This study compared the performances of subsurface drip irrigation (SDI) to sprinkler irrigation (SI) of cool-season turf mix (CS) and warm-season (WS) turfgrass species while investigating their response to different irrigation scheduling strategies. Moreover, the suitability of crop water stress index (CWSI) for monitoring water stress and scheduling irrigation was tested. Irrigation was applied up to the field capacity when 30%, 50% and 70% of total available water was consumed. All parameters, including color, quality, fresh yield, dry matter yield, irrigation water productivity, water productivity, vegetation height and mowing, differed significantly for different irrigation methods and water supply strategies for both species. The best visual turf was maintained under non-limiting soil moisture conditions (30%) in all main and sub-treatments. At this irrigation threshold, maximum and minimum amounts of irrigation water were applied in SI CS treatment (523.5 mm) and SDI WS treatment (298.6 mm), respectively. Warm-season turf required up to 40% less water than cool-season turf mix. In the water-scarce regions, 50% treatment for cool-season and 70% treatment for warm-season can be suggested for acceptable visual quality, lower water consumption and less frequent clipping. The mean CWSI before irrigation, representing irrigation threshold, ranged between 0.22–0.70.

Climate change, population growth, industrialization, overconsumption, and pollution strain water and resources, posing risks to ecosystem sustainability. Urgent action plans based on decision support systems are essential to protect environmental health and secure global food resources. This study employs the Wavelet model to analyze the impacts of agricultural and environmental factors on water resources in a selected irrigation basin by assessing water quality parameters, including chemical, physical, and biological properties, through seasonal sampling and wavelet transformations to detect temporal and spatial trends. Results showed increased salinity, nitrate, boron, total suspended solids (TSS), and chemical oxygen demand (COD) in groundwater and irrigation canals, particularly during dry periods. High nitrate (average 0.36 mg/L) and TSS levels (average 1152 mg/L) were linked to agricultural activities, while industrial influences contributed to the variability of boron ranging from 0.01 to 0.40 mg/L and COD ranging from 20 to 235 mg/L. The study highlights the temporal persistence of water quality challenges and spatial differences driven by external and environmental factors. Predictive wavelet analyses suggest that without intervention, water quality could worsen. These findings highlight the need for wavelet-based techniques to develop accurate management strategies for mitigating environmental impacts and ensuring long-term resource sustainability in irrigation-dependent regions.

The aim of this study is to determine the effects of deficit irrigation applications at different levels on the cool-season turf mix and warm-season turfgrass species irrigated by sprinkler irrigation method and sub-drip irrigation method. Field experiments were conducted in the Agricultural Production and Research Center (TURAM) of Silivri Municipality in the boundaries of Tekirdağ and Istanbul - TÜRKİYE (41°03ʹN; 28°00ʹE; 46 m a.s.l.) in the summertime of 2019 and 2020. In this research, two different irrigation methods (SI: Sprinkler and SDI: sub-drip), for two different turfgrass types (CS: Cool-season turfgrass mix and WS: Warm-season turfgrass), at three different irrigation levels (I1: full irrigation, I2: 1/3 deficiency, I3: 2/3 deficiency) were examined in split split plots in randomized blocks design with three replications. Soil moisture content was monitored via TDR for irrigation scheduling, climatic data needed for ETo estimation were taken from automatic meteorology station established in experimental area, canopy temperature for CWSI calculation was measured by infrared thermometer. When the results were evaluated in terms of irrigation methods, 6-36% less irrigation water was applied with SDI method according to SI method due to the high-water application efficiency and low evaporation. Besides, it has been concluded that deficit irrigation for cool season turfgrass mix has not been possible by SI method whereas deficit irrigation of 1/3 can be applied by SDI method on the condition of a little bit compromising the color quality. Thus, 38% irrigation water saving was achieved by SDI method. Although there was no any decrease in the density value, irrigation deficiency was not possible due to the decrease in the color parameter in Bermudagrass under SI method. However, irrigation water deficiency of 1/3 can be managed without any problem in visual quality in the same grass type under SDI method. Thus, approximately 50% irrigation water saving can be achieved compared to the SI method. Moreover, the CWSI is a valuable tool for monitoring and quantifying water stress and scheduling irrigations. CWSI of 0,12; 0,13; 0,31 and 0,39 are irrigation thresholds for CS and WS under SDI method for CS and WS under SI method, respectively. Keywords: Landscape irrigation, Turfgrass varieties, Irrigation methods, Irrigation water saving, Crop water stress index (CWSI) This Project was funded by The Scientific and Technological Research Council of Turkey (TÜBİTAK).

Bu çalışma, Tekirdağ koşullarında toprak altı damla sulama yöntemiyle sulanan serin ve sıcak iklim çim türlerinde, sulama zamanının planlanması amacıyla, Tekirdağ-İstanbul il sınırında Gümüşyaka köyünde yer alan Silivri belediyesine ait Tarımsal Üretim ve Araştırma Merkezi (TÜRAM) deneme alanında, 2017 yılı yaz döneminde yürütülmüştür. Araştırmada, çim türleri için üç farklı sulama düzeyi, tesadüf bloklarında bölünmüş parseller deneme deseninde 3 tekerrürlü olarak denenmiştir. Denemede sıcak iklim çim bitkisi olarak Bermudagrass (Cynodon spp.), soğuk iklim çimlerini temsilen ise 4’lü karışım kullanılmıştır. Karışım içeriği; %30 Lolium perenne, %25 Festuca rubra rubra, %35 Festuca arundinacea, %10 Poa pratensis türüne ait çeşitlerden oluşmaktadır. Sıcak iklim çeşidi olan Bermudagrass çimi araziye 30x30 cm aralıklarla 5 Mayıs’ta fide olarak dikilmiş, serin iklim çim çeşitleri karışımı ise her bir parsel için 50 g m-² tohum gelecek şekilde serpme yöntemi ile ekilmiştir. Serin iklim çim çeşitleri karışımının ekimi 7 Mayıs 2017 tarihinde gerçekleştirilmiş, çimlenme 14 Mayıs 2017 tarihinde ekim tarihinden 7 gün sonra başlamış, tam örtme 26 gün sonra tamamlanmıştır. Sıcak iklim çiminin alanı tam olarak örtmesi dikimden 51 gün sonra gerçekleşmiştir. Araştırmada çim bitkisinin su tüketimi belirlemeleri ve referens bitki su tüketimi hesaplamaları, sulama konularına başlanan 21 Temmuz ile denemenin sona erdiği 30 Eylül tarihleri arasındaki 72 günlük periyot için yapılmıştır. Deneme alanına A sınıfı buharlaşma kabı kurulmuş ve günlük buharlaşma değerlerinin ölçülmesinde kullanılmıştır. Sulama zamanının belirlenmesinde topraktaki nem miktarı değişimleri esas alınmıştır. Toprak nemi, Time Domain Reflactometer (TDR) esasına göre çalışan PR2 Probe ve HH2 Soil Moisture Meter aracı ile izlenmiş, elde edilen toprak nem değerlerinden 0-30 cm toprak derinliğindeki değerler uygulanacak sulama suyu miktarının belirlenmesinde, 0-60 cm toprak derinliğindeki değerler ise bitki su tüketiminin hesaplanmasında kullanılmıştır. Araştırmada uygulanacak sulama konuları; etkili kök derinliğinde kullanılabilir su tutma kapasitesinin yaklaşık %30'u, %50'si ve %70'i tüketildiğinde sulamalara başlanması ve eksik nemin tarla kapasitesine tamamlanması şeklinde oluşturulmuştur. Deneme sonunda serin iklim çim çeşitleri karışımında farklı sulama konularına uygulanan sulama suyu miktarları 324,2 mm – 195,7 mm; toplam bitki su tüketimi değerleri 382,7 mm – 260,2 mm; günlük bitki su tüketimleri değerleri ise; 5,38 mm gün-1 – 3,69 mm gün-1 arasında, sıcak iklim çiminde ise aynı değerler 298,6 mm – 117,1 mm; 357,9 mm – 180,4 mm; 5,03 mm gün-1 - 2,53 mm gün-1 arasında değişmiştir. Çalışmada, çimlenme ve kaplama süresi, vejetasyon yüksekliği, kalite, yüzey kaplama ve renk parametreleri ile ilgili ölçüm ve gözlemler yapılmıştır. Denemenin ilk yılı olması nedeniyle bitkiler kök ve vejetatif gelişimlerini ancak tamamlamışlar bu nedenle, ot verimleri belirlenmemiştir. Sonuç olarak, iki farklı çim türünde farklı sulama düzeylerinin, gelişim ve kalite unsurlarını istatistiksel açıdan önemli düzeyde etkilediği belirlenmiştir. Yöre koşullarında sulama suyu miktarı, biçim sıklığı ve kalite unsurları birlikte değerlendirildiğinde, serin iklim çimlerinde kullanılabilir su tutma kapasitesinin %50'si tüketildiğinde, sıcak iklim çiminde ise kullanılabilir su tutma kapasitesinin %70'i tüketildiğinde sulamaya başlanması önerilmiştir. Önerilen konular kıyaslandığında, sıcak iklim çiminin serin iklim çimlerine göre %43 daha az sulama suyu talep ettiği ve %52 daha az su tükettiği belirlenmiştir. Yöre koşulları için, en uygun bitki su tüketimi tahmin eşitliğinin ise serin iklim ve sıcak iklim çimleri için Blaney-Criddle yöntemi olduğu saptanmış ve bu yöntemlere ilişkin bitki katsayısı eğrileri oluşturulmuştur.

The aim of this study is to determine the effects of deficit irrigation applications at different levels on the cool-season and warm-season turfgrass species irrigated by sprinkler irrigation. Field experiments were conducted in the Agricultural Production and Research Center (TURAM) of Silivri Municipality in Gümüşyaka District located between the boundaries of Tekirdağ and Istanbul - TURKEY, at growing season 2019. In this research, two different turfgrass types (K: Cool season turfgrass and B: Warm season turfgrass), at three different irrigation threshold were examined in split-plots in randomized blocks design with three replications. Cool season turfgrass types lost its green colour completely after July due to the dry and hot summer season and the total amount of irrigation water applied in different irrigation strategies varied between 101.4 mm - 303.9 mm, seasonal evapotranspiration values varied between 217.7 mm - 391.5 mm, and daily evapotranspiration values varied between 2.4 mm/day - 4.3 mm/day. As for warm-season turfgrass types that managed to stay alive and kept its green colour throughout whole summer period; the same values varied between 203,6 mm - 591,6 mm; 328.4 mm - 593.9 mm; and 2,1 mm/day – 3,9 mm/day, respectively. In the 3-month period (May-June-July) in which both types of grass could survive, the seasonal evapotranspiration values were 11% more in the cool season turfgrass than that of warm season turfgrass. When daily evapotranspiration values were compared, it was observed that it was 10-14% more in cool-season turfgrass than in warm-season turfgrass. Average CWSI values calculated for different irrigation treatments were 0,57-0,66 for cool-season turf, 0,52-0,66 for warm-season turf besides, average CWSI values before irrigation application were 0,68-0,79 for cool-season turf, 0,69-0,79 for warm-season turf. Changes in the vegetation height, fresh yield, dry yield, plant density, color, and quality properties were monitored depending on the irrigation levels. When factors such as the amount of irrigation water applied, water-use and irrigation water-use efficiency, and quality parameters are evaluated together; none of treatments were adequate to keep cool-seasons varieties green after July. In the warm season turfgrass variety, although all irrigation levels provide the desired level for plant growth and quality, S2 treatment has been suggested when all parameters mentioned above are taken into consideration. Besides, Jensen Haise method (JH) was chosen as the best equation when reference evapotranspiration estimation methods were compared for both types of turf and crop coefficient (kc) curves have been prepared for both turfgrass species.