Estimating the water requirements of high yielding and young apple orchards in the winter rainfall areas of South Africa using a dual source evapotranspiration model

Dzikiti, Sebinasi; Volschenk, T.; Midgley, S.J.E.; Lötze, E.; Taylor, N. J.; Gush, Mark B; Ntshidi, Zanele; Zirebwa, SF; Doko, Q.; Schmeisser, M.; Jarmain, C.; Steyn, W.J.; Pienaar, Harrison

doi:10.1016/j.agwat.2018.06.017

Cited by 43 publications

(28 citation statements)

References 39 publications

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“…However, when the deep-rooted trees are felled and shallow-rooted crops are planted, soil water content begins to recover, and groundwater recharge could increase by an order of magnitude after several decades of land-use change [21]. There is abundant information on the evolution for soil water content during the development of apple orchards [19,[22][23][24][25][26][27][28][29]; however, there is limited information on the evolution of soil water after the trees are felled.…”

Section: Introductionmentioning

confidence: 99%

Deficit and Recovery of Deep Soil Water Following a Full Cycle of Afforestation and Deforestation of Apple Trees on the Loess Plateau, China

Zhang

Cheng

et al. 2020

Water

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Land-use change could substantially alter the soil water balance and hydrological cycles; however, little is known on the changes in deep soil water following a cycle of afforestation and deforestation. The purpose of this study was to quantify the soil water deficit in an apple orchard and subsequent replenishment of deep soil water after the orchard was felled. Soil water changes were quantified using the “space-for-time” method through a paired plot design. The results showed that the water storage in deep soil (>3 m in depth) began to decrease when the apple tree reached about 10 years of age. The cumulative deficit of deep soil water storage in the 3–18 m soil depth could reach about 1200 mm; however, deep soil water was so depleted that apple trees can no longer adsorb water from the deep soil when apple trees are older (>22 years old). After the apple orchard was converted to cropland, precipitation replenished the desiccated deep soil to a depth of about 7 m in the first two years, but thereafter, both water recovery amount and the advance rate of the wetting front were slowed down. After 15–16 years of recovery, soil water storage increased by 512–646 mm, accounting for 42.7–53.8% of the total cumulative soil water deficit caused by the apple orchard. However, it will take more than 26 years for soil water to be replenished to the level of the original cropland prior to planting apple trees. The considerable water deficit after afforestation and subsequent long water recovery time following deforestation extend our understanding of the effect of deep-rooted trees on water balance at the decade scale.

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Section: Introductionmentioning

confidence: 99%

Deficit and Recovery of Deep Soil Water Following a Full Cycle of Afforestation and Deforestation of Apple Trees on the Loess Plateau, China

Zhang

Cheng

et al. 2020

Water

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“…Using the original model and the suggested eco-physiological stress factors and parameters as published by Fisher et al (2008) on apple orchards led to significant poor model performance for ET estimation and its constituent components (T and E s ) for orchards of all age groups as will be discussed in detail in the results section. It is known that water use from apple orchards is highly sensitive to soil water deficit and the vapour pressure deficit of the air (VPD) (Dzikiti et al, 2018a;Lo Bianco, 2019). Therefore, the model was subsequently improved by introducing two stress factors; one for soil moisture (f SM ) and the other for vapour pressure deficit of the air (f VPD ).…”

Section: Modelling Water Use Of Apple Orchards With the Pt-jpl Modelmentioning

confidence: 99%

“…Dragoni and Lakso, 2011;Rana et al, 2005), dual source Shuttleworth and Wallace type models (e.g. Ortega-Farias et al, 2012;Li et al, 2010;Allen et al, 1998 andDzikiti et al, 2018a) and models using remote sensing data (Odi-Lara et al, 2016). Given the heterogeneity that characterises orchard environments comprising trees in rows, bare ground, cover crops, and at times the mulch, dual source models provide more accurate ET estimates.…”

Section: Introductionmentioning

confidence: 99%

“…Given the heterogeneity that characterises orchard environments comprising trees in rows, bare ground, cover crops, and at times the mulch, dual source models provide more accurate ET estimates. These models partition ET into transpiration (T) and substrate/orchard floor evaporation (Es) components (Kool et al, 2014;Dzikiti et al, 2017Dzikiti et al, , 2018a. However, many of these models require parameters such as the aerodynamic and stomatal resistances, which are not easy to obtain, and they can be sources of uncertainty.…”

Section: Introductionmentioning

confidence: 99%

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Modelling water utilization patterns in apple orchards with varying canopy sizes and different growth stages in semi-arid environments

Mobe

Dzikiti

Dube

et al. 2021

Scientia Horticulturae

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Accurate estimates of orchard evapotranspiration (ET) and its components are important for precise irrigation scheduling, irrigation system designs, and optimal on-farm water allocation particularly in water-limited environments. Direct measurements of ET remain costly, laborious and sometimes difficult to apply over heterogeneous surfaces such as crop fields. Therefore, accurate crop water-use models are required for on-farm precise water resources management. In this study, we adopted and improved the Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model developed by Fisher et al 2008 to estimate crop water use across different apple plants. Specifically, the model was developed to quantify the partitioning of apple orchard water use into beneficial (tree transpiration) and non-beneficial water use (orchard floor evaporation) as influenced by tree canopy cover. Data were collected in twelve orchards spread across key apple producing regions in the Western Cape Province of South Africa over three growing seasons (2014/15, 2015/16, 2016/17). Model ET estimates were tested against ET data measured; using the eddy covariance method and transpiration measured based on sap flow monitoring techniques. The results showed that the original Fisher PT-JPL model performed poorly in ET estimation across all the orchards under study. The model yielded lower R 2 , ranging from 0.02 to 0.64 and Nash-Sutcliffe Efficiency (NSE) from -10.93 to 0.20. Thus, we subsequently improved the model by incorporating soil moisture and vapour pressure deficit stress factors and by introducing a variable Priestley and Taylor coefficient (α). The modified PT-JPL model demonstrated an improvement in ET estimates. The root mean square of error (RMSE) of the estimated daily ET varied from ±0.60 mm/d to ±1.99 mm/d whereas the mean absolute error (MAE) varied from ±0.49 mm/d to ±1.91 mm/d, while the R 2 varied from 0.54 to 0.75 in orchards with varying canopy cover. The findings of this work underscore the utility of the modified PT-JPL model for estimating ET and its components in apple orchards from planting until the trees reach full-bearing age.

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“…Effective management of water resources in arid and semi-arid environments requires accurate tools to quantify key components of the hydrological cycle such as the evapotranspiration (ET). More than 70% of precipitation received in arid environments is returned to the atmosphere via ET annually (Zhang et al, 2016;Dzikiti et al, 2018). Consequently, ET is a major component in the processes and models of climate change, water balance, groundwater recharge, net primary productivity, floods, droughts and irrigation (Fisher et al, 2008;Műnch et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Comparison of two remote sensing models for estimating evapotranspiration: algorithm evaluation and application in seasonally arid ecosystems in South Africa

et al. 2019

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Remote sensing tools are becoming increasingly important for providing spatial information on water use by different ecosystems. Despite significant advances in remote sensing based evapotranspiration (ET) models in recent years, important information gaps still exist on the accuracy of the models particularly in arid and semi-arid environments. In this study, we evaluated the Penman-Monteith based MOD16 and the modified Priestley-Taylor (PT-JPL) models at the daily time step against three measured ET datasets. We used data from two summer and one winter rainfall sites in South Africa. One site was dominated by native broad leaf and the other by fine leafed deciduous savanna tree species and C 4 grasses. The third site was in the winter rainfall Cape region and had shrubby fynbos vegetation. Actual ET was measured using open-path eddy covariance systems at the summer rainfall sites while a surface energy balance system utilizing the large aperture boundary layer scintillometer was used in the Cape. Model performance varied between sites and between years with the worst estimates (R 2 <0.50 and RMSE>0.80 mm/d) observed during years with prolonged mid-summer dry spells in the summer rainfall areas. Sensitivity tests on MOD16 showed that the leaf area index, surface conductance and radiation budget parameters had the largest effect on simulated ET. MOD16 ET predictions were improved by: (1) reformulating the emissivity expressions in the net radiation equation; (2) incorporating representative surface conductance values; and (3) including a soil moisture stress function in the transpiration sub-model. Implementing these changes increased the accuracy of MOD16 daily ET predictions at all sites. However, similar adjustments to the PT-JPL model yielded minimal improvements. We conclude that the MOD16 ET model has the potential to accurately predict water use in arid environments provided soil water stress and accurate biome-specific parameters are incorporated. Citation: Sebinasi DZIKITI, Nebo Z JOVANOVIC, Richard DH BUGAN, Abel RAMOELO, Nobuhle P MAJOZI, Alecia NICKLESS, Moses A CHO, David C LE MAITRE, Zanele NTSHIDI, Harrison H PIENAAR. 2019. Comparison of two remote sensing models for estimating evapotranspiration: algorithm evaluation and application in seasonally arid ecosystems in South Africa. Journal of Arid Land, 11(4): 495-512. https://doi.

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Estimating the water requirements of high yielding and young apple orchards in the winter rainfall areas of South Africa using a dual source evapotranspiration model

Cited by 43 publications

References 39 publications

Deficit and Recovery of Deep Soil Water Following a Full Cycle of Afforestation and Deforestation of Apple Trees on the Loess Plateau, China

Deficit and Recovery of Deep Soil Water Following a Full Cycle of Afforestation and Deforestation of Apple Trees on the Loess Plateau, China

Modelling water utilization patterns in apple orchards with varying canopy sizes and different growth stages in semi-arid environments

Comparison of two remote sensing models for estimating evapotranspiration: algorithm evaluation and application in seasonally arid ecosystems in South Africa

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