Surface Drip System Research Articles

Effects of Fertigation Treatment Using a Subsurface Drip System on Spring Potato (Solanum Tuberosum L.) Growth and Yield

Background: In potato, irrigation and fertilization significantly affect yield. Subsurface drip irrigation and fertigation system are very effective in supplying water and fertilizers directly to crop root zones. Objective: This study was conducted to investigate the effect of fertigation treatment according to fertilizer concentration and composition on spring potato growth and yield using a subsurface drip system. Methods: Fertilizers containing nitrogen, phosphoric acid, and potassium were applied at various concentrations and fertilizer compositions during the tuber initiation and filling stages to determine the appropriate fertilizer concentration. And then, the selected EC 1.0 (NK) and K single-use treatments (K 20, K 50, and K 70 kg, ha-1) were used for fertigation treatment with a subsurface drip system. Results: The nutrient uptake by fertilizer concentration results for spring potato cultivation confirmed that nutrient absorption was best at EC 1.0. Accordingly, based on EC 1.0, the nutrient uptake rate by fertilizer composition (EC 1.0; NPK, NK, K) was the best in the NK and K treatments. The application of K 50 (50 kg ha-1) for subsurface fertigation had the highest yield, with an approximately 61% increase over the control treatment and a 19% increase over the irrigation treatment. Conclusion: Fertigation treatment using the surface drip system at the tuber initiation and filling stages will contribute to the stable production and improvement of potato productivity by increasing the efficiency of water and fertilization.

EVALUATION OF THE AQUACROP MODEL PERFORMANCE AND THE IMPACT OF FUTURE CLIMATE CHANGES ON POTATO PRODUCTION UNDER DIFFERENT SOIL MANAGEMENT SYSTEMS

This study was aimed to investigate the effect of surface sprinkler and drip irrigation systems using a model AquaCrop, irrigation intervals, bio-organic fertilizers and polymers in desert soils. Two field experiments were conducted during the spring season 2020 at Karbala governorate. The experiment included three factors: 1-Irrigation system surface drip T1 and sprinkler T2, 2- The Irrigation interval: every 2 days I1, 4 days I2 and 6 days I3, 3- Addition of soil conditioners: control without any addition C, bio-organic fertilizers (seek) B, polymer (zeba) P, and polymer+ bio-organic fertilizers P+B. The experiment was designed according to the nested design with three replicates results of regional climate models and AquaCrop model. The results showed that there was an increase in the amount of annual precipitation and seasonal during the periods (2016-2035) and (2046-2065) under RCP4.5 scenario, compared to the base period (1985-2005). With an increase in the amount of annual precipitation and seasonal during the period at scenario RCP8.5 with a slight decrease during the period (2046-2065) compared to the base period. Moreover, an increase in the maximum and minimum temperatures according to scenario RCP4.5 and RCP8.5 scenario during the period (2016-2035) and (2046-2065) compared to the base period. The expected productivity using the AquaCrop, as R2 was 0.85 and 0.81 for twelve years, under surface drip irrigation systems and sprinkler, respectively. The correlation coefficient (r) was 0.95 and 0.90, the root means square error (RMSE) 2.43 and 2.19, and the efficiency coefficient 0.66 and 0.42 for the surface drip and sprinkler systems, respectively. Finally, the increase in water productivity and productivity in the scenario RCP4.5 and RCP8.5 for the treatment of BP and the irrigation interval I1and treatment C and the irrigation interval I3 when comparing the base period with the periods (2016-2035) and (2046-2065) For surface drip irrigation systems and sprinkler.

Morphophysiological response of young Frantoio olive tree under different fertilizer types in sierozem with surface drip irrigation

The amount of yield and adaptation of a cultivar to a new environment is strongly related to nutrient uptake ability. This study was carried out during 2019, 2020 and 2021 seasons to investigate the effect of different forms of chemical compose 20.20.20 fertilization alone or incombination with other fertilizers on morphological plant parameters (number of leaves per shoot, stem length and stem thickness) and leaf nutrient contents (N, P, K and Mg) of young Frantoio olive tree grown in Turkestan region, South Kazakhstan. The study was conducted on 1 years old olive trees of Frantoio in sierozem, under surface drip irrigation, system and uniform in shape and received the common horticultural practices. It was determined that fertilizer treatments significantly influenced number of morphological plant parameters and leaf plant nutrients compared to control treatments at all seasons. Results revealed that all fertilizers as well as the combination between 20.20.20 and Biohumus treatment and/or Nitroammophos treatment significantly increased morphological plant parameters and nutrient contents of young Frantoio olive trees. It can be concluded that the variation in the nutrient uptake ability may be used as a criterion for adaptation of a variety to a new ecological environment.

Comparison of aerobic rice cultivation using drip systems with conventional flooding

AbstractIn this study, yield and water productivity response of rice to various irrigation levels applied with subsurface and surface drip systems in 2019 and 2020 in the Mediterranean Region of Turkey was evaluated in comparison with conventional flooding (CF). The treatments consisted of two irrigation methods namely surface drip (DI) and subsurface drip systems (SDI), three irrigation levels designated as plant pan coefficients (I1.00: Evaporation from Class A pan (Ep) × 1.00; I1.25: Ep × 1.25 and I1.50: Ep × 1.50) and CF as control. The effects of drip systems and coefficients on yield and yield components were statistically significant (P < 0.01). DI produced higher yield than SDI. CF produced significantly greater yield than both DI and SDI systems. With two drip systems, average water savings of 60.5% in I1.00, 54.5% in I1.25 and 49% in I1.50 were achieved as compared to CF. However, yield reductions of 15% in I1.50, 20% in I1.25, 29% in I1.00 were observed for DI; corresponding values for SDI were 20, 28 and 44%, respectively. Drip irrigation in aerobic rice production system had almost twice the water productivity based on total irrigation water applied (WPI) or total water input (irrigation + rainfall) (WPI+P) compared with CF. During the study years, the highest WPI and WPI+P values were found in DI-I1.00 (0.81–0.73 kg/m3) and (0.85 and 0.74 kg/m3), respectively. In conclusion, DI-I1.50 treatment is recommended for sustainable aerobic rice production since DI-I1.50 resulted in water saving of 49% but yield decrease of 15% as compared to CF.

Seasonal variations of transpiration efficiency coefficient of irrigated wheat

Global diminishing water resources, especially due to climate change have serious impacts on evaporation (E) from the soil surface, transpiration (T) from plants (crops) and grain yield, which relates to water use efficiency of different crops. A study was conducted at Kenilworth over two wheat cropping seasons (2007 and 2008) with the objectives of: (i) evaluating the effect of soils and seasons on T, E and yield, and (ii) relating these parameters to transpiration efficiency coefficient. The treatments included two soil types and two soil surface treatments (bare and mulched), which were all replicated four times. Weekly irrigation was done using a surface drip system while maintaining the water table at a constant depth. Soil water content was monitored using a neutron probe. Neither soils nor seasons were found to significantly influence the partitioning of evapotranspiration (ET), and T varied from 74 to 76% of ET while E varied between 24 and 26%. Surface treatments caused significant differences in grain yield in both seasons. Reducing evaporative loss improves the water productivity of wheat, which has an important implication in dryland farming.

Yield and water productivity response of quinoa to various deficit irrigation regimes applied with surface and subsurface drip systems

AbstractThis study evaluated the yield and water productiivty response of quinoa to regulated deficit irrigation (RDI), partial root-zone drying (PRD) and conventional deficit irrigation (DI) and full irrigation (FI) using surface (SD) and subsurface drip (SSD) systems in 2016 and 2017 in the eastern Mediterranean region of Turkey. The treatments consisted of RDI, PRD50, DI50, DI75 and FI. A rainfed treatment (RF) was also included in the study. The experimental design was split plots with four replications. DI75 and DI50 received 75 and 50% of FI, respectively. PRD50 received 50% of FI, but from alternative laterals. RDI received 50% of FI during vegetative stage until flowering, and then received 100% of water requirement. The results showed that quinoa under SD used slightly more water than SSD due to reduced surface evaporation. RDI resulted in water saving of 23 and 21% for SD and SSD, respectively, compared to FI; and RDI produced statistically similar grain yields to FI. DI75 treatment resulted in water savings of 16% for both drip methods in the first year and 10 and 25% for SD and SSD systems, respectively, in the second year. PRD50 produced greater yield than DI50 eventhough they received the same amount of irrigation water. RF and PRD50 treatments resulted in significantly greater water productivity (WP) values than other treatments. There was no significant difference between SD and SSD regarding the grain and dry matter yields and WP values. Thus, RDI and DI75 appear to be good alternatives to FI for sustainable quinoa production in the Mediterranean region.

Irrigation with treated wastewater containing nanobubbles to aerate soils and reduce nitrous oxide emissions

The objective of the present study was to examine whether we could improve the aeration of clayey soils that had been degraded by long-term irrigation with treated wastewater (TWW) through drip irrigation with TWW aerated with oxygen (O2) nanobubbles (ONB). A lysimeter set-up was irrigated using surface and subsurface drip systems, and the effects of those systems on soil oxygen concentration, nitrogen transformations, nitrous oxide (N2O) emissions, and crop yield were investigated. In the surface drip system, irrigation with ONB-aerated TWW increased soil oxygen concentrations from 15.6% to 19.7% (p = 0.0001). In the subsurface drip system, soil oxygen concentrations increased from 18.2% to 19.2% (p = 0.0266). In all treatments, nitrate was the dominant N form in the root zone porewater (soil solution) and leachates. Nitrite concentrations were low in all treatments (<4 mg L−1), yet a clear daily accumulation pattern (from ∼0.05 to ∼1.0 mg L−1) was observed in the ONB-aerated treatments. Irrigation with ONB-aerated TWW reduced cumulative N2O emissions by 37% in the surface irrigation system and 14% in the subsurface irrigation system. Our results imply that irrigation with ONB-aerated TWW may be an effective way to improve soil aeration, especially in clayey soils that have been degraded by prolonged irrigation with TWW. Such practices may reduce N2O production and the overall N leakiness of agricultural activity.

Evaluation of crop water stress index and leaf water potential for differentially irrigated quinoa with surface and subsurface drip systems

A 2-year field experiment was conducted with the objectives to evaluate the physiological and yield response of quinoa cv Titicaca to various deficit irrigation strategies applied with surface drip (SD) and subsurface drip systems (SSD) under the Mediterranean climatic conditions in 2016 and 2017. The treatments consisted of regulated deficit irrigation (RDI), partial root-zone drying (PRD50), conventional deficit irrigations (DI50, DI75) and full irrigation (FI) under SD and SSD. A rainfed treatment was also included. The experimental design was split plots with four replications. DI75 and DI50 received 75 and 50% of FI, respectively. PRD50 plots received 50% of FI, but from alternative laterals in each application. RDI received 50% of FI during vegetative stage until flowering, then received 100% of water requirement. The results indicated that RDI resulted in water saving of 23 and 21% for surface drip (SD) and SSD systems, respectively, and RDI produced statistically similar yield to FI treatment in both experimental years. DI75 treatment resulted in water savings of 16% for both drip methods in the first year and 10 and 25% for SD and SSD systems, respectively, in the second year. Thus, RDI and DI75 treatments appear to be good alternative to FI for sustainable quinoa production in the Mediterranean environmental conditions. Greater leaf water potential (LWP) and smaller crop water stress index (CWSI) values were measured in FI plots under both drip systems than deficit irrigation treatment plots. Significant second-order polynomial relations were determined between CWSI and LWP for the drip systems. Leaf area index (LAI), LWP decreased and CWSI increased as the drought increased. CWSI correlated significantly (P < 0.01) and negatively with grain yield, dry matter yield, LAI, and mean soil water content indicating that grain yield of quinoa declined with increasing CWSI values. All these relations are best described by significant second-order polynomial equations. The results revealed that quinoa should be irrigated at LWP values between − 1.35 and − 1.60 MPa, and average CWSI value of approximately 0.35 for high yields.

Crescimento e desenvolvimento do girassol irrigado e adubado com organomineral

O cultivo do girassol (Helianthus annuus L.) na segunda safrinha, na região Centro-Oeste brasileira é uma importante estratégia econômica e ecológica para o sistema de produção, cujo conhecimento de suas necessidades hídricas e nutricionais são indispensáveis, devido às condições do clima nesta época do ano. Objetivou-se no presente estudo, avaliar o crescimento e desenvolvimento da cultura do girassol cultivada sob diferentes condições de déficit hídrico e, níveis de adubações com NPK de origem mineral e organomineral. O experimento foi conduzido em vasos plásticos preenchidos com Latossolo Vermelho distroférrico, localizado em área experimental do Instituto Federal Goiano, no município de Rio Verde, Goiás. O delineamento experimental utilizado foi o de blocos ao acaso analisado em esquema fatorial 4×4×2, com três repetições. Os tratamentos foram as combinações de quatro reposições hídricas iguais a 50, 75, 100 e 125% da capacidade de água disponível no solo; quatro doses do formulado de NPK referentes a 50, 100, 150 e 200% da recomendação e duas fontes do formulado NPK, mineral e organomineral. As reposições hídricas foram determinadas através de lisímetros de pesagem eletrônica e a água aplicada via sistema de gotejamento superficial. O aumento na reposição hídrica proporciona a maior altura de planta e diâmetro de caule. As reposições hídricas de 125 e 103% proporcionaram os maiores acúmulos de matéria seca das folhas e do caule, da cultura do girassol. Na dosagem de 50% da recomendação de NPK, a fonte organomineral mostrou-se superior a mineral, para a massa seca das folhas e massa fresca do caule.

Área foliar e índice SPAD do girassol sob irrigação e adubação organomineral

Objetivou-se no presente estudo, avaliar a área foliar, a Clorofila a, b e total e o índice SPAD do girassol cultivada sob diferentes condições de déficit hídrico e, níveis de adubações com NPK de origem mineral e organomineral. O experimento foi conduzido em vasos plásticos preenchidos com Latossolo Vermelho distroférrico, localizado em área experimental do Instituto Federal Goiano, no município de Rio Verde, Goiás. O delineamento experimental utilizado foi o de blocos ao acaso analisado em esquema fatorial 4×4×2, com três repetições. Os tratamentos foram as combinações de quatro reposições hídricas iguais a 50, 75, 100 e 125% da capacidade de água disponível no solo; quatro doses do formulado de NPK referentes a 50, 100, 150 e 200% da recomendação e duas fontes do formulado NPK, mineral e organomineral. As reposições hídricas foram determinadas através de lisímetros de pesagem eletrônica e a água aplicada via sistema de gotejamento superficial. O número de folhas, a área foliar, a clorofila a, clorofila b, a clorofila total e o índice SPAD foram avaliados aos 20, 40, 60 e 80 dias após a semeadura. A reposição hídrica de 125% proporciona o maior número de folhas e área foliar do girassol cv. Aguará 6. O número de folhas, área foliar e índice SPAD do girassol cv. Aguará 6 é maior quando se utiliza o fertilizante mineral.

Grau de entupimento em um sistema de irrigação localizada submetido a diferentes tempos de funcionamento

O objetivo do estudo foi avaliar o grau de entupimento e a vazão relativa ao longo do tempo e em diferentes pressões de operação de um sistema de gotejamento superficial. O experimento foi realizado em uma casa de vegetação instalada na área experimental do IFGoiano – Campus Rio Verde. O delineamento experimental utilizado foi em blocos ao acaso, analisado em esquema fatorial 4 × 6, com três repetições. Os tratamentos consistiram em quatro pressões (0,8, 1,1, 1,4 e 1,7 kgf) e seis tempos de funcionamento (600, 650, 700, 750, 800, 850 horas). O sistema de irrigação utilizado foi o de gotejamento superficial dotado de emissores autocompensantes modelo iDrop PC-PCDS com vazão de 2,2 L h -1 e pressão de operação de 5 a 45 mca, inseridos em mangueira de polietileno de baixa densidade de 16 mm, com espaçamento de 0,5 m. Depois de tabulados os dados de vazão, foram efetuados os cálculos do coeficiente de uniformidade absoluto, grau de entupimento, vazão relativa e coeficiente de uniformidade estatístico. Para a pressão de serviço de 0,8 e 1,4 Kfg o tempo de funcionamento de 744 e 555 horas, respectivamente, promoveu o menor valor de GE (&lt;3,7%). As variações crescentes de pressão elevaram o CUA até atingir o seu valor máximo de aproximadamente 96,20% sob a pressão de operação de 1,24 kgf. A maior vazão relativa e Coeficiente de uniformidade estatístico são verificados no tempo de funcionamento inicial (600 horas).

Influence of soils and different phases of reproductive growth stage on transpiration efficiency of irrigated canola

AbstractMuch has been reported on the agronomic aspects of canola (Brassica napus L.), but there is a lack of information on the crop's transpiration (T). The objective of this study was to evaluate the influence of soils and growth periods on the T, transpiration efficiency (TE) and transpiration efficiency coefficient (TEC) of canola under irrigation. Twenty‐four lysimeters (2.5 m2) were used for the study. The experimental treatments comprised two soil forms and four growth phases during the reproductive stage, all replicated three times. Irrigation was applied weekly through a surface drip system and a water table was maintained at 1200 mm from the surface through subirrigation. Soil water content was monitored using a neutron probe. The contribution of an accessible water table was up to 60% of the total T requirement of the crop during the investigation period. TE, calculated as above‐ground biomass per unit transpiration, ranged between 2.81 and 3.32 g m−2 mm−1. TEC, obtained by normalizing TE to the vapour pressure deficit, resulted in values between 3.82 and 4.99 g kPa mm−1. Both TE and TEC were significantly different between growth periods and not amongst soils. © 2020 John Wiley &amp; Sons, Ltd.

Soil water status and growth of tomato with partial root-zone drying and deficit drip irrigation techniques

This study addresses water-saving irrigation strategies, including deficit irrigation (DI) at 70% and 50% crop evapotranspiration, ETc (DI70 and DI50, respectively), and partial root-zone drying (PRD) at 70% and 50% ETc (PRD 70 and PRD 50, respectively) to investigate the response of the tomato (Lycopersicon esculentum L.) using a surface drip system in the field on a sandy loam soil during years 2017 and 2018. Full irrigation (FI) at 100% ETc was used as the control treatment. Results revealed that the soil water content values for the DI and PRD treatments were lower than those in the FI treatment. The net photosynthesis rate, stomatal conductance, and transpiration rate decreased with decreasing irrigation water, whereas the xylem abscisic acid content increased. A significant decrease in fresh and dry vegetative parts for DI and PRD treatments was detected compared to the FI treatment in 2017, whereas there were no significant differences in 2018. Both DI70 and PRD70 treatments had fresh and dry tomato yields similar to the ones in the FI treatment, whereas the corresponding yields were significantly lower under DI50 and PRD50 treatments. This resulted in a water productivity increase by, on average, 28.15% and 38.24%, for DI70 and PRD70 treatments, respectively, compared to the FI treatment. The DI and PRD treatments significantly affected the tomato fruit quality. Fruits under DI and PRD treatments accumulated higher amounts of total soluble solids, vitamin C, and titratable acidity compared to FI Fruits. Therefore, the use of water-saving practices is feasible for tomato production in areas where water supply is limited.

Yield and quality response of surface and subsurface drip-irrigated eggplant and comparison of net returns

Yield and quality response to various irrigation regimes applied with subsurface and surface drip systems on eggplant and net profit generation in the Mediterranean Region of Turkey was evaluated. Surface drip (DI) and subsurface drip systems (SDI); two irrigation frequencies (IF3: 3-day; IF6: 6-day) and four irrigation regimes (Full irrigation, FI; deficit irrigations, DI50; DI75; and Partial Root-zone Drying PRD50, which received, respectively 50, 75 and 50% of FI) were tested in a split-split plot design. In general, SDI used slightly less water than the surface drip plots due to reduced evaporation losses from the soil surface. Irrigation systems, intervals and regimes resulted in significantly different yields and quality. The results showed that surface drip resulted in higher eggplant yield than SDI by 7.3 and 11% for 3-day and 6-day irrigation frequency in 2013, but the two systems performed similarly in 2014. IF3FI treatments under both drip systems produced significantly greater yields than other irrigation regimes. Water stress reduced eggplant yield significantly and PRD50 treatments resulted in the lowest yields in both growing seasons. Fruit weight, volume and number increased but fruit dry matter, total soluble solids and water productivity decreased with increasing irrigation. The highest water productivity (WP) was found in DI50 under subsurface drip 6-day interval (SDI IF6 DI50) and the lowest in PRD50 under subsurface drip 6-day interval (SDI IF6 PRD50). IF3FI in the surface drip system generated the highest net income followed by IF3FI in SDI. In case of water scarcity, IF3DI75 is recommended for high yields and higher net income in the Mediterranean region.

Evaluation of yield and leaf water potantial (LWP) for eggplant under varying irrigation regimes using surface and subsurface drip systems

This research was carried out to evaluate the effect of various irrigation regimes applied with subsurface and surface drip systems on yield, quality and midday leaf water potential (LWP) on eggplant in the Mediterranean Region of Turkey. The field experiments were carried out during the growing seasons of 2013–2014, in the experimental fields of Soil and Water Resources Research Unit in Tarsus. In the study, two irrigation systems namely surface drip (DI) and subsurface drip systems (SDI); two irrigation intervals (IF3: 3-day; IF6: 6-day) and four irrigation regimes (Full irrigation, FI; deficit irrigations, DI-50; DI-75); and Partial Root-zone Drying PRD-50, which received, respectively 50, 75, and 50% of FI were tested in split-split plot design with four replications. Leaf water potential were measured throughout the growing season with a pressure chamber. Irrigation methods, irrigation intervals and irrigation levels resulted in significantly different yields. Surface drip performed slightly better than the subsurface drip considering yield and quality of eggplants. The highest yield values were obtained from the full irrigation treatments DI IF3FI and SDI IF3FI with 3-day interval. In both trial years PRD-50 treatment in subsurface drip with 6-day interval plots resulted in the lowest yield. The highest water use efficiency (WUE) was found in subsurface drip 6-day interval deficit irrigation (SDI IF6 DI-50) (21.9 and 24.5kgm−3 in 2013 and 2014) and the lowest in subsurface drip 6-day interval PRD-50 (SDIIF6 PRD50) (12.2 and 16.6kgm−3). LWP values in the surface drip irrigation treatments ranged between −1.11 and −1.55MPa in 2013, and ranged between −0.98 and −1.48MPa in the 2014 growing season. In subsurface drip irrigation treatments LWP values ranged between −1.0 and −1.51MPa in 2013 and ranged between −0.91 and −1.43MPa in the 2014. The LWP values decreased with increasing water stress. A significant linear relationship between LWP and yield was obtained. The results revealed that eggplant should be irrigated at LWP values between −0.95 and −1.05MPa (−9.5 ile −10.5bar) for high and good quality yields. Thus, LWP can be used for irrigation scheduling for eggplant.

Low Nitrogen Fertigation Promotes Root Development and Transplant Quality in Globe Artichoke

Effective nutrition and irrigation are important nursery strategies to produce high-quality seedlings able to withstand heat and drought stress in the field. The objectives of this study were 2-fold, first to identify the influence of two nitrogen (N) levels (75 and 150 mg·L−1) and two fertigation (FR) methods, overhead (OH) and flotation (FL) of artichoke (Cynara cardunculus cv. Green Globe Improved) transplants on root/shoot growth and leaf physiology during the nursery period. A repeated greenhouse experiment was conducted and morphophysiological measurements were determined at 4 and 7 weeks after seeding (WAS). The second objective was to determine the impact of the nursery treatments (FR method and N level) on the subsequent crop growth and yield under three field irrigation methods [surface drip, subsurface drip, and overhead-linear system (OH-L)]. Field measurements were conducted at 50 and 150 days after field transplanting (DAT) during Fall–Winter 2015. Transplants fertilized with 75 mg·L−1 N (low N) had improved root components as compared to those with 150 mg·L−1 N (high N), especially at 4 WAS. The low N transplants had higher root surface area, root length, root branching, thinner root diameter, and less shoot area than the high N transplants. Wilting for low N transplants was 13.5% less than that for high N at 5 DAT, with a total yield similar or slightly higher than those of high N. Although growth of OH and FL transplants was statistically similar at transplanting, those irrigated with OH (greenhouse) had a 10% higher yield than FL irrigated transplants, regardless of the field irrigation method evaluated. Overall, low N level (75 mg·L−1 N) applied with OH irrigation in the nursery positively improved the transplant root system and transplant quality of artichoke seedlings.

Evaluation of Crop Water Stress Index (CWSI) for Eggplant under Varying Irrigation Regimes Using Surface and Subsurface Drip Systems

The main objective of this research is to evaluate crop water stress index (CWSI) on eggplant under various irrigation regimes applied with subsurface and surface drip systems in the Eastern Mediterranean Region of Turkey. The field experiments were carried out during the eggplant season of 2013, in the experimental fields of Soil and Water Resources Research Unit in Tarsus. In the study, two irrigation systems (surface drip (DI) and subsurface drip systems (SDI)) in main plots; two irrigation intervals in sub-plots (IF3: 3-day; IF6: 6-day) and four irrigation levels in sub-sub plots (Full irrigation, FI; deficit irrigation, DI-50; deficit irrigation, DI-75; and Partial Root-zone drying PRD-50% of full irrigation treatments) were tested in split-split plot design with four replications. Canopy temperatures were measured throughout the growing season with an infrared thermometer (IRT), and vapor deficit of air (VPD) was used for calculating empirical the CWSI. The effect of irrigation treatments on yield, crop growth and juice quality differed. Irrigation methods, irrigation intervals and irrigation levels resulted in significantly different yields. Surface drip performance was superior to subsurface drip considering yield and quality of eggplants. Full irrigation treatment with 3-day interval under the surface drip (IF3 FI) produced the highest yield (78.7 t ha-1), the lowest yield was obtained in subsurface drip IF6 PRD-50 treatment plots (40.9 t ha-1). The highest water use efficiency (WUE) was found in subsurface drip IF6 DI-50 (21.9 kg m-3) and the lowest in subsurface drip IF6 PRD-50 (12.2 kg m-3). The results revealed that eggplant should be irrigated at CWSI values between 0.18-0.20 for high and good quality yields. CWSI can be used for irrigation scheduling for eggplant.

Coeficientes de uniformidade em sistema de irrigação por gotejamento

The distribution uniformity is critical in assessing the performance of irrigation systems, and the use of correct method becomes deciding factor. The objective of this study demonstrate the discrimination of uniformity of water application for different methods in surface drip system and subsurface. The experiment was conducted in a bench trial in a greenhouse installed in the experimental area of the Federal Institute of Education, Science and Technology Goiano Campus Rio Verde. The experimental design was completely randomized analysis in scheme of split plot 6 x 20 with 10 repetitions, composed six plots distributions of solid particles and subplots 20 trials. The experimental unit consisted of PVC containers with dimensions of 0.1 m x 0.6 m (D x C), each container containing a dripper. Were made the Calculations of flow and uniformity of water application using the coefficients Christiansen (CUC), statistical (CUE), distribution (CUD), absolute (CUA), Hart (CUH) and standard efficiency of HSPA (UDH). The CUA was most discriminating in surface condition while CUC had greater discrimination in subsurface condition. The coefficients compared to each other, in descending order, presented the following classification of the percentage of discrimination superficially: CUA, CUC, CUE, CUH, UDH and CUD, already subsurface CUC, CUA, CUH, CUE, UDH and CUD.

Soil water in relation to irrigation, water uptake and potato yield in a humid climate

Efficiently controlling soil water content with irrigation is essential for water conservation and often improves potato yield. Volumetric soil water content ( θ v) in relation to irrigation, plant uptake, and yield in potato hills and replicated plots was studied to evaluate four water management options. Measurements of θ v using a hammer driven probe were used to derive a θ v index representing the relative θ v status of replicated plots positioned along a hill slope. Time series for θ v were determined using time domain reflectometry (TDR) probes at 5 and 15 cm depths at the center, shoulder, and furrow locations in potato hills. Sap flow was determined using flow collars in replicated field plots for four treatments: un-irrigated, sprinkler, surface drip, and sub-surface drip irrigation (40 cm depth). Irrigated yields were high/low as the θ v index was low/high suggesting θ v excess was a production problem in the wetter portions of the study area. The diurnal pattern of sap flow was reflected in the θ v fluctuation it induces at hill locations with appreciable uptake. Hill locations with higher plant uptake were drier as was the case for the 5 cm (dry) depth relative to the 15 cm (wet) depth and for locations in the hill (dry) relative to the furrow (wet). The surface drip system had the lowest water use requirement because it delivers water directly to the hill locations where uptake is greatest. The sub-surface drip system wetted the hill gradually (1–2 days). Measurement of the θ v index prior to experimental establishment could improve future experimental design for treatment comparisons.

EFFECTS OF MICRO-IRRIGATION SYSTEMS ON LETTUCE PRODUCTION

The main objective of this study was to evaluate the potential for producing high-value lettuce, grown in protected area, irrigated with micro-sprinkler and surface drip systems. The experiments were carried out in 2004-2006, in glass-covered solarium within the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. We utilized two irrigation method’s: drip irrigation and micro-sprinkler irrigation and three irrigation levels were established for each irrigation method. From the combination of the two irrigation method and the three times of watering resulted six experimental variants. Production of lettuce obtained at variants are presented in the following table. Water use efficiency was higher in case of drip irrigation in comparison to micro-sprinkler irrigation. The results obtained show the usefulness of drip irrigation in vegetable growing which considerably decreased water consumption and maintained proper moisture conditions for lettuce growth and yielding. Reducing irrigation had resulted in significant decrease of marketable yield. This was accompanied by a decrease in the crop water use, as a consequence of inadequate soil moisture in the rooting zone. Results also showed that water deficit reduced average fresh weight and dry matter of individual lettuces by an average varying between 20 to 30%. A significant reduction in the number of leaves per head was also obtained in the stressed treatments.