|Sudduth, Kenneth - Ken|
Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 6/20/2006
Publication Date: 7/10/2006
Citation: Adamchuk, V.I., Sudduth, K.A., Ingram, T.J., Chung, S. 2006. Comparison of two alternative methods to map soil mechanical resistance on-the-go. ASABE Annual International Meeting Proceedings, July 9-12, 2006, Portland, OR. 06-1057
Interpretive Summary: Precision agriculture aims to minimize costs and environmental damage caused by agricultural activities, and to maximize crop yield and profitability, all based on information collected at within-field locations. Soil strength, an indication of compaction, is a factor that can vary considerably within fields and can also greatly affect crop yields. Because of this, farmers need a quick and inexpensive way to measure compaction, such as could be provided by an on-the-go sensor. This research compares two new on-the-go sensors that can take measurements continuously at multiple depths while traveling across a field. In field tests we found that the on-the-go sensors performed well and gave comparable results. We also compared our sensors to the cone penetrometer, a device commonly used to measure compaction. Both sensors showed similar trends in compaction to those shown by the penetrometer. However, sensor measurements were easier to obtain and resulted in maps with more detail than the penetrometer measurements. Both sensors show promise as potential tools for improved compaction measurement. The results of this study will be useful to scientists and engineers seeking to improve on-the-go sensor design and to develop efficient test methods for evaluating sensor performance.
Technical Abstract: Soil mechanical resistance is an indicator of soil physical conditions and is frequently related to compaction, water content, and other factors. Since determining soil mechanical resistance using a standard cone penetrometer is time consuming, several different prototype soil sensors have been developed for on-the-go mapping. In this research, two alternative mechanical on-the-go soil sensing methods were tested in the same field. One sensor mapped soil mechanical resistance using five discrete-depth horizontal prismatic tips. The other sensor, an instrumented blade, determined the parameters required to characterize a soil mechanical resistance profile assumed to change linearly with depth. The correlation between corresponding estimates produced with each of these two sensors and with the standard cone penetrometer method was marginal (r2 = 0.32 to 0.46 for average soil mechanical resistance), while estimates from the two sensors were more strongly related to one another (r2 = 0.57 for average soil mechanical resistance). Differences were due in part to difficulties in obtaining data representing the same depth and field locations, along with differences in sensor geometry and operating conditions, particularly when comparing the on-the-go sensors to the cone penetrometer. Depth gradients of soil mechanical resistance obtained using cone penetrometer and instrumented blade methods were correlated with r2 = 0.33. However, the agronomic value of this characteristic of soil profiles within the near-surface rooting zone (5 - 30 cm) is yet to be determined through continued study.