3,387 research outputs found
A field vegetable transplanter for use in both tilled and no-till soils
A commercial, manually fed vegetable transplanter was modified and adapted to work in no-till soils. Details
of the modifications are described in this article. The aim of this research was to evaluate the performance of this transplanter
under actual field conditions in both tilled and no-till soils. The draft force in the no-till soil was measured for
different working tools mounted for tilling or loosening a narrow band of soil before passing with the furrower. The combination
of a ripper shank opener with a straight nose point resulted in the lowest draft force values per unit of working depth.
The transplanter accuracy and transplant success rate were evaluated in different vegetable crops. The accuracy parameters
(multiple index, miss index, quality of feed index, and precision) were estimated and in general were similar in the tilled
and no-till soils, indicating that the transplanter was able to operate in both soil conditions with the same accuracy. The
transplant success rates were also similar in both soil conditions. The transplanter thus offers a satisfactory technical solution
for transplanting vegetables in both tilled and no-till soils
Innovative living mulch management strategies for organic conservation field vegetables: evaluation of continuous mowing, flaming, and tillage performances
Organic vegetable production is particularly affected by weed pressure and mechanical
weeding is the major tactic implemented by growers to keep weeds under economic thresholds. Living
mulch (LM) has been shown to provide several environmental services; however, LM management
is required to avoid competition between service crops and cash crops. The aim of this trial was
to evaluate two innovative LM-based management systems: a system that provided LM growth
regulation by means of flaming (LM-FL) and a system where the LM was regularly mowed by an
autonomous mower (LM-AM), both compared with a control without LM and based on standard
tillage operations (TILL). The three management systems were evaluated in terms of crop production,
weed control, and energy consumption on a 2 yr organic crop rotation of cauliflower (Brassica oleracea L.
var botrytis) and eggplant (Solanum melongena L.). LM-AM produced an acceptable fresh marketable
yield for both vegetable crops. Moreover, the weed dry biomass obtained in LM-AM-managed
plots was lower compared to the LM-FL plots and ranged approximately from 200 to 300 kg ha1.
Furthermore, LM-AM management resulted in lower energy consumption (2330 kWh ha1 with
respect to the TILL system and 7225 kWh ha1 with respect to the LM-FL system). The results of
this trial suggest that autonomous mowers have a great potential to improve LM management and
help with implementing sustainable organic vegetable systems
Combining roller crimpers and flaming for the termination of cover crops in herbicide-free no-till cropping systems
The termination of cover crops in conventional no-till systems is mostly conducted mechanically
in combination with herbicides. Combining flaming and roller crimpers could be a viable
solution to avoid using herbicides for cover crop termination in farming systems where herbicides
are banned, or at least to reduce their use in an integrated management approach.
This research tested the effects of flaming used in combination with three different types of
roller crimpers to terminate a fall-sown cover crop mixture of winter pea and barley. The
cover crop termination rate was visually assessed in terms of percentage of green cover
provided by cover crop plants at different intervals from the termination date, and estimated
using a log-logistic non-linear regression model with four parameters. Machine performance
data are also reported. The results show that, irrespective of the roller type, flaming significantly
boosted the effect of the roller crimpers. In fact, an economic threshold for cover crop
suppression of 85% was reached only when the rollers were used in combination with flaming.
Nevertheless, none of the methods were able to reach the 100% of cover crop suppression.
In some case, the combined use of flaming and roller crimpers allowed reaching the
90% of cover crop devitalisation, which happened six weeks after the termination date.
More importantly, the use of flaming in combination with rollers shortened the time needed
to achieve the estimated levels of devitalisation, compared with the rollers used alone. We
conclude that flaming is an effective tool to increase the effectiveness of roller crimpers.
Nevertheless, further research is needed to identify solutions to overcome the barrier of the
high operational costs of flaming, which is constraining its wider adoption by farmers. Future
studies could focus, for instance, on the development of a new prototype of combined
machine for crimping and flaming the cover crops simultaneously, which could potentially
reduce the operational costs
Testing of Roller-Crimper-and-Undercutting-Blade-Equipped Prototype for Plants Termination
The use of roller crimpers to terminate plants and obtain a natural mulch before cash crop establishment has been identified as a valid and sustainable approach to control weeds. Several enhancements have been evaluated to improve and speed up plant termination to avoid delays in cash crop planting and consequent yield losses, which can occur with standard roller crimpers. In the present study, a new prototype machine provided with a roller crimper and an undercutting blade, allowing it to simultaneously crimp plant stems and cut root systems, has been designed, realized, and tested. The aim of the research was therefore to evaluate the effectiveness of the prototype for plant termination and to compare it with a commercial roller crimper. The termination was performed on a spontaneous vegetation cover (weeds). A monophasic exponential decay model to evaluate the weed termination rate over time was performed. The fitted model showed that the prototype is able to achieve a greater and faster weed devitalization compared to the commercial roller crimper, with a lower plateau (0.23 vs. 5.35 % of greenness of plant material, respectively) and higher constant of decay (1.45 vs. 0.39 dayâ1, respectively). Further studies are needed to evaluate the prototypeâs effectiveness in relation to different soil textures, moisture conditions, and amounts of plant biomass to manage, to further improve the machine and extend its use in a broad range of situations, including cover crop termination
An autonomous ground mobile unit for the precision physical weed control.
In this paper the design, the main characteristics and the automation systems of innovative
autonomous ground mobile units (GMU) for physical weed control (PWC) in maize are
described. The machine will be created within the activities of the European Project RHEA
(Robot fleets for Highly Effective Agriculture and forestry management), that aims to produce
different prototypes of autonomous terrestrial and aerial robot able to perform several
activities related to the general crop protection in different agricultural scenarios. The first
autonomous ground unit machine was designed in order to perform a mechanical and
thermal treatment removing weeds from the inter-row crop space and applying in-row
selective and precision flaming by means of two crossed LPG rod burners. By means of
some modifications of the tools it will be possible to realize also an autonomous unit for the
precision broadcast flaming application. In this case the design involves a replacement of the
mechanical tools working in the inter-row space with 50 cm wide burners able to perform
flaming at different intensities according to weed cover detected by the perception system of
the robot. The working width of both the PWC machines will be of 4.5 m, thus covering five
entire maize inter-row spaces of 0.75 m each and 2 half inter-row space of 0.375 m each.
The correct position of the tools (mechanical and thermal) will be guaranteed by an
automatic precision guidance system connected and supervised to an image based row
detection system. Each working elements will be provided by two crossed 0.25 m wide rod
burners, hitting one side of each crop row. The flame should hit the weeds growing in the âinrowâ
space (a 0.25 m wide strip of soil with the maize plant in the middle). Regarding the
control of the weed emerged in the âinter-rowâ space each working unit of the will be provided
with rigid tools (one central foot-goose and two side âLâ shaped sweeps). The mechanical
treatment will be performed, independently from the weed presence, as hoeing is a very
important agronomical practice. On the contrary, broadcast flaming in the inter-row space will
be performed after weed detection, using three different LPG pressures and doses according
to weed cover (no weed cover-no treatment, weed cover between 0 and 25%-flaming at 0.3
MPa, weed cover higher than 25%-flaming at 0.4 MPa). This very innovative application of
precision PWC in maize could represent not only a good opportunity for farmers in term of
herbicide use reduction, but also an environmental friendly and energy saving application of
flaming in organic farming
Assessment of a Chain Mower Performance for Weed Control under Tree Rows in an Alley Cropping Farming System
In the area under tree rows of alley cropping systems, coarse plant material as well as pruning material or stones may be present, so the use of a mower equipped with chains as cutting a tool could be advantageous. A mower designed for under-row weed control in orchards, equipped with an automatic tree-skipping mechanism, was modified by replacing blades with chains with the aim of evaluating its performance in an alley cropping system. A first trial was carried out in an open field to preliminarily compare the chain mower with the version equipped with blades in relation to different settings of working speed (1.6 and 2.4 km center dot h(-1)) and rotation speed of the cutting tool (1830 and 2500 rpm). Weed biomass reduction, weed cover reduction, weed height reduction, weed biomass regrowth, and clipping size were assessed. In a second trial, the performance of the mowers with different setting configurations was assessed in an alley cropping system under a more critical environmental condition for mowing, i.e., the presence of dew. Weed biomass reduction, weed cover reduction, weed height reduction, and the mowers' field capacity with different working speed settings were assessed. No major differences emerged between the mowers and the chain mower performance was comparable to that of the standard blade mower. The setting with the high working speed and high rotation speed of the cutting tool turns out to be the best compromise, obtaining a weed biomass reduction of 59.6%, a weed cover reduction of 40.9%, and a higher field capacity compared to the setting with the low working speed, with an increase of 47.9%
Visual 3-D SLAM from UAVs
The aim of the paper is to present, test and discuss the implementation of Visual SLAM techniques to images taken from Unmanned Aerial Vehicles (UAVs) outdoors, in partially structured environments. Every issue of the whole process is discussed in order to obtain more accurate localization and mapping from UAVs flights. Firstly, the issues related to the visual features of objects in the scene, their distance to the UAV, and the related image acquisition system and their calibration are evaluated for improving the whole process. Other important, considered issues are related to the image processing techniques, such as interest point detection, the matching procedure and the scaling factor. The whole system has been tested using the COLIBRI mini UAV in partially structured environments. The results that have been obtained for localization, tested against the GPS information of the flights, show that Visual SLAM delivers reliable localization and mapping that makes it suitable for some outdoors applications when flying UAVs
Generic and Layered Framework Components for the Control of a Large Scale Data Acquisition System
The complexity of today's experiments in High Energy Physics results in a large amount of readout channels which can count up to a million and above. The experiments in general consist of various subsystems which themselves comprise a large amount of detectors requiring sophisticated DAQ and readout electronics. We report here on the structured software layers to control such a data acquisition system for the case of LHCb which is one of the four experiments for LHC. Additional focus is given on the protocols in use as well as the required hardware. An abstraction layer was implemented to allow access on the different and distinct hardware types in a coherent and generic manner. The hierarchical structure which allows propagating commands down to the subsystems is explained. Via finite state machines an expert system with auto-recovery abilities can be modeled
The Updated Zwicky Catalog (UZC)
The Zwicky Catalog of galaxies (ZC), with m_Zw<=15.5mag, has been the basis
for the Center for Astrophysics (CfA) redshift surveys. To date, analyses of
the ZC and redshift surveys based on it have relied on heterogeneous sets of
galaxy coordinates and redshifts. Here we correct some of the inadequacies of
previous catalogs by providing: (1) coordinates with <~2 arcsec errors for all
of the Nuzc catalog galaxies, (2) homogeneously estimated redshifts for the
majority (98%) of the data taken at the CfA (14,632 spectra), and (3) an
estimate of the remaining "blunder" rate for both the CfA redshifts and for
those compiled from the literature. For the reanalyzed CfA data we include a
calibrated, uniformly determined error and an indication of the presence of
emission lines in each spectrum. We provide redshifts for 7,257 galaxies in the
CfA2 redshift survey not previously published; for another 5,625 CfA redshifts
we list the remeasured or uniformly re-reduced value. Among our new
measurements, Nmul are members of UZC "multiplets" associated with the original
Zwicky catalog position in the coordinate range where the catalog is 98%
complete. These multiplets provide new candidates for examination of tidal
interactions among galaxies. All of the new redshifts correspond to UZC
galaxies with properties recorded in the CfA redshift compilation known as
ZCAT. About 1,000 of our new measurements were motivated either by inadequate
signal-to-noise in the original spectrum or by an ambiguous identification of
the galaxy associated with a ZCAT redshift. The redshift catalog we include
here is ~96% complete to m_Zw<=15.5, and ~98% complete (12,925 galaxies out of
a total of 13,150) for the RA(1950) ranges [20h--4h] and [8h--17h] and
DEC(1950) range [-2.5d--50d]. (abridged)Comment: 34 pp, 7 figs, PASP 1999, 111, 43
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