Decoupling crop production from water consumption at some irrigation schemes in southern Africa

Wellington, Michael; Kuhnert, Petra M.; Lawes, Roger; Renzullo, Luigi J.; Pittock, Jamie; Ramshaw, Peter; Moyo, Martin; Kimaro, Emmanuel; Tafula, Miguel; Rooyen, André F. van

doi:10.1016/j.agwat.2023.108358

Cited by 7 publications

(1 citation statement)

References 26 publications

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“…A commonly used indicator of carbon assimilation is gross primary production (GPP) [9,10], which is the rate of carbon fixation per unit time and over a defined area [11][12][13]. In general, methods for measuring GPP and CO 2 fluxes have mostly been developed and evaluated for arable land (e.g., [14][15][16]). Therefore, the application of these methods in natural vegetation is the next challenge.…”

Section: Introductionmentioning

confidence: 99%

Validation of Gross Primary Production Estimated by Remote Sensing for the Ecosystems of Doñana National Park through Improvements in Light Use Efficiency Estimation

Gómez-Giráldez,

Cristóbal,

Nieto

et al. 2024

Remote Sensing

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Doñana National Park is located in the southwest of the Iberian Peninsula, where water scarcity is recurrent, together with a high heterogeneity in species and ecosystems. Monitoring carbon assimilation is essential to improve knowledge of global change in natural vegetation cover. In this work, a light use efficiency (LUE) model was applied to estimate gross primary production (GPP) in two ecosystems of Doñana, xeric shrub (drought resistant) and seasonal marsh (with grasslands dependent on water hydroperiod) and validated with in situ data from eddy covariance (EC) towers installed in both ecosystems. The model was applied in two ways: (1) using the fraction of absorbed photosynthetically active radiation (FAPAR) from Sentinel-2 and meteorological data from reanalysis (ERA5), and (2) using Sentinel-2 FAPAR, reanalysis solar radiation (ERA5) and the Sentinel-2 land surface water index (LSWI). In both cases and for both ecosystems, the error values are acceptable (below 1 gC/m2) and in both ecosystems the model using the LSWI gave better results (R2 of 0.8 in marshes and 0.51 in xeric shrubs). The results also show a greater influence of the water status of the system than of the meteorological variables in this area.

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