MCSE: Microplots in Treatment 5 (T5)

The microplot region of all T5 replicate plots will be subdivided into six different 14.6 m x 15 m microplots (see diagram below). Microplots will be marked with permanent corner posts. Fertilizer will be applied to microplots in each T5 replicate as follows: (N1) 0 lb N/acre; (N2) 50 lb N/acre, single application in 2011; (N3) 100 lb N/acre, single application in 2011; (N4) 50 lb N/acre, annual application; (N5) 100 lb N/acre, annual application and (N6) 100 lb N/acre, single application in the year prior to harvest (expected to be applied in 2015). Fertilizer treatments will be randomly assigned to individual microplots within each T5 replicate (see table below). Microplots will receive a broadcast application of granular CaNH4NO3 (27% N, w/w; CAN 27, Uniocal Corp., El Sequndo, CA) in early July, 2011.

Individual measurement trees (see below diagram) will be marked with numbered aluminum identification tags. Prior to fertilizer application, individual measurement trees within each microplot (12) will be measured for basal diameter at 15 cm above the soil surface. Basal diameter measurements will be repeated at the end of each subsequent growing season in December. Leaf litter will be collected in 0.8 × 1.2 wooden litter trap frames. Two traps will be placed in the alleyway between the two rows of measurement tree in each microplot in late August. Leaves within the traps will be collected weekly throughout the season, dried, weighed, ground and archived for tissue analysis. Foliage will also be sampled during the peak of the growing season (~ mid-July) each year to measure nutrient concentrations. Three recently mature leaves will be collected from branches in the current height-growth increment of three randomly selected measurement trees in each micropot. The composite sample of nine leaves per microplot will be analyzed for nutrient concentrations. Control (0 lb N/acre) microplots will be available for baseline measurements.