The role of bio-inoculants on phosphorous relations of barley

Electronic versions

Dogfennau

Abstract

Phosphorus (P) is one of the most limiting and important elements in crop production, yet often has limited availability in the soil. Manufactured inorganic P fertilisers are required to improve soil and crop P supply but their use depletes finite reserves of rock phosphate and impacts on water quality and ecosystem biodiversity. Bio-inoculants have a potential role to increase soil P supply and reduce dependence on expensive fertilisers. The objective of this thesis was to further understand the role of mycorrhizae (M) and P solubilizing bacteria (PSB) bio-inoculants and external P sources (super phosphate (SP), struvite (AMP) and rock phosphate (RP)on phosphorus availability in soil and their effects on the growth, yield and P uptake of barley. Field experiments on low P status soils in 2010 and 2011 demonstrated the potential for the use of bio-inoculants (PSB and M) in mobilizing P from soil and significantly (P <0.05) enhancing P uptake to increase growth of barley, and to a lesser extent, grain yield. It was postulated that bio-inoculant effects in the field were compromised by the presence of native M and PSB. Glasshouse pot experiments were conducted with a range of growth media: horticultural sand (zero P), field soil (low P status but with native micro-organisms) and heat sterilized field soil. These demonstrated the effects of bio-inoculants without the presence of native M and PSB, and to a lesser extent in the presence of native micro-organisms, in terms of increased plant root and shoot growth, grain yield and tissue P concentration. Across all experiments bio-inoculants (M and PSB) increased the effectiveness of water soluble SP, partially soluble AMP and insoluble RP. M and PSB were equally effective. In combination with these external P sources, bio-inoculants (M and PSB) significantly (P < 0.05) increased yield, P concentration and total P uptake, plant dry matter and concentration of P in the grain compared to P fertilizers without bio-inoculants. However, applications of P fertilizers reduced the colonization of roots by mycorrhizae. The potential role of P uptake enhancing bio-inoculants in reducing external inputs in agriculture is discussed.

Details

Iaith wreiddiolSaesneg
Goruchwylydd / Goruchwylwyr / Cynghorydd
    Dyddiad dyfarnuIon 2013