Mustafa Ünlü

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.

Methoden für die präzise obstbauliche Produktion

Der Ansatz von Precision Horticulture im Obstbau lehnt sich an das aus dem Ackerbau stammende Konzept der Prazisionslandwirtschaft bzw. der teilflachenspezifischen Bewirtschaftung an. Hierbei sollen prazise an das individuelle Geholzwachstum angepasste Pflegemasnahmen die bislang praktizierte einheitliche Behandlung aller Baume in einer Anlage ablosen. Voraussetzungen hierfur sind u. a. Bodenkarten und Informationen zum Pflanzenwachstum. Das Ziel ist es, den informationsgestutzten Obstbau voranzutreiben und durch ein raumlich und zeitlich differenziertes Management eine effizientere und nachhaltigere Bewirtschaftung zu erreichen.