IMPACT OF SOIL MANAGEMENT ON SOIL MICROBIAL COMMUNITIES
Agroecosystem Management Research
2012 Annual Report
1a.Objectives (from AD-416):
Determine the impact of soil management on soil microbial community structure and function using biochemical and molecular methods.
a. soil distubance effects on soil function
b. role of mycorrhiza on P nutrition of corn
1b.Approach (from AD-416):
Biochemical (e.g. lipid profiles) and molecular methods will be used to identify functional groups of soil microorganisms under contrasting management conditions. These measurements will be taken in conjunction with soil process (e.g. nutrient transformation and uptake) and crop production (e.g. yield and nutrient content) measurements.
Molecular methods were used to identify mycorrhizal species infecting maize grown in rotation with soybean. Long-term N fertilization did not reduce the incidence of mycorrhizal infection. A greenhouse experiment was conducted to study the expression of an epidermal-expressed phosphorus transporter gene and an arbuscular mycorrhizal specific induced phosphorus transporter gene in maize either colonized or not colonized by mycorrhiza. Expression of the mycorrhizal specific P transporter gene activity was positively correlated with mycorrhizal biomass on maize roots, plant P uptake and shoot weight but negatively correlated with epidermal-expressed P transporter gene activity.