Optimum Replacement Time for Cotton Pickers in Greece

In this paper an attempt has been made to determine the optimum replacement time for cotton pickers under the technical and economic conditions in Greece. For this purpose, five relevant methods have been applied to analyze real data taken by 62 cotton pickers working in Central Greece. Three of the methods consider that the optimum replacement time for cotton pickers is the year when the accumulated annual depreciation is equal to the corresponding repair and maintenance costs or the year when the aforementioned annual expenses of the machine per working hour are minimum. The fourth method considers the year in which the accumulated average total costs per working hour or per hectare harvested is minimum, while the fifth method refers to the year in which the accumulated annual “standardized†net income received from the use of a cotton picker is maximum. Based on the results of this study the optimum replacement time of a cotton picker is the 14th –15th year of its productive life combined with 4500 –5000 working hours and 1450 – 1550 hectares harvested.cotton pickers, optimum replacement time, costs, net income, Farm Management, Crop Production/Industries,

Law and Economics: Methodological Problems

Recent developments in economics and the science of law emphasize their cooperation for a better understanding of social structures and interactions, an effective application of social scientific knowledge and a rational evaluation and implementation of social norms. There are, however, difficult methodological problems in this project : Whereas economics is mainly (with the exception of welfare economics) an empirical science which collects information about economic activities and the functioning of the economic system, the science of law is a normative discipline aiming at solving social conflicts and establishing rational principles for judicial decisions. This paper elaborates on a three level-scheme for the interdisciplinary cooperation of law and economics addressing the different problems positive and normative economics face when applying economic knowledge on legal matters. The economic analysis of law is proposed as a model for a general transformation of the traditionally hermeneutical jurisprudence into an analytic – normative science of law based on theoretical explanation and rational evaluation of the consequences of legal rules and principles.

Evaluation of Four Conservation Tillage Methods in the Sugar Beet Crop

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 4 (2002): C.K. Cavalaris and T.A. Gemtos. Evaluation of Four Conservation Tillage Methods in the Sugar Beet Crop. Vol. IV. June 2002

Energy balance of sunflower production

ArticleThe aim of the present study was to make an energy analysis of sunflower crop in the Trakya Region of Turkey, to evaluate the potential for using it as bioenergy source. Actual data for the common cropping practices applied in the region were collected with questionnaires given to the farmers. Literature data were used to obtain necessary energy indices. The collected information was used to establish energy budgets. Two alternative scenarios were examined: 1st - Using only the seed for biofuel production and 2nd -using the seed for biofuel and the stalks as biomass for bioenergy. The results showed that sunflower presented positive energy balance for both cases. Net energy was 35,334 MJ ha-1 when only the seed was taken into account and 87,308 MJ ha-1 for both seed and stalks. Energy efficiency was 3.67 and 7.34 respectively. Fertilization was the most energy intensive input (6,594 MJ ha-1 ) accounting for 48–50% of the total inputs. Tillage was the second most energy intensive input (3,595 MJ ha-1 ) accounting for 26–27% of total inputs. There were 6 different tillage operations such as ploughing, 4 machinery passages for seedbed preparation and hoeing in the sunflower production. All these operations increased energy inputs of the tillage. The total energy inputs were relatively low because it was possible to achieve high yields without irrigation

Interrill Soil Erosion as Affected by Tillage Methods under Cotton in Greece

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 8 (2006): Interrill Soil Erosion as Affected by Tillage Methods under Cotton in Greece. Manuscript LW 05 006. Vol. VIII. February, 2006

Monitoring Sunflower and Maize Canopy Under Alternative Nitrogen Regimes with Lidar and Optical Sensors

Crop fertilization is an important part of cost and energy inputs in agriculture. The opportunity to apply the variable rate of nitrogen fertilizers according to the plant needs in each part of the field is a promising practice to increase the fertilizer use efficiency. An experiment was conducted in 2016 in the University of Thessaly farm, Central Greece in order to evaluate the use of lidar and optical sensors to monitor the crop canopy for sunflower and maize. The canopy development can serve as a good indicator for the nutrition state of the crops regarding especially the nitrogen, and it can be used as an indicator for variable rate application systems. In order to obtain plants with different canopy development, a field experiment was established with treatments receiving the normal, farmer's practice, nitrogen rates (100%N) at basic fertilization, treatments receiving 50% reduced nitrogen fertilizer (50%N) and treatments with no nitrogen application (0%N). During growing, the crop canopy was monitored with a lidar and an optical sensor. Manual measurements of plant height and weight were also made. The manual measurements revealed the effect of variable fertilizer rates to plant development. The plots with higher nitrogen rates had higher and more vigor plants. The lidar sensor depicted more clearly these differences compared to the optical sensor. Plant height was sufficiently assessed for both the sunflower and maize crop by lidar. Plant volume though was assessed only for the sunflower. A problem with the lidar sensor was the small sampling rate (almost 2Hz) but this can be compensated by its ability to scan simultaneously more than one crop rows (4 to 6) and obtain multiple sample information

Nitrogen replenishment using variable rate application technique in a small hand-harvested pear orchard

Precision agriculture is a management approach for sustainable agriculture. It can be applied even in small fields. It aims to optimize inputs, improve profits, and reduce adverse environmental impacts. In this study, a series of measurements were conducted over three growing seasons to assess variability in a 0.55 ha pear orchard located in central Greece. Soil ECa was measured using EM38 sensor, while soil samples were taken from a grid 17 × 8 m and analysed for texture, pH, P, K, Mg, CaCO3, and organic matter content. Data analysis indicated that most of the nutrients were at sufficient levels. Soil and yield maps showed considerable variability while fruit quality presented small variations across the orchard. Yield fluctuations were observed, possibly due to climatic conditions. Prescription maps were developed for nitrogen variable rate application (VRA) for two years based on the replacement of the nutrients removed by the crop. VRA application resulted in 56% and 50% reduction of N fertiliser compared to uniform application

Fossil Fuel Deficit-Conservation Tillage and on Farm Biofuel Production to Cope With the Problem

Abstract The limited resources of fossil fuels along with the highly fluctuating prices, call for investigation to find diesel alternatives. Biofuels from vegetable oils, seems the easiest accessible substitutes as they can be used in conventional diesel engines without lot of modifications. There are though two mainstream attitudes on this approach. The one points that it is immoral to divert environmental resources from food production to energy production when the global population increases and the other claims that without mechanization and fuel to power it, food production will finally be decreased. Conservation tillage adoption may contribute in significant fuel savings by eliminating tillage operations. If they would be combined with on farm biofuel production, they would certainly require less land to be devoted for this purpose. In the present work, based on data of a long term tillage experiment, it was calculated the percentage of land that would be required to cultivate with a biofuel crop (sunflower for instance) in order to cover the fuel requirements of an arable farm, for three alternative tillage methods: conventional (CT), reduced (RT) and no-tillage (NT). The results indicated that in CT, the 11% of the land would be enough to provide the biofuel for all the field operations (except irrigation). In RT, due to lower fuel consumption, the 7.5% of the land would be sufficient. That means that a 3.6% yield reduction is justified. In NT, only the 3.5% of the land is required to produce the biofuels justifying a 7.7% yield reduction. This sets the limits of yield reduction that can be acceptable. However we have to add in this balance the environmental effects of using conservation tillage like erosion reduction, increasing soil organic matter and biodiversity maintenance

Projections of the availability and cost of residues from agriculture and forestry

By-products of agricultural and forestry processes, known as residues, may act as a primary source of renewable energy. Studies assessing the availability of this resource offer little insight on the drivers and constraints of the available potential as well as the associated costs and how these may vary across scenarios. This study projects long-term global supply curves of the available potential using consistent scenarios of agriculture and forestry production, livestock production and fuel use from the spatially explicit integrated assessment model IMAGE. In the projections, residue production is related to agricultural and forestry production and intensification, and the limiting effect of ecological and alternative uses of residues are accounted for. Depending on the scenario, theoretical potential is projected to increase from approximately 120EJyr(-1) today to 140-170EJyr(-1) by 2100, coming mostly from agricultural production. To maintain ecological functions approximately 40% is required to remain in the field, and a further 20-30% is diverted towards alternative uses. Of the remaining potential (approximately 50EJyr(-1) in 2100), more than 90% is available at cost

Sugar Beet Root Properties in Relation to Harvesting Damage

Rosana G. Moreira, Editor-in-Chief; Texas A and M UniversityThis is a Technical article from International Commission of Agricultural Engineering (CIGR [Commission Internationale du Genie Rural] E-Journal Volume 1 (1999): (2) T.A. Gemtos. Sugar Beet Root Properties in Relation to Harvesting Damage