John E. Morrison

Planter Depth-Control: I. Predictions and Projected Effects on Crop Emergence

ABSTRACT PLANTER depth control with four wheel designs was evaluated on the basis of the predicted effects on simulated emergence for four crops. A linked front and rear depth control wheel design performed similar to rear and front depth control wheels. Side wheels produced the best performance, but they are too wide for solid-seeded planting narrow rows in crop residues. Depth control wheel position varied the simulated emergence as much as 36%. The simulation models proved useful in evaluating depth control mechanisms and could be extended to field situations by using specific surface topography and seed emergence data for response prediction.

Planter Depth Control: II. Empirical Testing and Plant Responses

ABSTRACT PLANTING depth control innovations are needed to improve the reliability of performance of no-tillage planters and drills. Four depth control designs were empirically evaluated with grain sorghum and corn crops in two different field conditions. An experimental no-tillage planter opener was used with each depth control. The field surface undulations were characterized prior to planting. Wheat stubble had higher frequency undulations than sorghum stubble. Stubble type affected mean planting depth and caused a shift in frequency distributions of planting depths for front and linked wheels. Dual rear presswheels malfunctioned by sinking into loosened soil and produced deeper and the most variable planting depths. Dual front depth control wheels gave significantly more variable planting depths than the side wheels and linked wheels at the highest applied downpressure. The best choice for depth control remains undecided between traditional wide dual side wheels and narrow experimental linked front-rear wheels. These results generally agree with simulation results from Part I of this series of papers

Design and Field Evaluation of a Hand-Pushed Digital Soil Penetrometer with Two Cone Materials

ABSTRACT AN experimental electronic hand-pushed soil penetrometer was mated with a commercial data logger to provide a portable penetrometer for determination of soil resistance to penetration in tillage studies. Machine pushing at the ASAE standard rate and at a much slower rate did not improve the performance over hand-pushing at the ASAE standard rate. Stainless steel and Delrin cones produced somewhat different cone index values in two of the three soils tested.

Interactive Planter Depth Control and Pneumatic Downpressure System

ABSTRACT AN experimental pneumatic downpressure system was designed to be interactive with the depth control system on a no-tillage planter. The interactive system uses position control monitoring and modulation of air flow to and from automotive pneumatic shock absorbers on individual furrow opener units. Automatic depth control is achieved by vertical force adjustments which occur for changing resistance to residue and soil cutting by a triple-disc furrow opener. The system response to dynamic pertubations was affected by the system pressure and somewhat by travel velocity.

Minimum Disturbance Fertilizer Knifing for No-Till

ABSTRACT SUBSURFACE application of fertilizer in no-till cropping systems to increase efficiency of use must be accomplished within constraints of minimum soil and crop residue disturbance. We evaluated a number of applicator knife and coulter combinations representative of those currently being used for this purpose. Applicator performance was measured as width of soil disturbed along the path of implement travel, as a function of soil penetration depth, travel speed, and soil water content. Width of soil disturbance increased on the average over all applicators, with an increase in each of these factors. Soil water content proved to be the more critical in light of its effect on adherence of the heavy clay soil to applicator surfaces. Applicators were ranked according to the amount of soil disturbance caused under each set of operating conditions. Rankings provided a means of relating the physical characteristics of applicators to relative level of performance, hence a guide in selecting adequate design criteria for their improvement.

Hydraulic Downpressure System Performance for Conservation Planting Machines

ABSTRACT AN experimental hydraulic downpressure system was designed and tested on a no-tillage grain drill. Regulated downpressure to individual row units provided centralized downpressure adjustment and unit flotation for improved uniformity of planting depth. The system performed adequately in several years of field use. Passage of the drill over simulated soil undulations produced hydraulic pressure surges which were significantly affected by transmittal distance, field speed, and system pressure. An air damping system reduced the magnitude of the pressure surges for more uniform planting depth. The system could be used to convert existing planters and drills for use in no-tillage conditions.

Expert System for Selecting Conservation Planting Machines: 'PLANTING'

ABSTRACT The expert system, PLANTING, has been designed to systematically develop specifications for soil-engaging components on conservation planters, drills and seeders. It is intended for use by farm advisors and others v^hen consulting with a farmer on adoption of conservation-tillage crop production. PLANTING is loaded with a soil and weather condition data base, specifically for the users area. Warning messages are given to the user if intended cropping practices may pro-duce excessive soil erosion, machine incompatibilities and other irregularities. A report is printed which con-tains recommended planting machine components for each of seven machine functions. Required components may be added to existing machines for conservation planting. The specifications are matched to available planting machines as a guide to machine selection.

Standing Stubble Protection of Soil from Winddriven Raindrop Impacts

ABSTRACT INTERILL erosion associated with raindrop impacts on bare soil surfaces has been characterized by many studies of vertical rainfall. Wind driven rainfall is of higher, more erosive energy and approaches the soil surface from nonvertical angles. Tall crop residues on conservation-tillage fields have varied effects on shielding the soil surface from direct raindrop impacts dependent upon the angle and direction of rainfall. Quantifying the effects of residue height and trajectory of rainfall on the effective soil cover could improve residue management techniques and erosion predictions. Undisturbed wheat and grain sorghum stubbles were viewed at various angles and orientations to determine the effective soil cover approached by winddriven raindrops. Angle of approach from vertical changed soil cover in every case. Orientation relative to row direction increased soil cover only for the special case of rain direction coincident with row direction in sorghum stubble. Increasing stubble height did not increase soil cover for sorghum as much as it did for wheat. Soil cover contributions from standing stubble were in addition to the approximately 50% soil cover from recumbent residues. A simulation model predicted soil cover for an idealized bare soil condition. The model was more sensitive to stubble height than was the empirical data