scholarly journals ROOT DISTRIBUTION OF TRICKLE AND FLOOD-IRRIGATED GRAPEFRUIT

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1109b-1109
Author(s):  
Dariusz Swietlik

Root distribution of trickle–and flood-irrigated 4-year-old `Ray Red' grapefruit (Citrus paradisi Macf.) trees on sour orange (C. aurantium L.) rootstock was studied utilizing a trench method. Irrigation treatments were: flooding at 50% soil water depletion, trickle irrigation (2 drippers per tree) at 0.5 Class A Pan evaporation or at 0.02 MPa soil tension. Two trees from each treatment were studied. Five 2.5 m deep trenches positioned perpendicular or parallel to the tree row at 0.6, 2.1, or 4.3 m from the tree trunks were dug per tree. After washing off a 0.5 cm thick layer of soil from the trench wall, 0.5 cm long root sections were marked on a transparent plastic film attached to the wall. Many roots of trickle-irrigated trees grew past the trickle wetted zone and extended beyond 2.1 but not 4.3 m of the trunk. However, the roots of flood-irrigated trees were present at all distances from the trunk. From 26 to 51% of the roots of trickle–irrigated trees were found 90-230 cm deep, despite the clayey texture of the top 1 m of soil which was underlaid by a sandy clay loam. The root systems-of flood-irrigated trees were shallower and in most cases confined to the top 90 cm soil layer.

1992 ◽  
Vol 117 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Dariusz Swietlik

Growth, fruiting, and mineral nutrition of trickle- or flood-irrigated young `Ray Ruby' grapefruit (Citrus paradisi Macf.) trees on sour orange (C. aurantium L.) rootstock were compared in a 4-year field study. Trickle irrigations (two emitters per tree) were scheduled based on: 1) 0.7 (first 3 years) or 0.5 (4th year) of Class A pan evaporation (TPAN) adjusted to the ground area covered by tree canopies, or 2) tensiometer readings (TTEN) of - 0.02 MPa at 30-cm soil depth. The flood irrigations (FLOOD) were scheduled at 50% available soil water depletion at 30 cm (first 3 years) or 30- and 60-cm soil depth (the 4th year). Nitrogen at NO (none), N1(20, 40, 80, 160 g N/tree per year in the four consecutive years), or N2(twice the amount of NJ was injected into the trickle lines from January to August or, under FLOOD, split into January and May soil applications. TPAN and TTEN trees were irrigated with <10% of the water amount applied to FLOOD trees without negatively affecting tree growth, yield, or fruit size. Growth of the trees was not affected by N fertilization, but fruit count and yield and leaf N concentration were increased by the N1 and N2 treatments in the fourth growing season. Frequent N fertigations under the trickle system provided no benefits over two split-soil broadcast applications under the flood system. Fruit size was reduced by the N2 treatment. Based on the water amounts applied to TTEN trees, irrigation needs under the trickle system were estimated to be 0.75, 0.57, 0.30, and 0.20 of Class A pan evaporation adjusted to the ground area covered by the plant canopies, in the first, 2nd, 3rd, and 4th year of orchard life. The decreasing pan coefficient indicated increasing extraction of water from outside the irrigated zones. Roots of TPAN and TTEN trees grew at least 210 cm past the wetted zones into the row middles. More than half of the roots in the TPAN and TTEN treatments were found at 60- to 230-cm soil depth compared to only 17% in the FLOOD treatment.


1981 ◽  
Vol 21 (111) ◽  
pp. 448 ◽  
Author(s):  
T Trochoulias ◽  
RD Murison

Supplementary trickle irrigation applied twice a week by single microtube at replacement rates of 0 (control), 20, 40, 60, 80, 100 and 120% of Class A pan evaporation (El from 1970 to 1976 increased bunch weight significantly (P= 0.02) above 40% E. Treatment 60% E gave a bunch weight of 27.6 kg compared with 25.7 for the control. The control, 20 and 40% treatments did not affect hand number from 1970 to 1976 while all other treatments increased hand number by 0.3 hands each year. Means of treatments over all years for fingers showed an annual increase of 4.6,4.0,5.8 and 5.0 fingers for 60,80,100 and 12O0Io treatments, respectively. Gravimetric sampling in 1974 showed the control plot had a lower water potential than other plots. There was little change in water potential in any of the other treatments. There was a significant linear decrease in water potential with increase in radius from the emitter. Root distribution studies showed that about 70% of the root systems in all treatments were concentrated in the upper 40 cm of soil. Forty per cent of the total root system was confined to a square, 60 x 60 cm, close to the base of the plant. Thus trickle irrigation with an emitter positioned near the base of the plant and a slow flow rate (3 litres/h) would reach most of the root system. Four out of the six years of the experiment were very wet (greater than 1700 mm rainfall). Only 29% of the total water over the 6 years in the 60% E treatment was provided by trickle irrigation. This experiment showed that 60% of Class A pan evaporation can be used as a reliable guide for the trickle irrigation of bananas on the East coast of Australia with free draining soils.


Irriga ◽  
2005 ◽  
Vol 10 (1) ◽  
pp. 64-75
Author(s):  
José Eduardo Pitelli Turco ◽  
Jarbas Dos Santos Júnior ◽  
Edemo João Fernandes

ESTUDO DO CONSUMO E CUSTO DE ENERGIA ELÉTRICA EM CULTURA DE SOJA IRRIGADA  José Eduardo Pitelli Turco; Jarbas Dos  Santos Junior;  Edemo João FernandesDepartamento de Engenharia Rural, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, CEP 14884-900,  Jaboticabal, SP [email protected]  1        RESUMO             Este trabalho teve por objetivo analisar o consumo e custo de energia elétrica em cultura de soja, submetida a quatro regimes de irrigação: T1 – irrigação efetuada quando o esgotamento da água do solo atingiu 40% da reserva utilizável (RU); T2 – irrigação efetuada quando o esgotamento da água do solo atingiu 60% da RU; T3 – irrigação efetuada quando o esgotamento da água do solo atingiu 80% da RU; T4 – sem irrigação; T5 – irrigação efetuada quando o esgotamento da água do solo atingiu 40% da RU. Sendo que, para T1, T2 e T3 a lamina de água determinada pelo ETo foi obtido pelo método do tanque Classe A, já para T5 o ETo foi obtido pelo método de Penman-Monteith. A cultura da soja foi irrigada com um sistema de irrigação por aspersão convencional. O consumo de energia elétrica do sistema de irrigação foi medido por meio da utilização de um Medidor de Energia (mod. Microvip3 - Elcontrol, Itália). Os resultados desse estudo mostraram que os tratamentos irrigados com maior freqüência apresentaram menor relação consumo de energia elétrica / produção de grãos. UNITERMOS: consumo de energia elétrica e custo de energia elétrica, soja  TURCO, J. E. P.; SANTOS JUNIOR, J.; FERNANDES, E. J.CONSUMPTION AND ELECTRICITY COSTS OF ELECTRIC ENERGY ONIRRIGATED SOYBEAN CROP  2        ABSTRACT             The aim of this investigation was to evaluate the consumption and electricity costs of electric energy on soybean crop under four irrigation regimes: T1 - irrigation started when the soil water depletion reached 40% of available reserve; T2 irrigation started when the soil water depletion reached 60% of available reserve; T3 - irrigation started when the soil water depletion reached 80% of available reserve; T4 – no irrigation; T5 – irrigation started when the soil water depletion reached 40% of available reserve. The water consumption of the T1, T2 and T3 was determined by Class A pan evaporation, and for T5 by Penman – Montheith method. The soybean crop was irrigated with a conventional sprinkle system. The consumption of electric energy of irrigation system was measured by a Measurer of Energy (mod. Microvip3 - Elcontrol, Italy). The results of this study showed that treatments irrigated with larger frequency present smaller relationship consumption of electric energy / grain yield.   KEYWORDS: consumption of energy, electricity costs, soybean. 


Irriga ◽  
2001 ◽  
Vol 6 (3) ◽  
pp. 120-127
Author(s):  
Reginaldo Ferreira Santos ◽  
Antonio Evaldo Klar

DISTRIBUIÇÃO DA EVAPORAÇÃO EM ESTUFA PLÁSTICA NA PRIMAVERA  Reginaldo Ferreira SantosCentro de Ciências Exatas e Tecnológica da UNIOESTE- CP 711CEP 858114-110, Cascavel, PR - Fone: 0XX45 2203155.  E-mail: [email protected] Evaldo KlarDepartamento de Engenharia Rural - Faculdade de Ciências Agronômica- UNESP - CEP 18603-970 - Botucatu, SP. CP: 237.  E-mail:  [email protected]  1  RESUMO O presente trabalho teve como objetivo avaliar a distribuição da evaporação no interior de uma estufa plástica, com uma cultura de pimentão, através da variabilidade espacial e comparar a evaporação dos microevaporímetros com os valores do Tanque classe "A". O experimento foi conduzido no Campus da Universidade Estadual Paulista - FCA/UNESP, no período de primavera, em estufa plástica de polietileno de baixa densidade (PEBD). Na distribuição da evaporação em estufa com orientação norte/sul, verificou-se que as maiores evaporações ocorreram nas extremidades sul e norte tendente ao lado oeste. Já as menores evaporações localizaram-se no centro. No período de primavera, a evaporação média nos microevaporímetros superestimou em 55% a evaporação determinada no Tanque classe "A". UNITERMOS: evaporação, geoestatística, estufa.  SANTOS, R.F, KLAR, A.E.  EVAPORATION DISTRIBUTION INSIDE A PLASTIC TUNNEL IN THE SPRING SEASON  2  ABSTRACT                 The main aim of this study was to verify the evaporation distribution inside a plastic tunnel, with pepper crop, oriented to north/south, through spatial variability and to compare Class A Pan evaporation to punctual evaporations of 40 equidistant microevaporimeters placed from 50cm the soil. The study was carried out at the College of Agricultural Sciences/UNESP, Botucatu – SP in the spring season.  The highest evaporation occurred next to north and to south sides of the tunnel, with tendency to west. Consequently, the lowest evaporations occurred at the center area. The microevaporimeter evaporations were 55% higher than those obtained from Class A Pan. KEYWORDS: evaporation distribution, microevaporimeter.


2021 ◽  
Vol 10 (8) ◽  
pp. 522
Author(s):  
Stavroula Dimitriadou ◽  
Konstantinos G. Nikolakopoulos

Actual evapotranspiration (ETa) has been insufficiently investigated in Greece. This study aimed to estimate annual ETa by empirical methods (Turc, modified Turc, and Coutagne) for the Peloponnese, Greece, a Mediterranean testbed, between 2016–2019, four of the warmest years since the preindustrial era, and compare them to MODIS ET. Furthermore, measurements of annual pan evaporation (Epan) were performed for two Class A pan stations in the Peloponnese with different reliefs and conditions. The empirical methods and statistical formulae (RMSD, MB, and NMB) were developed as models in ArcMap. The outcomes of the Turc method resembled MODIS ET ranges for all years, followed by those of Coutagne. The estimates by the modified Turc method were almost identical to MODIS ET. Therefore, the modified Turc method can be used as an alternative to MODIS ET (and vice versa) for the Peloponnese for 2016–2019. Moreover, the Epan at Patras University station (semiurban, low elevation) exhibited an upward trend resembling the trends of the empirical methods over the study years, whereas the Epan at Ladonas station (higher elevation, lakeside) required investigation on a monthly time scale. Additionally, the gradual decrease of pan-water icing at Ladonas in December (from 20 d in 2016 to 0 d in 2019) could imply an undergoing decrease in snowpack storage retention across the mountains of the Peloponnese.


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