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 withinthe soil. The aim of this study was to compare influences of agroecosystems on soil porecharacteristics (number of pores, macropores, coarse mesopores, porosity, macroporosity,coarse mesoporosity, pore circularity) using computed tomography (CT). This experimentwas 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 30-40cm) from each treatment with three replications. Five scan images from each sample wereacquired using a X-ray CT scanner with 0.19 by 0.19 mm pixel resolution with 0.5 mmslice thickness and analyzed with Image-J. TP, PF, CRP, and RC treatments had 195, 88,112, and 49 pores on a 2500 mm2 area, respectively across all the depths. Soil under TPand CRP treatment had significantly higher porosity (0.046 m3 m-3, 0.046 m3 m-3), andmacroporosity (0.036 m3 m-3, 0.041 m3 m-3) values than other treatments. The CTmeasured number of macropores (>1000 μm diam.) were 5 times higher for TP whencompared with RC treatment. The CT-measured pore circularity values were lower forCRP and RC treatments. CT-measured number of coarse mesopores, and mesoporositywere significantly greater under TP treatment. Results show that native prairie canimprove soil pore parameters.