearance and tiller number were not affected by treatments.The white clover content of the pasture was decreased 10‐fold by application of N and increased by lime and P (1·45 and 1·46‐fold. respectively). The DM response to P was most apparent in limed soil and was also affected by the siting of the plots in the experimental area. Effects of lime and P on growth of white clover were to increase the number of stolon growing points and root nodule numbers per unit area.The results emphasize the importance of lime and P fertilizer for establishment and growth of pasture in this soil and the differences between white clover and ryegrass in their responses to these.