The green manure value of seven clover species grown as annual crops on low and high fertility temperate soils

Abstract

, J. T. 2009. The green manure value of seven clover species grown as annual crops on low and high fertility temperate soils. Can. J. Plant Sci. 89: 465Á476. Annual and perennial clover species may differ in green manure value. Seven clover (Trifolium) species were grown as annual crops on low fertility (Breton) and high fertility (Edmonton) soils in Alberta. Four annual clovers [balansa (T. michelianum Savi), berseem (T. alexandrinum L.), crimson (T. incarnatum L.), and Persian (T. resupinatum L.)], three perennial clovers [alsike (T. hybridum L.), red (T. pratense L.), and white Dutch (T. repens L.)] and a non-legume reference crop [fall rye (Secale cereale L.)] were ploughed-down as green manure in autumn, and followed by barley (Hordeum vulgare L.). Annual clovers had greater biomass yields than perennial clovers, and berseem clover had the highest yield. At Breton, mean biomass N content was greater for perennial clovers (2.9 g N kg(1 ) than annual clovers (1.9 g N kg(1 ). Clover biomass at Breton yielded an average of 77 kg N ha (1 , with N derived from the atmosphere averaging 88% by N difference method and 75% by 15 N natural abundance method. At Edmonton, the green manures had few effects on soil nitrate and subsequent barley yields. At Breton, all clover green manures except balansa increased barley yields, and grain yields were greater following perennial clovers than annual clovers in one year. Annual clovers will provide forage biomass and add N in areas where rainfall is adequate, and they may be preferable under zero tillage. However there is no advantage of annual clovers, relative to perennial clovers, in terms of N supply. . Les espe`ces de tre`fle annuelles ont donne´plus de biomasse que les espe`ces vivaces, le tre`fle d'Alexandrie enregistrant le meilleur rendement. À Breton, la teneur en N moyenne de la biomasse e´tait plus e´leve´e pour les espe`ces vivaces (2,9 g de N par kg) que pour les espe`ces annuelles (1,9 g de N par kg). Toujours aB reton, la biomasse du tre`fle a donne´en moyenne 77 kg de N par hectare, l'azote issu de l'atmosphe`re en repre´sentant en moyenne 88 % quand on calcule sa proportion par soustraction et 75 % quand on la calcule en fonction de l'abondance de l'isotope 15 N dans la nature. À Edmonton, les engrais verts ont eu peu d'incidence sur les nitrates du sol et le rendement subse´quent de l'orge. À Breton, tous les engrais verts a`base de tre`fle sauf le tre`fle de Micheli ont accru le rendement de l'orge et le rendement ce´re´alier e´tait plus important apre`s la culture du tre`fle vivace qu'apre`s celle du tre`fle annuel. Les espe`ces annuelles de tre`fle produisent de la biomasse fourrage`re et ajoutent de l'azote au sol des endroits ou`il pleut suffisamment; il pourrait eˆtre pre´fe´rable de les cultiver quand on pratique le non-travail du sol. Ne´anmoins, cultiver des espe`ces annuelles plutoˆt que des espe`ces vivaces de tre`fle ne pre´sente aucun avantage en ce qui concerne l'apport de N.

Root interactions between intercropped legumes and non-legumes—a competition study of red clover and red beet at different nitrogen levels

“…However, the decreased performance of clover at increased N supply was not likely to be caused by N deficiency, as root nodules were observed on its roots, and its N concentration was not reduced.. The N concentration in the aboveground biomass of clover was comparable with an N percent of 2.5-3.2 % measured in red clover grown on a soil with a low N content (Ross et al 2009) and 2.52-3.61 % measured in red clover grown in a mixture with timothy at N fertilization rates up to 160 kg N ha −1 (Nesheim and Oyen 1994). Thus, the decreased performance of clover in mixture at increasing N supply may be caused by competition for other soil resources such as other macronutrients (P, K, Ca, Mg or S) or water.…”

N2-fixation and residual N effect of four legume species and four companion grass species

“…The N 2 -fixation values found for the four forage legumes in this study show that the choice of forage legume strongly affects the N input to an agricultural production system. Only a few studies compare more than two forage legumes under similar management, environmental and climatic conditions (Askegaard and Eriksen, 2007;Heichel and Henjum, 1991;Mallarino and Wedin, 1990;Mallarino et al, 1990a and b;Ross et al, 2009;Ta and Faris, 1987). In relation to the N yield from forage legume N 2 -fixation we conclude that alfalfa and red clover are superior compared to white clover and bird's-foot trefoil (see summary in Table 6; Heichel and Henjum, 1991;Mallarino et al, 1990a;Ta and Faris, 1987).…”

Viral infection can reduce the net nitrogen inputs of legume break crops and cover crops

“… Data sources: a, Kandel (2014); b, Marchetto and Power (2018); c, Clark and Carpenter (2000); d, Ross et al (2009); e, Khadhair et al (1984); f, Smith and Maxwell (1971); g, Sofy et al (2014); h, Bohl (1981); i, Ohki et al (1986); j, Justes et al (2002); k, Goins and Russelle (1996); l, Lemaire et al (1992); m, Robbins and Carter (1980); n, Chen et al (2004). …”

“…The clover estimated NNI is for green manure and is parameterized for green‐manure‐specific biomass data (Ross et al 2009) using proportional growth reductions caused by WClMV or BYMV (Smith and Maxwell 1971, Khadhair et al 1984). Here, a biomass per area term ( B i ) is used rather than a term for plants per area, and reflects the complete aboveground biomass of the crop without removal through harvest (Eq.…”