Imaging soil pore characteristics using computed tomography as influenced by agroecosystems

Abstract

Soil pore parameters are important for water infiltration into the soil and transport within the soil. The aim of this study was to compare influences of agroecosystems on soil pore characteristics (number of pores, macropores, coarse mesopores, porosity, macroporosity, coarse mesoporosity, pore circularity) using computed tomography (CT). This experiment was carried out four different agroecosystem field [ Tucker Prairie (TP): native prairie, Prairie Fork (PF): restored prairie, Conservation Reserve Program (CRP), and row crop (RC): corn/soybean rotation] in Missouri state of United States during the year of 2017. Undisturbed soil samples were collected at four soil depths (0-10, 10-20, 20-30, and 30-40 cm) from each treatment with three replications. Five scan images from each sample were acquired using a X-ray CT scanner with 0.19 by 0.19 mm pixel resolution with 0.5 mm slice thickness and analyzed with Image-J . TP, PF, CRP, and RC treatments had 195, 88, 112, and 49 pores on a 2500 mm 2 area, respectively across all the depths. Soil under TP and CRP treatment had significantly higher porosity (0.046 m 3 m -3 , 0.046 m 3 m -3 ), and macroporosity (0.036 m 3 m -3 , 0.041 m 3 m -3 ) values than other treatments. The CT-measured number of macropores (>1000 μm diam.) were 5 times higher for TP when compared with RC treatment. The CT-measured pore circularity values were lower for CRP and RC treatments. CT-measured number of coarse mesopores, and mesoporosity were significantly greater under TP treatment. Results show that native prairie can improve soil pore parameters.