Realización de ensayos de experimentación en olivares ecológicos

El olivar es un cultivo de elevado interés social y económico en Andalucía. Actualmente se cultivan 1,5 Mha de olivar en la región, que representan un 60% del olivar español, y más del 30% de la superficie agraria útil de la comunidad

Assessment of the Accuracy of a Multi-Beam LED Scanner Sensor for Measuring Olive Canopies

MDPI. CC BYCanopy characterization has become important when trying to optimize any kind of agricultural operation in high-growing crops, such as olive. Many sensors and techniques have reported satisfactory results in these approaches and in this work a 2D laser scanner was explored for measuring canopy trees in real-time conditions. The sensor was tested in both laboratory and field conditions to check its accuracy, its cone width, and its ability to characterize olive canopies in situ. The sensor was mounted on a mast and tested in laboratory conditions to check: (i) its accuracy at different measurement distances; (ii) its measurement cone width with different reflectivity targets; and (iii) the influence of the target’s density on its accuracy. The field tests involved both isolated and hedgerow orchards, in which the measurements were taken manually and with the sensor. The canopy volume was estimated with a methodology consisting of revolving or extruding the canopy contour. The sensor showed high accuracy in the laboratory test, except for the measurements performed at 1.0 m distance, with 60 mm error (6%). Otherwise, error remained below 20 mm (1% relative error). The cone width depended on the target reflectivity. The accuracy decreased with the target density

Field sprayer for inter- and intra-row weed control: performance and labor savings

Studies of new tools and methods for weed control have been motivated by increased consumer demand for organic produce, consumer and regulatory demands for a reduction in environmentally harmful herbicide use, and the decreased availability of farm workers willing to perform manual tasks, such as hand weeding. This study describes the performance of a new sprayer system for commercial production that integrates two herbicide applications in a single pass, selective herbicide (SH) application in narrow bands over the crop row, and a non-selective herbicide (NSH) application between crop rows. A real-time kinematic (RTK) global positioning system (GPS) was used for auto-guidance in seeding and spraying operations. Conventional broadcast SHs and experimental treatments were applied at a constant nominal speed of 5.5 km h-1 for comparison. Trials in commercial sugar beet fields demonstrated the following: (i) average hand-weeding time can be reduced by 53% (ii) the new sprayer system reduced SH use by 76%, and (iii) sugar beet density did not change significantly during treatment. These results demonstrate the feasibility of using the new RTK-GPS controller sprayer system for differential and efficient herbicide application in inter- and intra-row zones in row crop production

An Approach to Precise Nitrogen Management Using Hand-Held Crop Sensor Measurements and Winter Wheat Yield Mapping in a Mediterranean Environment

Regardless of the crop production system, nutrients inputs must be controlled at or below a certain economic threshold to achieve an acceptable level of profitability. The use of management zones and variable-rate fertilizer applications is gaining popularity in precision agriculture. Many researchers have evaluated the application of final yield maps and geo-referenced geophysical measurements (e.g., apparent soil electrical conductivity-ECa) as a method of establishing relatively homogeneous management zones within the same plot. Yield estimation models based on crop conditions at certain growth stages, soil nutrient statuses, agronomic factors, moisture statuses, and weed/pest pressures are a primary goal in precision agriculture. This study attempted to achieve the following objectives: (1) to investigate the potential for predicting winter wheat yields using vegetation measurements (the Normalized Difference Vegetation Index—NDVI) at the beginning of the season, thereby allowing for a yield response to nitrogen (N) fertilizer; and (2) evaluate the feasibility of using inexpensive optical sensor measurements in a Mediterranean environment. A field experiment was conducted in two commercial wheat fields near Seville, in southwestern Spain. Yield data were collected at harvest using a yield monitoring system (RDS Ceres II-volumetric meter) installed on a combine. Wheat yield and NDVI values of 3498 ± 481 kg ha−1 and 0.67 ± 0.04 nm nm−1 (field 1) and 3221 ± 531 kg ha−1 and 0.68 ± 0.05 nm nm−1 (field 2) were obtained. In both fields, the yield and NDVI exhibited a strong Pearson correlation, with rxy = 0.64 and p < 10−4 in field 1 and rxy = 0.78 and p < 10−4 in field 2. The preliminary results indicate that hand-held crop sensor-based N management can be applied to wheat production in Spain and has the potential to increase agronomic N-use efficiency on a long-term basis

Development and assessment of a prototype as an innovative method for teaching agricultural machinery

An educational variable‐rate application (VRA) sprayer was developed and laboratory tested at the University of Seville (Spain). It was designed and built during 2009 by the undergraduate engineering students in a Precision Agriculture course and used as a teaching model in an Agricultural Machinery course during 2010. The first stage involved mounting all the instrumentation, sensors, and the hydraulic system on a metal platform. The second stage involved mounting a DGPS receiver, flowmeter, automated application control system, and all necessary electrical connections to the platform. Preliminary calibration tests of the equipment at a constant speed of 0.375 m s‐1 (1.35 km h‐1) showed good performance for pressure (kPa) and application rate (L ha‐1) (R2 = 0.998, p < 0.001). To evaluate the teaching method based on the prototype, a short‐answer assessment test was conducted consisting of ten multiple‐choice questions, each with one possible correct answer. Data were analyzed using analysis of variance (ANOVA). The factors were the teaching method (TM), repeated course (R), and attended theory (AT). In addition, the effect of a covariate (number of times a student repeated the course) in the factors was controlled with an analysis of covariance (ANCOVA). The effect of teaching method was significant for the score on the VRA sprayer questions (SPS) variable and the score on the conventional sprayer questions (SCS) variable (p < 0.001 for both). The average success for students using the prototype sprayer was 86%, compared to 60% for those using a conventional sprayer. The total cost of the VRA prototype sprayer was 40% less than the cost of retrofitting a conventional sprayer with precision agriculture equipment. Since the students were engaged in their own learning, they maintained a high level of enthusiasm throughout the course when utilizing the VRA prototype sprayer. It has proved to be a complementary and beneficial alternative for improving the students' education in the Agricultural Machinery course

In-Field Estimation of Orange Number and Size by 3D Laser Scanning

The estimation of fruit load of an orchard prior to harvest is useful for planning harvest logistics and trading decisions. The manual fruit counting and the determination of the harvesting capacity of the field results are expensive and time-consuming. The automatic counting of fruits and their geometry characterization with 3D LiDAR models can be an interesting alternative. Field research has been conducted in the province of Cordoba (Southern Spain) on 24 ‘Salustiana’ variety orange trees—Citrus sinensis (L.) Osbeck—(12 were pruned and 12 unpruned). Harvest size and the number of each fruit were registered. Likewise, the unitary weight of the fruits and their diameter were determined (N = 160). The orange trees were also modelled with 3D LiDAR with colour capture for their subsequent segmentation and fruit detection by using a K-means algorithm. In the case of pruned trees, a significant regression was obtained between the real and modelled fruit number (R2 = 0.63, p = 0.01). The opposite case occurred in the unpruned ones (p = 0.18) due to a leaf occlusion problem. The mean diameters proportioned by the algorithm (72.15 ± 22.62 mm) did not present significant differences (p = 0.35) with the ones measured on fruits (72.68 ± 5.728 mm). Even though the use of 3D LiDAR scans is time-consuming, the harvest size estimation obtained in this research is very accurate

Assessment of Spray Deposit and Loss in Traditional and Intensive Olive Orchards with Conventional and Crop-Adapted Sprayers

Plant protection product (PPP) applications to isolated olive trees are commonly performed with regular air-assisted sprayers, which are not adapted to their particular characteristics. Whilst strong efforts have been undertaken over the last years to improve technical aspects like canopy detection and automated proportional dosing, nearly no efforts have been made regarding the sprayer adaption to the crop. For this reason, three prototype sprayers were developed for traditional and intensive olive cultivations systems (P1: centrifugal fan; P2: six small side axial fans; P3: two axial fans in tower structure) with the purpose to improve the application efficiency. The main goal of the present study was to check spray quality and efficiency in comparison with the conventional sprayer in both cultivation systems. The sprayers were tested in two different olive groves and properly calibrated according to the tree dimensions. The spray deposition, coverage, drift, and losses to the ground were measured in five trees per cultivation system by placing the appropriate collectors. The sprayers performed very differently in both cultivation systems. In the intensive system, the spray deposition did not present significant differences (p = 0.105). However, it did in the traditional system (p = 0.003), with P3 obtaining the best results. The spray coverage followed the same trend, with significant differences only in the traditional orchard (p = 0.011), with the prototypes leading. The conventional equipment generated the highest spray losses in both cultivation systems. Crop adapted spraying can significantly improve the spray quality and efficiency in difficult crops like olive. This topic may have a key importance to match the environmentally sustainable use of PPP

Laboratory Tests to Assess Optimal Agricultural Residue Traits for an Abrasive Weed Control System

International Conference of Agricultural Engineering Aarhus, Denmark 26 - 29 June (2016)One of the biggest challenges to organic agricultural production and herbicide resistant crops in industrialized countries today is the non-chemical control of weed plants. Studies of new tools and methods for weed control have been motivated by an increased consumer demand for organic produce and consumer and regulatory demands for a reduction in environmentally harmful herbicide use. The objective of this study is to assess different agricultural residues as gritty weed-abrading materials that are delivered through condensed-air machinery. This is a new weed control technology based on highly-directed air-propelled, innocuous, abrasive grit. Laboratory equipment was designed to calculate the angle of repose of seven different agricultural residues (crushed olive seed, walnut shell, maize cob, poultry manure, soybean seed, almond shell and grape seed). Color, digital, high-speed computer vision analysis of the motion and energy of the air-propelled particles was conducted. The high-speed video analysis determined the capability of each grit to damage a reference surface and kill weeds (species of Amaranthus, Centaurea, and Chenopodium) at different growth stages. A preliminary laboratory trial showed that walnut shell grit has great potential to damage/break the reference surface when it was propelled at 600, 700 and 800 kPa air pressure. Abrasive-weeding reduced final weed biomass by 80% compared with the weedy control at early growth stages. Field research tests are needed in different cropping systems to improve the technical and economic efficiency of this novel system before on-farm adoption