Responses of Hedysarum boreale Nutt. to mycorrhizas and Rhizobium: plant and soil nutrient changes in a disturbed shrub‐steppe

Abstract

SU MMARYEffects of inoculation of Hedysarum boreale ssp. boreale Nutt. (Fabaceae) witb mycorrbizal fungi (topsoil inoculum) and Rhizobiiiyn (pure inoculum) were studied in tbe field in soutbwestern Wyoming, USA. After 3 years, plants receiving botb itiocula bad greater total aboveground biomass atid leaflet biomass, more leaves, bigber aboveground nitrogen and pbospbotus contents and greater survival tban plants wbicb received single or no inoculum. Soil 20-40 cm deep (wbere roots were concentrated) beneatb Hedysarum individuals from all treatments had a lower concentration of total nitrogen tban did soil between plants. Hedysarum plants, inoculated or not, apparently extracted sufficient nitrogen from tbe soil, as tbey bad similar leaflet nitrogen concentrations. Hedysarum decreased tbe size of tbe pool of soil nitrogen even witb Rhizobium inoculation on disturbed land in a semi-arid environmet-it during tbe first 3 years of growtb.

Inoculation of woody legumes with selected arbuscular mycorrhizal fungi and rhizobia to recover desertified Mediterranean ecosystems

“…Nevertheless, mycorrhizal biotechnology can be of view, the following two integrated into nursery and revegetation management, which (i) whether the inability of is based mainly on the use of transplants of vegetatively )ecome established can be produced plant material. It appears that appropriate miinappropriate management crosymbiont management can help legumes (4,19) to pro-;vhether the effectiveness of mote the stabilization of a self-sustaining ecosystem (9,24). proving outplanting perfor-…”

“…Thus, mycorrhizae have been found to increase legume performance (4). Moreover, woody legumes usually exhibit a considerable degree of dependence on mycorrhizae to thrive in stressed situations (9,12,13,18,20,24). Arbuscular mycorrhizae, which are by far the most widespread mycorrhizae in nature, are the most common mycorrhizae in nodulated, N2-fixing legumes (4).…”

“…This causes a decline in plant productivity and in the degree of soil protection against further activity from erosive agents (11,15). The establishment of a suitable plant cover is known to improve the chemical, physical, and biological properties of the soil (11,15,21); however, the scarcity of microbial propagules in the eroded soil (9,12,13,23,24) (10,17). The scarcity of available P and the imbalance of trace elements in desertified ecosystems actually limit legume establishment and N2 fixation (5).…”

Some Mediterranean plant species (Lavandula spp. and Thymus satureioides) act as potential ‘plant nurses’ for the early growth of Cupressus atlantica

“…For instance, it has been clearly demonstrated that land degradation was associated with reductions in the belowground microbial diversity and/or activity (Kennedy and Smith 1995;Garcia et al 1997). Mycorrhizal symbioses are known to be key components of natural systems, particularly in semiarid ecosystems (Carpenter and Allen 1988;Brundrett 1991). They are involved in governing the cycles of major plant nutrients and in sustaining the vegetation cover in natural habitats (Requena et al 2001).…”

The Exotic Legume Tree Species Acacia holosericea Alters Microbial Soil Functionalities and the Structure of the Arbuscular Mycorrhizal Community

“…These multipurpose trees are useful for revegetation of degraded ecosystems that have low availability of nitrogen and phosphorus (4,6,13,14,55) because of their ability to form symbiotic associations with both rhizobial bacteria and mycorrhizal fungi. These bacterial and fungal symbionts are known to be key components of natural systems (8,64,65,66), since they are involved in governing the cycles of major plant nutrients and in sustaining the vegetation cover in natural habitats (63). However, the success of revegetation programs may be limited by the low density of mycorrhizal propagules generally observed in degraded soils in semiarid and arid ecosystems (25).…”