The Jornada LTER added 3 principal investigators in 1987: Drs. Marsha Conley and Fred Fisher have moved from research associate to senior investigator status; Dr. Tim Ward of New Mexico State’s CMI Engineering Department has joined the LTER research group.
Dr. Conley, who has been responsible for data collection on consumer populations, will be directing efforts to assess the role of consumers (i.e. ants, kangaroo rats, gophers, rabbits, etc.) In creating and maintaining disturbance patches. Results to date indicate that soil disturbance by consumers plays an important role in developing spatial heterogeneity, producing patches of enhanced primary production.
In the coming year Dr. Fisher will continue studying decomposition and nitrogen mineralization processes, and direct our assessment of the importance of below- ground decomposition. The timing of ephemeral root decomposition in relation to moisture availability could dramatically affect the extent to which rainfall is able to stimulate primary production since this could produce either a N source or sink. These investigations are designed to develop predictive relationships for those critical water/nitrogen interactions.
Dr. Ward has previously investigated the effects of termite activity on infiltration, runoff, and sediment yield at Jornada. During 1987 he will be developing a simulation model of runoff. The model will be used to predict fluvial redistribution of organic matter along the watershed. We plan to combine this model with the point models of decomposition, nitrogen mineralization, and primary production being developed under the direction of Jim Reynolds (now at San Diego State) to predict spatial patterns of primary production.
Dr. Peter J. Wierenga (S0H Physics Laboratory, NMSU) has continued funding of a field study at Jornada from the Nuclear Regulatory Commission. With LTER funds a lysimeter facility was built to study chemical transport through 6 m deep caissons. This experience was used to design a trench study to monitor chemical transport through deep, unsaturated, arid soils. Results will be compared with predictions using a stochastic computer model developed by Dr. Lynn Geihar at MIT. Further evaluation of this and other models will be performed for the NRC by Dr. Glendeon Gee at Battelle, Richland, WA.
Walt Whitford is on sabbatical leave in Australia during Spring ‘87. We look forward to his returning with new ideas and enthusiasm.