@article{bowers_collins_harris_2006, title={Low soil moisture planting of cotton for optimum emergence}, volume={22}, DOI={10.13031/2013.22248}, abstractNote={A row crop planter field study was conducted to optimize cotton seed emergence. The depth of moist soil scraped off below the drying front (the interface between the air-dry and initially moist soil) was varied from 1.3 to 5.1 cm to determine the moist soil scraping depth that produced optimum emergence. Next, the effect of seed planting depth below this scraped moist soil surface was varied from 2.5 to 5.1 cm to determine optimum planting depth. Finally, the V-closing/press wheel force was varied from 89 to 356 N to determine optimum press wheel force. A planter automatic seed depth control system (Weatherly and Bowers, 1997) was modified to sense the drying front depth and then scrape off a set depth of moist soil below the drying front. The field study planter was a two row unit with each row consisting of a drying front sensor, an automatic scraper depth control system, a V-wing scraper blade, and a John Deere MaxEmerge™ planter unit. The moist soil scraping depth that gave the highest emergence was 3.8 cm below the drying front. The V-trench seed depth with the highest emergence ranged from 3.8 to 5.1 cm. The V-closing/press wheel force for highest cotton seed emergence ranged from 178 to 267 N. Setting these three planter functions, in the ranges stated above, produced cotton seed emergence as high as 80% in low soil moisture conditions.}, number={6}, journal={Applied Engineering in Agriculture}, author={Bowers, C. G. and Collins, C. A. and Harris, E. P.}, year={2006}, pages={801–808} }
 @article{chukwu_bowers_2005, title={Instantaneous multiple-depth soil mechanical impedance sensing from a moving vehicle}, volume={48}, DOI={10.13031/2013.18492}, abstractNote={A three-depth soil mechanical impedance sensor was developed and tested within a laboratory soil bin. Soil 
mechanical impedance measurements were made on a continuous basis at three simultaneous depths of 178, 279, and 381 mm 
from one end of the soil bin to the other using three prismatic tips and three Omega LCF500 load cells. This article discusses 
how the sensor can be used for measuring the soil mechanical impedances that plant roots encounter during normal growth. 
The soil sensor also offers excellent opportunities to study the forces acting on soil-engaging implements and subsequent 
control of tillage tools. Compaction created from past tillage machinery operation and trafficking by heavy equipment 
sometimes forms “plowpans” in crop fields. These layers, as well as other naturally occurring dense soil layers that impede 
water infiltration and root penetration, can be located using the three-depth soil mechanical impedance sensor. The 
laboratory experiment for testing and verifying the device’s performance showed that the three-depth sensor can measure 
differences in soil mechanical impedance with depth and location and that these impedances correlate well with 
corresponding cone penetrometer measurements.}, number={3}, journal={Transactions of the ASAE}, author={Chukwu, E. and Bowers, C. G.}, year={2005}, pages={885–894} }
 @article{automatic depth control of a seed planter based on soil drying front sensing_1997, volume={40}, number={2}, journal={Transactions of the ASAE}, year={1997}, pages={295–305} }
 @article{bowers_1989, title={Tillage draft and energy measurements for twelve southeastern soil series}, volume={32}, DOI={10.13031/2013.31178}, abstractNote={ABSTRACT Tillage drafts and fuel measurements were made for 12 soil series and major implements used in North Carolina crop production systems. Implements included moldboard plows, chisel plows, offset and tandem disks, planters, ridger-disk bedders, ridger-planter and subsoiler. An 81 kW tractor instrumented with a personal computer and a data interface measured ground speed, fuel consumption and implement draft. Draft measurements were compared to those predicted by ASAE Machinery Management Data and were found to vary. Measured fuel consumptions for conventional tillage systems ranged from 25.96 to 40.39 L/ha while minimum tillage systems ranged from 20.88 to 28.36 L/ha.}, number={5}, journal={Transactions of the ASAE}, author={Bowers, C. G.}, year={1989}, pages={1492} }