Soil Analysis - Both the macrosurvey and microsurvey soil samples were analyzed for four conservative soil fertility indicators: cation exchange capacity (CEC), pH, organic matter content (OM), and field capacity (FC) (Weischet and Caviedes 1993), as well as foliar nitrogen. Field capacity was determined using a laboratory centrifugation method (Cassel and Nielsen, 1986). Field and laboratory methods for pH, CEC, OM and foliar nitrogen are described in Landon (1991) and Lal and Sanchez (1992). Several leaves were collected from plants on the plot, and analyzed for total Nitrogen. Foliar nitrogen can indicate level of soil fertility, but more commonly is related to use of nitrogenous fertilizer. Soil and foliage samples were analyzed in the laboratory at Kasetsaat University under the supervision of Professor Irb Keorhumramne, Department of Soil Science.

Soil moisture tension (and soil temperature) - Checked weekly at 5 locations in each microsurvey village. Soil moisture tension is also measured at two-day intervals after storms until tension stabilizes or it rains again (again at the same 5 locations in each microsurvey village).

In-situ water chemistry - Temperature, pH, and conductivity is measured bi-weekly (5 locations in each microsurvey village, mostly in ponds, streams, or canals, but in a few cases in rainwater cisterns to get an idea about rainfall chemistry and a few wells to get an idea about groundwater chemistry). In-situ water chemistry (see above) is also measured after the first rain of each month, to capture the "first-flush" water quality in general terms.

Lab Water Chemistry - The microsurvey year one water chemistry included, in addition to the field measurements in 3, Total Nitrogen, Organic Nitrogen, Ammonia-Nitrogen, Nitrite Nitrogen, Nitrate Nitrogen, Ortho- Phosphorus, Total Phosphorus in samples from all water stations (again, 5 per village) once per month for 12 months.

Daily precipitation - One rain gauge is checked each day in each microsurvey village.

Plot Photos - For each plot with a soil sample, the enumerator took photographs from the center of the field in the four cardinal directions, and one photograph diagonally across the field. The enumerator also described the general characteristics of the surrounding landscape, including vegetation present, topography, proximity towater bodies etc. (I need to ask Khun Sombat to send these)

Aerial Photos - Photos of each of the initial survey villages were obtained, including the earliest in the 50's, and the latest in the 80's. (If you need heights resolution etc - need to ask Todd and then e-mail Sombat).