Construction and calibration of weighing lysimeters with an automated drainage system

Sanches, Arthur Carniato; Souza, Dmitri; Mendonça, Fernando Campos; Maffei, R. G.

doi:10.1590/1807-1929/agriambi.v21n7p505-509

Cited by 7 publications

(17 citation statements)

References 11 publications

(9 reference statements)

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“…The drainage system comprised a plastic recipient and a drainage valve, with a load cell automatically driven by a solenoid valve. Sanches et al (2017a) described further details of the drainage system.…”

Section: Crop Coefficients Of Forage Cropsmentioning

confidence: 99%

Crop coefficients of tropical forage crops, single cropped and overseeded with black oat and ryegrass

Sanches

Souza

Jesus

et al. 2019

Sci. agric. (Piracicaba, Braz.)

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Crop coefficient (Kc) is the ratio between crop evapotranspiration (ETc) and reference evapotranspiration (ETo), representing the phenological effects on crop water consumption. Kc is fundamental to estimating ETc by agrometeorological methods. This research study aimed to determine Kc and ETc values for Guinea grass (Megathyrsus maximus cv. Mombaça) and Bermuda grass (Cynodon spp.), both single cropped for one year and overseeded with black oat (Avena strigosa) and ryegrass (Lolium multiflorum) during fall/winter. The experiment in the field comprised four plots, two for each tropical forage, with and without overseeding. At the center of each plot, there was a weighing lysimeter with an automated system for data collection. ETc was measured daily over four seasons following the lysimetric method; ETo was calculated using the Penman-Monteith equation. ETc and ETo values were used to estimate Kc values. The single cropped Guinea grass showed the highest values for ETc, with mean ETc and Kc of 3.99 mm d-1 and 1.07, respectively. The single cropped Bermuda grass showed ETc and Kc values of 3.57 mm d-1 and 0.96, respectively. The results of paired t-testing for Kc showed no significant differences (p = 0.05) between single cropped and intercropped for both Guinea grass and Cynodon spp. During winter, intercropped Guinea grass did not show an ETc significantly higher than single cropped Guinea grass, with mean Kc values 0.98 for intercropped and 1.10 for single cropped. Similarly, Bermuda grass did not show significant differences between mean Kc values for intercropped (1.02) and single cropped (1.00).

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Section: Crop Coefficients Of Forage Cropsmentioning

confidence: 99%

Crop coefficients of tropical forage crops, single cropped and overseeded with black oat and ryegrass

Sanches

Souza

Jesus

et al. 2019

Sci. agric. (Piracicaba, Braz.)

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“…Weighing lysimeters were used for determining crop evapotranspiration (ETc), which consisted of circular rigid PVC boxes of 500 L with upper and lower diameters and height of 1.22, 0.95, and 0.58 m, respectively. Each lysimeter had a weighing system and a water collection and drainage system, as in Sanches et al (2017).…”

Section: Methodsmentioning

confidence: 99%

“…The coefficients were obtained by calibrating the probe. Probe readings were performed daily (early in the morning) from the variation of soil water storage by subtracting the previous reading (initial) from PVC access tubes were installed with a reading capacity of up to 0.7 m. However, the water variation data in the profile was used up to 0.6 m for consumption calculation, being the last layer used only to determine the underground drainage, thus simulating the effective lysimeter depth (0.6 m), as in Sanches et al (2017).…”

Section: Methodsmentioning

confidence: 99%

“…For calculating the crop evapotranspiration (ETc) obtained by FDR probes, surface runoff was disregarded since the terrain is flat (smooth wavy variation data in the profile was used up to 0.6 m for consumption calculation, being the last layer used only to determine the underground drainage, thus simulating the effective lysimeter depth (0.6 m), as in Sanches et al (2017).…”

Section: Methodsmentioning

confidence: 99%

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Comparison of water consumption estimates for tropical and winter forages by FDR probes and weighing lysimeters

Sanches

Souza

Jesus³

et al. 2019

SCA

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Soil moisture determination is essential for a good use of available water resources. In this regard, the use of frequency domain reflectometry (FDR) probes has as advantages mobility and practicality in relation to lysimeters. The experiment was carried out between April and June 2016 at the Luiz de Queiroz College of Agriculture (ESALQ/USP), located in Piracicaba, SP at the geographical coordinates 22°42?14.6? S and 47°37?24.1? W and altitude of 546 m. This study aimed to assess these FDR probes to estimate water consumption in comparison to measurements by weighing lysimeters (ETcLys) and reference evapotranspiration (ETo) in Mombaça and Bermuda grass pastures under single cultivation and overseeded with oat and ryegrass. Soil moisture was assessed daily by FDR probes by estimating crop evapotranspiration (ETcFDR probe) from soil water balance calculation, which was correlated with ETcLys and ETo (Penman-Monteith, FAO 56). For all treatments, FDR probes presented the highest water consumptions when compared to the other two evapotranspiration methods, with accumulations of 126.5 and 125.6 mm for single and overseeded Mombaça grass, respectively. For Bermuda grass, water consumption was 123.4 mm in the single cultivation and 128.5 mm when overseeded. The method of estimating evapotranspiration by FDR probes showed good correlations with ETo and ETcLys.

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“…Brachiaria) está na rusticidade delas . Pastagens bem manejadas com forrageiras dos gêneros Cynodon e Panicum podem alcançar melhores índices produtivos e nutricionais (SANCHES et al, ,2017SANTOS et al, 2016a). Entretanto, estima-se que 80% das pastagens cultivadas no Brasil Central, responsáveis por mais de 55% da produção de carne nacional, encontrem-se em algum estágio de degradação (PERON; EVANGELISTA, 2004).…”

Section: Pastagens No Brasilunclassified

Coeficiente de cultura (Kc) e correlações de consumo de água, fatores produtivos e biométricos de gramíneas tropicais em cultivo exclusivo e em sobressemeadura com forrageiras de inverno

Sanches¹

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Cultivation coefficient (Kc) and water consumption, productive and biometric factors of tropical grasses in exclusive cultivation and overseeding with winter forages Pastures represent the largest part of the agricultural area and contribute to the second and fifth activities that make up the Brazilian GPD, meat and milk. The increasing use of pasture irrigation primarily arose in dairy areas, along with processes that improve the production, and subsequently reache areas of beef cattle. Thus, there is a need for an adequate irrigation management, and it is fundamental to know the crop evapotranspiration of pastures, their productive limits and their characteristics in this intensification process. Therefore, this work aimed to determine the crop water consumption, the values of crop coefficient (Kc), and the productive and biometric parameters of two tropical grasses (Panicum maximum cv. 'Mombasa' and Cynodon spp.) single cropped and intercropped in oversseeding with black oats and ryegrass. As secondary goals, it sought: (i) measuring the biometric parameters of forage canopy height (ADF) and leaf area index (LAI) between the cycles, identifying the best cutting period; (ii) estimating the mean accumulation of degree-days of development (GDD) in the different seasons, correlating them with forage growth; (iii) estimating the crop water consumption with the FDR probe Diviner 2000® and correlating its data with the crop water consumption measured on weighing lysimeters. The study was carried out at the "Luiz de Queiroz" College of Agriculture (ESALQ/USP), at Piracicaba, SP (Latitude 22°42'14"S; Longitude 47°37'24"W; Altitude de 569 m a.s.l.). The experiments were conducted from March 2015 to February 2017, with a randomized complete block design with 4 treatments: 1-single cropped 'Mombasa guinea grass ; 2-'Mombasa' guinea grass intercropped with oats and ryegrass; 3-single cropped Cynodon spp.; 4-Cynodon spp. intercropped with oats and ryegrass. The winter forages were black oats (Avena strigosa) cv. Embrapa 29 (Garoa) and ryegrass (Lolium multiflorum) cv. Fepagro São Gabriel. The calibrations of the lysimeters and the FDR probe had good adjustments, with high correlation coefficients. The results obtained of crop water consumption by the grasses showed a great variation by period and inside the growing cycles with great water consumption, often obtaining Kc values above 1. Good correlations were obtained between crop growth, LAI and degrees-days accumulation (GDD). The accumulated values of crop coefficient (Kc) were higher with the FDR sensor than with the lysimeters. The detailed results can be found in the chapters of this work.

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Construction and calibration of weighing lysimeters with an automated drainage system

Cited by 7 publications

References 11 publications

Crop coefficients of tropical forage crops, single cropped and overseeded with black oat and ryegrass

Crop coefficients of tropical forage crops, single cropped and overseeded with black oat and ryegrass

Comparison of water consumption estimates for tropical and winter forages by FDR probes and weighing lysimeters

Coeficiente de cultura (Kc) e correlações de consumo de água, fatores produtivos e biométricos de gramíneas tropicais em cultivo exclusivo e em sobressemeadura com forrageiras de inverno

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