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Efficient water delivery systems such as drip irrigation can contribute towards increasing crop yield potential, improving crop water and fertilizer use efficiency. However, critical management considerations such as subsurface drip irrigation are necessary to attain improved irrigation efficiencies and production benefits particularly under arid regions. The objective of this study was to determine the effect of two irrigation methods, surface and subsurface drip irrigation combined with four irrigation levels, 100, 80, 60 and 40% of crop evapotranspiration on yield and yield components of potato grown on sandy soil. The field experiments were conducted in the years 2008 and 2009. In terms of soil water availability to plants, subsurface drip provided more favorable growth conditions for plant growth and maintained higher soil water content at the root zone, which resulted in a significant higher potato yield compared to surface drip irrigation. The difference between the two irrigation methods on yield components was concentrated on the mean tuber weight per plant, while no significant difference was found on the tuber number per plant. Reducing the amounts of applied water significantly decreased total potato yield and its components. Under subsurface drip irrigation, reducing amounts of applied water to 80% ETc gave comparable yield and yield components to surface drip at full irrigation supply, indicating that 20% irrigation water can be saved without affecting the potato yield. At all irrigation levels, subsurface drip recorded higher water use efficiency (WUE) over surface drip. Maximum value was observed at 40% ETc. Fertilizer use efficiency (FUE) was also higher under subsurface drip and reduced significantly under both irrigation methods with increasing water deficit. These results suggested that subsurface drip offers the potential of better water management with respect to saving and distribution of water in the root zone and to obtain maximum yield accompanied by highest water and FUE.Keywords Subsurface drip irrigation · Dry stress · Potato · Water use efficiency · Fertilizer use efficiency Die Effizienz der Unterflur-Tropfbewässerung im Kartoffelanbau unter verschiedenen TrockenstressbedingungenZusammenfassung Effiziente Bewässerungssysteme, wie Tröpfchenbewässerung können zur Steigerung des Ertragspotenzials, sowie zur Verbesserung der Wasser-und Dün-gernutzungseffizienz beitragen. Allerdings sind kritische Erwägungen des Unterflur-Tröpfchenbewässerungs-Managements notwendig, um eine verbesserte Effizienz der Bewässerung und Produktionsvorteile, vor allem in ariden Regionen, zu erreichen. Ziel dieser Studie war es, die Wirkung von zwei Bewässerungsmethoden, eine oberflächliche und eine unterirdische Tropfbewässerung, kombiniert mit vier Bewässerungsstufen 100, 80, 60 und 40 % der Evapotranspiration, auf Ertrag und Ertragskomponenten der Kartoffel auf sandigen Böden zu untersuchen.

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With rising concern about current irrigation and fertilizer NPk management, the present study was conducted to evaluate the effect of sources and methods of fertilizer application on nutrient distribution, uptake, recovery and fruit yield of tomato grown in a sandy soil. equal amounts of NPk were applied in solid form or through fertigation at levels of 0%, 50%, 75% and 100% with the remainder 100%, 50% and 25% applied as solid fertilizers to the soil. available NO 3 − -N and K were confined to the root zone of tomato in 75% and 100% NPk fertigation levels, while they moved beyond the root zone when they applied in two equal splits as solid fertilizers with drip (0% fertigation) and furrow irrigation. the mobility of P was greater in the root zone following its application through fertigation compared to a solid application as super phosphate. Drip irrigation showed significantly higher absolute growth rate (aGr), total dry weight (tDW) and leaf area index (lai) of tomato over furrow irrigation. Moreover, tomato plants were able to utilize applied nutrients more efficiently in fertigation system than with conventional solid fertilizer application. highest aGr, tDW and lai were recorded when nutrients were applied to 100% by drip fertigation. the fruit yield of tomato was higher with drip irrigation (58.62 t ha −1 ) than with furrow irrigation, (47.37 t ha −1 ). Maximum fruit yield was recorded with 100% NPk fertigation (74.87 t ha −1 ) and was associated with a higher number of fruits per plant and a bigger fruit size than the solid applied fertilizers under both drip and furrow irrigation. On average, tomato accumulated more NPk across the fertigation levels than with drip and furrow irrigation. similarly, the more controlled application of nutrients in fertigation treatments improved NPk recovery and fertilizer use efficiency (FUE) and resulted in lesser leaching of NO 3 − -N and k to deeper soil layers.Keywords Drip irrigation · Growth rate · NPk distribution · Nutrient uptake · sandy soil Nährstoffaufnahme und Ertrag von Tomaten bei unterschiedlichen Düngungsanwendungsmethoden und Bewässerungsdüngungsstufen in TrockengebietenZusammenfassung Die bedeutung des bewässerungsma-nagements und der NPk-Düngüng steigt stetig an. in einer studie wurde die Wirkung der Düngerformen und der anwendungsmethoden auf Nährstoff- Verteilung, -aufnahme, und -Verwertung untersucht. Weiterhin wurde der ertrag von tomaten, die auf sandigem boden angebaut wurden, untersucht.es wurden gleiche Mengen an NPk-Düngemittel ausgebracht (Fertigation* in Stufen von 0%, 50%, 75% und 100% und der rest von 100%, 50%, 25% und 0% als feste Form). Verfügbares NO 3 − -N und k wurde in der Wurzelzone von Tomaten bei einer Fertigationsstufe von 75% und 100% NPk gefunden, während bei einer anwendung mit festem Düngemittel (0% Fertigation) und Furchenbewäs-Gesunde Pflanzen (1 3 12 M. a. badr et al. serung sich NO 3 − -N und k über die Wurzelzone hinaus bewegten.Die Mobilität von P war größer bei einer ausbringung durch bewässerungsdüngung als bei einer...

Various techniques such as AI and ET have been reported to improve reproductive efficiency and genetic potential in camelids. In vitro fertilization and the development of IVP embryos are considered an alternative for genetic improvement in this species. This study investigated the effects of different sperm cell concentrations (1, 2, 3 and 4 × 106 sperm mL–1), different capacitating materials (5 mM caffeine, 10 μg mL–1 of heparin, 10 mg mL–1 of theophylline, 1 mM calcium ionophore A23178 and 10 μg of heparin + 5 mM caffeine), post-slaughter epididymal flushing time and fertilization media supplements (Fert-TALP + 6 mg mL–1 of BSA and Fert-TALP + 3 mg mL–1 of polyvinylpyrrolidone ) on fertilization rates and subsequent development of dromedary camel oocytes. Cumulus–oocyte complexes obtained at slaughter were matured in vitro in TCM-199 for 36 h at 39°C in a humidified atmosphere of 5% CO2. For IVF, spermatozoa were collected from epididymides of slaughtered male camels at 1 to 2 h post-slaughter or after 24 h of epididymal storage at 4°C. The spermatozoa were then prepared for IVF by the swim-up technique. Following sperm capacitation, oocytes and spermatozoa were co-incubated for 18 h. Oocytes were then stained using aceto-orcein for evaluation of fertilization events. Presumptive zygotes were cultured in vitro in TCM-199 medium supplemented with 5% FCS for 9 days at 39°C in a humidified atmosphere of 5% O2, 5% CO2 and 90% N2. At least 3 replicates were performed for each experimental group. Data were analysed by chi-square test. Fertilization rates were 55.5, 62.5, 62.7 and 47.2% in oocytes inseminated with 1, 2, 3, or 4 × 106 sperm mL–1, respectively. Normal fertilization rate (oocytes with 2 pronuclei) was higher (P =  0.06) in oocytes inseminated with 2 × 106 sperm mL–1 (29.7%) than in those inseminated by 4 × 106 sperm mL–1 (11.1%). Treatment of epididymal spermatozoa with 5 mM caffeine significantly increased (P ≤ 0.05) fertilization rate (61.9%) compared with calcium ionophore A23178 (32.4%). These values were not significantly different from other groups (38.5, 54.1 and 50.0% in heparin, theophylline and heparin + caffeine, respectively). Normal fertilization was highest (25.4%) in oocytes inseminated with caffeine-treated spermatozoa. Insemination of oocytes in Fert-TALP medium containing BSA resulted in a higher fertilization rate (21.4%) compared with oocytes in polyvinylpyrrolidone-supplemented medium (5.7%; P =  0.06). Storage of camel epididymides at 4°C for 24 h did not affect fertilization rates. Cleavage rate (48 h post-insemination) was higher in oocytes fertilized with caffeine-treated spermatozoa than in oocytes in the theophylline group (26.8 vs 10.5%; P =  0.08). No significant difference was observed in the frequency of blastocyst development (5 days post-insemination) between the 2 groups (5.4 vs 2.6%); based on the number of cleaved oocytes, the same proportions of blastocyst embryos were reported (20.0 and 25.0%). Taken together, these results suggest that dromedary camel oocytes can be matured, fertilized and subsequently developed in vitro with high developmental potential. Epididymal spermatozoa at a concentration of 2 × 106 sperm mL–1 prepared in a medium containing caffeine as a capacitating agent can be used effectively in IVF of camel oocytes.