An investigation into the fertilizer particle dynamics off-the-disc

The particle size range specifications for two biosolids-derived organomineral fertilizers (OMF) known as OMF10 (10:4:4) and OMF15 (15:4:4) were established. Such specifications will enable field application of OMF with spinning disc systems using conventional tramlines spacing. A theoretical model was developed, which predicts the trajectory of individual fertilizer particles off-the-disc. The drag coefficient (Cd) was estimated for small time steps (10-6 s) in the trajectory of the particle as a function of the Reynolds number. For the range of initial velocities (20 to 40 m s-1), release angles (0° to 10°) and particle densities (1000 to 2000 kg m-3) investigated, the analysis showed that OMF10 and OMF15 need to have particle diameters between 1.10 and 5.80 mm, and between 1.05 and 5.50 mm, respectively, to provide similar spreading performance to urea with particle size range of 1.00 to 5.25 mm in diameter. OMF10 and OMF15 should have 80% (by weight) of particles between 2.65 and 4.30 mm, and between 2.55 and 4.10 mm, respectively. Due to the physical properties of the material, disc designs and settings that enable working at a specified bout width by providing a small upward particle trajectory angle (e.g., 10°) are preferred to high rotational velocities. However, field application of OMF with spinning discs applicators may be restricted to tramlines spaced at a maximum of 24 m; particularly, when some degree of overlapping is required between two adjacent bouts. The performance of granular fertilizers can be predicted based on properties of the material, such as particle density and size range, using the contour plots developed in this study

Design, development and field evaluation of a map-based variable rate granular fertilizer application control system

Site-specific application of agricultural chemicals including granular fertilizers is an effective way of resource savingand environmental protection. The objective of this research was to develop and to evaluate the performance of a map-basedvariable rate row crop granular fertilizer placement system. The applicator system consists of an AVR microcontroller forcontrolling the driving step motor of the fertilizer metering screw and a ground driven wheel integrated with a rotary encoderfor the applicator displacement and speed measurement. Initially, the applicator was calibrated in laboratory to derive arelationship among the step motor speed, the input frequency, and the rate of fertilizer application as a function of meteringscrew rotational speed. Laboratory evaluation included measurement of the lag time while changing the application rate fromlow to high and vice versa. In the field tests, a factorial experiment with a split-split design was used to investigate the effectsof fertilizer type (urea and triple super phosphate), applicator forward speed (3, 6 and 9 km/s) and application rate (75, 125 and175 kg/ha) on precision of application rate (the percent of deviation between actual and target rates). The results showed thatthe forward speed and the application rate both had significant effect on precision of application rate, while fertilizer type hadno significant effect. The precision of application rate decreased when forward speed and application rate were increased.Keywords: precision agriculture, travel speed, fertilizer type, application rat

A SPATIAL MODEL FOR EVALUATING VARIABLE-RATE FERTILIZER APPLICATION ACCURACY

The popularity of variable-rate technology (VRT) has grown. However, the limitations and errors ofthis technology are generally unknown. Therefore, a spatial data model was developed to generate asapplied surfaces to advance precision agricultural (PA) practices. A test methodology based on ASAEStandard S341.2 was developed to perform uniform-rate (UR) and variable-rate (VR) tests to characterizedistribution patterns testing four VRT granular applicators (two spinner spreaders and two pneumaticapplicators). Single-pass UR patterns exhibited consistent shapes for three of the applicators with patternsshifts observed for the fourth applicator. Simulated overlap analysis showed that three of the applicatorsperformed satisfactorily with most CVs less than 20% while one applicator performed poorly (CVs andgt;25%). The spinner spreaders over-applied at the margins but the pneumatic applicators under-appliedsuggesting a required adjustment to the effective swath spacing. Therefore, it is recommended that CVsaccompany overlap pattern plots to ensure proper calibration of VRT application.Quantification of the rate response characteristics for the various applicators illustrated varying delayand transition times. Only one applicator demonstrated consistent delay and transition times. A sigmoidalfunction was used to model the rate response for applicators. One applicator exhibited a linear responseduring a decreasing rate change. Rate changes were quicker for the two newer VR control systemssignifying advancement in hydraulic control valve technology. This research illustrates the need forstandard testing protocols for VRT systems to help guide VRT software developers, equipmentmanufacturers, and users.The spatial data model uses GIS functionality to merge applicator descriptive patterns with a spatialfield application file (FAF) to generate an \u27as-applied\u27 surface representing the actual distribution ofgranular fertilizer. Field data was collected and used to validate the as-applied spatial model.Comparisons between the actual and predicted application rates for several fields were madedemonstrating good correlations for one applicator (several R2 andgt; 0.70), moderate success for anotherapplicator (0.60 andlt; R2 andlt; 0.66), and poor relationships for the third applicator (R2 andlt; 0.49). A comparison ofthe actual application rates to the prescription maps generated R2 values between 0.16 and 0.81demonstrating inconsistent VRT applicator performance. Thus, as-applied surfaces provide a means toproperly evaluate VRT while enhancing researchers\u27 ability to compare VR management approaches

Design and Testing of an Online Fertilizing Amount Detection Device Based on the Moment Balance Principle

Based on the principle of moment balance, this paper designs a fertilizer application amount online detection device, which is mainly composed of two major parts: the fertilizer guide mechanism and the fertilizer metering and discharging mechanism.Under the electromagnetic reversing and buffering of the fertilizer guide mechanism, the fertilizer discharged into the device falls alternately into the storage box of the two metering units of the metering and discharging mechanism. Once the gravity of the fertilizer in the storage box is greater than the suction of the electromagnetic sucker, the fertilizer discharging board is automatically opened for fertilizer discharge, and the metering pulse signal is accumulated once. Meanwhile, the fertilizer guide plate is driven by the electromagnetic commutator to reverse the material, and then another storage box is started for fertilizer storage and metering. In this approach, online detection of fertilizer flow can be realized by repeatedly guiding and reversing and metering the incoming fertilizer. According to the single metering fertilizer quality and the number of metering pulse signals, the fertilization amount can be calculated in real-time.The performance of the device was verified by bench test. The test results indicated that: The established fertilizer application detection model is a quadratic function (R2>0.98), and the verification error was less than 3.73% in the detection of alternating cycle fertilizer discharge; the coefficient of determination (R2) and the root mean square error (RMSE) reached 0.992 and 9.858 respectively, indicating high detection accuracy of the device is

Rate Response Assessment from Various Granular VRT Applicators

Variable-rate technology (VRT) adds complexity to application equipment, thereby confounding the assessment of applicator performance. The intent of this investigation was to assess the rate response of various VRT granular applicators: two spinner spreaders (A and B), and two pneumatic applicators (C and D). Variable-rate (VR) tests were conducted to quantify the rate response characteristics (delay and transition times) for the applicators. A sigmoidal function was used to model the rate response for five of the six tests. Applicator A exhibited a linear response during decreasing rate changes. Results indicated that only applicator B demonstrated consistent delay and transition times, enabling the use of a single “look-ahead” time for rate response time correction. Contouring of prescription maps increased the transition times for applicator D by enlarging the adjustment area between management zones. Rate changes were quicker for the two newer VR control systems, signifying advancement in hydraulic control valve technology. This research illustrates the need for standard testing protocols for VRT systems to help guide VRT software developers, equipment manufacturers, and end users

Development of a stereovision-based technique to measure the spread patterns of granular fertilizer spreaders

Centrifugal fertilizer spreaders are by far the most commonly used granular fertilizer spreader type in Europe. Their spread pattern however is error-prone, potentially leading to an undesired distribution of particles in the field and losses out of the field, which is often caused by poor calibration of the spreader for the specific fertilizer used. Due to the large environmental impact of fertilizer use, it is important to optimize the spreading process and minimize these errors. Spreader calibrations can be performed by using collection trays to determine the (field) spread pattern, but this is very time-consuming and expensive for the farmer and hence not common practice. Therefore, we developed an innovative multi-camera system to predict the spread pattern in a fast and accurate way, independent of the spreader configuration. Using high-speed stereovision, ejection parameters of particles leaving the spreader vanes were determined relative to a coordinate system associated with the spreader. The landing positions and subsequent spread patterns were determined using a ballistic model incorporating the effect of tractor motion and wind. Experiments were conducted with a commercial spreader and showed a high repeatability. The results were transformed to one spatial dimension to enable comparison with transverse spread patterns determined in the field and showed similar results

Ornamental plants, 1988: a summary of research

Follow-up evaluation of Cyanazine, Terbacil and Metolachlor slow-release herbicide tablets on woody landscape crops / E. M. Smith and S. A. Treaster -- Tolerance of daylily and peony to Surflan, Devrinol and Treflan / E. M. Smith and S. A. Treaster -- Growth response of euonymus, juniper and azalea treated with differing rates of Osmocote 18-6-12 / E. M. Smith and S. A. Treaster -- Evaluation of Ronstar wettable powder on woody landscape crops / E. M. Smith and S. A. Treaster -- An evaluation of Ronstar plus Diflufenican on container-grown landscape crops / E. M. Smith and S. A. Treaster -- Prodiamine evaluation in container-grown landscape / E. M. Smith and S. A. Treaster -- Evaluation of flowering crabapple susceptibility to apple scab in Ohio-1987 / E. M. Smith and S. A. Treaster -- Field study of root zone heating systems in greenhouses / M. F. Brugger and R. H. Zondag -- Costs of producing field rapid-growing evergreens (]uniperus) in Ohio / R. D. Taylor, H. H. Kneen, E. M. Smith, D. E. Hahn and S. Uchida -- Costs of producing field ornamental trees (Malus) in Ohio / R. D. Taylor, H. H. Kneen, E. M. Smith, D. E. Hahn and S. Uchid

The effect of farmyard manure and urea on grain yield and agronomic characteristics of maize (Zea mays)

Combining organic and inorganic fertilizer has been proved to be an effective and sustainable soil management strategy for increased crop yield and safe environment. Field experiments were conducted in two locations in Nigeria namely Malete and Shao during 2018 and 2019 seasons. This was to find out the efficacy of organic and inorganic fertilizer (including prilled and granular urea) and their various combinations on grain yield and agronomic characteristics of maize. The use of full dose of P and K + 75% N through Granular Urea + 25 % N through farmyard manure improved most of the soil chemical properties with high economic returns. It was concluded from the experiment that a combination of organic and inorganic fertilizers is an environmentally friendly practice and could lead to high yields and improve farmers’ income and their livelihoods