Competition for nutrients between grasses and white clover

Competition for phosphate between establishing plants of Lolium perenne and Trifolium repens under differing cultivation treatments in an upland pasture

“…It must be concluded in this instance that the reduced uptake of phosphate in the slot-seeded treatment is due to the greater ability of the mature sward to interfere with this process within the soil. Although there is little information on the efficiency of exploitation of available soil phosphate by Trijolium repens it is noted as a poor competitor with grasses (Mouat & Walker, 1959;Jackman & Mouat, 1972 a, b). This poor competitive ability has been related to differences of root morphology and cation exchange capacity (Evans, 1977;Haynes, 1980).…”

Soil Fertility and Herbage Productivity*

“…Now it has been shown that grasses will utilize virtually all the mineral nitrogen available to a grass-legume association (10), and grasses will also compete intensively with legumes for phosphorus, potassium and sulphur (3). There is reason to believe that the time arrives when all the available inorganic phosphorus is tied up in the organic cycle, and that grasses which utilize virtually the whole ofthe mineral nitrogen from the breakdown of soil organic matter, also take up most of the phosphorus made available from this source.…”

“…Initially all or most of the phosphorus in the profile will be in the inorganic form, but as organic matter accumulates the available inorganic phosphorus will slowly be converted to organic forms, and the amount of inorganic phosphorus will decline as shown in Fig A small fraction of the organic phosphorus will be mineralized annually by soil microorganisms in the same manner as 1 or 2 per cent, of the organic nitrogen may be mineralized, and will be available once more for plant growth. Now it has been shown that grasses will utilize virtually all the mineral nitrogen available to a grass-legume association (10), and grasses will also compete intensively with legumes for phosphorus, potassium and sulphur (3). There is reason to believe that the time arrives when all the available inorganic phosphorus is tied up in the organic cycle, and that grasses which utilize virtually the whole ofthe mineral nitrogen from the breakdown of soil organic matter, also take up most of the phosphorus made available from this source.…”

Responses of a Perennial Grass‐Legume Mixture to Applied Nitrogen and Differing Soil Textures

“…Brock ( 3) and Brougham et al (4) suggested that white clover requires high levels of soil fertility, including N, for optimal growth. Because of its root morphology, (8,12,13), ladino clover also has been considered a poor competitor for the major soil nutrients, especially when grown in association with competitive grasses ( 13). This emphasizes the importance of complete (i.e., root, nodule and leaf) nodal unit development and adequacy of soil nutrients for continued regrowth of the legume as the pasture moves toward grass dominance.…”