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

Energy analysis of three energy crops in Greece

To assess the potential of energy crops to provide a stock material for biofuel production three crops (rapeseed, sunflower and sweet sorghum) were studied in field experiments in Thessaly, Central Greece in 2007 and 2008. The cropping activities were recorded. Energy analysis was carried out to assess benefits from the crops. Power requirements and energy consumption during field operations were measured directly using instrumented tractors. Literature data was used for the energy sequestered to the inputs of the system (indirect energy). Energy budgets were produced taking into account as output either the seed or including the stalks for the two oil seed crops. The results showed that in all cases positive energy balances were achieved. Analysis of the inputs showed that energy for fertilizer was the most important for the rain fed rapeseed but irrigation for sunflower and sweet sorghum. Pumping depth of the irrigation water had a high impact on the energy inputs of the irrigated crops. The overall results gave maximum energy efficiency coefficients of 4.62 for rapeseed without the stalks and 10.68 with stalks, of 2.89 for sunflower without the stalks and 6.16 with stalks and 8.92 for sweet sorghum. An analysis of data from the literature was carried out to assess the effect of new technological developments to the energy sequestered to different inputs. Several developments are expected to improve energy efficiency coefficient, such as variable rate application of inputs, as well as properly designed crop rotations and use of cover crops

A five-point penetrometer with GPS for measuring soil compaction variability

Measuring soil compaction is a factor of interest to monitor soil fertility, which plays an important role in crop production cycle. Soil penetration resistance is the most commonly used method to measure soil compaction. It is fast and simple although it presents important limitations due to its close relationship with soil water content and the existence of high variability in the field, which requires increased number of samples that is effort demanding and time consuming. In this work, a fast and robust 5-point penetration resistance system was developed attached on the tractor three point hitch using load cells and combined with a GPS receiver. An ultrasonic sensor to monitor the penetrating depth was also attached. A software program using Microsoft Visual Basic was developed for data acquisition. Security pins and software alarm was added to secure the equipment safety when stones or soil harder than a limit was encountered. The system was successfully tested in an experimental field, where five tillage methods were studied, including no tillage. The results indicated the system's ability to recognize compacted soil layers and depict the spatial variability. (C) 2013 Elsevier B.V. All rights reserved