Developing soil management recommendations for improving plant beneficial microbial interactions to increase nutrient availability and carbon sequestration in forest lands
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Sustainable management of forests is important to maintain provisional (wood fiber production) and other ecosystem services. Nutrient availability, which is dependent on complex interactions between plants, soil microbial communities and management, can be a major limitation for plantation establishment, productivity and sustainable intensification of planted forests. Many soils with lower soil organic carbon (SOC) and poor soil health present challenges to maintain beneficial microbial interactions, which further contribute to limited nutrient availability and decline of ecosystem services. Planted forests in East Texas and expansive regions of South Eastern US are more commonly associated with these soil types. These soils are naturally low in soil fertility and require higher fertilization for successful establishment and higher productivity. Inorganic fertilization is costly and can also produce undesired environmental consequences. Additionally, many management practices used for forest site preparation impose range of soil profile disturbances leading to loss of SOC and diminish microbial diversity and beneficial interactions. Thus, documenting trends in SOC and important microbial processes in response to various forest management techniques is essential to develop effective interventions to improve conditions for sustainable growth. Objectives of this project are; (i) to develop soil management recommendations to enhance beneficial soil microbiomes for improving N and P availability in planted loblolly pine forests, (ii) identify suitable soil biology indices for quantifying soil health and (iii) to estimate soil health and soil carbon sequestration in response to forest management practices.Procedure: For objective 1, two major tasks will be undertaken. Task 1 will be initiated in year 1 of this project, for soil monitoring to evaluate soil nutrients at several forest sites under different management scenarios representing planted and natural forests, with minimal management to intensively managed sites, different soil types, chronosequence and vegetation mix. Root zone soil samples will be collected at multiple time points (seasons) and analyzed for several major and micro nutrients, microbial diversity of beneficial microbes relevant for nutrient fluxes. Results will be used for identifying nutrient imbalances, and link with soil health parameters and relevant microbial activities. Task 2 will be initiated in year 2 to evaluate several soil management interventions for their effects on beneficial microbial interactions. Major soil treatments will include phosphorus and micronutrient fertilization and soil amendments for stimulation of beneficial plant-microbe interactions. These treatments will be tested for microbial diversity estimates, establishment of mycorrhizal interactions with loblolly pine (Pinus taeda L.) roots, activity of free living nitrogen fixation, N and P availability for establishment and growth. Results will be used for evaluating treatments to increase plant beneficial microbial interactions and N and P supply to plantations.For objectives 2, suitable biology indices will be developed for evaluating forest soil health...............