Nitrogen fixation in sainfoin (Onobrychis viciifolia) 1. Responses to changes in nitrogen nutrition

Abstract

Development and nodulation of the forage legume sainfoin (Onobrychis viciifolia Scop.) were observed under glasshouse conditions for 50 days after sowing. Growth changes caused by different nitrogen (N) nutrition were investigated from Day 50. The quantity of nodule tissue produced compared favourably with values reported for a range oflegumes. In spite of this, the symbiotic N 2fixing system of sainfoin appeared unable to provide sufficient N to meet the plant's requirements. The relative growth rate of the whole plant, and the relative N accumulation rate were substantially lower in plants dependent on N 2 fixation compared to plants provided with 210 mg/litre nitrate N. Development of the below-ground portion of the plant was rapid relative to that of the top. Relative growth rates, top: root + nodule ratio, and leaf area ratio of sainfoin were lower than values reported for other legumes. The mode of N nutrition affected dry matter distribution, with proportionately much greater below-ground development in plants dependent on symbiotic N 2 fixation. This resulted in lower leaf area ratios and hence probably reduced the availability of energy for symbiotic N 2 fixation. The application of 35 mg/Iitre nitrate N to plants previously solely dependent on symbiotic N 2 fixation appeared to substitute for, rather than supplement, N 2 fixation. Applying 35 mg/Iitre nitrate N to plants previously given 210 mg/Iitre nitrate N resulted in nodulation, the initiation of symbiotic N 2 fixation, and a substantial change in dry matter distribution in favour of the root system.

Sainfoin production in western Canada: A review of agronomic potential and environmental benefits

“…Due to the symbiosis with N 2 ‐fixing rhizobia, perennial forage legumes have the opportunity to reduce N requirements, thereby potentially enhancing the sustainability of forage‐based livestock production systems (Carlsson & Huss‐Danell, ). However, Hume and Withers () and Hume, Withers, and Rhoades () provided a negative perspective on N 2 fixation in sainfoin: There was not enough N fixation to fully support the plant, resulting in larger root systems and lower shoot growth rate compared to plants supplied with mineral N. However, fertilization with N supplanted N 2 fixation before it augmented N supply to the plant when using a commercial rhizobium culture. Large pink nodules were formed suggesting that the inoculant was effective (Hume & Withers, ; Hume et al., ).…”

Condensed tannin accumulation and nitrogen fixation potential of Onobrychis viciifolia Scop. grown in a Mediterranean environment

“…Only chicory was considered further for the quantification of aerial fixed N. The N dfa achieved by sainfoin, based on chicory as a reference species, ranged from 82.8 to 86.7% and was in agreement with that of other forage legumes such as alfalfa and white clover . In spite of the plentiful available data regarding the effects of different strain inoculations in sainfoin and its N fixation under glasshouse conditions estimated by acetylene reduction assays, very little information an N dfa values of sainfoin obtained in the field by isotopic methods is available . Provorov and Tikhonovich reported an N dfa value of 80% determined using the isotope dilution method under Russian conditions.…”

“…31 In spite of the plentiful available data regarding the effects of different strain inoculations in sainfoin and its N fixation under glasshouse conditions estimated by acetylene reduction assays, very little information an N dfa values of sainfoin obtained in the field by isotopic methods is available. 13,14,[32][33][34] reported an N dfa value of 80% determined using the isotope dilution method under Russian conditions. In a biodiversity experiment in Germany, Roscher et al 35 reported N dfa values ranging from about 65 to 75% obtained using the natural abundance method.…”

Comparative response of lucerne (Medicago sativa L.) and sainfoin (Onobrychis viciaefolia Scop.) to applications of P, K and lime

“…In contrast to the meagre data on P and K response, mention is often made in the literature to the fact that sainfoin responds readily to N fertilizer (Jensen & Sharp, 1968;Meyer, 1975) because of its inefficient N2 fixing ability (Hume & Withers, 1985).…”

“…This finding corresponds with some published data (Ditterline & Cooper, 1975;Wilman & Asiedu, 1983;McGraw & Marten, 1986). The relatively low CP content obtained in sainfoin can probably be related to inefficient N2 fixation of this species (Hume & Withers, 1985).…”