International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

Influence of nitrogen rates and row spacing on corn yield, protein content, and other plant parameters

New maize hybrids has been intensively used as the first and second crop at the Cukurova region of Turkey in recent years. Therefore, nutritional problems of corn needs to be solved for the optimum yield, and protection from the potential insect and disease damages. Influence of nitrogen (N) and row spacing (RS) on corn yield, grain protein content, and selected plant parameters have been studied under field conditions in 1994 and 1995. Nitrogen was applied in the rates of 200, 250, 300, and 350 kg N ha-1 to main plots where row spacings were 10, 15, 20, and 25 cm in each subplots. Phosphorus (P) and potassium (K) were applied to each plot as basal rates. The experiment was arranged in a split-plot design in three replications. During course of the experiment and after harvest, selected plant parameters, leaf nutrient contents, root length, grain yield, and crude protein content were measured, and the data were statistically analyzed for determination of treatment effects. The selected plant parameters either influenced by N, RS, or both in 1994 and 1995. The learn content was affected by N and RS in 1995, and a RS effect was only observed in 1994. Grain yield was influenced by RS and N and RS in the first and second years, respectively. Grain yield ranged between 7.3 to 12.8 Mg ha-1 for both years. Treatment effects on crude protein content was significant in 1994 but no response was obtained in 1995

Determination of critical period for weed control in the second crop corn under Mediterranean conditions

Weeds are a major constraint in corn production. Understanding the critical period for weed control (CPWC) can be a tool for effective weed control and reducing the impacts of weeds. Three experiments were conducted to determine CPWC in the second corn crop from 1996 to 1998. The critical period for weed control in the second crop corn in the mediterranean region was determined to be from 131 to 927 growing degree days (GDD) after sowing in 1996, from 337 to 731 GDD in 1997 and from 266 to 551 GDD in 1998 for 10% yield loss; for 2.5 - 5% yield loss, the critical period starts with germination and lasts longer. Preemergence (PRE) or presowing (PPI) herbicides would be preferred to avoid higher yield losses. If a farmer can tolerate 10% yield loss, a postemergence (POST) herbicide can be applied in the second week after crop sowing, and the field should be kept weed free for 4 or 5 weeks. The duration of weed competition and time of weed removal also affect tasseling, silking, plant height, stem diameter, first ear's height and number of kernels in an ear, all of which correlate with corn yield. © 2009 Academic Journals

Modeling approach to nitrogen uptake by field-grown corn

Although the plant root system is one of the most important plant parameters affecting nutrient uptake by plants, root studies in field experiments are rarely conducted in plant nutrition and fertility studies. Since collection of root samples and measurements are difficult and time consuming, they are not considered as a routine plant parameter. Therefore, the effect and importance of the corn root system on plant nitrogen (N) uptake and grain yield was studied under field conditions in Adana, Turkey. Nitrogen was applied at rates of 200, 250, 300, and 350 kg N ha-1 as urea in a randomized complete block design experiment with three replications. During course of the experiment, soil, plant, root, and grain samples were collected and prepared for chemical analysis. Nitrogen uptake by plants was predicted using a COMP8 mathematical computer model and compared to actual plant uptake. Grain yield and learn content increased with increasing N rates, but root length did not change statistically. Predicted N uptake increased with added N, but was much smaller than observed N uptake under field conditions. Consequently, additional soil and plant parameters should be considered in nutrient uptake models to make the prediction more sensitive

Responses of wheat genotypes to phosphorus fertilization under rainfed conditions in the Mediterranean region of Turkey

Phosphorus (P) deficiency is a common crop growth-limiting factor in Mediterranean climatic and soil conditions because of low availability of native and added P, with consequent low use efficiency. Adaptation to such conditions is a function of the type of crop and also varies with genotypes within crops. The study evaluated responses of some of wheat genotypes to P application rates under typical rainfed Mediterranean climatic conditions in southern Turkey. Five wheat genotypes (Genc-99, Balatilla, Adana-99, Golia, and Panda) and five P application rates (0, 9, 17, 35 and 70 kg P ha-1) were used in a 2- year (2002/03, 2003/04) field experiment. In general, increasing P application level enhanced the leaf (0.18 - 0.44%) and grain P (0.08 - 0.18%) concentrations of the genotypes. Grain yields values ranged from 1.48 - 4.85 t ha-1 and optimum yields were achieved with 35 kg P ha-1 application rate in both years. The relationship between leaf P and grain yield was significant in the first year, but grain P and grain yield were not significantly related. Thus, leaf P (flag leaves) concentration can be used for identification of genotypes that could be adapted to low or high soil P availability under rainfed conditions. The relative yield changed among the genotypes, especially Balatilla and Adana-99 were different from the other genotypes and had a fairly good performance. While yield and drought efficiency are major objectives in wheat breeding programs in the Mediterranean region, the study indicates that attention should also be given to crop P efficiency. © 2010 Academic Journals

Grain yield response and N-fertiliser recovery of maize under deficit irrigation

Grain yield response and nitrogen (N) fertiliser recovery of maize (Zea mays L. cv. Sele) were assessed as influenced by deficit irrigation that was imposed either using conventional deficit irrigation (DI) or partial root drying (PRD) practice. The two deficit irrigation treatments were compared with FULL irrigation, the control treatment where rooting zone soil-water content was increased to field capacity at each irrigation, whereas 50% deficit irrigation was applied to the deficit treatments, DI50 and PRD50. Under the PRD practice, one-half of the rooting zone was wetted while the other half was maintained partially dry, thereby reduced amount of irrigation water was needed. The wetted and partially dry sides were interchanged in the subsequent irrigations. Under conventional DI, plants again received reduced amounts of water but the water was uniformly applied to both sides of the plant row. A popular hybrid maize-cultivar Sele was planted, following harvest of wheat. The study was conducted for two consecutive years in 2001 and 2002. A composite fertiliser of N, P and K, all at 80 kg ha-1 was applied before planting. At the ninth leaf (V9) stage, a second application of N-fertiliser at 170 kg N ha -1 rate was made. Difference method (plots with or without N-fertiliser application) was used for estimation of plant N-uptake efficiency. Contrary to earlier reports, the PRD treatment did not result in any yield benefit compared to the conventional deficit irrigation. The range of grain yield reduction under deficit irrigation treatments, DI50 and PRD50, was 10-25% and significant (P ? 0.01), compared to FULL irrigation practice. Measurements, including xylem sap abscisic acid concentration, photosynthetic rate and stomatal conductance under DI50 and PRD50 treatments followed a nearly identical trend. The PRD irrigation practice had the highest N-fertiliser recovery among the irrigation treatments, with minimal mineral N residue left after maize harvest. The recoveries under FULL and DI50 treatments were 17 and 24% less, respectively, than the PRD treatment. The PRD irrigation practice was not only as effective as conventional deficit irrigation (DI) in saving water, but it should also be regarded as an environmentally friendly irrigation practice due to its association with low mineral N residue left in the soil. © 2004 Elsevier B.V. All rights reserved.European Commission: ICA3-CT-1999-00008The authors gratefully acknowledge that this work was funded by European Union, through INCO-MED RTD project (ICA3-CT-1999-00008). Thanks are due to the Staff of Department of Biological Sciences, University of Lancaster, UK, for their help in ABA analysis, and to Dr. J.S. Schepers in Agronomy Department, University of Nebraska, USA, for editing the paper and valuable comments

Genotypic responses of corn to phosphorus fertilizer rates in calcareous soils

In the Mediterranean region, much emphasis is placed on the role of fertilizers in enhancing crop production to achieve food security. Given the complex nature of phosphorus (P) reactions in soils, considerable research has dealt with fertilizer aspects related to efficient P use, but comparatively less emphasis has been given to plant variation with respect to P efficiency. In this study, selection and adaptation of P-efficient corn genotypes was seen as one possible approach to enhancing P efficiency. Thus, a greenhouse experiment with 10 corn genotypes (traditional to modern), five P application rates (0-200mg kg-1), and four field trials with three genotypes for 2 years were carried out on various calcareous soils (Vertic Torrifluvent, Vertic Calciorthid, Entic Chromoxerert, and Typic Xerofluvent). Measurements were made of root characteristics. Treatments in the field trials were five P application rates as main plots (0-68P ha-1) and three corn genotypes as subplots. Genotypes were selected for the field trials from the greenhouse experiment as "efficient-responsive," "efficient-nonresponsive," and "inefficient-responsive." Dry-matter (DM) yield and plant P uptake by plants increased with P application rates in the greenhouse experiment. Root length and mass were considerably increased by increasing P levels. Genotypes were classified for P efficiency. The studies indicated that because corn genotypes respond to P-fertilizer application differently, this trait could be utilized to exploit native and applied P more efficiently, especially at low levels of available P and when P- fertilizer use is limited. This differential response derives from morphological, physiological, and genetic variability among the genotypes. Although genotypic efficiency is important for fertilizer management, the contribution of the efficiency is not a substitute for fertilizers, especially if high yields are required. Nevertheless, breeding for P-use efficiency should be a component of any program to improve crop yield potential. © Taylor & Francis Group, LLC.The authors thank the World Phosphate Institute (IMPHOS), Casablanca, Morocco, for this research grant and Cukurova University Research Foundation, Adana, Turkey, for their partial financial support

Assesment of Corn (Zea Mays L.) Genotypes in relation to nitrogen fertilization under irrigated cropping conditions in Turkey

Efficient nitrogen (N) fertilizer management in crop production is based on supplying adequate amounts of the nutrient for optimum economic yield, while minimizing losses to the environment. Exploiting genotypic differences in N use is an additional consideration in achieving nutrient-use efficiency. Thus, in order to identify N-efficient corn genotypes, we established N-response field trials at 2 locations (University Research Farm, and Cutaem) for 2 years (1999, 2000) in the Cukurova region of Turkey. Ten corn genotypes, commonly grown in the region, were fertilized with N at application rates of 160, 240, 320 and 400kg N ha-1. The optimum N fertilizer rate was probably in the 160-240kg N ha-1 rate based on response data. There were no significant or consistent differences between genotypes and N application for grain yield and N uptake. The average agronomic efficiency ranged between 20 to 65% across the genotypes and decreased with increasing N application rates. The pattern was similar for other efficiency indices with decreases with applied N, but little or no genotype differences. It is apparent that the genotypes used were bred for N as well as yield. There was little evidence of differences between genotypes or their response to N. Thus, while genotypic selection of corn can be one of the suitable potential N management practices in the Mediterranean region where genetic diversity exists, it is not appropriate considering genotypes are homogenous with respect to N use

Phosphorus use efficiency of wheat genotypes grown in calcareous soils

Phosphorus (P) deficiency and low P-use efficiency are induced by soil properties, especially in calcareous soils, which are dominant in semi-arid regions of the world such as the Mediterranean region. Alternative approaches to P fertilization involve exploiting plant genetics in order to achieve more efficient use of P by the growing crop. Accordingly, in a greenhouse pot experiment, we evaluated P-efficiency in wheat genotypes grown in typical calcareous soils in southern Turkey. Ten common local genotypes were grown in six soil series for eight weeks using five P application rates (0, 25, 50, 100, and 200 mg P kg-1). Dry matter (DM) yield and P content were significantly increased by increasing P rates, with significant differences between soils. Some genotypes performed better under P stress because of better P utilization efficiency. Shoot DM was the most sensitive indicator of genetic variability under P-deficient conditions. Genotypes classified as efficient-responsive (Adana-99, 1014, Golia, Balatilla) had above average DM yield when P was not added, and responded well to P applications; efficient-non-responsive genotypes (Firat-93, Seri-82, Genc-99, Panda) had below average DM yield, but responded to P applications; inefficient-non-responsive genotypes (Fuat Bey and Ceyhan-99) had below average DM yield; and no genotypes were in the inefficient responsive category. Such P response categorization is needed for better breeding programs for nutrient-use efficiency. The study may aid in selecting P-efficient genotypes in low-P soils, especially where little P is used. The use of P-efficient genotypes should be seen as complement to, rather than a substitute for, chemical P fertilization depending on local conditions. © Taylor & Francis Group, LLC.The authors thank to World Phosphate Institute (IMPHOS), Casablanca, Morocco and Cukurova University Research Foundation Adana, Turkey for their financial support

Phosphorous fertilizer efficiency and mycorrhizal infection in corn genotypes

In a world of limited resources and inexorable pressure to produce food for burgeoning populations, innovative approaches are needed to exploit these resources in a sustainable manner. Phosphorous (P) fertilizers are used extensively throughout the world for commercial crop production, and are a major factor in global food security. Yet, in developing countries, limited or no P fertilizer is used, often because of cost and infrastructure constraints, and this is therefore an impediment to sustainable production. The challenge facing soil scientists involved with soil and fertilizer P research is to produce adequate crops on inadequately fertilized soils in poorer countries and, at the same time, improve the efficiency of P use where excessive amounts are used, thus avoiding negative environmental impacts. Soil-plant fungi, especially arbuscular mycorrhizae (AM), may have a role in solving both horns of the P-use dilemma, since such associations have been shown to vary with plant species, and indeed genotypes within species, and to enhance crop utilization and uptake of P from soils low in soluble or available P. Therefore, as corn is an important feed and food crop in the Mediterranean coastal area of Turkey, we conducted two greenhouse studies to assess the P efficiency of a range of widely grown local corn genotypes and to establish the possible role of mycorrhizae in determining differences in observed P efficiency. The nine genotypes were grown with low to high P fertilizer rates (25-200 mg kg-1) and assessed for P efficiency, based on visual observations, dry matter yield, and tissue P concentration. Two efficient and two inefficient genotypes were then grown with and without P fertilizer and added mycorrhizae. The experimental bulk soil had natural mycorrhizal colonization. The genotypes XL 72AA, DK 626 and LG 60, LG 2777 responded differently to both P and mycorrhizal infection. The efficient genotypes were more dependent on added P (twofold yield increase) and mycorrhizae than the inefficient ones. Thus, while mycorrhizal colonization is not a substitute for fertilizer use, it is complementary to it. While difficulties still remain for AM inoculation of crops in the field, more attention to mycorrhizae should be given by plant breeders in the process of crop improvement. © CAB International 2004.Acknowledgements. The authors thank to World Phosphate Institute (IMPHOS, Casablanca, Morocco) and Cukurova University Research Foundation for their financial support, and Dr. Ibrahim Ortas for his review of the manuscript in terms of the mycorrhizal aspect