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Abstract
Improvements in nitrogen (N) uptake efficiency and plantation growth require refined silvicultural systems that consider soil type, stand development, ecology, and their interactions. On four unthinned, mid-rotation loblolly pine plantations in Louisiana located on a gradient of soil drainage classes, soil, plant, and microbial N dynamics were measured in response to fertilization and understory vegetation control. Treatments consisted of an untreated control, N and phosphorus (P) fertilization, and N + P fertilization with herbicide understory suppression. Results indicated understory suppression was necessary to effectively promote increases in pine foliage N concentrations when stands had no prior history of herbicide application. Understory control was most effective in enhancing pine response to fertilization on a well-drained site. Soil N returned to background levels within 6 months of application at all sites, and microbial biomass N was relatively unaffected by fertilization and brush control at all sites.
Parent Publication
Citation
Blazier, Michael A.; Scott, D. Andrew. 2006. Nitrogen distribution within the soil-plant-microbial system in response to pre-thinning fertilization treatments in Louisiana. Gen. Tech. Rep. SRS-92. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pp. 129-134
