Selçuk Özmen

The effects of deficit irrigation on nitrogen consumption, yield, and quality in drip irrigated grafted and ungrafted watermelon

Abstract The aim of this study is to determine the effects of deficit irrigation on nitrogen consumption, yield, and quality in grafted and ungrafted watermelon. The study was conducted in Cukurova region, Eastern Mediterranean, Turkey, between 2006 and 2008, and employed 3 irrigation rates (full irrigation (I100) with no stress, moderate irrigation (DI70), and low irrigation (DI50); DI70 and DI50 were considered deficit irrigation) on grafted (CTJ, Crimson Tide+Jumbo) and the ungrafted (CT, Crimson Tide) watermelon. The amount of irrigation water (IR) applied to the study plots were calculated based on cumulative pan evaporation that occurred during the irrigation intervals. Nitrogen consumption was 16% lower in CTJ plants than in CT plants. On the other hand, consumption of nitrogen was 28% higher in DI50 plants than in DI70 plants while it was 23% higher in DI50 plants than in I100 plants. By grafting, the average amount of nitrogen content in seeds, pulps and peels for CTJ was 30, 43 and 56% more than those of CT, respectively. The yield and the quality were not significantly affected by the deficit irrigation. In this respect, grafting of watermelon gave higher yield, but, it had a slight effect on fruit quality. The highest yield values of 16.90 and 19.32 kg plant−1 in 2008 were obtained with I100 and in CTJ plants, respectively. However, DI50 treatment could be taken into account for the development of reduced irrigation strategies in semiarid regions where irrigation water supplies are limited. Additionally, the yield increased by applying CTJ treatment to the watermelon production.

Distribution of water loss via evapotranspiration in a pistachio tree orchard under drip irrigation and non-irrigation conditions.

The present study aimed to measure the distribution of water loss via evapotranspiration (ET) in a pistachio tree orchard under drip irrigation and non-irrigation conditions at the experimental orchard of the Pistachio Research Institute, Gaziantep, Turkey. The experimental design consisted of a 10 × 10 m 2 grid system constructed of PVC pipes spaced 2 m apart (horizontally and vertically) that was placed around each tree for the drip irrigation condition (water applied every 7 days) and the non-irrigated condition. Moisture content was measured using the neutron scattering method for both treatments. Water loss via ET was estimated based on the soil water balance method, which included measurement of soil moisture, precipitation, and irrigation. Total water loss via ET under drip irrigation conditions was 518 mm vs 220 mm under non-irrigated conditions. Water loss via ET for the total soil profile and individual layers under non-irrigated conditions was higher at the four outer corners of each 10 × 10 m 2 grid than under irrigated conditions. Moreover, water loss via ET was the highest at the grid system pipes closest to the two laterals under irrigation conditions. In addition, the total percentage of water loss via ET was the highest at the 60-80-cm and 20-40-cm soil layers under drip irrigation and non-irrigation conditions, respectively, and the total percentage of water loss via ET was the lowest at the 40-60-cm and 0-20-cm soil layers under drip irrigation and non-irrigation conditions, respectively. Lastly, it could be considered that root density increased as water loss via ET increased.

Assessing the performance of irrigation schemes in Antalya valley located in Mediterranean Region of Turkey

This study examined evaluation of the physical and financial performance criteria of 24 irrigation schemes in Antalya Valley located in the Mediterranean Region in Turkey between 2007 and 2012. In this study, physical and financial performances included irrigation ratio, sustainability of irrigated area and relative water supply ratios, and water fee collection efficiency and service area per personnel, were examined. The results of this study indicated that irrigation ratios of schemes are between 12 and 84%. The rate of sustainability in irrigated land of schemes was close to 1.0 except Čayboğazı, Deniztepesi and Döşemealti schemes. The relative water supply of most of the schemes such as Aksu-North, Aksu Middle, Alara Left Bank, Çayboğazı, Gazipaşa, Karaman Duraliler, Köprüçcay Right Bank, Kumluca Birlik and Manavgat Right Bank is higher than 2.5 because they consumed more water. The water fee collection efficiency was between 28 and 100% while service area per personnel between 10.7 and 1834.8 ha/person in all schemes from studied area. However, irrigation ratios of some schemes are needed to be recovered. The water fee collection efficiency and service area per personnel in most of schemes are satisfactory.

Comparative performance analysis of irrigation schemes in Kastamonu area located in northern Turkey

Performance analysis of six irrigation schemes in Kastamonu area located in northern Turkey were assessed using comparative performance indicators between the years 2008 and 2012. Performance indicators used for the analysis included relative water supply, financial performance as cost recovery ratio, maintenance expenditure to revenue ratio, operational cost per unit area, total cost per personnel employed on water delivery, revenue collection performance and service area per personnel. Additionally, production performance of the schemes were evaluated in terms of output per unit command area, output per unit irrigated area, output per unit irrigation supply and output per unit consumed-water. The results of the analysis indicated that all irrigation schemes except Asar had enough performance for the relative water supply ratios. Furthermore, cost recovery ratio and revenue collection performance was not satisfactory. On the other hand, maintenance expenditure to revenue, operational cost per unit area, total cost per person employed on water delivery and service area per personnel had performed well in most of schemes during the study years. Output per unit command area, output per unit irrigated area, output per unit irrigation supply and output per unit consumed-water were performed well for all schemes in the investigation year. Key words: Comparative analysis, irrigation performance, performance indicators, irrigation schemes.