Estimating evapotranspiration and determining crop coefficients of irrigated sweet potato (Ipomoea batatas) grown in a semi-arid climate

Mulovhedzi, Ntsieni Eliah; Araya, Nadia A.; Mengistu, M. G.; Fessehazion, Melake K.; Plooy, C. P. du; Araya, Hintsa T.; Laan, M. van der

doi:10.1016/j.agwat.2020.106099

Cited by 18 publications

(20 citation statements)

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“…The paper by Tasumi and Allen (2007) is the only one that distinguishes long from short season potato; however, both K c mid values are very close, while no information was provided for K c end . Two papers on sweet potato were selected, the first referring to the determination of ET c act with a SWB supported by neutron probe measurements, however without using a model (Gomes and Carr, 2003), and the second reporting on the use of EC to measure ET c act (Mulovhedzi et al, 2020). The latter, a more recent study, reported smaller mid-and end-season crop coefficients than the former, likely in relation to the variety, the precision of the applied sprinkler irrigation, and the accuracy of ET measurements used.…”

Section: Roots Tubers Bulbs and Stem Vegetable Cropsmentioning

confidence: 99%

“…The studies on potato and sweet potato derived seasonal ET c act from a soil water balance (SWB) based upon field observations. The exceptions were the study by Tasumi and Allen (2007), which used remote sensing observations combined with the METRIC model, and that by Mulovhedzi et al (2020) using EC in a large sweet potato field. Soil water content (SWC) measurements were performed with various methods and data analysis was performed with different SWB models: the ISAREG model (Sousa and Pereira, 1999;Zairi et al, 2003), the SIMDualKc model (Paredes et al, 2018), and the MOPECO model (Martínez-Romero et al, 2019).…”

Section: Roots Tubers Bulbs and Stem Vegetable Cropsmentioning

confidence: 99%

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Standard single and basal crop coefficients for vegetable crops, an update of FAO56 crop water requirements approach

Pereira

Paredes

López-Urrea³

et al. 2021

Agricultural Water Management

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Many research papers on crop water requirements of vegetables have been produced since the publication of the FAO56 guidelines in 1998. A review of this literature has shown that determination of crop evapotranspiration (ET c ) using the K c -ET o approach, i.e., the product of the specific crop coefficient (K c ) by the reference evapotranspiration (ET o ), is the most widely-used method for irrigation water management. Consequently, a review was made to provide updated information on the K c values for these crops. The reviewed research provided various approaches to determine K c in its single and dual versions. With this purpose, actual crop ET (ET c act ) was determined with lysimeters, or by performing the soil water balance using measured soil water content and computational models, or by using Bowen ratio energy balance and eddy covariance measurements, or by using remote sensing applications. When determining the basal K c (K cb ), the partitioning of ET c act was evaluated using different approaches, though mainly using the FAO56 dual K c method. Since the accuracy of experimentally-determined K c and K cb values depends upon the procedure used to compute ET o , as well as accuracy in determining and partitioning of ET c act , the adequacy of the measurement requirements for each approach was carefully reviewed. The article discusses in detail the conceptual methodology relative to crop coefficients and the requirements for transferability, namely distinguishing between actual and standard K c and the need to appropriately use the FAO segmented K c curve. Hence, the research papers selected to update and consolidate mid-season and end-season standard K c and K cb were those that computed ET o with the FAO56 PM-ET o equation; and that also used accurate approaches to determine and partition ET c act for pristine, non-stressed cropping conditions. Under these experimental conditions, the reported K c and K cb values relative to the mid-and end-season could be considered as transferable standard K c and/or K cb values after adjustment to the standard climate adopted in FAO56, where average RH min = 45% and average u 2 = 2 m s −1 over the mid-season and late season growth stages. For each vegetable crop, these standard values were then compared with the FAO56 tabulated K c and K cb values to define the updated values tabulated in the current article. In addition, reported ancillary data, such as maximum root zone depth, maximum crop height, and soil water depletion fraction for no water stress, were also collected from selected papers and tabulated in comparison with those given for the crops in FAO56. The presentation of updated crop coefficient results is performed by grouping the vegetables differently than in FAO56, where distinction is made according to their edible parts:(1) roots, tubers, bulbs and stem vegetables; (2) leaves and flowers vegetables; (3) fruit and pod vegetables; and (4) herbs, spices and special crops, with most of them being newly introduced herein. The updated K c and K cb of veget...

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Section: Roots Tubers Bulbs and Stem Vegetable Cropsmentioning

confidence: 99%

Section: Roots Tubers Bulbs and Stem Vegetable Cropsmentioning

confidence: 99%

Standard single and basal crop coefficients for vegetable crops, an update of FAO56 crop water requirements approach

Pereira

Paredes

López-Urrea³

et al. 2021

Agricultural Water Management

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“…The duration of the growth cycle was 160 days, the initiation period was 40 days, its vegetative growth was 42 days, the tuber was 39 days and the final stage was 39 days (Wohleb et al, 2014). Similarly, Kc values for two experimental seasons were: initiation 0.4, development 0.7, tuber bulking 1.2 and at maturity 0.8, depending on local conditions (Mulovhedzi et al, 2020). At establishment, the sweet potato crop had a low per cent canopy cover which may have resulted in the minimum water needed to compensate for atmospheric demand (Karuku et al, 2014).…”

Section: Effect Of Intercropping Systems On Per Cent Canopy Covermentioning

confidence: 99%

GROWTH AND YIELD OF SWEET POTATO (Ipomoea batatas L.) MONOCROPS VERSUS INTERCROPS IN THE SEMI-ARID KATUMANI, KENYA

Mbayaki

Karuku

2021

Trop Subtrop Agroecosyst

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Background: Sweet potato producers in Kenya practice either sole cropping of or relay cropping and rarely do intercropping which aims at maximizing on time and space. Objective. To assess the relative performance of sweet potato under various cropping systems. Methodology: This study was conducted in Katumani, Kenya for two seasons; 2018/2019 and 2019/2020. The treatments comprised of sole cropping of Kabode, sole cropping of Bungoma, Kabode + common bean, Bungoma + common bean, and sole cropping of common beans (Mwezi mbili) were laid out in a randomized complete block design (RCBD) in 3 replications. Monocropped sweet potato and beans served as the control treatment. Weather data, leaf area, leaf area index, vine length, and percent canopy cover were collected throughout the cropping period. The data were analysed by a two-way ANOVA at 0.05% significance level followed by a Pearson’s correlation analysis on the extent to which length of vines, percent canopy cover, leaf area index, and weather parameters; ETo, aridity index, and rainfall influenced the attained tuber yields. Results: Intercropping significantly (p < 0.05) reduced sweet potato yields of Kabode and Bungoma varieties by 19.3% and 44%, respectively. Monocropped Kabode yielded 31.4 t ha-1, significantly (p< 0.05) higher than monocropped Bungoma with 23.9 t ha-1 whereas their common bean intercrops yielded 26.2 t ha-1 and 18.1 t ha-1,respectively. Correlation analysis showed that rainfall, ETo, LAI, vine length, and percent canopy cover negatively affected tuber yields. Implication: Land equivalent ratio revealed that intercropping sweet potato varieties with common beans was biologically efficient and that the percentage of the land saved averagely ranged from 8% to 33%. More studies should be conducted to determine the extent of sweet potato allelopathy on companion crops and nutrient use under intercropping systems. Conclusion: Yield stability analysis showed that orange-fleshed Kabode was the most stable variety across seasons to be grown in Katumani.

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“…Nonetheless, it has been demonstrated that the crop coefficient method in general is not suitable for determining ET a of native vegetation adapted to arid conditions, because transpiration is overestimated when plants encounter suboptimal conditions of soil water as a result of not considering stomatal regulation and plant adaptations to drought [9]. Only in few exceptions has the crop coefficient method been suitable to estimate ET a in crops cultivated in arid or semi-arid regions [10,11].…”

Section: Introductionmentioning

confidence: 99%

Actual Evapotranspiration Estimates in Arid Cold Regions Using Machine Learning Algorithms with In Situ and Remote Sensing Data

Mosre

Suárez

2021

Water

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Actual evapotranspiration (ETa) estimations in arid regions are challenging because this process is highly dynamic over time and space. Nevertheless, several studies have shown good results when implementing empirical regression formulae that, despite their simplicity, are comparable in accuracy to more complex models. Although many types of regression formulae to estimate ETa exist, there is no consensus on what variables must be included in the analysis. In this research, we used machine learning algorithms—through implementation of empirical linear regression formulae—to find the main variables that control daily and monthly ETa in arid cold regions, where there is a lack of available ETa data. Meteorological data alone and then combined with remote sensing vegetation indices (VIs) were used as input in ETa estimations. In situ ETa and meteorological data were obtained from ten sites in Chile, Australia, and the United States. Our results indicate that the available energy is the main meteorological variable that controls ETa in the assessed sites, despite the fact that these regions are typically described as water-limited environments. The VI that better represents the in situ ETa is the Normalized Difference Water Index, which represents water availability in plants and soils. The best performance of the regression equations in the validation sites was obtained for monthly estimates with the incorporation of VIs (R2 = 0.82), whereas the worst performance of these equations was obtained for monthly ETa estimates when only meteorological data were considered. Incorporation of remote-sensing information results in better ETa estimates compared to when only meteorological data are considered.

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Estimating evapotranspiration and determining crop coefficients of irrigated sweet potato (Ipomoea batatas) grown in a semi-arid climate

Cited by 18 publications

References 38 publications

Standard single and basal crop coefficients for vegetable crops, an update of FAO56 crop water requirements approach

Standard single and basal crop coefficients for vegetable crops, an update of FAO56 crop water requirements approach

GROWTH AND YIELD OF SWEET POTATO (Ipomoea batatas L.) MONOCROPS VERSUS INTERCROPS IN THE SEMI-ARID KATUMANI, KENYA

Actual Evapotranspiration Estimates in Arid Cold Regions Using Machine Learning Algorithms with In Situ and Remote Sensing Data

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