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

Effectiveness of Three Terminating Products on Reducing the Residual Moisture in Dwarf Castor Plants: A Preliminary Study of Direct Mechanical Harvesting in Central Greece

The contribution of castor oil for reaching the targets set by RED1 and RED2 in Europe can be tangible if the problem related to the mechanical harvesting is overcome. Dwarf hybrids suitable for mechanical harvesting are already available on the market but the residual moisture of plants and capsules has to be lowered in order to allow mechanization. In the present case of study, three common terminating products (Glyphosate GLY, Diquat DIQ and Spotlight DEF) were tested on Kaiima C1012 hybrid in a complete randomized block design to assess the effectiveness of using chemical products to decrease residual moisture in castor plants. Plants were harvested via combine harvester equipped with cereal header to evaluate seed loss (due to dehiscence, impact and cleaning shoe) and the dehulling capacity of the combine harvester’s cleaning shoe. DIQ decreased significantly moisture content of capsules (7.32%) in comparison to the other treatments, while the lowest plant moisture was recorded in DIQ (62.38%) and GLY (59.12%). The use of DIQ triggered the highest impact seed loss (61.75%) in comparison with GLY (46.50%) and DEF (29.02%). Control plants could not be harvested mechanically due to the high residual moisture content and high density of weeds. The present case of study provides highlights regarding the need to further investigate the best practice to terminate castor plants and to develop a specific combine header to reduce seed loss from impact. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Monitoring Chemical-Induced Ripening of Castor (Ricinus communis L.) by UAS-Based Remote Sensing

Castor is a crop with an evergreen habit so artificially-induced ripening is an essential precondition for mechanical harvesting of new dwarf annual hybrids. Plants’ moisture imposes a determinant effect both on pre-harvest and post-harvest seed loss, so frequent monitoring of crop ripening is crucial for identifying the optimum moisture for harvest. Remote sensing information from Unmanned Aerial Systems (UASs) along with field measurements were utilized in the present study in order to evaluate three harvest aid chemicals, herbicides glyphosate (GLY) and diquat (DIQ) and the defoliant Spotlight® (DEF) for terminating the castor crop and identifying opportunities for using remote sensing as a tool for monitoring crop ripening. The results showed that glyphosate required more than two weeks to dry out the crop while diquat and spotlight® presented a rapid action within two to four days. Nineteen vegetation indexes (VIs) were derived from a multispectral and an RGB camera mounted on two UAS and were plotted against field measurements. NDVI presented a higher accuracy (R2 = 0.67) for predicting the castor stems’ and leaves’ moisture content while OSAVI and SIPI2 were more powerful in predicting moisture of capsules (R2 > 0.76). High efficiency was also obtained with VARIgreen, an index estimated from the common bands of a conventional RGB camera. The best performing VIs were further utilized in multiple linear regression models also incorporating the date of spraying as information. The VI models further improved the predicting power with an R2 of up to 0.73 for stems and leaves and 0.81 for capsules. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

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

MONITORING CASTOR BEANS MATURITY VIA REMOTE SENSING

Castor is a crop with an evergreen habit so artificial induced ripening is an essential precondition for mechanical harvesting of new dwarf annual hybrids. Plants water content impose a determinant effect both on preharvest and post-harvest seed losses so frequent monitoring of crop ripening is crucial for identifying the optimum moisture for harvest. Remote sense information from Unmanned Aerial Systems (UASs) along with field measurements were utilized in the present study in order to evaluate three harvest aid chemicals, herbicides glyphosate (GLY) and diquat (DIQ) and the defoliant Spotlight® (DEF) for terminating the castor crop and identify opportunities of using remote sensing as a tool for monitoring crop ripening. The scope of the present work was to evaluate the effects of alternative harvest aids in terminating the castor crop through field measurements and UAS remote sensing and investigate the opportunities of using UAS remote sensing as a tool for monitoring crop ripening and scheduling mechanical harvest. The results showed that glyphosate required more than two weeks to dry out the crop while diquat and spotlight® presented a rapid action within two to four days. Nineteen vegetation indexes were extracted from a multispectral and an RGB camera mounted on two UAS and were plotted against field measurements. NDVI presented the higher accuracy (R2=0.67) for predicting the castor stems and leaves moisture content while OSAVI and SIPI2 where more powerful in predicting moisture of capsules (R2>0.76). High efficiency was also obtained with VAR(green) an index estimated from the common bands of a conventional RGB camera. © 2022, ETA-Florence Renewable Energies., All rights reserved

CASTOR BEAN MECHANICAL HARVESTING: CROP TERMINATION AND COMPARISON BETWEEN CEREAL AND SUNFLOWER HEADERS’ PERFORMANCE INSTALLED ON A CONVENTIONAL COMBINE HARVESTER

Among the species currently cultivated for industrial vegetable oil production, castor bean (Ricinus communis, L.) could be a good candidate for future investments due to the good resistance to pests, tolerance to drought, and suitability for marginal lands cultivation. However, the mechanization is still not properly developed and high seed loss is experienced during the harvesting mainly due to the impact of the header on the plants. In the present study, the suitability of conventional combine harvester equipped with sunflower and cereal header was investigated by testing performance, seed loss from impact (ISL) and cleaning systems (CSL), and related cost. The effective seed quantity harvested by using both sunflower and cereal header was 92% w/w and 86% w/w of potential seed yield, respectively. This significant difference is due to the lower ISL associated with sunflower header which relies on different cutting system. On the other hand, the use of different headers did not affect significantly the cleaning of the seeds which averaged at 20% of the total seeds collected in both cases. In conclusion, the study highlights that a conventional combine harvester equipped with a sunflower performs well and the sunflower header could be the starting point for developing ad-hoc header specifically designed for castor beans harvesting. © 2022, ETA-Florence Renewable Energies., All rights reserved

Using Post-Emergence Herbicides in Combination with the Sowing Date to Suppress Sinapis arvensis and Silybum marianum in Durum Wheat

Wild mustard (Sinapis arvensis L.) and milk thistle (Silybum marianum (L.) Gaertn.) are two competitive broad-leaved weeds commonly found in cereals in Europe, while several weed species have developed resistance to the main herbicides that are applied on these crops. Thus, the implementation of integrated weed management (IWM) programs is of great importance. Field experiments were conducted based on a split-plot design with two factors (sowing date and herbicides). Our results showed that the density of wild mustard and milk thistle was higher in the early sowing compared to the late sowing, while the total weed density was up to 75% higher in early sowing. Moreover, the herbicides florasulam + 2.4-D and bromoxynil + 2.4-D exhibited high efficacy (>98%) against milk thistle and wild mustard, while tribenuron-methyl and florasulam + clopyralid provided greater efficacy in the late sowing compared to the early sowing. Among the four herbicides, the lowest dry biomass and grain yield of wheat were observed in tribenuron-methyl and florasulam + clopyralid, while in the weed-infested treatment, the highest values of both parameters were recorded in late sowing. Finally, the results showed that the sowing date is a cultural weed control method that should be implemented in IWM programs, since it can affect both weed density and herbicide efficacy. © 2022 by the authors