Record ID No. |
1887 |
Author(s) |
Cheng, XM; Euliss, A; Baumgartner, K. , 2008 |
Affiliation |
Baumgartner K, Agr Res Serv, USDA, 1 Shields Ave, Davis,CA 95616 USA |
Title |
Nitrogen capture by grapevine roots and arbuscular mycorrhizal fungi from legume cover-crop residues under low rates of mineral fertilization |
Source. Vol.(no):Page |
Biology and Fertility of Soils, 44(7): 965-973 |
Categories |
Arbuscular Mycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Country |
USA< North America |
Abstracts |
The influence of mineral fertilization on root uptake and arbuscular mycorrhizal fungi-mediated N-15 capture from labeled legume (Medicago polymorpha) residue was examined in winegrapes (Vitis vinifera) in the greenhouse, to evaluate compatibility of fertilization with incorporation of cover-crop residue in winegrape production. Plants grown in marginal vineyard soil were either fertilized with 0.25x Hoagland's solution or not. This low fertilization rate represents the deficit management approach typical of winegrape production. Access to residue in a separate compartment was controlled to allow mycorrhizal roots (roots + hyphae), hyphae (hyphae-intact), or neither (hyphae-rotated) to proliferate in the residue by means of mesh core treatments. Leaves were weekly analyzed for N-15. On day 42, plants were analyzed for N-15 and biomass; roots were examined for intraradical colonization; and soils were analyzed for N-15, inorganic N, Olsen-P, X-K, and extraradical colonization. As expected, extraradical colonization of soil outside the cores was unaffected by mesh core treatment, while that inside the cores varied significantly. N-15 atom% excess was highest in leaves of roots + hyphae. In comparison, leaf N-15 atom% excess in hyphae-intact was consistently intermediate between roots + hyphae and hyphae-rotated, the latter of which remained unchanged over time. Fertilization stimulated host and fungal growth, based on higher biomass and intraradical colonization of fertilized plants. Fertilization did not affect hyphal or root proliferation in residue but did lower %N derived from residue in leaves and stems by 50%. Our results suggest that even low fertilization rates decrease grapevine N uptake from legume crop residue by both extraradical hyphae and roots. |