The effects of different irrigation regimes on yield and silage quality of corn under semi-arid conditions

The aim of this study was to evaluate the effects of different quantities of drip irrigation water on the corn yield and silage quality under semi-arid conditions. The seasonal evapotranspiration (ETc) for the different irrigation regimes varied from 434 to 947 mm in 2004 and from 468 to 1003 mm in 2005 for total irrigation periods of 108 and 113 days, respectively. Combining data from both years, the relative evapotranspiration deficit (1−ETa/ETm) for different regimes was 19 to 54% in corn compared to the maximum seasonal ETc when water was not limited in the (I100) regime. During the course of both years, irrigation had an apparent effect on the total fresh silage yield (FSY), with yields increasing steadily from water stress to fully irrigated conditions, while silage yields increased linearly with the total depth of irrigation water applied between planting and harvest. Combining data from both years showed that the FSY was 35.0, 53.6, 83.3 and 88.9 t ha-1 for I25, I50, I75 and I100, respectively. Moreover, the largest FSY recorded amongst these experiments at maximum seasonal yield in single treatment was 89.1 t ha-1 in 2004 and 88.7 t ha-1 in 2005. The water content decreased considerably in all but FSY, while the dry matters yield (DMY), organic matter (OM), acid detergent fiber yield (ADFY) and in vitro dry matter digestibility (IVDMD) increased. Furthermore, the study substantiated that the highest yield and silage quality were obtained at the full (I100) irrigation regime.Key words: Silage, deficit irrigation, yield, silage quality

Examination of modern and traditional applications in hazelnut production

Hazelnut production in Turkey, which is carried out in a land area of approximately 700 thousand ha and yields ~600 thousand t year-1 of in shell nuts, makes up about 70% of the world’s hazelnut production. Turkey is followed by Italy, Georgia, USA, Azerbaijan, China, Iran, Spain, respectively, in terms of major hazelnut producing countries. Italy is the second largest hazelnut producing country with a production area of 70 thousand ha. Its share of world production is approximately 10%. Spain is one other main hazelnut producing country with 14 thousand t year-1. A new European ERASMUS + Project “Examination of modern and traditional applications in hazelnut production” was prepared highlighting a “Cooperation for Innovation and the Exchange of Good Practices”. Four partners from Turkey (Ordu Commercial Exchange, Ordu University, Ordu Governor and Altınordu Chamber of Agriculture), one from Italy (Università degli Studi della Tuscia, Viterbo), and one from Spain (IRTA-Mas de Bover, Tarragona) are involved in this EU project. The most fundamental problem in hazelnut is low quality and low yield according to the World trade union. Accordingly, teaching new methods to the farmers by sharing the best practices with vocational training in Turkey, Italy and Spain, which enjoy the highest shares in hazelnut culture, would make great contributions to this issue. At the same time, this would also provide policy makers with new ideas. Farmers learning appropriate agricultural methods and implementing them would increase the hazelnut production and improve fruit quality. The expected goals of the project are to develop cooperation between the institutions, increase hazelnut quality and productivity, learn and adopt new farming methods, plant a pilot orchard, draft a hazelnut booklet, increase the communication between farmers, and share the best practices among three countries. At the end of the project, the outputs obtained will be disseminated to all hazelnut sectors.s

Effects of urbanization and land-use type on monthly extreme temperatures in a developing semi-arid region, Turkey

Climate change is a great concern and attracted attention of many researchers in the world. A study was conducted to determine the effects of regional parameters such as population change (?P), number of motor-driven vehicles (NMDV), area covered by industrial crops (A), number of buildings (NB), and monthly extreme temperature trends in a developing semi-arid southeast region of Turkey, known as GAP area. Monthly extreme temperature series observed at 16 observation stations, covering the period of 1932-2002, with record length varying between 27 and 71 years, were utilized. Nonparametric Mann-Kendall test procedure was employed to detect monthly trends. Multiple and univariate linear regression analysis were employed to relate Mann-Kendall test statistic Z to the regional parameters. Spatial coverage maps of statistically significant upward and downward trends for each month were produced by using inverse distance squared weighting (IDSW) method. The most widespread upward trend was determined in January and July covering 42.9% and 40.9% of total area for maximum (Tmax) and minimum (Tmin) temperatures. There were no statistically significant (P ? 0.05) downward trends for extreme temperature series in the area studied. Multiple regression analysis (overall model) results revealed that determination coefficients for Tmax and Tmin were the highest as 94.0% in August and 87.8% in June. Univariate regression analysis led us to conclude that ?P and A were the most important parameters to detect trends in Tmin and Tmax series. Mann-Kendall test statistic Z for Tmax in summer time was negatively correlated with A. This was likely due to direct human influence through irrigation practices as well as the construction of large man-made water bodies in the region. The ?P, NMDV, and NB were positively correlated with Tmin, indicating that the cool period is gradually becoming warmer with time. We concluded that, as the area sown with industrial crops increases, there is a decrease in maximum temperatures due to the evaporative cooling mechanism. Increase in urbanization and/or industrialization, causes an increase in minimum temperatures in the area. © 2006 Elsevier Ltd. All rights reserved

The impact of water resources development projects on water vapor pressure trends in a semi-arid region, Turkey

The aim of this study was to investigate long-term seasonal trends and decadal change patterns of monthly mean water vapor pressure (WVP) observation series at 16 meteorological stations scattered point-wisely over the Southeastern Anatolian Project (GAP) area in Turkey, where large-scale soil and water development projects have been put into practice since the 1970s. The record length of WVP observation series of each station varied between 31- and 41-years between 1962 and 2002. The monthly mean WVP observation series of each station was rearranged on seasonal basis. Sequential Mann-Kendall trend test, Sen's slope estimator, and Spearman's rank-order correlation tests were employed for detection of likely trends, and Kruskall-Wallis test was used to detect decadal variations in WVP series of each observation station. A possible area of representation for each meteorological station was determined by using the Thiessen polygons technique in a geographical information systems media. It was found that 15 seasonal WVP series have a positive trend covering 97% of the GAP area in the summer season; although one WVP series has a negative trend direction. However, in the spring season, 33% of the area had a positive trend, and a negative trend did not appear in any stations. WVP records in the winter season showed an increasing trend over 19% of the GAP area, whereas a decreasing trend prevailed in 9% of the area. The study results led us to conclude that the substantial increase of WVP observations in summer season could be attributed to both the shift from rain-fed agriculture to irrigated agriculture being made increasingly spacious year by year and building large water reservoirs in the GAP located in a semi-arid region. The results also indirectly suggested that the historical trends in the WVP parameters might be related to global climate change phenomenon. © 2007 Springer Science + Business Media B.V