Assessment of irrigation schemes in Turkey based on management types

Increasing population and demand for food, combined with finite land and water resources makes developing and monitoring the performance of irrigation systems inevitable in the 21st century. This study presents a comparative performance analysis of irrigation schemes based on their management types (State Hydraulic Works (SHW) and Water User Associations (WUAs)-operated schemes). The assessment used the International Water Management Institute (IWMI)’s six performance indicators for the year 2001. Analysis of variance (ANOVA) test results indicated that the differences in the output per cropped area (OPCA), output per unit water consumed (OPUWC), and irrigation intensity (II) between the two management types were statistically significant, whereas the differences in the output per unit command (OPUC), output per unit irrigation supply (OPUIS), and relative water supply (RWS) between the two management types were not significant. Although the II was higher and RWS was lower in the WUAs-operated schemes comparing with SHW, the other indicators (OPCA, OPUIS and OPWC) were also lower in the WUAs-operated schemes except for OPUC indicator. This suggests that the WUAs-operated schemes are not optimally managed, possibly due to factors such as inappropriate crop pattern and intensity, irrigation infrastructure, lack of an effective monitoring and evaluation system, insufficient awareness among managers and farmers, or unstable administrative structure.Key Words: Comparative indicators, irrigation project, management types, irrigation management, performance, Turkey

Soil Temperatures Affected by Different Solarization Practices

The recognition of using solar energy for soil solarization in protected agriculture is gaining ground as the ecological awareness of the public has increased. The primary main effect of solarization is to increase soil temperature. The determination of soil thermal properties before solarization can provide a key criterion for making a decision in regard to the benefit of solarization at a particular site. A two-year study was carried out in glass and plastic greenhouses under mainly clay and sandy soil conditions in the East-Mediterranean Region of Turkey, respectively. Three different applications of solarization were tested: solarization, solarization plus CO2 application, and solarization plus manure application. Solarization was applied on individual plots of 2 m x 2 m using transparent polyethylene mulching from 6 to 8 weeks in July and August. CO2 and manure were applied as additions to the solarization for increasing the effectiveness of solarization. Soil temperatures were recorded continuously at 15 min. intervals, measured at 5, 20 and 30 cm depths. The soil thermal diffusivity was calculated using temperature data of the soils in a temperature-amplitude equation derived from re-arranging the heat equation. It was observed that soil thermal diffusivity increased in proportion to the increase of water content. The result showed that thermal diffusivity was higher under clay soil conditions in the glasshouse compared to sandy soil conditions in the plastic greenhouse. The highest values for the soil temperatures were observed at 20 cm and 35 cm soil depths at the volumetric soil water contents of 0.285-0.290 cm3 cm-3 and 0.315-0.330 cm3 cm-3, respectively. Measured temperatures varied between 55 and 57°C at 5 cm depth, while maximum soil temperatures were obtained under CO2 application at 5 cm depth. It was concluded that an effective soil solarization can be achieved when soils were tilled, wetted with CO2 or covered with manure

Effects of CO2 enriched air and soil tillage on greenhouse solarization

High soil temperatures achieved with solarization practice used in greenhouses may prevent diseases infested from soils with soil pathogens. Physical manipulations like tillage, increasing soil water content and addition of organic residues to soil increase effectiveness of solarization by way of facilitating downward heat flux and increasing temperature in subsoil. A two-year work assessing importance of soil tillage, soil wetting and CO2 enriched air (for simulating organic residue addition to soil) on solarization was carried out in glass and plastic greenhouses (1 glass and 2 of plastic) with clay and sandy soils in Eastern Mediterranean region of Turkey. Four treatments were tested: (1) with tillage (T), (2) no tillage (NT), (3) with tillage and CO2 addition (TCO2) and (4) no tillage and no CO2 addition (NTCO2). The CO2 enrichment of air under plastic mulch covering soil during the solarization was done using dry ice (i.e. CO2). The levels of the highest temperatures attained under different treatments during solarization period were assessed and recorded. The results showed that the highest temperature was recorded throughout the complete solarization period under the treatment with soil tillage and CO2 addition (TCO2) over all soil depths (5, 20 and 35 cm). The mean highest temperatures recorded for 30 days of solarization period did not exhibit any consistent trend in clay soils (Greenhouse 1 and 2) whereas the ranking of the treatments TCO2>T>NT>NTCO2 was maintained in sandy soil (Greenhouse 3). The highest temperature attained in Greenhouses 1 and 2, with soils of clay texture, and 3 with soil of sandy texture, at soil depths of 5, 20 and 35 cm were 55.4, 45.3 and 41.4°C; 56.8, 46.6 and 42.7°C; 56.6, 48.4 and 44.7°C, respectively. While the CO2 enrichment increased soil temperature only at 5 cm depth, close to soil surface, no significant (P<0.05) benefit was observed at deeper soil depths of 20 and 35 cm. Increase of mean maximum temperature with CO2 addition was of the order 1 to 3.5°C in clay soils (Greenhouse 1 and 2) and 1.2°C in sandy soils (Greenhouse 3). Additionally it was noted that addition of CO2 provided no benefit under no tillage conditions (NTCO2). While temperature at 5 cm soil depth was over 50°C at frequencies of 65 to 95% during 23 days of solarization period, it was not over 45°C at 35 cm soil depth. The results showed that the high soil temperatures obtained with solarization under climatic conditions of Eastern Mediterranean may be adequate to eliminate soil-borne diseases without the need of using chemicals such as methyl bromide

Genotypic differences of maize in grain yield response to deficit irrigation

This study was undertaken to investigate genotypic differences of five maize cultivars in grain yield response to two different modes of deficit irrigation, conventional deficit irrigation and partial root zone irrigation. Three irrigation treatments were implemented: (1) FULL irrigation, the control treatment where plant water requirement, 100% Class-A pan evaporation, was fully met and the furrows on both sides of the plant rows were irrigated; (2) partial root zone irrigation (PRI), 35% deficit irrigation, compared to FULL treatment, was applied in every other furrow thus irrigating only one side of the plant rows. The furrows irrigated were alternated every irrigation; (3) conventional deficit irrigation (CDI), the same amount of water as PRI was applied in furrows on both sides of the plant rows, similar to FULL irrigation treatment. Five maize cultivars (P.31.G.98, P.3394, Rx:9292, Tector and Tietar) showing extreme growth response to water stress were selected out of ten cultivars tested with earlier completed greenhouse-pot experiment. A split-plot experimental design, comprising three irrigation treatments and five maize cultivars with four replicates, was used during two years of work, in 2005 and 2006. Total of nine irrigations, with one-week irrigation interval, were annually applied using a drip-irrigation system. Soil water status was monitored using a neutron moisture gauge, in addition to measuring leaf water potential and above-ground biomass production throughout the growing season. Grain yield and other yield attributes were measured at harvest as well as assessing differences in plant root distributions. Decrease in grain yield and harvest index of the tested cultivars, compared to FULL treatment, was proportionally less under PRI than CDI. Whether or not a significant yield advantage can be obtained under PRI compared to CDI showed significant (P< 0.05) genotypic variability. Tector and Tietar among the tested cultivars of maize showed significantly higher grain yield (P< 0.05) under PRI than CDI. The yield advantage of the genotypes (P.3394 and Tector) under PRI compared to CDI seems related to their enhanced root biomass developed under PRI. © 2010 Elsevier B.V.The authors gratefully acknowledge that this work was supported with a research grant through the project ZF2004D2 by Cukurova University . Thanks are due Koseoglu Tarim, May Agro, Monsanto, Pioneer and Syngenta firms for supplying the seeds of different maize cultivars and to Prof. Dr. Ahmet Can Ulger for his help for implementing the field trials

LEPA and trickle irrigation of cotton in the Southeast Anatolia Project (GAP) area in Turkey

This study was designed to evaluate the yield response of low-energy precision application (LEPA) and trickle-irrigated cotton grown on a clay-textured soil under the arid Southeast Anatolia Project (GAP) area conditions during the 1999 growing season at Koruklu in Turkey. The effects of four different irrigation levels (100, 75, 50, and 25% of cumulative Class-A pan evaporation on a 6-day basis) for LEPA, and two irrigation intervals (3-day and 6-day) and three different levels (100, 67, and 33% of cumulative Class-A pan evaporation on a 3-day and 6-day basis) for the trickle system on yield were investigated. Water was applied to alternate furrows through the double-ended Fangmeier drag-socks in the LEPA system. Trickle irrigation laterals were laid out on the soil surface at a spacing of 1.40 m. A total of 814 mm of water was applied to the full-irrigation treatments (100%) for both irrigation systems. Seasonal water use ranged from 383 to 854 mm in LEPA treatments; and 456 to 868 mm in trickle treatments. Highest average cotton yield of 5850 kg/ha was obtained from the full-irrigation treatment (100%) in trickle-irrigated plots with 6-day intervals. The highest yield in LEPA plots was obtained in LEPA-100% treatment with an average value of 4750 kg/ha. Seed cotton yields varied from 2660 to 5040 kg/ha and 2310 to 5850 kg/ha in trickle irrigation plots with 3-day and 6:day intervals, respectively, and from 2590 to 4750 kg/ha in LEPA plots. Irrigation levels both in LEPA and trickle-irrigated plots significantly increased yield. However, there was no significant yield difference between 100 and 67% irrigation levels in trickle-irrigated plots. Maximum irrigation water use efficiency (IWUE) and water use efficiency (WUE) were found as 0.813 and 0.741 kg/m3 in trickle-irrigated treatment of 67% with 6-day interval. Both IWUE and WUE values varied with irrigation quantity and frequency. The research results revealed that both the trickle and LEPA irrigation systems could be used successfully for irrigating cotton crop under the arid climatic conditions of the GAP area in Turkey. © 2002 Elsevier Science B.V. All rights reserved.National Council for Scientific Research: 1856We wish to acknowledge the financial support provided to this project by the TUBITAK (Turkish Scientific and Research Council) as TARP #1856. In addition, we would like to thank Dr. T.A. Howell at USDA-ARS, Bushland, TX for providing double-ended LEPA drag socks for this study

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 24.5 kg m-3 in 2013 and 2014) and the lowest in subsurface drip 6-day interval PRD-50 (SDIIF6 PRD50) (12.2 and 16.6 kg m-3). LWP values in the surface drip irrigation treatments ranged between -1.11 and -1.55 MPa in 2013, and ranged between -0.98 and -1.48 MPa in the 2014 growing season. In subsurface drip irrigation treatments LWP values ranged between -1.0 and -1.51 MPa in 2013 and ranged between -0.91 and -1.43 MPa 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 -1.05 MPa (-9.5 ile -10.5 bar) for high and good quality yields. Thus, LWP can be used for irrigation scheduling for eggplant. © 2017 Elsevier B.V

Using electromagnetic induction technique to determine soil salinity within layers of varying depths: A case study in the mediterranean farmlands, Turkey

Diagnosis of soil salinity and characterizing its spatial variability both vertically and horizontally are needed to establish control measures in irrigated agriculture. In this regard, it is essential that salinity development in varying soil depths be known temporally and spatially. The main objectives of this paper were to investigate potential use of electromagnetic induction technique, i.e. EM38 device, to determine soil salinity, ECe, at varying soil depths through utilizing apparent electrical conductivity, ECa, measurements at horizontal- and vertical-dipole configurations of the device, and to develop soil salinity maps to delineate severity of salinity in large-scale irrigation schemes. The salinity of a large area, irrigated with irrigation return flows in Yemisli irrigation district (7 110 ha), Adana, Turkey was assessed using the EM38 device at 112 randomly selected sites distributed homogeneously over the area in horizontal- (ECa-H) and vertical-dipole (ECa-v) configurations. The EM38 data was calibrated against standard soil extract conductivity measurements (ECe) of gravimetric samples collected from 20 randomly selected sites, representing the whole area. The values of ECa-Hand ECa-V had asymmetrical hypergeometric and poisson distributions, respectively, with most readings in the non-saline range (ECe&lt;4 dS m-1) and a sharp transition to relatively high readings. Most salinity profiles were in regular configuration (i.e. ECa-V &gt; ECa-H), except in areas with similar salinity values where the profiles were uniform (i.e. ECa-H = ECa-V). Soil salinity contour maps were produced from the 112 ECe values estimated from the EM38 data and the 20 measured values of ECe. Even though it was claimed that [e.g., 1, 2] horizontal and vertical dipóle positions is suitable for diagnostic and agronomic purposes for the soil layers of 0-100 and 0-200 cm, respectively, this study showed that ECa-H values should be preferred to ECa-V to predict ECe values at all soil depths. This is especially true for assessing and characterizing salinity in 0-30 and 0-60 cm depths in the areas irrigated with low quality irrigation return flows. Theoretical frequency curves developed exclusively for varying depths in this work can be used for assessing the probability of observing a given soil salinity, or vice versa. © by PSP

Effect of solarization under different applications on soil temperature variation and microbial activity

Soil solarization is an environment-friendly soil pasteurization technique which uses the solar energy to increase the soil temperature to diminish soil-related pests and pathogens. The efficiency of this technique is closely related with a number of factors such as soil water and organic matter contents and feature of cover material; therefore, the effect of solarization was studied under applications of CO2, basaltic tuff (BT), organic matter (OM) and a different color plastic cover (PE2) on soil temperature and microbial activity as dehydrogenase enzyme activity (DHA) and soil respiration (CO2). The trial was carried out in a greenhouse for 32 days. Organic matter, salt and lime contents, pH and texture class of greenhouse soil were 1.7%, 0.055%, 38.5%, 7.7 and clay, respectively. According to the results, while the lowest CO2 value was determined as 12.9 mg/100 g ds. 24 h in the A6 (PE2) application, the highest CO2 value was determined as 16.3 mg/100 g ds. 24 h in the A4 (+OM 1.5 kg/m2) application. The dehydrogenase enzyme activities (DHA) yielded similar results with the applications, however, the highest value (291.2 µg TPF/10 g ds.) was in A7 (control). Soil (0-5 cm) temperatures varied between 28.1 and 60.1°C with applications and the lowest soil temperature was determined in the control plot. The effect of the applications to soil temperature led to significant differences statistically (p&lt;0.05). The results documented that the organic matter (OM) and CO2 amendments (OM or +OM+CO2) had a role in protecting soil microbial activity (dehydrogenase-DHA) and soil respiration (CO2) from the detrimental effects of the heating of solarization