Differences in Annual Clover Responses to Phosphorus and Sulfur¹

Abstract

Many new varieties of winter annual legumes are now available for pastures in Mediterranean type climates. Since little work has been reported comparing the relative responses of these legumes to fertilization, 10 varieties of subclover, 6 of rose clover, 3 annual Medicagos, and 2 other annual clovers were grown in the greenhouse on a soil known to be deficient in P and S. There were four levels of P with S applied. The nil and highest P levels were repeated without S. Yield differences between varieties and species were small where no P or S was applied. Responses to S alone were generally not significant, but responses to P only and P plus S varied significantly. Differences in response to P and S fertilization were as great among varieties of a given species as between species. Highest yielding clover varieties tended to have lowest percentages of P and S. Differences in P and S uptake by the clover varieties were significant; however, uptake responses to fertilization tended to be relatively smaller than yield response differences, indicating that some varieties utilized absorbed nutrients more efficiently than others. Response to fertilization apparently must be considered on a varietal basis rather than generalizing about species.

Legumes in low‐input perennial pastures of southern Australia: Historical role and future development

“…Several studies have raised questions about the ability of legume species to be more efficient at using P. Begg (1963) concluded that native legumes were relatively unresponsive to added P compared to naturalised and introduced species even though Lespedeza cuneata was proportionately as responsive as any of the exotic species. Differences in P use efficiency (amount of growth per unit P applied) have been documented at the species level (Spencer et al 1980), and within cultivars of T. subterraneum (Millikan 1963;Jones et al 1970), T. repens (Snaydon & Bradshaw 1962;Godwin & Blair 1991), and T. ambiguum (Spencer et al 1980). Ecotypic adaptation to low P within T. repens has been demonstrated in some situations (Snaydon & Bradshaw 1962) but not in others (Spencer et al 1980).…”

Strategies and agronomic interventions to improve the phosphorus-use efficiency of farming systems

“…Nevertheless, there are a few studies that indicate significant intraspecific variation in the critical P requirements of some pasture legumes (e.g. subterranean clovers when compared at similar shoot weights, Jones et al 1970; white clover populations from high-and low-P soils, Snaydon and Bradshaw 1962). In general, however, the P requirements of keystone pasture legumes and the newer, alternative species are ill-defined and there have been few demonstrations that pastures can be highly productive at lower soil P fertility levels when P-efficient legumes are used.…”

Biogeochemical Interactions Governing Terrestrial Net Primary Production

“…In California grasslands, for example, grass-dominated sites are nitrogen-limited but can be sulfur-and phosphorus-limited if legumes are present (Jones and Martin, 1964;Jones et al, 1970Jones et al, , 1983. Limitation by nitrogen versus phosphorus also changes over the course of soil development, with soils being nitrogen-limited early in primary succession, then becoming phosphorus-limited as P from the parent material is weathered over thousands of years (Vitousek, 2004;Vitousek and Farrington, 1997;Walker and Syers, 1976).…”

“…For example, phosphorus and sulfur can limit nitrogen fixation, and thus nitrogen availability (Bromfield, 1975;Jones et al, 1970). Phosphorus also stimulates nitrification and net nitrogen mineralization (Cole and Heil, 1981).…”