Effects of high temperature on the growth and composition of sugarcane internodes

Sugarcane grown in the Ord River district of Western Australia has lower sucrose content than expected from earlier trials and experience in other irrigated districts. High temperatures have been hypothesised as a possible cause. The effects of high temperature (above 32 degrees C) on growth and carbon partitioning were investigated. A temperature regime of (25-38 degrees C) was compared with (23-33 degrees C). In one experiment, 7-month-old plants of cvv. Q117 and Q158 were subjected to the treatments for 2 months. In another experiment, the plants were allowed to regrow (ratoon) for 6 months. In both experiments, the higher temperature resulted in more, shorter internodes and higher moisture content. Most internodes from plants in the higher temperature treatment had lower sucrose content than internodes from the lower temperature. On a dry mass basis the internodes from the plants in the higher temperature had proportionately more fibre and hexoses but lower sucrose. Combined with an increased number of nodes in a stem of similar or shorter length this would result in higher stalk fibre and lower sucrose content. The data provided evidence that sugarcane partitions less carbon to stored sucrose when grown under high compared with low temperatures. The two cultivars partitioned carbon between soluble (sugars) and insoluble (fibre) fractions to different degrees. These experiments also indicate that the current models describing leaf appearance and perhaps sugarcane growth at temperatures above 32 degrees C, in general, need revision.

Pattern analysis on grain yield performance of Chinese and CIMMYT spring wheat cultivars sown in China and CIMMYT

Understanding the relationships among testing environments is essential for better targeting cultivars to production environments. To identify patterns of cultivar, environment, cultivar-by-environment interactions, and opportunities for indirect selection for grain yield, a set of 25 spring wheat cultivars from China and the International Maize and Wheat Improvement Center (CIMMYT) was evaluated in nine environments in China and four management environments at CIMMYT in Cd. Obregon, Mexico, during two wheat seasons. Genetic background and original environment were the main factors influencing grain yield performance of the cultivars. Baviacora M 92, Xinchun 2 and Xinchun 6 showed relatively more stable and higher grain yields, whereas highly photoperiod sensitive cultivars Xinkehan 9, Kefeng 6 and Longmai 19 proved consistently inferior across environments, except in Harbin and Keshan, the two high latitude environments. Longmai 26, also from high latitude environments in the northeastern Heilongjiang province, was however probably not as photoperiodicly sensitive as other cultivars; from that region, and produced much higher grain yield and expressed a broader adaptation. None of the environments reported major diseases. Pattern analyses revealed that photoperiod response and planting option on beds were the two main factors underlying the observed interactions for grain yield. The production environment of planting on the flat in Mexico grouped together with Huhhot and Urumqi in both wheat seasons, indicating an indirect response to selection for grain yield in this CIMMYT managed environment could benefit the two Chinese environments. Both the environment of planting on the flat with Chinese Hejin and Yongning, and the three CIMMYT enviromnents planting on raised beds with Chinese Yongning grouped together only in one season, showing that repeatability may not be stable in this case.

SADC planning workshop on Newcastle Disease control in village chickens : Maputo, Mozambique, 6-9 March, 2000

This publication is a record of papers presented at a workshop in Maputo, Mozambique 6-9 March, 2000 on Newcastle disease in village chickens. A thermostable vaccine suitable for use in the control of Newcastle Disease in village chickens has been developed by the University of Queensland, with funding from ACIAR

Studies on the nutrition and metabolism of turbot (Scophthalmus maximus L) with reference to fish farming

This thesis provides the first detailed study of maximal oxygen consumption of turbot on a fish farm over a range of fish sizes and temperatures. Also provided is a study of the diets used in turbot farming and the development of a diet that contains no fresh fish. A detailed study of previous research on flatfish nutrition, identified fresh fish, sprat in particular, as the optimum diet for turbot farming. A series of experiments was undertaken that confirmed this and also identified one possible explanation for the optimum performance of sprat, as a function of high non-protein energy ratios in sprat. This factor was exploited in the production of a diet containing no fresh fish and which produced superior results to diets containing fresh fish; the optimum level of lipid in the diet was determined as 18%. The study of oxygen consumption was on fully-fed fish so that maximum demand could be quantified. Continuous monitoring of tank water oxygen levels enabled the calculation of the Specific Dynamic Action (SDA) effect in turbot and the relation of it to dietary energy. Variation of SDA with the dietary energy profile was identified as a contributing factor to differential fish growth on various diets. Finally, the implications of this work to fish farming were considered. Economic appraisal and comparison of the diets routinely used in turbot farming identified that the diet developed as a result of this work, ie the diet containing no fresh fish protein, was more cost effective on the basis of the production of one tonne of turbot. The study of oxygen consumption enables water supply to be calculated for any fish size between 1g and 1000g between the temperatures of 7® C and 16® C. The quantification of SDA enables correct adjustment of oxygen flows according to the feeding status of the fish.

Fish farm effluent control and the development of an expert system

In recent years, freshwater fish farmers have come under increasing pressure from the Water Authorities to control the quality of their farm effluents. This project aimed to investigate methods of treating aquacultural effluent in an efficient and cost-effective manner, and to incorporate the knowledge gained into an Expert System which could then be used in an advice service to farmers. From the results of this research it was established that sedimentation and the use of low pollution diets are the only cost effective methods of controlling the quality of fish farm effluents. Settlement has been extensively investigated and it was found that the removal of suspended solids in a settlement pond is only likely to be effective if the inlet solids concentration is in excess of 8 mg/litre. The probability of good settlement can be enhanced by keeping the ratio of length/retention time (a form of mean fluid velocity) below 4.0 metres/minute. The removal of BOD requires inlet solids concentrations in excess of 20 mg/litre to be effective, and this is seldom attained on commercial fish farms. Settlement, generally, does not remove appreciable quantities of ammonia from effluents, but algae can absorb ammonia by nutrient uptake under certain conditions. The use of low pollution, high performance diets gives pollutant yields which are low when compared with published figures obtained by many previous workers. Two Expert Systems were constructed, both of which diagnose possible causes of poor effluent quality on fish farms and suggest solutions. The first system uses knowledge gained from a literature review and the second employs the knowledge obtained from this project's experimental work. Consent details for over 100 fish farms were obtained from the public registers kept by the Water Authorities. Large variations in policy from one Authority to the next were found. These data have been compiled in a computer file for ease of comparison.

Multiterminal DC wind farm collection grid internal fault analysis and protection design

The multiterminal dc wind farm is a promising topology with a voltage-source inverter (VSI) connection at the onshore grid. Voltage-source converters (VSCs) are robust to ac-side fault conditions. However, they are vulnerable to dc faults on the dc side of the converter. This paper analyzes dc faults, their transients, and the resulting protection issues. Overcurrent faults are analyzed in detail and provide an insight into protection system design. The radial wind farm topology with star or string connection is considered. The outcomes may be applicable for VSCs in the multi-VSC dc wind farm collection grid and VSC-based high-voltage direct current (HVDC) offshore transmission systems.

A cloud-based farm management system:architecture and implementation

Recent technological advances have paved the way for developing and offering advanced services for the stakeholders in the agricultural sector. A paradigm shift is underway from proprietary and monolithic tools to Internet-based, cloud hosted, open systems that will enable more effective collaboration between stakeholders. This new paradigm includes the technological support of application developers to create specialized services that will seamlessly interoperate, thus creating a sophisticated and customisable working environment for the end users. We present the implementation of an open architecture that instantiates such an approach, based on a set of domain independent software tools called "generic enablers" that have been developed in the context of the FI-WARE project. The implementation is used to validate a number of innovative concepts for the agricultural sector such as the notion of a services' market place and the system's adaptation to network failures. During the design and implementation phase, the system has been evaluated by end users, offering us valuable feedback. The results of the evaluation process validate the acceptance of such a system and the need of farmers to have access to sophisticated services at affordable prices. A summary of this evaluation process is also presented in this paper. © 2013 Elsevier B.V.

Effects of the current financial and economic crisis on the rural landscape as well as the agri-food sector in Europe and Central Asia

This paper reviews the expected effects of the current financial crisis and subsequent recession on the rural landscape, in particular the agri-food sector in Europe and Central Asia (ECA) on the basis of the structure of the rural economy and of different organisations and institutions. Empirical evidence suggests that the crisis has hit the ECA region the hardest. Agriculture contributes about 9% to gross domestic product (GDP) for the ECA region as a whole with 16% of the population being employed in the agricultural sector. As far as the impact of the financial crisis on the agri-food sector is concerned, there are a few interconnected issues: (1) reduction in income elastic food demand and commodity price decline, (2) loss of employment and earnings of rural people working in urban centres, implying also costly labour reallocation, (3) rising rural poverty originating mainly from lack of opportunities in the non-farm sector and a sizable decline of international remittances, (4) tightening of agricultural credit markets, and the (5) collapse of sectoral government support programs and social safety-net measures in many countries. The paper reveals how the crisis hit farming and broader agri-business differently in general and in the ECA sub-regions.

Land Policy and Farm Structure: Challenges and Opportunities for Agriculture in the Western Balkan

Although Western Balkan countries are quite different, they can all be characterised by their one shared goal, to achieve the quickest possible accession to the European Union. Even though agriculture plays an important key role within all Western Balkan states, it’s share is the highest in Albania and only Serbia has a trade surplus. Land is a key production factor but all the analysed countries can be characterized by fragmented land structure and low average farm sizes. Mostly based on land ownership issues, a land reform index can be calculated. The major contribution of this paper to the literature is the reevaluated land reform index for the Western Balkans.

Ethnic identification: Impact on HIV/AIDS risk among migrant and seasonal workers in South Florida

Migrant workers are one of the most rapidly growing populations in the United States (U.S.) and have been significantly affected by HIV/AIDS. More than 9 million people in the U.S., primarily concentrated in Texas, Florida, Washington, California, Oregon, and North Carolina, are migrant farm workers. High prevalence rates are also suspected among migrant worker communities where risky health behaviors appear to be common. Constant mobility, isolation, limited education, substandard housing, and poverty are some of the factors that migrant workers experience and in many cases increases their HIV risk. Recent studies have suggested that ethnic identity or the level of attachment with one's ethnic group may influence engagement in HIV risk behaviors, a fact that may be important in the development of interventions among ethnic minorities. This study assesses the relationship between ethnic identity and HIV risk behaviors in two different samples; one assesses this relationship at baseline with a total of 431 African American migrant and seasonal workers in Immokalee, Florida. The second analyzes changes in ethnic identity and HIV behaviors in a sample of 270 Hispanic and African American migrant and seasonal workers in Immokalee, Florida. Data from baseline and 6-month follow-up were used in the analyses presented. The results suggest that individuals with higher levels of ethnic identity report lower levels of engagement in some, but not all, of the risky behaviors examined. These findings point to a potentially protective role for ethnic identity among this sample.

The Effect of Nutrient-Rich Effluents from Shrimp Farming on Mangrove Soil Carbon Storage and Geochemistry Under Semi-Arid Climate Conditions in Northern Brazil

A semi-arid mangrove estuary system in the northeast Brazilian coast (Ceará state) was selected for this study to (i) evaluate the impact of shrimp farm nutrient-rich wastewater effluents on the soil geochemistry and organic carbon (OC) storage and (ii) estimate the total amount of OC stored in mangrove soils (0–40 cm). Wastewater-affected mangrove forests were referred to as WAM and undisturbed areas as Non-WAM. Redox conditions and OC content were statistically correlated (P < 0.05) with seasonality and type of land use (WAM vs. Non-WAM). Eh values were from anoxic to oxic conditions in the wet season (from − 5 to 68 mV in WAM and from < 40 to > 400 mV in Non-WAM soils) and significantly higher (from 66 to 411 mV) in the dry season (P < 0.01). OC contents (0–40 cm soil depth) were significantly higher (P < 0.01) in the wet season than the dry season, and higher in Non-WAM soils than in WAM soils (values of 8.1 and 6.7 kg m− 2 in the wet and dry seasons, respectively, for Non-WAM, and values of 3.8 and 2.9 kg m− 2 in the wet and dry seasons, respectively, for WAM soils; P < 0.01). Iron partitioning was significantly dependent (P < 0.05) on type of land use, with a smaller degree of pyritization and lower Fe-pyrite presence in WAM soils compared to Non-WAM soils. Basal respiration of soil sediments was significantly influenced (P < 0.01) by type of land use with highest CO2 flux rates measured in the WAM soils (mean values of 0.20 mg CO2 h− 1–g− 1 C vs. 0.04 mg CO2 h− 1–g− 1 C). The OC storage reduction in WAM soils was potentially caused (i) by an increase in microbial activity induced by loading of nutrient-rich effluents and (ii) by an increase of strong electron acceptors [e.g., NO3−] that promote a decrease in pyrite concentration and hence a reduction in soil OC burial. The current estimated OC stored in mangrove soils (0–40 cm) in the state of Ceará is approximately 1 million t.

The diet and influence of the spionid polychaete Marenzelleria on benthic communities in coastal Newfoundland

Spionid polychaetes within the genus Marenzelleria are common inhabitants of organically enriched sediments in the Northern hemisphere. The species M. viridis has unique ventilation behaviors that create dynamic, fluctuating oxygen conditions in sediments, enhancing sulfate reduction. These behaviours may have negative effects on other macrofauna and positive effects on sulfur bacteria. A Marenzelleria species recently sampled in Newfoundland is here identified as M. viridis, and its abundance correlates little with abiotic factors and macrofaunal community composition at examined sites. Various types of surrounding sediments (oxic and suboxic as well as M. viridis burrow linings) contained surprisingly similar total prokaryotic, sulfate reducing and sulfur oxidizing bacteria numbers. The high abundance of sedimentary prokaryotes, combined with the stable isotopic composition of M. viridis tissues and lack of obvious symbionts, suggest that, thanks to its ventilation behaviour, this species may “farm” sulfur bacteria in sediments and use them as a primary food source.

Short-term impact of soybean management on ammonia oxidizers in a Brazilian savanna under restoration as revealed by coupling different techniques

Acknowledgments The authors are very grateful to Mr. Fabiano Bielefeld Nardotto, owner of the Tabapuã dos Pireneus farm, for allowing our free movement around the farm and collection of soil samples, as well as providing information about soybean cultivation. The authors also thank Dr. Plínio de Camargo, who performed the isotopic analysis in the CENA laboratory at the University of São Paulo (USP). This work was supported by grants from the National Council of Technological and Scientific Development (CNPq), Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES), and Foundation for Research Support of Distrito Federal (FAP-DF).