HighlightsPrior and post-knowledge surveys showed that students had varied knowledge levels in the course topics. Knowledge gains were higher for the course topics with lower prior knowledge scores. Knowledge surveys can be used to adapt to the needs of the students in real-time, improve instructional material, identify effective teaching methods, and modify the course. Abstract. Precision agriculture technologies offer several benefits, and most important among them are higher farm profits and improved environmental health. The quality of precision agriculture education is one of the main barriers to the adoption of these technologies. There are studies documenting the development of precision agriculture technology courses for the world regions with higher levels of adoption. However, there are limited studies for the world regions typically characterized by lower adoption of these technologies. This study attempts to develop and teach a precision agriculture technology course for such a world region Puerto Rico, a U.S. territory. This study also consisted of collecting and analyzing the pre- and post-knowledge levels of the students attending the developed course. Using the procedure for calculation of overall grade point average, the knowledge score for each course topic was calculated from all the pre- or post-survey responses for the course topic. Additionally, the knowledge gain for each course topic was calculated by subtracting the prior knowledge score from the post knowledge score of the course topic. The results indicated that knowledge gains were higher for the course topics with the lower prior knowledge scores and were lower for the course topics with the higher prior knowledge scores. The study indicates that a prior knowledge survey can be used to adapt to the needs of the students in real-time. Likewise, a post-knowledge survey can be used to improve instructional material, identify suitable teaching methods, and modify the course. World regions with limited adoption of precision agriculture technology may begin with a precision agriculture technology course without laboratory exercises, and later add laboratory exercises as equipment becomes available and adoption level increases. Keywords: Agricultural and environmental systems, Course development, Curriculum, Precision agriculture technologies, Student assessment

Unmanned aerial vehicles (UAVs) or drones are being studied for many agricultural applications. One application is plant phenotyping to reduce the time and effort required in collecting field data. This study aims to explore the use of a UAV, 4K-color camera and a commercial image analysis service to measure citrus plant parameters that are important to a crop scientist or grower with limited technical background and resources. Citrus spp. are important crops in Puerto Rico and the United States. Currently, the citrus industry is struggling to contain the devastating effects of citrus greening or Huanglongbing disease. The disease is associated with a phloem-limited bacteria, Candidatus Liberibacter asiaticus (CLAs), vectored by the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. The use of insecticides for vector control is the primary strategy used in nurseries and orchards. However, once the citrus plant is infected, there is no effective control available for the disease. In Puerto Rico this disease has reduced Citrus spp. yields by more than 50%; studies are underway to find effective control measures such as supplemental nutrients, vector management practices, planting disease-free vegetative material and protective screen structures. An experiment at the Fortuna Agricultural Experiment Substation, in Juana Díaz, Puerto Rico, was conducted to address the challenges posed by citrus greening. The experiment was established in a four-year-old grove of Tahiti lime (Citrus latifolia Tan.) on Cleopatra mandarin (Citrus reshni hort. ex Tanaka), naturally infected with Candidatus Liberibacter asiaticus. The experiment was arranged in a randomized complete block design with four replicates and three treatments: supplemental nutrients, supplemental nutrients + salicylic acid, and granular fertilization. Tree growth parameters were measured, and laboratory analyses were carried out to determine nutrient levels and disease severity levels from the leaf samples. The color camera, on board the UAV, was employed to acquire images of the experimental plot. Drone Deploy application was used for planning the UAV flights and image analysis. Field-measured plant height and canopy diameter compared well with the parameters determined from the color images. The average errors in measuring canopy diameter (14.5%) and plant height (22.4%) could be considered within an acceptable range, especially for comparing different treatments or crop varieties. However, the average errors in measuring canopy volume (47.5%) were high and can be considered unacceptable. It appears that the assumed conical shape of the trees could be one of the main reasons, besides the algorithms used in calculating plant volume, and built-in inaccuracies of the single frequency GPS (global positioning system) used in estimating altitude. Further studies could help in reducing errors and exploring other applications. The method used can be of importance in evaluating fruit trees.

This study compared energy consumption during harvest of Miscanthus Giganteus with a New Holland H8080 mower-conditioner among three cutting blade designs being 1) straight, 2) straight, angled at 30 degrees and 3) serrated. Square bales were produced by a New Holland BB9080 large square baler. To calculate energy consumption per unit crop mass in MJ Mg-1, bales of known mass were identified, and the cutting energy to produce this bale was calculated by accumulating the mower-conditioner's energy consumption across the collection area associated with that bale. Energy consumption was also expressed as a Percentage of Inherent Heating Value (PIHV), where energy consumption was divided by the heating value of Miscanthus Giganteus (17.7 GJ Mg-1). Average energy requirement for the whole machine were 12.31 MJ Mg-1 (0.070 PIHV), 11.31 MJ Mg-1 (0.064 PIHV), and 9.27 MJ Mg-1 (0.052 PIHV) for straight, angled and serrated blades respectively. Average energy requirements for the header were 9.50 MJ Mg-1 (0.054 PIHV), 8.32 MJ Mg-1 (0.047 PIHV), and 7.20 MJ Mg-1 (0.041 PIHV) for straight, angled and serrated blades respectively. Average energy requirements for traction were 0.96 MJ Mg-1 (0.005 PIHV), 1.21 MJ Mg-1 (0.007 PIHV), and 1.04 MJ Mg-1 (0.006 PIHV) for straight, angled and serrated blades respectively. The theoretical field capacity increased from straight blades at 1.35 ha h(-1) to angled blades at 1.52 ha h(-1) to serrated blades at 2.23 ha h(-1). Evidently, the design of cutting blades had a significant effect on energy consumption and field performance of biomass harvesting equipment.

Improving harvesting efficiencies and logistics is one of the challenges sugarcane farmers face. CAN bus and GPS data were recorded while harvesting with a 3520 John Deere sugarcane harvester. Algorithms were developed to identify machine states from the recorded data. Three machine states: cutting, turning and stopped were identified from the data recorded in five sugarcane plots in Florida. Time spent in the cutting state varied from 46 to 76%, in the turning state from 8 to 17%, and in the stopped state from 9 to 38%. Up to 20-30% improvements in field efficiencies is possible by implementing the insights learned from the analysis of data collected from sugarcane harvesters.

Biomass harvesting, achieved through a combination of mowing and baling operations, constitutes a significant portion of biomass provision costs. The spatial variations in biomass yield lead to the challenge of achieving high harvesting efficiency. This study quantifies the impact of harvesting operations on Miscanthus provision costs through the integration of in-field harvesting performance data and systems-level BioFeed optimization modeling. The in-field experimental results showed that biomass harvesting throughput is highly dependent on biomass yield and machinery performance, such as operating speed. By incorporating these experimental results, the BioFeed optimization modeling analysis showed that Miscanthus provision costs varied with different operating speeds. With the adoption of real-time sensing and control technologies, the biomass harvesting rate associated with mowing and baling operations could be increased and maintained subject to a maximum throughput rate for the machine. The increase in operating throughput could reduce Miscanthus provision costs from $69.8 to $62.7 Mg -1 for a farm study in Champaign, Illinois. Given optimal machinery management supported by a sensing system, the optimization model was applied to estimate county-level Miscanthus provision costs to quantify the impact of biomass yield changes and farm size. The results showed that Miscanthus provision costs decrease with higher yield and larger farm size, ranging from $49 to $82 Mg -1 for 30 counties in Illinois.

Lignocellulosic biomass in bale form has a low bulk density. Current in-field balers can achieve a bulk density of merely 120 to 180 kg dry matter (DM) m−3, whereas modern high-compression cutting balers produce up to 230 kg m−3. Mechanical compression is a straightforward technique to increase the material density, which significantly improves the efficiency of transportation and storage, and simplifies handling. Traditional compression technology mainly produces pellets, but conceivably bales could be compressed to a higher density as well. To design compression machinery in general, it is essential to determine the mechanical properties of biomass under compression and compression energy consumption. In addition, the material rebound percentage after compression is needed to design low-cost containerization methods for highly compressed bales. In this research, we established pressure–bulk density relationships and calculated Poisson’s ratio for Miscanthus (Miscanthus × giganteus, Poaceae/Gramineae) and switchgrass (Panicum virgatum L. Poacea/Gramineae). We also calculated rebound percentages for Miscanthus in two particle sizes. The results showed that the energy consumption for compression of Miscanthus and switchgrass is low, ranging from 0.01 to 0.05 % of the inherent heating value of the materials. Poisson’s ratios of Miscanthus and switchgrass ranged from 0.2 to 0.3 for various particle sizes. The rebound percentage was found as 28 % for unground Miscanthus and 23 % for Miscanthus ground to 6.35-mm particles. A common opinion is that high-level compression of biomass may reduce its energy content. Although in this research some of the biomass was exposed to an extreme pressure of 750 MPa, microscopic imagery revealed no fractions in the cell walls, leading to the conjecture that compression does not negatively impact the conversion potential of the biomass.

Energycane is emerging as a candidate bioenergy crop, and it resembles sugarcane in stature and cultivation practices. Preliminary trials indicated that sugarcane billet harvesters have insufficient power to harvest energycane. This study quantified the power requirements of selected harvester components and field performance of harvesters for sugarcane and energycane. The elevator pour rate for energycane was lower (43.3 Mg h(-1), wet weight) than for sugarcane (132.7 Mg h(-1), wet weight). At the observed pour rates, power consumption of the basecutter, elevator, and the entire harvester was comparable for energycane and sugarcane. However, the power requirements of the chopper were 1.65 times higher for energycane than for sugarcane. Greater stem damage and higher stubble heights were observed for energycane compared to sugarcane. Overflowing of the elevator was observed for energycane because of lower bulk density of the biomass (billets and trash, 143.8 kg m(-3)) compared to sugarcane (predominantly billets, 349.4 kg m(-3)). The field capacity of the harvester for energycane (0.32 ha h(-1)) was lower than for sugarcane (0.61 ha h(-1)), and the harvesting cost for energycane (5.91 $ Mg-1) was considerably higher than for sugarcane (1.87 $ Mg-1). Design modifications to the existing sugarcane harvester models would be needed to adapt them to harvest energycane. (C) 2015 Elsevier Ltd. All rights reserved.

This paper summarizes research at Oklahoma State University (OSU) to develop innovative technologies that provide solutions to issues and problems affecting pecan production and processing. Some of the projects areas include; Pecan yield estimation technique using backscattered terrestrial microwave sensing. Dielectric spectroscopy for estimating quality of in-shell pecans. Wireless image sensor networks in estimating the population of pecan weevils. Low-cost small-scale sanitizer for in-shell pecans. Optical sensors and algorithms that adequately predict plant N status for nitrogen management. X-ray machine vision inspection systems for pecan defect identification. Accurate estimates of pecans in the field prior to harvest are critically important for production management decisions and marketing. Pecan producers, processors and marketers identified improved accuracy of crop estimates as a research priority for the industry. The pecan weevil (Curculio caryae) is considered a key pest. Without timely insecticide treatments, crop losses can exceed 75%. Research has focused on the design of a wireless sensor network for real-time monitoring and population estimation of pecan weevils. Nitrogen (N) has become a major cost in producing pecans. Traditionally, N is applied once or twice per season. Application rates usually exceed the minimum N requirement for optimum production. Research has focused on reducing N inputs while maintaining production levels. Sorting of defective nuts is difficult because nutmeat defects are not fully recognizable by physical properties, color and appearance of whole unshelled nuts. Commercial sorters are available to sort nutmeat after shelling the nuts, but this results in unnecessary shelling of defective nuts. Development of automated inspection systems to identify good pecan nuts from defective ones before shelling would reduce processing costs. Due to space limitations, only the highlights of each research area will be presented. Interested readers desiring more comprehensive discussion of the projects are encouraged to access the references.

Miscanthus is emerging as a potential bioenergy crop because of its high yield and ability to reduce greenhouse gas emissions. However, there is a lack of data on harvesting machinery performance for the USA conditions, and influence of yield on harvesting cost and fuel consumption. This study quantified performance of a mower-conditioner and a large square baler for Illinois conditions, and investigated influence of yield on fuel consumption and harvesting costs. To calculate performance parameters, a field area was segmented from which a bale was formed. Then in the segmented field area, yield and machine performance parameters were determined. The mower-conditioner's field capacity was 1.8 ha h(-1), and diesel consumption was 19.2 L ha(-1). The baler's field capacity was 1.4 ha h(-1), and diesel consumption was 19.7 L ha(-1). The mowing cost was 4.8 $ Mg-1, and baling cost was 6.8 $ Mg-1. An inverse correlation (R-2 = 0.62) was found between miscanthus yield and harvesting cost ($ Mg-1), and a direct correlation (R-2 = 0.67) was found between miscanthus yield and fuel consumption (L ha(-1)). It is expected that this study would help in more accurate assessment of environmental impact and economic feasibility of miscanthus, and may lead to further studies for quantifying crop yield and machine performance interactions. (c) 2015 Elsevier Ltd. All rights reserved.

Energycane is a promising bioenergy crop for warm south-eastern US regions and existing sugarcane machinery is being adapted for energycane cultivation. Because of energycane's comparatively higher fibre content and smaller stem diameters, the cutting blades must be optimized for energycane harvesting and size reduction. To optimize cutting blade designs, this study investigated the effect of cutting speed and blade oblique angle on cutting energy. An impact type cutting mechanism was used to determine the cutting energy cost of individual stems. The results showed that the specific cutting energy increases with cutting speed. The lowest average specific energy was 0.26 J mm(-1) for a 60 degrees oblique cut at an average cutting speed of 7.9 m s(-1), whereas the highest average specific cutting energy was 1.24 J mm(-1) for a straight cut at an average cutting speed of 16.4 m s(-1). The specific cutting energy showed a close correlation with stem diameter and stem cross-sectional area. For a 30 degrees oblique angle at 11.3 m s(-1) average cutting speed, the cutting energy varied from 4.5 to 15 J as the energycane stem diameter varied from 11 to 17 mm. Comparisons with sugarcane studies indicated that optimisation of cutting speed and blade oblique angle can result in significant savings in cutting energy, whilst simultaneously improving the quality of cut. This study emphasises the need for further investigation of the energycane cutting process especially at higher cutting speeds with cutting devices with varying moments of inertia. (C) 2015 IAgrE. Published by Elsevier Ltd. All rights reserved.

Napiergrass, which resembles sugarcane in stature and cultivation practices, is emerging as a candidate bioenergy crop. However, limited studies investigating harvesting and yield sensing of napiergrass are available. This study investigated stem-bending force, and the hydraulic pressures of basecutter, chopper and elevator drives in a John Deere 3522 sugarcane billet harvester as indicators of napiergrass yield. The coefficients of determination (R2) between napiergrass yield and hydraulic pressures were 0.73, 0.88 and 0.81, respectively for the basecutter, chopper and elevator drives. The highest correlation (R2=0.92) was found between stem-bending force and napiergrass yield. The yield prediction errors were 4.9% and 8.6% for the calibration and validation plots with the stem-bending force yield sensor. Cross-validation, in which each harvested row was treated as a data point, showed that the average yield prediction errors were 10.9% and 11.8% for the calibration and validation data sets. Yield maps were also generated employing the stem-bending yield sensor. In addition, it was expected that the stem-bending yield sensor could be utilized to control harvester operation such as travel speed. Further studies would be needed to extend the stem-bending concept to other thick stemmed crops.

One of the reasons for relatively high biomass harvesting cost is challenges in adjusting the ground speed of harvesting machines with respect to the yield level within a field A real-time biomass yield sensor that can predict the yield in front of a machine could be a useful tool to control ground speed. It was hypothesized that the force required to bend Miscanthus stems is a reliable predictor of biomass yield. Based on this novel concept, a stem bending force-sensing system was developed and field tested with a disk mower-conditioner A bale-specific method, segmenting the field area from which a bale was formed, was developed to correlate sensed bending force and Miscanthus yield The measured bending force showed a logarithmic relationship (R-2 = 0.80) with Miscanthus yield The average error in predicting bale-specific yield was 10.3% for training data and 12.9% for validation data. The average error in predicting plot yield was 3.4% for training plots and 10.0% for validation plots. Using the developed logarithmic correlation model, yield maps were also generated For the specific case analyzed, a proper control strategy to maximize throughput rate (mass per unit time) would be to either operate the mower-conditioner at the maximum feasible ground speed (9 km h(-1)) or at the maximum achievable throughput rate (60 Mg h(-1)). The yield-sensor controlled machine would result in 44.2% higher field capacity, 41.3% higher throughput rate, and 31.2% lower mowing-conditioning cost for the specific case analyzed compared to the operator-controlled machine. Studies are needed to extend the stem bending force-sensing concept to other thick-stemmed crop harvesting machines, such as sugarcane harvesters and coppice harvesters.

Previous studies have shown that cutting speed and blade configurations play a critical role in crop harvesting. This study investigated the effect of cutting speed, blade oblique angle, and blade mounting in afield setting. To investigate their effect on Miscanthus harvesting power consumption, a hydraulically-driven single disk cutter head platform was developed. It has the provisions to adjust cutting parameters and was instrumented to measure the bending force on a push bar, torque, and cutting speed of the disk cutter. The cutting energy was determined at three oblique angles (0 degrees, 30 degrees, 40 degrees), two blade mountings (fixed, flexible), and three hydraulic flow settings to drive the developed platform. Three hydraulic flow settings were used that resulted in average recorded cutting speeds of 31.5, 47.3, and 63.0 m s(-1). The differences between the blade mountings were found to be negligible. A 40 degrees oblique angle operating at 31.5 m had the lowest energy consumption, averaging 9.1 MJ ha(-1). Similarly, a 30 degrees oblique angle consumed 16.9 MJ ha(-1) and a straight blade consumed 23.1 MJ ha(-1). The results indicate that the cutting speed and blade oblique angle are directly related to the power requirements and efficiency of Miscanthus harvesting machinery. Information about the bending force of the Miscanthus was also collected and compared to the energy consumption of the machine. The data show that the energy consumption was correlated to the bending force. It is expected that the results of this study would help in modifying existing Miscanthus harvesters.

The cost of harvesting is one of the constraints in improving biofuel economics. Adjusting the ground speed of harvesting machines to maximize their throughput rate in relation to yield level is one of the ways to reduce harvesting cost. To control the ground speed of a baler, a real-time sensor that can predict the swathed-biomass yield in front of the baler would be an invaluable tool. It was hypothesized that the swathed-biomass volume is a reliable predictor of the swathed-biomass yield. A light detection and ranging (LIDAR) based sensing system was developed to sense swathed-biomass volume and was field tested. To correlate the sensed swathed-biomass volume with the Miscanthus yield, a new bale-specific method was developed. A linear correlation (R-2 = 0.76) was found between Miscanthus yield and sensed swathed-biomass volume at the time of mowing-conditioning. Yield maps were generated using the developed correlation model. The model was also used to predict the harvested plot biomass. The average percent error in predicting the harvested plot biomass was 12.4% for training plots and 10.1% for validation plots. The analysis revealed that a proper control strategy to maximize the baler throughput rate would be to either operate the large square baler at the maximum feasible ground speed (6 km h(-1)) or at the maximum achievable throughput rate (35 Mg h(-1)). For the specific case analyzed, the proposed control strategy would result in the following advantages: 38.0% higher field capacity, 35.6% higher throughput rate, and 30.4% lower baling cost. Further studies and field evaluation of the proposed control strategy are needed. Studies are also needed to extend the swathed-biomass volume sensing concept to corn stover, other energy grasses, and forage crops.

Terahertz (THz) rays interact with materials at intermolecular levels, and because of this they are the focus of many active research areas. The developments in THz technology were hindered by lack of hardware, but the advent of the femtosecond laser in the 1980s started the advancement in THz generation and detection technologies. THz technology is transitioning from laboratory scale to many practical applications, including security screening, pharmaceuticals, plastics, and others, but there are few studies pertaining to food and agricultural applications. This study reviews the articles related to food and agriculture applications of THz spectroscopy and THz imaging. It also briefly introduces important THz techniques. The survey of the literature reveals great potential for this emerging and promising technology in agriculture. Food inspection, crop inspection, and material characterization could be potential research areas.

Biomass harvesting constitutes a significant portion of farm gate biomass cost and it also affects the delivered form and cost at the biorefinery. This study aims to analyze miscanthus supply logistics utilizing harvesting performance data collected over the last three years in Illinois. The experimental results showed that biomass provision efficiency is highly dependent on the biomass yield and machine operating performance. The Miscanthus harvesting and baling costs were further evaluated through the BioFeed model, a systems optimization model to analyze different biomass production operations that include harvesting, packing, storage, handling, and transportation. The modeling results showed that biomass harvesting and baling costs could be reduced with better management of machine operation. It is suggested that with the adoption of novel biomass sensing technology and machine control system, biomass harvesting and baling efficiency would be increased.

X-ray imaging studies in the food and agriculture sector were surveyed This survey of the literature revealed that x-ray hardware and software have improved considerably since 1990s, when digital x-ray imaging studies began. X-ray imaging has been extensively researched for food inspection. Additionally, there are studies utilizing x-rays to characterize plant and soil properties. Poor image contrast, due to similarity in the attenuation properties of an object and its background, pose a challenge in image segmentation. Development of local adaptive approaches has improved image segmentation and classification accuracies. Hardware developments have resulted in commercial-grade x-ray inspection systems. Future developments in x-ray generation and detection technologies, advances in image processing algorithms, and worldwide food safety concerns indicate increased opportunities for x-ray inspection in the food and agriculture sector.