water amendment

Dataset: 

Study number: 

27

Data set ID: 

210278001

Date range: 

2007-07-24 to 2009-08-10

Original investigator: 

Lara G Reichmann

Data contact: 

Abstract: 

A 2-year experiment with ambient, reduced, and enhanced precipitation was designed to compare the performance of the  encroaching C3 shrub (honey mesquite Prosopis glandulosa) to the dominant C4 grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates and leaf water status.

A 2-year experiment with ambient, reduced, and enhanced precipitation was designed to compare the performance of the  encroaching C3 shrub (honey mesquite Prosopis glandulosa) to the dominant C4 grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates and leaf water status. Precipitation manipulations dramatically enhanced natural variability and generated a range of rainfall scenarios that could have only been studied only after a multi-decade effort using natural conditions. Responses were highly asymmetric, with precipitation (PPT) additions generally influencing volumetric water content (vwc) to a greater extent than PPT reductions. Desert soils are usually close to their minimum water content  and thus when soils were dry, the effects of reducing PPT were relatively minor compared to the effects of adding PPT. Volumetric soil water content was, on average, lower and more variable at the shallower (0–5 cm) depth (mean 9.3 ± 0.14%; range 5.7–14.3%) than at the deeper (30–50 cm) depth (mean 14.4 ± 0.12%; range 10.8–18.1%. This study is complete. For further information and results, see:

Throop, H., L. G. Reichmann, Os. Sala, and S. Archer. 2012.  Response of dominant grass and shrub species to water manipulation: an ecophysical basis for shrub invasion in a Chihuahuan desert grassland. Oecologia 169: 373-383.

 

 

 

Data download: 

Description: 

Water content in precipitation treatment plots at 2 depth profiles

LTER Core Area(s): 

Dataset: 

Study number: 

27

Data set ID: 

210278002

Date range: 

2006-10-01 to 2008-09-30

Original investigator: 

Lara G Reichmann

Data contact: 

Abstract: 

A 2-year experiment with ambient, reduced, and enhanced precipitation as well as nitrogen additions was designed to compare the performance of the  encroaching C3 shrub (honey mesquite Prosopis glandulosa) to the dominant C4 grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates and leaf water status.
A 2-year experiment with ambient, reduced, and enhanced precipitation as well as nitrogen additions was designed to compare the performance of the  encroaching C3 shrub (honey mesquite Prosopis glandulosa) to the dominant C4 grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates and leaf water status. Precipitation manipulations dramatically enhanced natural variability and generated a range of rainfall scenarios that could have only been studied only after a multi-decade effort using natural conditions.We use vegetation cover as a proxy for plant biomass to avoid confounding spatial and temporal variability or confounding the impact of harvesting.  Individual cover of plant species was measured  using three parallel transects per plot. This study is complete.

Data download: 

Description: 

Data file information for the following Jornada data set: Plant cover in precipitation and nitrogen treatment plots (by species)

LTER Core Area(s): 

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