Ustun Sahin

Evaluation of water use and yield responses of drip-irrigated sugar beet with different irrigation techniques

Effective water use should be investigated in terms of sustainable production strategy in arid and semi-arid regions. A 2 yr field study was conducted in order to investigate the effects of full root-zone wetting (FI) and partial root-zone drying (PRD) irrigation techniques with 4 and 8-d (I2) irrigation intervals and three different irrigation levels (W1, W2, W3) adjusted according to Class A pan evaporation on root, leaf, and sugar yields and irrigation water use efficiency (IWUE) of sugar beet (Beta vulgaris L.) Three different plant-pan coefficients (0.70, 0.60, and 0.50) were used for adjusting the three different irrigation levels. The irrigation techniques and levels affected yields significantly. Seasonal meanly irrigation quantities were 280.4 mm in FI treatments and 162.4 mm in PRD treatments. While mean root yield of 33.80 t ha-1 is obtained in FI treatments, it was 26.43 t ha-1 in PRD treatments. Similarly, mean white sugar yield (WSY) for FI treatments (5 t ha-1) was higher than PRD treatments (3.81 t ha-1). There were significant polynomial relationships between irrigation quantities and root yield or WSY in both FI and PRD treatment. PRD technique increased by 34.9% IWUE compared to FI. Although the highest root yield was determined in FI-I1W1 sub treatment as 37.57 t ha-1, the highest IWUE was determined in PRD-I1W3 sub treatment as 173.9 kg ha-1 mm-1 since it has the lowest irrigation water amount as 140.6 mm. However, among PRD treatments for more root yield and for more white sugar yield, I1W1 and I1W2 sub treatments were the best.

Bacterial application increased the flow rate of CaCO3-clogged emitters of drip irrigation system

CaCO(3) is one of the most common emitter clogging factors among chemical precipitates in drip irrigation systems. Continuous acid application as a classical approach to prevent CaCO(3) clogging can be tricky, expensive and hazardous for soil. In order to develop an environmentally friendly method to address the problem, two bacterial strains, one renowned as a PGPR and the other having extensive CaCO(3) dissolving capacity, were used in treatments of artificially clogged drip irrigation emitters. Results showed the flow rates of clogged emitters significantly increased in drip lines which were treated with bacterial suspensions but no increase was observed in control drip lines which were treated with sterile nutrient broth. Furthermore, scanning electron and florescence microscopies were used to examine residual CaCO(3) precipitates. Thus, in consideration of its extensively studied PGPR characteristics, microbial treatment with Bacillus subtilis OSU-142 was shown to be promising for field applications as a novel and environmentally friendly treatment for clogged emitters of drip irrigation systems.

Reclamation of Saline Sodic Soils with the Use of Mixed Fly Ash and Sewage Sludge

Reclamation of saline sodic soils is a main problem at most of arid lands. Improving soil properties with waste materials has been investigated earlier but the effect of these materials on saline sodic soils is not fully known. A fly ash and sewage sludge mixture was applied to saline sodic soils with the intention of soil reclamation and eco-friendly waste recycling. Fly ash and sewage sludge mixtures were applied at a ratio of 1:1 to soils with three different levels of electrical conductivity (EC) and exchangeable sodium percentage (ESP) (soil I: 4.27 dS m−1, 6.09%; soil II: 73.20 dS m−1, 51.03%; soil III: 38.2 dS m−1, 86.2%) at 3 different doses, that is, 40, 80, and 120 t ha−1. Saturated hydraulic conductivity and porosity generally increased in all the soils tested, whereas bulk density and pH decreased. ESP and EC values of the amended layers decreased considerably with the application of increasing doses of waste material. These results indicate that when properly applied, two industrial residues, sewage sludge and fly ash, that are associated with a negative environmental impact, can be recycled allowing for the cheap reclamation of barren saline sodic soil.

Fruit Yield and Quality, and Irrigation Water Use Efficiency of Summer Squash Drip-Irrigated with Different Irrigation Quantities in a Semi-Arid Agricultural Area

Fruit yield, yield components, fruit mineral content, total phenolic content, antioxidant activity and irrigation water use efficiency (IWUE) of summer squash responses to different irrigation quantities were evaluated with a field study. Irrigations were done when the total evaporated water from a Class A pan was about 30 mm. Different irrigation quantities were adjusted using three different plant-pan coefficients (Kcp, 100% (Kcp1), 85% (Kcp2) and 70% (Kcp3)). Results indicated that lower irrigation quantities provided statistically lower yield and yield components. The highest seasonal fruit yield (80.0 t ha−1) was determined in the Kcp1 treatment, which applied the highest volume of irrigation water (452.9 mm). The highest early fruit yield, average fruit weight and fruit diameter, length and number per plant were also determined in the Kcp1 treatment, with values of 7.25 t ha−1, 264.1 g, 5.49 cm, 19.95 cm and 10.92, respectively. Although the IWUE value was the highest in the Kcp1 treatment (176.6 kg ha−1 mm−1), it was statistically similar to the value for Kcp3 treatment (157.1 kg ha−1 mm−1). Total phenolic content and antioxidant activity of fruits was higher in the Kcp1 (44.27 μg gallic acid equivalents (GAE) mg−1 fresh sample) and in the Kcp2 (84.75%) treatments, respectively. Major (Na, N, P, K, Ca, Mg and S) and trace (Fe, Cu, Mn, Zn and B) mineral contents of squash fruits were the highest in the Kcp2 treatment, with the exception of P, Ca and Cu. Mineral contents and total phenolic content were significantly affected by irrigation quantities, but antioxidant activity was not affected. It can be concluded that the Kcp1 treatment was the most suitable for achieving higher yield and IWUE. However, the Kcp2 treatment will be the most suitable due to the high fruit quality and relatively high yield in water shortage conditions.

Determining Crop and Pan Coefficients for Cauliflower and Red Cabbage Crops Under Cool Season Semiarid Climatic Conditions

Abstract The aim of this study was to estimate the evapotranspiration of cauliflower and red cabbage crops grown under cool season semiarid climatic conditions from Class A pan evaporation. Actual evapotranspiration ( ET c ) of cauliflower and red cabbage crops was calculated according to the water balance approach. Reference evapotranspiration ( ET o ) was calculated with FAO Penman-Monteith equation. Pan evaporation ( E pan ) was measured by using Class A pan. Seasonal ET c was determined as 475 mm for cauliflower and 556 mm for red cabbage. Seasonal pan coefficient ( k p = ET o / E pan ) was determined as 0.82, and the seasonal crop coefficient ( k c = ET c / ET o ) was determined as 0.84 for cauliflower and 0.83 for red cabbage. So the evapotranspiration of cauliflower and red cabbage crops was estimated as 70% Class A pan evaporation.

Decrease in Hydraulic Conductivity of Clay Soils with Salinity-Sodicity Problems due to Freezing and Thawing Effect

Freezing and thawing effects on soil structure are an important dynamic property of a soil. Consecutive freeze-thaw cycles in soil may affect aggregation either positively or negatively. Therefore, pore size distribution, hydraulic conductivity, infiltration rate and vulnerability of soil are also affected by freezing and thawing processes (Lehrsch et al., 1991). Radke & Berry (1998) determined a decrease in bulk density after freezing in soils which have a high value of bulk density at the start. Ice crystals forming within pores during freezing widen the diameter of the pores and thus decrease the bulk density (Kay et al., 1985). Aggregate stability is affected by freezing rate, soil moisture content at the time of freezing, and number of freeze-thaw cycles (Benoit, 1973; Edwards, 1991). Oztas & Fayetorbay (2003) found that aggregate stability generally increased when the number of freezing and thawing cycles increased from 3 to 6, but decreased after that point. Thus, freeze-thaw cycles may have negative or positive effects on soil structure. The determination of effects of freeze-thaw cycles in saline-sodic soils on the hydraulic conductivity is of importance for soil management and reclamation. Therefore, this study investigated the effect of freeze-thaw cycles on the hydraulic conductivity in soils. Materials and methods

Evaluation of CaCO3 clogging in emitters with magnetized saline waters

Abstract High water application uniformity is essential for an effective irrigation. Clogging of emitters in drip irrigation systems is one of the most important factors decreasing uniformity. In this study, the possible effect of magnetization of water on chemical clogging of dripline emitters was investigated. Separate experiments were conducted with three different saline waters (W-1: 0.314 dS m−1, W-2: 0.665 dS m−1, W-3: 0.937 dS m−1) having a high pH and a positive Langelier saturation index (LSI). Discharge rates, electrical conductivity (EC) and pH’s of discharge water from emitters in driplines were measured. Uniformity of driplines was evaluated by using the statistical uniformity coeffi cient (Uc ) and the emission uniformity coeffi cient (Eu ). The pH and EC values of discharge water from emitters in driplines were found to be slightly lower when operated with magnetized water. However, discharge rates under non-magnetized water were lower than those of magnetized water. Magnetic effect was obs...

Responses to the Irrigation Water Amount of Spinach Supplemented with Organic Amendment in Greenhouse Conditions

The effect of organic amendment applications on some agrophysiological properties of pot-grown spinach was investigated under drought stress. The I1, I2, I3, and I4 irrigation treatments received water amounts up to 100, 80, 60, and 40 percent of evaporation from a reduced pan, respectively. A liquid organic amendment was applied to spinach seeds as seed treatment at the ratios of 0.1 percent (H1) and 0.2 percent (H3). Furthermore, in the H2 and H4 treatments the amendment was foliar applied to spinach seedlings at the ratios of 0.1 percent and 0.2 percent in addition to the seed treatments, respectively. Organic amendment treatments positively affected root and leaf growth. The plants responded to water stress by lower growth. Leaf relative water content, membrane permeability, chlorophyll reading, and stomatal conductance values also indicated significant changes. These results support the view that organic amendment application increased growth. However, it could not provide a significant contribution for growth under water stress.

A comparison study on the removal of suspended solids from irrigation water with pumice and sand–gravel media filters in the laboratory scale

Abstract In this study, different bed materials in media filter systems were examined. For this purpose a laboratory experiment was established to determine the solids removal efficiency, total outlet flow volume and outlet flow velocity of pumice that has numerous open spaces, vesicles and irregular cavity, sand–gravel and combination of pumice and sand–gravel. In the experiment, two different filter column diameters (150 and 200 mm) and two different inlet flow pressures (100 and 150 kPa) were used. The results show that the total outlet flow volumes increased logarithmically as the filtration test period progressed, while the outlet flow velocities and the outlet concentrations of suspended solids decreased logarithmically for all filter types. Pumice media filters provided higher total outlet flow volumes and lower solid removal efficiency in comparison with sand–gravel media filters. However, the highest average solid removal efficiency was determined by pumice plus a sand–gravel media filter at 90.5...

Changes in gas exchange capacity and selected physiological properties of squash seedlings (Cucurbita pepo L.) under well-watered and drought stress conditions

ABSTRACT Water use efficiency (WUE) is considered as an important component of adaptation to drought stress. This study was conducted to determine the effect of drought stress on gas exchange parameters and selected physiological properties, and also its relations with WUE in summer squash seedlings (Cucurbita pepo L.). Plants were grown in pots under different irrigation levels (D0: 100%, D1: 67% and D2: 33% of the water required to reach the field capacity) in controlled greenhouse. The results show that drought treatments significantly decreased the leaf chlorophyll reading values (LCRV), leaf relative water content (LRWC), stomatal conductance (gs), photosynthetic rate (PN), transpiration rate (Tr), fresh weight (FW) and dry weight (DW) of squash seedlings by 7, 42, 69, 62, 62 63 and 82%, respectively, in D2 treatment compared to D0. However, electrolyte leakage (EL) values increased 72% with severe drought treatments (D2). The highest WUE was obtained by D0 treatment as 0.26 g mm−1. The relationship between PN and WUE is the strongest one among all leaf gas exchange parameters. Together with Tr, the linear relation with WUE was considerably higher compared to other measured parameters.