EFFECTS OF BIOSOLIDS APPLICATION ON SWEET SORGHUM BIOMASS, WATER USE EFFICIENCY AND ETHANOL PRODUCTION

The effects of biosolids application to sweet sorghum crop were examined during the years 2009-2011 at Central Greece. Considering sweet sorghum as a possible alternative crop for biomass and bio-ethanol production in Greece in the near future, the present research focuses on the biomass productivity, water use efficiency, and ethanol productivity of this crop as affected by the application of biosolids. Three treatments with three replications were organized in a randomized complete block design as follows: a) Biosolids application, b) Inorganic fertilizer application (same amount of N, P, K as the biosolids), and c) Control (no application of fertilizer or biosolids). The supplied amount of water was the same for all treatments and equal to the 100% of the daily evapotranspiration. The results of this study showed that biosolids application of 5 Mg ha(-1) to sweet sorghum crop increased the production of fresh and dry biomass by 15.4% and 13.2%, respectively, compared to the fresh and dry biomass produced by the application of inorganic fertilizer to the crop. Additionally, water was used more efficiently by the crop when biosolids were applied to the soil. Finally, the biosolids application produced about 14.3% more ethanol (theoretical) compared to the fertilizer application. In conclusion, the biosolids application to sweet sorghum crop transcends the fertilizer application in biomass productivity, water use efficiency, and theoretical ethanol production. Biosolids application can replace the application of fertilizers and also save valuable irrigation water which can lead to energy saving in agriculture

COMPARATIVE STUDY OF THE OPTIMAL HEAD OF THE IRRIGATION PUMP STATIONS USING NONLINEAR PROGRAMMING METHOD

Οι καθοριστικοί παράγοντες για το βέλτιστο σχεδιασμό των αρδευτικών δικτύων υπό πίεση είναι το κόστος των αγωγών και το κόστος άντλησης. Και οι δύο εξαρτώνται άμεσα από το μανομετρικό φορτίο του αντλιοστασίου. Η αύξηση του μανομετρικού φορτίου οδηγεί σε μείωση του κόστους κατασκευής του δικτύου και σε αύξηση του κόστους άντλησης. Για το λόγο αυτό είναι σημαντικό να υπολογίζεται κάθε φορά το βέλτιστο μανομετρικό φορτίο του αντλιοστασίου από το οποίο προκύπτει το ελάχιστο συνολικό κόστος του αρδευτικού έργου. Στην παρούσα εργασία υπολογίζεται το βέλτιστο μανομετρικό φορτίο με μια νέα προτεινόμενη απλοποιημένη συνεχή μέθοδο μη γραμμικού προγραμματισμού και γίνεται συγκριτική αξιολόγηση των αποτελεσμάτων αυτής με τη γενική συνεχή μέθοδο μη γραμμικού προγραμματισμού σε συγκεκριμένη εφαρμογή.The designating factors in the design of irrigation networks are the cost of pipes and the cost of pumping. They both are depended directly on the head of the pump station. An increase of the pump head involves a reduction of the construction cost of the network and an increase of the pumping cost. For this reason, it is important the optimal head of the pump to be calculated every time from which the minimum initial total cost of the irrigation network is derived. In this paper a comparative study of the optimal head is presented, using the general nonlinear programming method and a new simplified nonlinear method. Application and comparative evaluation in a particular irrigation network is also included

Estimation of unsaturated flow in layered soils with the finite control volume method

Water movement in unsaturated soil is described by Richards' equation, which is strongly nonlinear and cannot be solved analytically. For this reason numerical methods such as finite difference and finite element methods have been used to solve it. This paper presents another numerical solution of Richards' equation, based on the finite control volume method. This method has important advantages over other numerical methods, such as conservativeness of the system and flexibility of the grid intervals. To validate the numerical model a series of experiments were carried out in the laboratory in a vertical column of unsaturated two-layered soil (coarse and fine sand). The upper boundary condition was a second kind or Newman one and the lower boundary condition was a third kind or Newton's law condition. The soil water content was measured using the gamma -ray absorption method, while the water pressure in the pore media was measured using a tensiometer system with ceramic cups and pressure transducers. The numerical results of the new computational scheme are in good agreement with the experimental points. Copyright (C) 2001 John Wiley & Sons, Ltd

FIBER SORGHUM BIOMASS YIELD, WATER USE EFFICIENCY AND ECONOMIC RESULTS UNDER DIFFERENT LEVELS OF WATER, USING SUBSURFACE AND SURFACE IRRIGATION SYSTEMS

In 2007, an attempt was made to study the biomass production and the economic results of sorghum (Sorghum bicolor L. Moench, variety H 132), growing in Greece, under two different irrigation methods, surface and subsurface, and three different amounts of irrigating water: 100%, 70% and 50% of the daily evapotranspiration (ET). The study is part of a wider research concerning the potential growing of energy plants, and using biomass for energy production. A field experiment comprising of a completely randomized block design with six treatments and four replications was conducted at the Experimental Farm Station of the University of Thessaly. Water needs were satisfied by using full (100% ET) and supplement (70% and 50% ET) amounts of irrigating water. Crop production was measured in terms of dry biomass, while gross revenue, production expenses and gross margin were the economic parameters measured and examined. The comparative data analysis of the two irrigation methods showed that the subsurface drip irrigation method significantly excels the surface one, in biomass production and other economic results

The effect of an intelligent surface drip irrigation method on sorghum biomass, energy and water savings

Over the last few decades, precipitation has decreased as a result of climate change. This change increases crop water requirements, while irrigation water is wasted because of improper irrigation scheduling. Soil moisture sensors could be used to improve irrigation scheduling and save both water and energy. The objective was to study the energy and water savings, and the gross margin achieved, when using an intelligent surface drip irrigation method on sorghum bicolor (L.) Moench. In the years 2008 and 2009, a study was conducted at the farm of the University of Thessaly, Central Greece. A Class A evaporation pan and an automated frequency domain reflectometry soil moisture sensor were used for irrigation scheduling. Two treatments in four replications were organized in a randomized complete block design: (1) pan surface drip irrigation (PSDI100) and amount of water equal to 100 % of the daily evapotranspiration (ETd), as determined by a Class A evaporation pan, and (2) automated surface drip irrigation (ASDI100) and amount of water equal to 100 % of the ETd, as determined by an automated soil moisture sensor. The mean dry biomass production and the gross margin were greater in the PSDI100 treatment. The fully automated treatment remained profitable despite the high first costs. The mean water saving was 12.5 %, while the mean energy saving was 12.4 %, and the irrigation water-use efficiency was higher in the ASDI100 treatment

Assessment of water requirements of crops for the reuse of municipal wastewaters from the wastewater treatment plant at Patras, Greece

The possibilities of reuse, for irrigation, of the treated wastewaters produced in the biological wastewater treatment plant at Patras, Greece, have been examined. The practice of water reuse in soils, and cultivation, releases large amounts of water that are very useful to areas that face water shortage; it also contributes to the protection of the water ecosystem. The suggested safe reuse in seaside Mediterranean cities such as Patras will be the commencement of irrigation with treated wastewaters in other cities where there are areas with important primary production

Design of optimal irrigation networks

The problem of selecting the best pattern of pipe diameters of an irrigation network has long been given considerable attention by engineers when designing hydraulic works. The classical optimization techniques, which have been proposed until now, are the following: (1) the linear programming method; (2) the nonlinear programming method; (3) the dynamic programming method; and (4) Labye's method. Mathematical research of the problem, using the previous methods, is very complex, and for this reason the numerical solution calls for a lot of calculations, especially in the case of a network with many branches. In this study, the formulation of a new simplified nonlinear programming method is presented, which can replace the existing ones with the best results. A comparative evaluation between the proposed simplified method and the general nonlinear programming method in a particular irrigation network is also developed. The results of the proposed simplified method are fully identical with the results of the nonlinear programming method. Consequently, this method can be equally used for the classical methods. Copyright (c) 2006 John Wiley & Sons, Ltd

Potential and planning to reuse municipal wastewater for the irrigation of vinicultures in Attica, Greece

The investigation of the reuse potential of liquid urban wastes from Wastewater Treatment Plants (WWTPs) for the irrigation of vinicultures is a new technique in Greece. It requires holistic planning, which will take into account all the parameters related to the WWTPs operation, as well as the geological, soil and hydrological characteristics of the area, the microclimate, and the wastewater quality in terms of chemical and microbiological composition. Finally, it will take into account all the equivalent quality characteristics of the soils and the vinicultures, for the successful and safe reuse of the wastewaters. This holistic reuse planning will substantially contribute to the protection of the environment, and to irrigated viniculture's expansion in the east of Attica, since grapevine culturing is a single-crop farming in the wider area

Comparative calculation of irrigation networks using Labye's method, the linear programming method and a simplified nonlinear method

The designating factors in the design of branched irrigation networks are the cost of pipes and the cost of pumping. They both depend directly on the hydraulic pump head. It is mandatory for this reason to calculate the optimal pump head as well as the corresponding economic pipe diameters, in order the minimal total cost of the irrigation network to be produced. The classical optimization techniques, which have been proposed so long, are the following: the linear programming optimization method, the nonlinear programming optimization method, the dynamic programming optimization method and Labye's method. The mathematical research of the problem using the above classical optimization techniques is very complex and the numerical solution calls for a lot of calculations, especially in the case of a network with many branches. For this reason, many researchers have developed simplified calculation methods with satisfactory results and with less calculation time needed. A simplified nonlinear optimization method has been developed at the Aristotle University of Thessaloniki - Greece by M. Theocharis. The required calculating procedure is much shorter when using Theocharis' simplified method than when using the classic optimization methods, because Theocharis' method requires only a handheld calculator and just a few numerical calculations. In this paper a comparative calculation of the pump optimal head as well as the corresponded economic pipe diameters, using: (a) Labye's optimization method, (b) the linear programming optimization method and (c) Theocharis' simplified nonlinear programming method is presented. Application and comparative evaluation in a particular irrigation network is also developed. From the study it is concluded that Theocharis' simplified method can be equally used with the classical methods. (C) 2009 Elsevier Ltd. All rights reserved

Systematic reuse potential of wastewater effluents for soils and agriculture obtained from the biological treatment plant of Agrinion, Greece

The reuse of biologically treated municipal wastewater effluents on soils and in agriculture requires the development of a comprehensive plan, which must take into consideration all the parameters relative to the operation of the plant, the physical characteristics of the area, the microclimate, the qualitative characteristics of the effluents in terms of their physical, chemical and microbiological behaviour, and which plan will finally examine the corresponding qualitative characteristics of the soils and cultivations with regard to the question of safe effluent reuse. Such planned reuse will contribute significantly towards the protection of the environment in the extension of irrigated cultivations, and in the development of greeneries in areas with marginal soils. It is conceivable that such a plan could be incorporated into a broader, much needed effort for the development of green areas in major cities as it would resolve the otherwise problematic irrigation of plants and trees according to their water needs