ABSTRACT

Cone index (CI) penetration profiles were recorded up to a depth of 45 cm (18 in.) in two cotton fields in the State of Arkansas. In the field in Forrest City profiles at 369 locations along a transect measuring approximately 1600 m (1 mile) in length and 200 m (1/8 mile) in width were collected. In the field in Fayetteville, 48 profiles were collected in 1307.5 cm X 359.6 cm (429 ft. X 118 ft.) area. Electrical Conductivity (ECa) was measured in only Forrest City field. Electrical Conductivity and the maximum soil compaction at depths beyond 4 inches were found highly correlated to each other (R²>0.90). An average plant yield was measured for each plot based on machine harvest in the first field and hand-harvest in the second field respectively. Average yield was compared to maximum CI beyond 10 cm (4 in.) depth. Maximum CI readings at or above 1.38 MPa (200 psi) resulted in below average yields for 75-percent of the readings exceeding this limit. Yield was not strongly correlated with CI, and correlation coefficients was 0.067 for the Fayetteville field and ranged 0.008 to 0.017 for Forrest City Field, but showed a very significant trend of negative relationship between yield and the mean CI values as expected.